B-cell infiltration is associated with survival outcomes following programmed cell death protein 1 inhibition in head and neck squamous cell carcinoma

BACKGROUND

Programmed cell death protein 1 (PD-1) axis blockade has become the mainstay in the treatment of recurrent and/or metastatic (R/M) head and neck squamous cell cancer (HNSCC). Programmed death-ligand 1 (PD-L1) is the only approved biomarker for patient selection; however, response rate is limited even among high expressors. Our primary objective was to investigate the association of immune cell-related biomarkers in the tumor and tumor microenvironment with PD-1 checkpoint inhibitors' outcomes in patients with R/M HNSCC.

PATIENTS AND METHODS

NCT03652142 was a prospective study in nivolumab-treated platinum-refractory R/M HNSCC, aiming to evaluate biomarkers of response to treatment. Tumor biopsies and blood samples were collected from 60 patients at baseline, post-treatment, and at progression. Immune cells in the tumor and stromal compartments were quantified by immunofluorescence using a five-protein panel (CD3, CD8, CD20, FoxP3, cytokeratin). Tertiary lymphoid structures (TLSs), PD-L1 expression, and peripheral blood immune cell composition were also evaluated for associations with outcome. Our findings were validated by gene set enrichment analysis (GSEA) messenger RNA in situ expression data from the same patients, for B-cell- and TLS-associated genes.

RESULTS

High pre-treatment density of stromal B cells was associated with prolonged progression-free survival (PFS) (P = 0.011). This result was validated by GSEA, as stromal enrichment with B-cell-associated genes showed association with response to nivolumab. PD-L1 positivity combined with high B-cell counts in stroma defined a subgroup with significantly longer PFS and overall survival (P = 0.013 and P = 0.0028, respectively).

CONCLUSIONS

Increased B cells in pre-treatment HNSCC biopsy samples correlate with prolonged benefit from PD-1-based immunotherapy and could further enhance the predictive value of PD-L1 expression.

Abstract ES1-3: Assessment of PD-L1 in Breast Cancer to Predict Response to Immunotherapy

Many tumors showed promise in phase one trials of immunotherapy, but breast cancer was not high on the list. Since then, focus in breast cancer has shifted to Triple Negative Breast Cancer (TNBC) which has shown promise in both the metastatic and neo-adjuvant setting. This presentation will provide a history of the PD-L1 assay to select response to therapy in lung cancer where it was most successful and then discuss its transition to breast cancer. In TNBC, there are successful trials and even FDA approval, but there is also deep concerns related to the IHC-based patient selection assay. This presentation will discuss the breast cancer PD-L1 assay(s) and the controversy surrounding its implementation.

Citation Format: DL Rimm. Assessment of PD-L1 in Breast Cancer to Predict Response to Immunotherapy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr ES1-3.

Abstract P4-02-01: Analytical validation of an automated digital scoring protocol for Ki67: International multicenter collaboration study

Background/Goal: Ki67 expression has been a valuable prognostic marker in breast cancer, but has not seen broad adoption due to lack of standardization between institutions. Automation could represent a solution. Here we tested 3 automated digital image analysis (DIA) platforms including an open source platform to: (i) Investigate the reproducibility of Ki67 measurement across platforms with supervised classifiers performed by the same operator and by multiple operators. (ii) Compare accuracy of the 3 DIA platforms against outcome (prognostic potential). (iii) Assess inter-laboratory reproducibility of a calibrated DIA tool to evaluate Ki67 in breast cancer among 10 participating labs of the International Ki67 in Breast Cancer Working Group (IKWG).

Methods: The Mib-1 antibody (Dako) was used to detect Ki67 (dilution 1:100). HALO (H) (IndicaLabs), QuantCenter (QC) (3DHistech), QuPath (QP) (open-source software) digital image analysis (DIA) platforms were used to evaluate Ki67 expression. As a ground truth, we evaluated Ki67 LI with meticulous manual tissue segmentation using the Spectrum Webscope (SW) (Aperio). Calibration was performed using 30 ER+ breast cancer cases from phase 3 of the IKWG initiative where blocks were centrally cut and stained for Ki67. The inter-laboratory analysis was done with 10 participating laboratories divided into 2 groups where members within the same group were given the same set of images. The outcome cohort consisted of 149 breast cancer cases from the Yale Pathology archives in tissue microarray format. Intra-class correlation coefficient (ICC) was used to measure reproducibility with the pre-specified criterion for success being to exceed 0.80. Kaplan-Meier analysis supported with log-rank test was performed to assess prognostic potential.

Results: All 3 DIA platforms showed excellent inter-platform reproducibility (ICC: 0.933, CI: 0.879-0.966). Also, excellent reproducibility was found between all DIA platforms and the reference standard Ki67 values of SW (QP ICC: 0.970, CI: 0.936-0.986; H ICC: 0.968, CI: 0.933-0.985; QC ICC: 0.964, CI: 0.919-0.983). The intra-DIA reproducibility was also excellent for all platforms (QP ICC: 0.992, CI: 0.986-0.996; H ICC: 0.972, CI: 0.924-0.988; QC ICC: 0.978, CI: 0.932-0.991). Comparing each DIA against outcome, the hazard ratios were similar (QP=3.309, H=3.077, QC=3.731). The inter-operator reproducibility was particularly high (ICC: 0.962-0.995). As QP is open source software and also showed the lowest intra-DIA platform variability, we selected the QP platform to investigate inter-laboratory reproducibility among 10 IKWG labs. The different-section ICC across the 10 labs was 0.974 (CI: 0.954 - 0.986). The same-section ICC estimate was 0.984 (CI: 0.971-0.992) for group 1 and 0.978 (CI: 0.956-0.989) for group 2.

Conclusions: Our results showed outstanding reproducibility both within and between DIA platforms. We also found the platforms essentially indistinguishable with respect to prediction of breast cancer patient outcome. Automated Ki67 evaluation using a calibrated, open-source DIA platform (QuPath) met the pre-specified criterion of success in the multi-institutional setting. Assessment of clinical utility is planned.

Citation Format: Acs B, Leung SC, Pelekanou V, Bai Y, Martinez-Morilla S, Toki M, Chang MC, Gholap A, Jadhav A, Hugh JC, Bigras G, Laurinavicius A, Augulis R, Levenson R, Todd A, Piper T, Virk S, van der Vegt B, Hayes DF, Dowsett M, Nielsen TO, Rimm DL. Analytical validation of an automated digital scoring protocol for Ki67: International multicenter collaboration study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-02-01.

A dormant TIL phenotype defines non-small cell lung carcinomas sensitive to immune checkpoint blockers

The biological determinants of sensitivity and resistance to immune checkpoint blockers are not completely understood. To elucidate the role of intratumoral T-cells and their association with the tumor genomic landscape, we perform paired whole exome DNA sequencing and multiplexed quantitative immunofluorescence (QIF) in pre-treatment samples from non-small cell lung carcinoma (NSCLC) patients treated with PD-1 axis blockers. QIF is used to simultaneously measure the level of CD3+ tumor infiltrating lymphocytes (TILs), in situ T-cell proliferation (Ki-67 in CD3) and effector capacity (Granzyme-B in CD3). Elevated mutational load, candidate class-I neoantigens or intratumoral CD3 signal are significantly associated with favorable response to therapy. Additionally, a "dormant" TIL signature is associated with survival benefit in patients treated with immune checkpoint blockers characterized by elevated TILs with low activation and proliferation. We further demonstrate that dormant TILs can be reinvigorated upon PD-1 blockade in a patient-derived xenograft model.

Pathway level alterations rather than mutations in single genes predict response to HER2-targeted therapies in the neo-ALTTO trial

Background

We performed whole-exome sequencing of pretreatment biopsies and examined whether genome-wide metrics of overall mutational load, clonal heterogeneity or alterations at variant, gene, and pathway levels are associated with treatment response and survival.

Patients and Methods

Two hundred and three biopsies from the NeoALTTO trial were analyzed. Mutations were called with MuTect, and Strelka, using pooled normal DNA. Associations between DNA alterations and outcome were evaluated by logistic and Cox-proportional hazards regression.

Results

There were no recurrent single gene mutations significantly associated with pathologic complete response (pCR), except PIK3CA [odds ratio (OR) = 0.42, P = 0.0185]. Mutations in 33 of 714 pathways were significantly associated with response, but different genes were affected in different individuals. PIK3CA was present in 23 of these pathways defining a ‘trastuzumab resistance-network’ of 459 genes. Cases with mutations in this network had low pCR rates to trastuzumab (2/50, 4%) compared with cases with no mutations (9/16, 56%), OR = 0.035; P < 0.001. Mutations in the ‘Regulation of RhoA activity’ pathway were associated with higher pCR rate to lapatinib (OR = 14.8, adjusted P = 0.001), lapatinib + trastuzumab (OR = 3.0, adjusted P = 0.09), and all arms combined (OR = 3.77, adjusted P = 0.02). Patients (n = 124) with mutations in the trastuzumab resistance network but intact RhoA pathway had 2% (1/41) pCR rate with trastuzumab alone (OR = 0.026, P = 0.001) but adding lapatinib increased pCR rate to 45% (17/38, OR = 1.68, P = 0.3). Patients (n = 46) who had no mutations in either gene set had 6% pCR rate (1/15) with lapatinib, but had the highest pCR rate, 52% (8/15) with trastuzumab alone.

Conclusions

Mutations in the RhoA pathway are associated with pCR to lapatinib and mutations in a PIK3CA-related network are associated with resistance to trastuzumab. The combined mutation status of these two pathways could define patients with very low response rate to trastuzumab alone that can be augmented by adding lapatinib or substituting trastuzumab with lapatinib.

Mutation profiles in early-stage lung squamous cell carcinoma with clinical follow-up and correlation with markers of immune function

Background

Lung squamous cell carcinoma (LUSC) accounts for 20–30% of non-small cell lung cancers (NSCLCs). There are limited treatment strategies for LUSC in part due to our inadequate understanding of the molecular underpinnings of the disease. We performed whole-exome sequencing (WES) and comprehensive immune profiling of a unique set of clinically annotated early-stage LUSCs to increase our understanding of the pathobiology of this malignancy.

Methods

Matched pairs of surgically resected stage I-III LUSCs and normal lung tissues (n = 108) were analyzed by WES. Immunohistochemistry and image analysis-based profiling of 10 immune markers were done on a subset of LUSCs (n = 91). Associations among mutations, immune markers and clinicopathological variables were statistically examined using analysis of variance and Fisher’s exact test. Cox proportional hazards regression models were used for statistical analysis of clinical outcome.

Results

This early-stage LUSC cohort displayed an average of 209 exonic mutations per tumor. Fourteen genes exhibited significant enrichment for somatic mutation: TP53, MLL2, PIK3CA, NFE2L2, CDH8, KEAP1, PTEN, ADCY8, PTPRT, CALCR, GRM8, FBXW7, RB1 and CDKN2A. Among mutated genes associated with poor recurrence-free survival, MLL2 mutations predicted poor prognosis in both TP53 mutant and wild-type LUSCs. We also found that in treated patients, FBXW7 and KEAP1 mutations were associated with poor response to adjuvant therapy, particularly in TP53-mutant tumors. Analysis of mutations with immune markers revealed that ADCY8 and PIK3CA mutations were associated with markedly decreased tumoral PD-L1 expression, LUSCs with PIK3CA mutations exhibited elevated CD45ro levels and CDKN2A-mutant tumors displayed an up-regulated immune response.

Conclusion(s)

Our findings pinpoint mutated genes that may impact clinical outcome as well as personalized strategies for targeted immunotherapies in early-stage LUSC.

Abstract P2-09-18: Multiplexed (18-Plex) measurement of protein targets in trastuzumab-treated patients using imaging mass cytometry

Introduction: Recent studies have shown that the molecular heterogeneity of HER2 intracellular (ICD) and extracellular (ECD) domains, as well as overall immune infiltration, are associated with response to adjuvant trastuzumab. Traditional strategies for in situ measurement in the tumor microenvironment allow the combination of up to 6 targets, limiting our capability for in-depth interrogation of tissues. Imaging Mass Cytometry (IMC) uses metal-conjugated antibodies to provide multidimensional, objective measurement of protein targets. We used this high-throughput multiplexing platform to perform an 18-plex assessment of HER2 ICD/ECD, cytotoxic T cell infiltration and other structural and signaling proteins in a cohort of patients treated with trastuzumab.

Methods: An antibody panel for detection of 18 targets (Pancytokeratin, HER2 ICD, HER2 ECD, CD8, vimentin, cytokeratin 7, beta-catenin, HER3, MET, EGFR, ERK 1-2, MEK 1-2, PTEN, PI3K p110 alpha, Akt, mTOR, Ki67 and Histone H3) was conjugated to unique metals for detection in an IMC instrument (Fluidigm). All assays were objectively standardized and validated using quantitative immunofluoresce (QIF). Finally, the IMC technique was validated against HER2 single marker assays by QIF. We used a collection of trastuzumab-treated patients from the HeCOG 10/05 trial (n=180), and identified a case:control series using 5-year recurrence events (n=19), which were matched to controls (n=41) by age and TNM stage. Formalin-fixed, paraffin embedded tissues in tissue microarray format were ablated in the IMC attachment to the CyTOF flow cytometer for simultaneous detection of markers. Image visualization was conducted using MCD Viewer (Fluidigm). Statistical analyses were performed using a range of platforms.

Results: Patients that recurred after adjuvant treatment with trastuzumab showed a decreased fraction of HER2 ECD pixels over threshold in a compartment determined by CK and HER2 ICD compared to cases without recurrence (p=0.057). After exclusion of the lowest HER2 expressers (that would have fallen below the threshold for positive by current HER2 assays), 5-year recurrence events where associated with reduced total ECD/ ICD ratio intensity in tumor (p=0.044). Patients below the median for total ECD/ICD ratio showed a trend for decreased benefit from trastuzumab (p=0.066). Levels of cytotoxic T cell infiltration, depicted by total CD8 intensity, were lower in patients with recurrences (p=0.05).

Conclusion: Objective measurement of highly multiplexed protein targets in routine, fixed breast cancer tissues shows that a decreased ratio of HER2 ECD/ ICD is associated with 5-year recurrence after trastuzumab treatment. This observation is consistent with our previous work using QIF but represents the first time this has been done on identical cell content (on a single tissue section). Additionally, on the same section we found that lower levels of overall cytotoxic T cell infiltration were associated with worse outcome. Further analysis of the multiplexed data, including both correlative and distance-based analyses are underway.

Citation Format: Carvajal-Hausdorf DE, Stanton KP, Patsenker J, Villarroel-Espindola F, Esch A, Montgomery RR, Psyrri A, Kalogeras KT, Kotoula V, Fountzilas G, Schalper KA, Kluger Y, Rimm DL. Multiplexed (18-Plex) measurement of protein targets in trastuzumab-treated patients using imaging mass cytometry [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-09-18.

Abstract P1-08-02: Breast tumor-specific MHC-II expression drives a unique pattern of adaptive resistance to antitumor immunity through MHC-II receptor checkpoint engagement

Background: We have previously shown that some breast cancers express major histocompatibility complex II (MHC-II), correlating with enhanced immune infiltration. In other tumor types, we have shown that MHC-II expression on tumor cells predicts clinical response to checkpoint inhibition. We sought to determine the direct effects of MHC-II on anti-tumor immunity and characterize mechanisms of immune escape in this breast cancer subset.

Methods: To determine the functional effects of MHC-II on tumor cells, we generated isogenic mouse breast tumor cells with enforced MHC-II expression and determined their ability to generate tumors in syngeneic mice, the impact on immunity, and their response to checkpoint inhibition. In a series of molecularly-characterized HER2+ (n=8) and triple-negative breast cancers (TNBC; n=103), we performed immunohistochemistry (IHC) and quantitative immunofluorescence (QIF) for Lag-3, PD-L1, CD4, CD8, FCRL6, and granzyme B.

Results: Following injection in syngeneic immunocompetent mice, MHC-II+ mouse breast tumors were more frequently rejected (p=0.04) and recruited greater numbers of CD4+ TILs. When MHC-II+ tumors escaped rejection, they expressed higher degrees of PD-1 and Lag-3 in the tumor and in the draining lymph node. Since Lag-3 is a checkpoint that specifically targets MHC-II, we hypothesized that MHC-II+ breast cancers escape anti-tumor immunity through suppressing MHC-II-mediated antigen presentation. Combinations of anti-Lag-3 and anti-Pd-1 antibodies inhibited growth of MHC-II+ tumors. These findings led us to also explore Fc receptor-like 6 (FCRL6), a previously reported MHC-II receptor expressed on NK and cytotoxic T cells. Residual MHC-II+ TNBC post-neoadjuvant chemotherapy (NAC) recruited greater numbers of CD4+ and CD8+ TILs (p=0.0001 and p=0.0002), suggesting enhanced immune recognition. However, MHC-II+ TNBCs also demonstrated a greater frequency of Lag-3+ and FCRL6+ TILs (p&lt;0.001 and p=0.01, respectively) which frequently co-occurred (p=0.003). Thus, our data suggest that MHC-II expression in breast tumors supports recruitment of MHC-II-specific checkpoint-positive TILs. In line with this concept, QIF analysis demonstrated that the presence of Lag3+ and/or FCRL6+ TILs was strongly associated with suppression of T cell cytotoxicity as assessed by granzyme-B+ CD8+ T cells (p=0.0001 and p=0.002, respectively). Functional analyses of FCRL6 on human NK cell lines and peripheral blood mononuclear cells (PBMCs) demonstrated that like Lag3, FCRL6 is a checkpoint which engages MHC-II and suppresses cytotoxic NK and T cell activity.

Conclusions: These data suggest that MHC-II+ breast tumors are immunologically active and circumvent anti-tumor immunity by targeting MHC-II antigen presentation through recruitment of Lag-3+ and FCRL6+ TILs. We describe herein FCRL6 as a novel bona fide immune checkpoint which targets MHC-II, which may impact a variety of cancers. MHC-II expression status may be a useful biomarker for patient stratification on anti-PD-1/anti-Lag-3 combination, and eventually, anti-PD-1/anti-FCRL6 combinations in patients with breast cancer.

Citation Format: Balko JM, Johnson DB, Ericsson-Gonzalez P, Nixon MJ, Salgado R, Sanchez V, Shreeder DM, Rimm DL, Loi S, Kim JY, Bordeaux J, Sanders ME, Davis RS. Breast tumor-specific MHC-II expression drives a unique pattern of adaptive resistance to antitumor immunity through MHC-II receptor checkpoint engagement [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-08-02.

Abstract PD6-08: Analysis of immune infiltrates (assessed via multiplex fluorescence immunohistochemistry) and immune gene expression signatures as predictors of response to the checkpoint inhibitor pembrolizumab in the neoadjuvant I-SPY 2 trial

Background: Pembrolizumab (Pembro), an anti-PD-1 immune checkpoint inhibitor, has been approved for the treatment of a variety of cancers including melanoma, non-small cell lung cancer, head and neck squamous cell carcinoma, and urothelial carcinoma. Pembro was recently evaluated in HER2- breast cancer patients in the neoadjuvant I-SPY 2 TRIAL and graduated in the triple negative (TN), HR+HER2-, and HER2- signatures. HER2- patients were randomized to receive Pembro+paclitaxel followed by doxorubicin/cyclophosphamide (P+T -&gt; AC) vs. T -&gt; AC. We and others have shown that TN breast cancers tend to have high numbers of immune infiltrates, including T cells and tumor associated macrophages (TAMs). We evaluated expression signatures representing 14 immune cell types (TILs, T cells, CD8 T cells, exhausted T cells, Th1, Tregs, cytotoxic cells, NK, NK CD56dim, dendritic cells, mast cells, B cells, macrophages, and neutrophils) as specific predictors of response to Pembro.

Methods: Data from 248 patients (Pembro: 69; controls: 179) were available. Pre-treatment biopsies were assayed using Agilent gene expression arrays. Signature scores are calculated by averaging cell type specific genes. All I-SPY 2 qualifying biomarker analyses follow a pre-specified analysis plan. We used logistic modeling to assess biomarker performance. A biomarker is considered a specific predictor of Pembro response if it associates with response in the Pembro arm but not the control arm, and if the biomarker x treatment interaction is significant (likelihood ratio test, p&lt;0.05). This analysis is also performed adjusting for HR status as covariates, and within receptor subsets. For successful biomarkers, we use Bayesian modeling to estimate the pCR rates of 'predicted sensitive' patients in each arm. Our statistics are descriptive rather than inferential and do not adjust for multiplicities of other biomarkers outside this study.

Results: 10 out of the 14 cell-type signatures tested are associated with response in the Pembro arm. Higher expression levels of 9 of these cell-type signatures are associated with higher pCR rates (T cells, exhausted T cells, Th1, cytotoxic cells, NK, NK CD56dim, dendritic cells, B cells, and macrophages), whereas higher mast cell signature expression is associated with non-pCR. Interestingly, many of these same signatures also associate or trend towards association with response in the control arm; and in a model adjusting for HR status, only 3 of these signatures (Th1, B cells and dendritic cells) show significant interaction with treatment. Within the whole population and the TN subtype, the dendritic cell signature is the strongest predictor of specific response to Pembro (OR/1SD: 4.04 and 4.4, LR p &lt; 0.001 overall and in TN). Although other immune signatures (T cells, exhausted T cells, NK, and macrophages) also associate with response in the Pembro arm in the TN subtype, only the dendritic cell and Th1 signatures have a significant interaction with treatment. In contrast, in the HR+HER2- subtype, only 3 signatures (Th1, B cells, and mast cells) associate with response to Pembro; but none of these signatures have significant interaction with treatment. Of note, in both the Pembro and control arms, HR+HER2- patients with higher average mast cell marker expression have lower pCR rates (OR/1SD: 0.33 and 0.51, LRp: 0.006 and 0.04 in Pembro and control arm).

Conclusion: As expected, multiple immune cell expression signatures are predictive of response in the Pembro arm; but only dendritic cells and Th1 cells are specific to Pembro in both the population as a whole and the TN subtype. Interestingly, the presence of mast cells may impede response, especially in HR+HER2- patients. Correlation of these signatures with multiplex-IF immune markers is pending.

Citation Format: Campbell M, Yau C, Borowsky A, Vandenberg S, Wolf D, Rimm D, Nanda R, Liu M, Brown-Swigart L, Hirst G, Asare S, van't Veer L, Yee D, DeMichele A, Berry D, Esserman L. Analysis of immune infiltrates (assessed via multiplex fluorescence immunohistochemistry) and immune gene expression signatures as predictors of response to the checkpoint inhibitor pembrolizumab in the neoadjuvant I-SPY 2 trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD6-08.

Abstract P2-09-06: Quantitative spatial profiling of tumor associated macrophages and the PD-1/PD-L1 interaction in breast cancer

Background: Although immunotherapy approaches are being successfully administered in some breast cancer (BC) patients (pts), biomarkers of response remain elusive. Tumor associated macrophages (TAMs) are the most prominent immune cells in breast tumors, mediating the cross-talk between tumor cells and tumor infiltrating lymphocytes (TILs). Specific biomarkers of breast TAMs' functional status remain to be defined. CSF-1R, is a TAMs regulator and key target across cancers clinically tested, alone or combined with anti-PD-1 checkpoint inhibitors.

The goals of the study were: 1) to objectively measure CSF-1R expression within all CD68+ and M2-like CD163+TAMs, as well as PD-L1/PD-1 spatial interaction and 2) to determine whether objectively quantifying these key immune mechanisms related to TAMs immunomodulation within the tumor microenvironment can predict outcome and potentially response to immunotherapy.

Methods: Tissue Microarrays (TMAs) from two Yale BC cohorts (Cohort A, all breast cases, n=320) (Cohort B, TNBC, n=132) were assessed by quantitative immunofluorescence (QIF) for CSF-1R/CD163/CD68; PD-1/PD-L1 interaction score (proportion of PD-1+ cells co-localized with PD-L1) and co-expression of the multiplexed biomarker panels. Biomarker positive cells and their co-localization were objectively measured using the AQUA method of QIF. QIF scores were compared by linear regression coefficients (R2). Overall and recurrence-free survival (OS and RFS) were assessed. Our protein data were compared with transcriptome data from the METABRIC study obtained from www.cbioportal.org.

Results: CSF-1R expression was associated with expression of both CD68 and CD163 in both cohorts (A: R2=0.64, B: R2=0.49). CSF-1R in CD163/CD68 was higher in TNBC Cohort B (p&lt;0.01) and in ER- cases of Cohort A (p=0.004). In Cohort A high CSF-1R expression (top 10%) in CD163+/CD68+ cells was associated with worse OS and RFS (All cases, p=0.015 and p=0.0005, respectively). After ER-status adjustment, high CSF-1R (in CD68 and CD163) was associated with worse OS and RFS only in ER- cases. High CSF-1R/CD68 (top 10%) was associated with ER- (p=0.0078), PR- (p=0.004) and increased recurrence rate (p=0.009). High CSF-1R/CD163 (top 10%) was also associated with increased recurrence rate (p=0.004). In TNBC, high CSF-1R correlated with worse OS (p=0.01) only in CD163+ TAMs. High CSF-1R scored as a continuous variable was related with worse RFS in both CD68+ (p=0.0026, RR 1.00/2.86) and CD163+ TAMs (p=0.006, RR 1.00/2.76). However, in multivariate analysis CSF-1R was not an independent prognostic factor for OS or RFS.

PD-L1 mostly co-localized with CD68 TAMs (R2=0.7). Tumor PD-L1 tended to be mutually exclusive of CSF-1R. PD-L1/PD-1 colocalization was higher in TNBC (p&lt;0.01) and associated with better OS (p=0.01). CSF-1R in TAMs tended to be higher when PD-1/PD-L1 colocalization was low.

The trend of mutual exclusivity between CSF-1R in TAMs and PD-1/PD-L1 was confirmed by expression (mRNA) data from METABRIC study.

Discussion: This novel multiplexed method profiling key tumor-immune suppression pathways could identify BC pts likely to respond to anti-PD-1/anti-CSF-1R therapy. This method could help stratify pts for mono- or combined therapy in future clinical trials.

Citation Format: Pelekanou V, Neumeister V, Pusztai L, Rimm DL. Quantitative spatial profiling of tumor associated macrophages and the PD-1/PD-L1 interaction in breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-09-06.

Abstract P2-03-02: Macrodissection prior to closed system RT-qPCR is not necessary for estrogen receptor and HER2 concordance with IHC/FISH in breast cancer

Background: An on-demand, closed system RT-qPCR (the GeneXpert system, Cepheid, Sunnyvale, CA) has the potential to provide biomarker information in low resourced settings. The system consists of an inexpensive, single-use, disposable, macrofluidic cartridge and an instrument that automates RT-qPCR. Here we use it with a research use only cartridge (STRAT4) that measures the mRNA expression levels of ESR1, PGR, ERBB2, and MKi67 using a single 5uM thick FFPE tissue section from an excisional or core biopsy specimen containing invasive carcinoma of the breast. The assay, results are expressed as a delta cycle threshold (dCt) value, defined as the Ct of a control gene (CYFIP1) minus the Ct of the target gene (ESR1, PGR, ERBB2, or MKi67). We determine whether the dCt result for each marker is equivalent using the entire non-macrodissected section (non m-d) to the dCt results obtained following tumor macro-dissection (m-d) to eliminate non-tumor elements from the assay.

Methods: We evaluated the impact of m-d versus non m-d using STRAT4 on a cohort of 62 formalin-fixed paraffin-embedded (FFPE) tumor core needle biopsy specimens with a range of HER2 expression determined by clinical immunohistochemistry and fluorescence in situ hybridization (IHC/FISH). Concordance (sensitivity and specificity) of the STRAT4 ESR1 and HER2 mRNA versus ER and HER2 IHC/FISH measurements were also assessed.

Results: We observed excellent agreement of the resulting dCt between the paired samples, m-d versus non m-d, for ESR1 (R2=0.92), PGR (R2=0.90), ERBB2 (R2=0.94) and MKi67 (R2=0.90). No significant difference (P value &gt; 0.99) was observed when we compared the dCt between the paired samples m-d versus non m-d. In addition, using the predefined STRAT4 dCt cutoff for ESR and ERBB2 positivity, we found a significant concordance between RT-qPCR and IHC/FISH for ESR-positivity for the paired samples, m-d (P value &lt; 0.001; sensitivity = 0.98; specificity = 1; PPV = 1; NPV = 0.95) versus non m-d (P value &lt; 0.001; sensitivity = 0.98; specificity = 1; PPV = 1; NPV = 0.95) and HER2-positivity for the paired samples, m-d (P value &lt; 0.001; sensitivity = 0.85; specificity = 0.98; PPV = 0.92; NPV = 0.96) versus non m-d (P value &lt; 0.001; sensitivity = 0.71; specificity = 0.98; PPV = 0.90; NPV = 0.92), respectively.

Conclusion: These data suggest that mRNA for ESR and ERBB2 is sufficiently low in surrounding tissues that m-d of whole sections is not required for accurate assessment of key breast cancer mRNA markers in a closed system RT-qPCR assay. The simplicity of the assay workflow may be particularly valuable in low resourced settings where routine access to pathology expertise and to high quality IHC/FISH is challenging.

Citation Format: Gupta S, Carvajal-Hausdorf DE, Wasserman BE, Ho K, Weidler J, Wong W, Rhees B, Bates M, Rimm DL. Macrodissection prior to closed system RT-qPCR is not necessary for estrogen receptor and HER2 concordance with IHC/FISH in breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-03-02.

Whole-exome sequencing and immune profiling of early-stage lung adenocarcinoma with fully annotated clinical follow-up

Background

Lung adenocarcinomas (LUADs) lead to the majority of deaths attributable to lung cancer. We performed whole-exome sequencing (WES) and immune profiling analyses of a unique set of clinically annotated early-stage LUADs to better understand the pathogenesis of this disease and identify clinically relevant molecular markers.

Methods

We performed WES of 108 paired stage I-III LUADs and normal lung tissues using the Illumina HiSeq 2000 platform. Ten immune markers (PD-L1, PD-1, CD3, CD4, CD8, CD45ro, CD57, CD68, FOXP3 and Granzyme B) were profiled by imaging-based immunohistochemistry (IHC) in a subset of LUADs (n = 92). Associations among mutations, immune markers and clinicopathological variables were analyzed using ANOVA and Fisher's exact test. Cox proportional hazards regression models were used for multivariate analysis of clinical outcome.

Results

LUADs in this cohort exhibited an average of 243 coding mutations. We identified 28 genes with significant enrichment for mutation. SETD2-mutated LUADs exhibited relatively poor recurrence- free survival (RFS) and mutations in STK11 and ATM were associated with poor RFS among KRAS-mutant tumors. EGFR, KEAP1 and PIK3CA mutations were predictive of poor response to adjuvant therapy. Immune marker analysis revealed that LUADs in smokers and with relatively high mutation burdens exhibited increased levels of immune markers. Analysis of immunophenotypes revealed that LUADs with STK11 mutations exhibited relatively low levels of infiltrating CD4+/CD8+ T-cells indicative of a muted immune response. Tumoral PD-L1 was significantly elevated in TP53 mutant LUADs whereas PIK3CA mutant LUADs exhibited markedly down-regulated PD-L1 expression. LUADs with TP53 or KEAP1 mutations displayed relatively increased CD57 and Granzyme B levels indicative of augmented natural killer (NK) cell infiltration.

Conclusion(s)

Our study highlights molecular and immune phenotypes that warrant further analysis for their roles in clinical outcomes and personalized immune-based therapy of LUAD.

Abstract P4-03-04: Tumor infiltrating macrophages, lymphocytes and matrix metalloproteinase 9 (MMP-9) expression in breast cancer

Background: Immune therapy has been highly successful in tumors with high lymphocytic infiltrate, but they only represent the minority of breast neoplasms. Macrophages rather than lymphocytes, are more prominent in mammary development and disease. Specific markers of breast tumor associated macrophages (TAMs) remain to be defined. Local interactions define their plasticity and activity, rendering in situ investigation important in their characterization. MMP-9 is an important regulator of breast cancer microenvironment that could mediate cross-talk between TAMs and tumor cells. Here we objectively measure CD68 and CD163 and also MMP-9 within each macrophage subtype to determine the relationship between macrophage expression, tumor infiltrating lymphocytes (TILs) and molecular subtypes in breast cancer.

Methods: Using a multiplexed quantitative immunofluorescence (QIF)-based assay for simultaneous detection of DAPI (all cells), Cytokeratin (epithelial cells, clone CK8/CK18), CD163 (M2 Macrophages, clone CD163-L-U), CD68 (pan macrophage marker, clone PG-M1), and MMP-9 (Matrix Metalloproteinase 9, clone D6O3H XP). We measured the levels of protein expression in breast carcinomas on two sets of Yale tissue microarrays (TMA) [YTMA201 (all breast cases, n=399) and YTMA149 (Triple Negative, n=160)]. Markers were measured using the AQUA method of QIF on TMAs at two-fold redundancy. Linear regression coefficients (R2) were used to compare antibody QIF scores within cores from different areas of the tumors. Median cut-point was used to stratify patients for overall and disease specific survival (OS and DSS).

Results: Cases with high TILs, as shown by assessment of CD3, 8 and 20, generally show an inverse relationship with both CD68 and CD163, especially in ER+ cases. MMP-9 was then measured in both subtypes of macrophages. In ER+ tumors MMP-9 was expressed in CD163+ macrophages (p=0.007), while in TNBC it was found in CD68+/CD163- macrophages (p&lt;0.001). In all cases MMP-9 was significantly higher in ER- cases (CD68+/CD163- p=0.0001), (CD163+ p=0.01). In ER+ cases high MMP-9 expression was associated with shorter OS (p&lt;0.0001 in CD163+ cells). On the contrary, in TNBC high MMP-9 was associated improved DSS in the CD68 compartment (p=0.007).

Discussion: Using an objective, quantitative multiplex assay for synchronous measurement in tumor and microenvironment, we found an inverse relationship between TILs and macrophage infiltration, suggesting immune modulation by different cellular elements. Within the macrophage population, we found that MMP9 expression is a function of the breast cancer molecular phenotype. Most significantly, the ER status of the tumor is correlated with the macrophage subtypes that express MMP9. Efforts to determine the clinical value of these observations are underway to better determine the balance between pro- and antitumor immunity in breast cancer.

Citation Format: Pelekanou V, Brown JR, Rimm DL. Tumor infiltrating macrophages, lymphocytes and matrix metalloproteinase 9 (MMP-9) expression in breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-03-04.

Abstract P1-03-01: An international multicenter study to evaluate reproducibility of automated scoring methods for assessment of Ki67 in breast cancer

Background: The nuclear proliferation biomarker Ki67 has multiple potential roles in breast cancer, including prognosis-based decisions, but unacceptable between-laboratory variability has limited its clinical value. The International Ki67 Working Group (IKWG) has undertaken a systematic program to determine whether Ki67 immunohistochemistry can be analytically validated and standardized across laboratories. Technological advances and broader availability of devices for automated assessment of stained slides raise the possibility that these machines may improve on reproducibility of traditional pathologist-based visual Ki67 assessment.

Aims: To characterize reproducibility of automated machine-measured Ki67 expression using slides previously analyzed in the IKWG phase 3 study that evaluated reproducibility of visual Ki67 assessment.

Methods: Two sets of 30 previously stained slides containing core-cut biopsy sections of breast tumors were circulated to 14 laboratories for scanning and automated assessment of Ki67 expression. Sites were instructed to return average and maximum percentage of tumor cells positive for Ki67 for each slide, where maximum is designed to reflect “hot spot” analysis. Two laboratories returned scores from 2 operators; not all laboratories reported values for maximum Ki67 scores. Different operators were treated as distinct laboratories in analyses. Sixteen and 10 score sets were available for average and maximum Ki67 analyses, respectively, encompassing 7 unique scanner and 10 software platforms. Pre-specified analyses included evaluation of reproducibility across all laboratories as well as within a subgroup limited to those using Aperio scanners. The primary reproducibility metric was intraclass correlation coefficient between laboratories (ICC), regardless of device platform or software.

Results: Geometric means across 30 cases for 16 operators ranged from 11.06% to 38.11% with overall mean 16.75% (95% CI:14.45-19.42) for average scores. Geometric means for 10 operators ranged from 16.44% to 68.73% with overall mean 25.16% (95% CI: 18.71-33.84) for maximum scores. ICC for automated average scores across 16 operators was 0.83 (95% CI: 0.73-0.91) and ICC for maximum scores across 10 operators was 0.63 (95% CI: 0.44-0.80) although one outlier lab dramatically affected results. For the laboratories using the Aperio platform (8 score sets), ICC for automated average scores was 0.89 (95% CI; 0.81-0.96). These results are similar to ICC of 0.87 (95%CI; 0.81-0.93) reported using these same slides in the Phase 3 visual assessment reproducibility study in which observers counted 500 cells per slide (Leung et al, NPJBrCancer, in press).

Conclusions: Between-laboratory reproducibility for automated machine assessment of average Ki67 is similar to that for pathologist-based visual assessment of Ki67. However, the observed ICC was markedly numerically lower for the maximum score method compared to the average method, suggesting that the maximum score may not be useful as a reproducible measure of proliferation. Automated average scoring methods show promise for standardization of Ki67 scoring, supporting future studies to clinically validate Ki67.

Citation Format: Rimm DL, McShane LM, Leung SCY, Bai Y, Bane AL, Bartlett JMS, Bayani J, Chang MC, Dean M, Denkert C, Enwere E, Galderisi C, Gholap A, Hugh JC, Jadhav A, Kornaga E, Laurinavicius A, Levenson R, Lima J, Miller K, Pantanowitz L, Piper T, Ruan J, Srinivasan M, Virk S, Wu Y, Yang H, Hayes DF, Nielsen TO, Dowsett M. An international multicenter study to evaluate reproducibility of automated scoring methods for assessment of Ki67 in breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-03-01.

Abstract P1-03-07: High concordance of a closed system, near point of care, RT-qPCR breast cancer assay for HER2 (ERBB2) mRNA compared to both IHC/FISH and quantitative immunofluorescence

Background

Reliable assessment of HER2 receptor status in breast cancer by either IHC or FISH does not unequivocally define receptor expression, due to their semi-quantitative nature, and as many as 10-15% of cases fall into the ASCO/CAP “equivocal” category. Historically, RNA measurements by PCR, including using several commercially available platforms, have been tested, but have not gained broad acceptance for assessment of HER2. However, RNA measurement, as a continuous value, has potential for use for adjudication of the equivocal category. In the current study, we used a real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) assay (GeneXpert® Breast Cancer Stratifier RUO Assay, Cepheid, Sunnyvale, CA, USA) for ERBB2 (HER2) mRNA on the GeneXpert® (GX) platform (Cepheid), which utilizes a closed-system, single-use cartridge, automated system. The RT-qPCR results from GX were then compared with results from clinical HER2 IHC/FISH assays following ASCO/CAP 2013 HER2 testing guidelines (Wolff et al JCO 2013) and quantitative immunofluorescence (QIF).

Methods

Multiple cores (1mm in diameter) were retrospectively collected from 80 formalin-fixed paraffin-embedded (FFPE) tissue blocks with invasive breast cancer seen by Yale Pathology Labs between 1998 and 2011. Tissue cores were processed as lysates for testing at Yale in the automated GX assay. Briefly, gene-specific reverse transcription was performed, followed by RT-qPCR (TaqMan) and ERBB2 mRNA results were expressed as the difference in cycle threshold values (delta Ct) between the endogenous control transcript (CYFIP1) and the ERBB2 mRNA transcript. Results from IHC and FISH were extracted from the pathology reports for the Yale CLIA lab and QIF for each case was measured as previously described (Carvajal et al, JNCI 2015).

Results

Quality control testing showed that the GX platform shows no case to case cross contamination on material from routine histology practices. Concordance between RT-qPCR and IHC/FISH was 91.25% (sensitivity = 0.87; specificity = 0.94; PPV = 0.89; NPV = 0.92) using a pre-defined delta Ct cut-off (dCt ≥ -1) for HER2 (+) based on prior concordance studies with HER2 IHC/FISH. Concordance between RT-qPCR and QIF was 99% (sensitivity = 0.97; specificity = 1.0; PPV = 1.0; NPV = 0.98) using dCt ≥ -1 and the pre-defined cut-point for positivity by QIF.

Conclusions

The GX closed system RT-qPCR assay shows greater than 90% concordance with the ASCO/CAP 2013 HER2 IHC/FISH scoring. Additionally, the GX RT-qPCR assay is highly concordant (99%) with the continuous variable HER2 QIF assay, and may better reflect the true continuum of HER2 receptor status in invasive breast cancer. These initial results suggest that rapid, closed system molecular assays may have future value for the adjudication of the ASCO/CAP HER2 equivocal category. This pilot study did not include ASCO/CAP 2013 “equivocal” cases, but that effort is underway.

Citation Format: Wasserman B, Carvajal-Hausdorf D, Ho K, Wong W, Wu N, Chu VC, Lai EW, Weidler JM, Bates M, Neumenister V, Rimm DL. High concordance of a closed system, near point of care, RT-qPCR breast cancer assay for HER2 (ERBB2) mRNA compared to both IHC/FISH and quantitative immunofluorescence [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-03-07.

Abstract P6-10-02: MHC-II positive breast tumors are more immunogenic and may preferentially select for LAG-3-positive tumor immune infiltrates

Background: Lymphocyte-activation gene 3 (LAG-3) is a T-cell checkpoint regulator and a current target in immunotherapy trials. LAG-3's main ligand is MHC class II (MHC-II), to which it binds with higher affinity than CD4. Binding of LAG3 to MHC-II antigen-presenting cells negatively regulates cellular proliferation, activation, and homeostasis of T cells, similarly to CTLA-4 and PD-1, suggesting that antibodies targeting LAG-3 may demonstrate similar anti-tumor immune effects.

Hypothesis: We recently reported an association of MHC-II on tumor cells and its involvement in mediating sensitivity to PD-1/PD-L1 monoclonal antibodies. MHC-II demonstrates a strong bimodal expression pattern on tumor cells from a variety of tissues, including those of the breast. In breast cancer patients, tumor-specific MHC-II expression on TNBCs is correlated with a 'hot' immune environment. We hypothesized that 1) MHC-II expression may drive potent anti-tumor immune responses and 2) MHC-II-positive tumors that generate immunotolerance may develop a specific immune checkpoint dependency on LAG-3, since LAG-3 is the inhibitory receptor for MHC-II-mediated antigen presentation.

Methods: To determine the functionality of MHC-II in driving anti-tumor immune responses, we constitutively expressed the MHC-II master regulator CIITA in MMTV-neu mouse tumor cells and determined their ability to form tumors in immunocompetent syngeneic hosts. To evaluate the association of MHC-II+ tumors with LAG-3 expression, we evaluated LAG-3-positivity by immunohistochemistry (IHC) in lymphocytic infiltrates in a series of 111 post-NAC TNBC specimens from patients with residual disease remaining after presurgical chemotherapy. Tumor-infiltrating lymphocytes (TILs) were scored by H&E, PD-L1 and MHC-II (HLA-DR) were scored in the stroma and tumor compartments using automated quantitative immunofluorescence (AQUA).

Results: Enforced expression of MHC-II via constitutive expression of CIITA caused rejection in 60% of mice, while only 11% of mice rejected MMTV-neu tumors expressing the vector control (Fisher's exact p=0.04). All rejecting mice were immune to rechallenge with parental (non-CIITA-expressing) MMTV-neu cells, suggesting a memory effector response.

Clinically, 11/102 patients (10.8%) had LAG-3+ immune cells in their tumor. LAG-3+ tumors were strongly correlated with MHC-II positivity in tumor cells (p&lt;0.0001). Presence of LAG-3+ cells also correlated strongly with overall TILs (p&lt;0.0001), and PD-L1 expression on TILs (p&lt;0.02). Since the likelihood of identifying LAG3+ lymphocytes is confounded by the inclusion of poorly-infiltrated tumors, we performed a subset analysis on only those tumors with substantial TILs (&gt;20%). When this subset was analyzed, LAG-3 positivity retained its association with tumor MHC-II expression (p=0.0001), while the association of LAG-3 with stromal PD-L1 was reduced below the level of significance (p=0.052).

Conclusions: MHC-II expression causes increased immune activation in breast cancers, consistent with our previous findings. MHC-II positivity in breast tumors may identify a population with preferential dependence on the LAG-3 checkpoint, which may be important for future immunotherapy trials.

Citation Format: Balko JM, Loi S, Giltnane JM, Combs S, Estrada MV, Sanchez V, Rimm D, Sanders ME, Salgado R, Gomez H, Johnson DB. MHC-II positive breast tumors are more immunogenic and may preferentially select for LAG-3-positive tumor immune infiltrates [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-10-02.

Abstract P3-07-06: Objective measurement of HER2 (ERBB2) intracellular and extracellular domain spatial co-localization stratifies benefit from adjuvant trastuzumab

Background: The ASCO/CAP guidelines consider chromogen-based immunohistochemistry (IHC) as the primary assay to determine HER2 status in breast cancer. U. S. Food and Drugs Administration (FDA) approved HER2 antibody assays target the protein's intracellular domain (ICD). Studies suggest that quantitative, domain-specific measurement of HER2 might predict benefit from trastuzumab therapy, further classifying traditional HER2-positive breast cancer. Here we define a method of simultaneous, objective measurement of HER2 ICD and extracellular (ECD) domains, and determine its effect on trastuzumab benefit in the adjuvant setting.

Methods: We measured co-expression of HER2 ICD and ECD using a proximity ligation assay (PLA) and quantitative immunofluorescence (QIF) in a HER2 standardization tissue microarray (TMA) with CLIA-lab defined HER2 status. Previously validated, standardized HER2 antibodies were used to detect ICD and ECD (CB11 and SP3, respectively). We determined the relationship between HER2 PLA scores, HER2 clinical status and domain-specific scores. Finally, we measured HER2 ICD/ECD PLA in 180 patients from a clinical trial of adjuvant chemotherapy followed by trastuzumab (HeCOG 10/05). Median cut-point was used to stratify patients according to HER2 PLA scores. Cut-points for HER2 ICD and ECD were obtained using Joinpoint software. All statistical tests were two-sided.

Results: In the standardization TMA, HER2 PLA levels were associated to HER2 CLIA status (P&lt;0.0001). There was a good correlation between HER2 PLA scores and HER2 ICD and ECD (R2=0.57 and R2=0.54, respectively). In trastuzumab-treated patients from HeCOG 10/05, a similarly good correlation was observed between HER2 PLA scores and HER2 ICD and ECD (R2=0.41 and R2=0.3, respectively). In univariate analysis, HER2 PLA-low status was associated with ER-positive status (P=0.005). There was no association with age, histological grade, tumor size, lymph node status and TNM stage. Although all tumors were HER2-positive, HER2 PLA-high status was significantly associated with longer 5-year disease-free survival (DFS) (log-rank P=0.036, HR=0.32, 95% CI: 0.132-0.935). HER2 PLA status was superior to ICD status (log-rank P=0.67) and numerically comparable to ECD status (log-rank P=0.049, HR=0.31, 95% CI: 0.144-0.997) to predict benefit from adjuvant trastuzumab, as previously published by our group. HER2 PLA-high status was independent predictor of better outcome in a Cox proportional hazards model including age, histological grade, ER status, tumor size, lymph node status and TNM stage.

Discussion: Using an objective, quantitative HER2 assay for synchronous, domain-specific measurement, we stratified benefit from adjuvant trastuzumab treatment in patients from a prospective cohort. Our results further support the concept that benefit from HER2 ECD-targeted therapies might be modulated by the presence of truncated HER2 protein variants and that tyrosine kinase inhibitors (ICD-directed) may be advantageous for a subset of HER2-positive patients. Furthermore, this technique that uses two antibodies has the potential to increase both sensitivity and specificity of the IHC assay to predict response to HER2 pathway inhibitors.

Citation Format: Carvajal-Hausdorf DE, Toki M, Schalper KA, Pusztai L, Psyrri A, Kalogeras KT, Kotoula V, Fountzilas G, Rimm DL. Objective measurement of HER2 (ERBB2) intracellular and extracellular domain spatial co-localization stratifies benefit from adjuvant trastuzumab. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-06.

Abstract S5-01: Whole exome sequencing of pre-treatment biopsies from the neoALTTO trial to identify DNA aberrations associated with response to HER2-targeted therapies

Background: We examined if alterations in nucleic acid variants, genes, pathways, and overall mutational load and clonal entropy are associated with pathologic complete response (pCR) and survival after neoadjuvant anti-HER2 therapies in the NeoALTTO trial.

Methods: Whole exome sequencing was performed of 203 baseline biopsies with outcome information. The mean nucleotide coverage was 150x with &gt;90% of target bases showing &gt; 30x coverage in &gt; 99% of samples. Somatic mutations were called by MuTect and indels by Strelka, using pooled reference normal DNA. Significantly mutated genes (FDR&lt;10%) were identified by MutSigCV. Mutations in 714 canonical biological pathways were assessed and mutational load and genome clonal entropy (MATH) were calculated. Association with pCR and survival were evaluated by logistic regression adjusted for ER status and Cox-proportional hazards regression.

Results: Only 12 genes had mutation rates significantly above background and among these only PI3KCA was associated with lower pCR rate (OR=0.42, p=0.019). Genes with somatic mutations in more than 10 patients were also assessed, but none were associated with pCR or survival. Clonal entropy or adjusted mutation load also did not correlate with response. Mutations in 33 pathways showed significant association with response in the entire cohort. In the trastuzumab arm, 23 of the 33 pathways showed an association with response but none was independent of PIK3CA mutation. We constructed "PIK3CA-gene network" that included all unique genes (n=439) from theese 23 pathways. Of the 66 patients in the trastuzumab arm, 50 carried at least one mutation in one of the 439 genes and among these only 2 achieved pCR (4%) compared to 9 of 16 pCR (56%) among the wild type (OR=0.035; p &lt; 0.001). The same genes/mutations had little impact on pCR in the lapatinib arm (pCR 20%). In the lapatinib arm, mutations in 3 pathways conferred higher probability of pCR. The "Regulation of RhoA activity" pathway, had the most significant association with pCR in the entire cohort (OR=3.77, p=0.0009) and in the lapatininb (pCR 67% vs 17%, OR=14.8, p=0.008) and lapatinib + trastuzumab (OR=3.0, p=0.06) arms, but not in the trastuzumab arm (OR=1.4, p=0.7). Event free and overall survival were also significantly higher in patients who had mutations in this pathway. Twenty seven of the 48 genes in this pathway had mutations affecting 33 patients but different genes were affected in different individuals.

Conclusions: There are no high frequency recurrent single mutations associated with response to HER2-targeted therapies, other than PIK3CA. We identified several biological pathways, including RhoA activity, and a network of PIK3CA associated genes that are significantly associated with response when affected by mutations, however, different genes are mutated in different individuals.

Citation Format: Pusztai L, Shi W, Jiang T, Nuciforo P, Holmes E, Harbeck N, Sotiriou C, Rimm D, Hatzis C, de la Peña L, Armour A, Piccart-Gebhart M, Baselga J. Whole exome sequencing of pre-treatment biopsies from the neoALTTO trial to identify DNA aberrations associated with response to HER2-targeted therapies. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S5-01.

Abstract P5-07-12: Local nuclear architecture features from H&E images predict early versus distant recurrence in lymph node negative, ER+ breast cancers

Introduction: Breast cancer (BCa) Patients with ER+ tumors that are lymph node negative (LN-) typically receive hormonal therapy. There is a need to identify ER+ LN- patients that will not benefit from adjuvant chemotherapy and will respond to hormonal therapy alone. Oncotype DX, a quantitative prognostic and predictive gene assay, provides a recurrence score that has been correlated with distant and early recurrence. In this work we present an approach that employ computer extracted features of nuclear architecture and morphology from routine H&E slides alone that can distinguish early and distant recurrence in ER+ breast cancers. By constructing graph networks within epithelium and stroma regions, built using nuclei as vertices and edge connections between proximal nuclei, local nuclear architecture can be quantitatively characterized. Hosoya index (HI) (originally introduced for analysis of chemical bonds) is a measure of a bond (in this context nuclei connections in a graph). In this work, we leverage HI to measure structural similarities of graphs across the populations that are indicative of recurrence in LN- ER+ breast cancer tissue microarray (TMA) images.

Design: In this study we considered two tissue microarrays (TMAs) comprising 453 early-stage lymph-node negative (LN-) estrogen receptor positive (ER+) breast cancer (BCa) patients (diagnosed with invasive ductal carcinoma), with a total of N=90 patients experiencing lifetime distant recurrence and N=343 patients who did not. All TMA cores were digitized at 20x magnification (0.33 um/pixel spatial resolution) using a digital whole-slide scanner. Each nucleus was identified via an automated computerized image analysis algorithm developed by our group. Then, using a cluster cell graph that encodes a link between a pair of nodes based on proximity, a series of graphs are constructed for a TMA. A HI value was then assigned to each local graph. A support vector machine classifier was trained in conjunction with the distribution of HI values for the early and distant recurrence cases on the training TMA (n=243, 50 early recurrences). Independent validation of the SVM classifier was performed on the second TMA (n=210, 40 early recurrences).

Results: For the LN- ER+ breast cancer dataset, our method was able to distinguish tumors with early and distant recurrence with an accuracy of 75.4%, a positive predictive value of 78.6% and a negative predictive value of 76.4%. The separation between the Kaplan-Meier curves for early and distant recurrence of LN-, ER+ breast cancers on the validation set was statistically significant (p &lt; 0.00102).

Conclusion: Based only on tiny H&E punches, a computer-aided morphometric classifier appears to identify lymph node negative, ER+ breast cancers with a low likelihood of recurrence. With further validation, this approach could be developed into an image based assay which could serve as a lower cost alternative to Oncotype DX.

Citation Format: Ali S, Rimm D, Ganesan S, Madabhushi A. Local nuclear architecture features from H&E images predict early versus distant recurrence in lymph node negative, ER+ breast cancers. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-07-12.

Abstract P5-07-09: Heterogeneity of tumor infiltrating lymphocytes in breast cancer and its impact for use as a biomarker

Background: In breast cancer, elevated tumor infiltrating lymphocytes (TILs) is associated with PD-L1 expression, hormone receptors negativity, and better outcome. The presence of numerous CD8+ cytotoxic T cells in pre-treatment specimens is associated with clinical benefit from PD-1 axis blockade in melanoma and lung cancer, suggesting its predictive value. Despite recent efforts to standardize the pathologist evaluation of TILs in breast cancer, objective determination of lymphocyte subpopulations and their distribution/uniformity within tumor tissues remains largely unexplored. Here, we simultaneously measured diverse TIL subpopulations using quantitative immunofluorescence (QIF) in different areas of breast tumors to determine the heterogeneity of TILs and its possible impact for use as biomarker.

Methods: Using a multiplexed QIF-based assay for simultaneous detection of DAPI (all cells), Cytokeratin (epithelial cells, M3515-DAKO), CD3 (T lymphocytes, E272--Novus), CD8 (cytotoxic T cells, C8/144B--DAKO), and CD20 (B cells, clone L26-DAKO), we measured the levels of TIL subpopulations in whole tissue section slides of 3 tumor cores obtained from different areas of 31 breast carcinomas. The levels of the markers were measured using the AQUA method of QIF and the heterogeneity was studied using numerical correlations of log2 transformed scores and variance component analysis with linear mixed effects (LME). The concordance (kappa index [κ]) between binarized scores obtained measuring 1 vs 3 cores of the same tumor was also evaluated.

Results: As expected, we found a positive correlation between CD3 and CD8 levels across all patients (Pearson correlation coefficient [CC]=0.827). The levels of CD3 and CD8 showed weaker association with CD20 signal (CC=0.446 and 0.363, respectively). For all the TIL markers, the intra-tumor variation was higher than the inter-tumor differences with intraclass correlation coefficients (ICC) of 0.411 for CD3, 0.324 for CD8, and 0.252 for CD20. In the variance component analysis, 66-69% of the variance was attributable to signal differences between areas of the same tumor core and 30-33% was due to differences between cores from different areas. Consistent with this and using the median score as cutpoint to stratify cases in high/low marker levels, the concordance of measuring TILs in 1 vs 3 cores of the same tumor was κ=0.705 for CD3, κ=0.655 for CD8, and κ=0.603 for CD20.

Conclusion: Objective measurement of TIL markers indicates that T and B lymphocytes show heterogeneity in breast cancer. The tumor variation of the markers is driven predominantly by differences within the same tumor core. The data from our study suggests that although a single core biopsy of tumors provides considerable information regarding the degree of lymphocyte infiltration in breast cancer patients, caution should be taken when using this as a clinical biomarker.

Citation Format: Mani NL, Schalper K, Hatzis C, Chagpar A, Pusztai L, Rimm DL. Heterogeneity of tumor infiltrating lymphocytes in breast cancer and its impact for use as a biomarker. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-07-09.

Abstract P4-09-22: Quantitative immuno-fluorescent evaluation of Her2 expression levels in a prospectively collected cohort of breast cancer cases: Comparison to conventional IHC scoring and FISH

Background: According to the 2013 guidelines breast cancers are defined as Her2 positive if there is evidence of protein expression in at least 10% of tumor cells by IHC and/or gene amplification by FISH. Nevertheless, there are still IHC 2+ and FISH equivocal breast cancers resulting in repeat testing. It is also known that not all Her2 positive breast cancers respond to Trastuzumab, while up to 8% of Her2 "negative" classified patients benefit from Her2 targeting regimens. Toward the goal of generating a more accurate test, we report in situ quantification of Her2 protein levels on a prospectively collected cohort of breast cancers and comparison to conventional IHC and FISH evaluation.

Materials and Methods: A prospectively designed study was initiated at Yale University, comparing quantitative, in situ measurement of Her2 protein levels with conventional IHC and FISH evaluation. All breast cancer specimens were analyzed by IHC and FISH in our routine clinical laboratory, read and signed out by the breast pathologists. Serial sections were then stained and quantified for Her2 expression levels using the AQUA method of quantitative immunofluorescence (QIF). Data for all assays were obtained on 120 samples over a period of 6 months. Staining was performed using the DAKO Herceptest and the Epitomics EP3 Her2 antibody for IHC, the DAKO rabbit polyclonal antibody for QIF. The 30 highest cases were then retested for QIF and IHC using the Biocare c-erbB-2 [CB11] antibody. Each staining run included an index tissue microarray (TMA) consisting of 80 cases, cell lines and normal tissue for quality control, assay reproducibility and threshold definition of AQUA scores correlated to HER2 over expression and amplification.

Results: Out of 120 specimens analyzed for HER2, 13 were diagnosed as IHC 2+/3+, FISH amplified, 1 case had an equivocal score, 14 cases were IHC 2+/non amplified, 2 cases IHC 1+/FISH amplified and 89 specimens IHC 0/1+ non amplified. The continuous AQUA scores for Her2 expression of the samples significantly correlate with traditional clinical Her2 scoring. However, 5 IHC 0/1+, non amplified cases revealed high AQUA scores in the range of HER2 overexpression/amplification. Repeat testing of these by both QIF and IHC showed reproducibility of the results. AQUA scores of one IHC 3+/amplified sample were lower than the threshold of HER2 overexpression/amplification.

Conclusions: QIF measurement of HER2 protein levels in a prospectively collected cohort of 120 breast cancer specimens reveals significant association between continuous HER2 protein levels and the ordinal conventional scoring system. However, five discordant cases that were above the threshold for HER2 protein by QIF, were classified as negative by conventional methods. Given the accuracy and reproducibility of the QIF test, it raises the possibility that some of these patients might benefit from HER2 targeted therapy. In summary, while continuous scoring of HER2 protein correlates well with conventional methods, it identifies a subset of patients that are discordant with current methods. Further comparative studies in a patient cohort with response to targeted therapy need to be evaluated.

Citation Format: Neumeister VM, Yan SS, McGuire JA, Carvajal DE, Prasad ML, Rimm DL. Quantitative immuno-fluorescent evaluation of Her2 expression levels in a prospectively collected cohort of breast cancer cases: Comparison to conventional IHC scoring and FISH. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-09-22.

The evaluation of tumor-infiltrating lymphocytes (TILs) in breast cancer: recommendations by an International TILs Working Group 2014

BACKGROUND

The morphological evaluation of tumor-infiltrating lymphocytes (TILs) in breast cancer (BC) is gaining momentum as evidence strengthens for the clinical relevance of this immunological biomarker. Accumulating evidence suggests that the extent of lymphocytic infiltration in tumor tissue can be assessed as a major parameter by evaluation of hematoxylin and eosin (H&E)-stained tumor sections. TILs have been shown to provide prognostic and potentially predictive value, particularly in triple-negative and human epidermal growth factor receptor 2-overexpressing BC.

DESIGN

A standardized methodology for evaluating TILs is now needed as a prerequisite for integrating this parameter in standard histopathological practice, in a research setting as well as in clinical trials. This article reviews current data on the clinical validity and utility of TILs in BC in an effort to foster better knowledge and insight in this rapidly evolving field, and to develop a standardized methodology for visual assessment on H&E sections, acknowledging the future potential of molecular/multiplexed approaches.

CONCLUSIONS

The methodology provided is sufficiently detailed to offer a uniformly applied, pragmatic starting point and improve consistency and reproducibility in the measurement of TILs for future studies.

The evaluation of tumor-infiltrating lymphocytes (TILs) in breast cancer: recommendations by an International TILs Working Group 2014

BACKGROUND

The morphological evaluation of tumor-infiltrating lymphocytes (TILs) in breast cancer (BC) is gaining momentum as evidence strengthens for the clinical relevance of this immunological biomarker. Accumulating evidence suggests that the extent of lymphocytic infiltration in tumor tissue can be assessed as a major parameter by evaluation of hematoxylin and eosin (H&E)-stained tumor sections. TILs have been shown to provide prognostic and potentially predictive value, particularly in triple-negative and human epidermal growth factor receptor 2-overexpressing BC.

DESIGN

A standardized methodology for evaluating TILs is now needed as a prerequisite for integrating this parameter in standard histopathological practice, in a research setting as well as in clinical trials. This article reviews current data on the clinical validity and utility of TILs in BC in an effort to foster better knowledge and insight in this rapidly evolving field, and to develop a standardized methodology for visual assessment on H&E sections, acknowledging the future potential of molecular/multiplexed approaches.

CONCLUSIONS

The methodology provided is sufficiently detailed to offer a uniformly applied, pragmatic starting point and improve consistency and reproducibility in the measurement of TILs for future studies.

EGFR expression is associated with decreased benefit from trastuzumab in the NCCTG N9831 (Alliance) trial

BACKGROUND

Epidermal growth factor receptor (EGFR) has been hypothesised to modulate the effectiveness of anti-HER2 therapy. We used a standardised, quantitative immunofluorescence assay and a novel EGFR antibody to evaluate the correlation between EGFR expression and clinical outcome in the North Central Cancer Treatment Group (NCCTG) N9831 trial.

METHODS

Tissue microarrays were constructed that allowed analysis of 1365 patients randomly assigned to receive chemotherapy alone (Arm A), sequential trastuzumab after chemotherapy (Arm B) and chemotherapy with concurrent trastuzumab (Arm C). Measurement of EGFR was performed using the EGFR antibody, D38B1, on the fluorescence-based AQUA platform. The result was validated using an independent retrospective metastatic breast cancer cohort (n=130).

RESULTS

Epidermal growth factor receptor assessed as a continuous (logarithmic transformed) variable shows an association with disease-free survival in Arm C (P=0.009) but not in Arm A or B. High EGFR expression was associated with worse outcome (Hazard ratio (HR)=2.15; 95% CI 1.28-3.60, P=0.004). Validation in a Greek metastatic breast cancer cohort showed an HR associated with high EGFR expression of 1.92 (P=0.0073).

CONCLUSIONS

High expression of EGFR appears to be associated with decreased benefit from adjuvant concurrent trastuzumab. Since other treatment options exist for HER2-driven tumours, further validation of these data may select patients for alternative or additive therapy.

Induction cetuximab, paclitaxel, and carboplatin followed by chemoradiation with cetuximab, paclitaxel, and carboplatin for stage III/IV head and neck squamous cancer: a phase II ECOG-ACRIN trial (E2303)

BACKGROUND

E2303 evaluated cetuximab, paclitaxel, and carboplatin used as induction therapy and concomitant with radiation therapy in patients with stage III/IV head and neck squamous cell carcinoma (HNSCC) determining pathologic complete response (CR), event-free survival (EFS), and toxicity.

PATIENTS AND METHODS

Patients with resectable stage III/IV HNSCC underwent induction therapy with planned primary site restaging biopsies (at week 8 in clinical complete responders and at week 14 if disease persisted). Chemoradiation (CRT) began week 9. If week 14 biopsy was negative, patients completed CRT (68-72 Gy); otherwise, resection was carried out. p16 protein expression status was correlated with response/survival.

RESULTS

Seventy-four patients were enrolled; 63 were eligible. Forty-four (70%) were free of surgery to the primary site, progression, and death 1-year post-treatment. Following induction, 41 (23 CR) underwent week 8 primary site biopsy and 24 (59%) had no tumor (pathologic CR). Week 14 biopsy during chemoradiation (50 Gy) in 34 (15 previously positive biopsy; 19 no prior biopsy) was negative in 33. Thus 90% of eligible patients completed CRT. Overall survival and EFS were 78% and 55% at 3 years, respectively. Disease progression in 23 patients (37%) was local only in 10 (16%), regional in 5 (8%), local and regional in 2 (3%), and distant in 5 patients (8%). There were no treatment-related deaths. Toxicity was primarily hematologic or radiation-related. p16 AQUA score was not associated with response/survival.

CONCLUSIONS

Induction cetuximab, paclitaxel, and carboplatin followed by the same drug CRT is safe and induces high primary site response and promising survival.

CLINICAL TRIALS NUMBER

NCT 00089297.

Abstract P1-08-09: EGFR expression is associated with decreased response from HER2 targeted therapeutics in the neo-adjuvant setting in the NeoALTTO trial

Background: Epidermal Growth Factor Receptor (EGFR, HER1) is known to heterodimerize with HER2 and may modulate the effectiveness of trastuzumab or lapatinib. Historically, it has been difficult to measure, but recently we reported a new, standardized, quantitative immunofluorescence assay and a novel EGFR antibody which showed that high levels of EGFR were associated with decreased benefit in the concurrent arm of the North Central Cancer Treatment Group (NCCTG/Alliance) N9831 trial (Rimm et al, SABCS 2012). Here we assess its value in the neo-adjuvant setting in the NeoALTTO trial.

Methods: NeoALTTO randomized 455 breast cancer patients to neoadjuvant trastuzumab, lapatinib or both and showed benefit in both single anti-HER2 therapy arms, and the combination therapy showing about twice as much benefit as either single drug arm. We used the previously described AQUA method of quantitative immunofluorescence to measure EGFR levels using the D38B1 antibody on between 4 and 140 fields of view per slide on 353 specimens. The averaged EGFR score was standardized to the absolute concentration using cell lines and western blots and the 13 ng/ug total protein established in the N9831 trial was tested to determine predictive value for pathological complete response (pCR) defined as ypT0/is.

Results: In NeoALTTO, 19% of the patients had EGFR levels above 13 ng/ug, compared to 16% in NCCTG N9831. The pCR rate was 35.3% in the patients with low EGFR, compared with 29.8% for high EGFR but this difference was not statistically significant. However, when adjusted for treatment and hormone receptor (HR) status, high EGFR is statistically significantly associated with lower response rate(p = 0.038). Continuous analysis measures were not significant. The effect on overall response at 6 weeks was also weakly significant when adjusting for treatment and HR status (p = 0.06). Surprisingly, for HR negative patients in the lapatinib only arm, the pCR rate in the low EGFR group was 47.2% compared with 16.0% in the high group. While this difference is statistically significant (p = 0.014), it should be interpreted cautiously because of the small numbers of patients and the multiple tests performed.

Conclusions: High expression of EGFR by the AQUA platform appears to be associated with decreased pCR rate from HER2 targeted therapy in the neoadjuvant setting. This observation is consistent with NCCTG N9831. Although underpowered, high EGFR levels predicted decreased pCR rate from lapatinib, the opposite of that anticipated for this small molecule dual EGFR/HER2 inhibitor. Further studies are required to determine the clinical utility of this assay and the biological mechanisms underlying these observations.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-09.

Abstract P2-10-02: PD-L1 protein expression is a prognostic biomarker in breast cancer

BACKGROUND: Programmed death ligand 1 (PD-L1) and its receptor, PD1, are involved in limiting immune response. In the context of cancer, tumor cells expressing PD-L1 can suppress the immune response of PD1-expressing tumor infiltrating lymphocytes (TILs). Disruption of this pathway with antibodies to either the ligand or the receptor has shown promise in the treatment of non small cell lung cancer, melanoma and renal cell cancer. Here we investigate the pathway in breast cancer.

METHODS: PD-L1 protein expression was assessed on two Yale TMA breast cancer cohorts with two-fold redundancy by quantitative immunofluorescence (QIF) using AQUA technology. Cohort 1 (YTMA201) consists of 400 patients with has extensive follow-up and adjuvant treatment information. Cohort 2 (YTMA128) consists of 245 patients with limited follow-up and no treatment information. The PD-L1 antibody (Lieping Chen, clone 5H1) has been previously validated for specificity and reproducibility using transfected cell models. TILs were assessed by a pathologist for each cohort using a score from 0-3 based on the amount of TILs within the spot. AQUA scores for PD-L1 were used as a continuous variable and also cut at the median for outcome analysis.

RESULTS: PD-L1 protein is positively correlated with TILs (p&lt;0.0001 on cohort 1 and p = 0.0072 on cohort 2) and inversely correlated with estrogen receptor status (p&lt;0.0001 on cohort 1 and p = 0.0188 on cohort 2) on both breast cancer cohorts examined (total n = 594). On cohort 1, PD-L1 protein expression is a marker of good prognosis as a continuous variable (p = 0.0271) as well as when cut at the median (p = 0.0151), particularly in the estrogen receptor positive subset of patients.

CONCLUSIONS: PD-L1 expression in breast cancer is positively associated with TILs and inversely associated with estrogen receptor status on two independent breast cancer cohorts. PD-L1 protein expression shows prognostic value in breast cancer patients, particularly the ER positive subset of patients. Further assessment of PD-1 axis marker expression may be valuable as the associated therapeutics are being tested in breast cancer patients.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-10-02.

Pin1 modulates ERα levels in breast cancer through inhibition of phosphorylation-dependent ubiquitination and degradation

Estrogen receptor-alpha (ERα) is an important biomarker used to classify and direct therapy decisions in breast cancer (BC). Both ERα protein and its transcript, ESR1, are used to predict response to tamoxifen therapy, yet certain tumors have discordant levels of ERα protein and ESR1, which is currently unexplained. Cellular ERα protein levels can be controlled post-translationally by the ubiquitin-proteasome pathway through a mechanism that depends on phosphorylation at residue S118. Phospho-S118 (pS118-ERα) is a substrate for the peptidyl prolyl isomerase, Pin1, which mediates cis-trans isomerization of the pS118-P119 bond to enhance ERα transcriptional function. Here, we demonstrate that Pin1 can increase ERα protein without affecting ESR1 transcript levels by inhibiting proteasome-dependent receptor degradation. Pin1 disrupts ERα ubiquitination by interfering with receptor interactions with the E3 ligase, E6AP, which also is shown to bind pS118-ERα. Quantitative in situ assessments of ERα protein, ESR1, and Pin1 in human tumors from a retrospective cohort show that Pin1 levels correlate with ERα protein but not to ESR1 levels. These data show that ERα protein is post-translationally regulated by Pin1 in a proportion of breast carcinomas. As Pin1 impacts both ERα protein levels and transactivation function, these data implicate Pin1 as a potential surrogate marker for predicting outcome of ERα-positive BC.

Molecular profile of head and neck squamous cell carcinomas bearing p16 high phenotype

BACKGROUND

We sought to determine biomarker expression differences in head and neck squamous cell cancers (HNSCCs) based on p16/human papillomavirus (HPV) classification. In addition, our aim was to explore how expression of biomarkers is modulated after E6/E7 repression in HPV16⁺ oropharyngeal cancer cells.

METHODS

HPV16⁺ and HPV⁻ HNSCC cells were infected with retroviruses expressing short hairpin RNA targeting HPV16 E6/E7. Components of the epidermal growth factor receptor (EGFR) pathway before and after E6/E7 gene silencing were analyzed by immunoblotting and qRT-PCR. Protein expression of 13 biomarkers was analyzed using AQUA on a tissue microarray (TMA). The HPV16 status was determined using HPV16 in situ hybridization (ISH).

RESULTS

In HPV16⁺ cells, E6/E7 silencing was associated with PTEN upregulation and reduction of phosphorylated EGFR. Tumors were classified into four categories based on the HPV and p16 status. HPV⁺/p16⁺ tumors expressed significantly higher levels of E-cadherin (P = 0.003), PTEN (P = 0.004), lower levels of PI3Kp110 and β-catenin (P = 0.07). There was a significant difference in overall survival (OS, P = 0.016) among the four subsets. The median OS was 24.83 months for p16⁻/HPV⁻ patients, 11.63 for p16⁻/HPV⁺ patients and was not reached for p16⁺/HPV⁻ and p16⁺/HPV⁺ groups.

CONCLUSIONS

Aberrant EGFR signaling contributes to malignant conversion of HPV16⁺ HNSCC cells. These results validate β-catenin as a distinct biomarker in HPV⁺/p16⁺ HNSCC. Wnt signaling inhibitors merit exploration in HPV⁺/p16⁺ HNSCC.

Abstract P3-14-01: Molecular definition of the transition of ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC)

Background: Ductal carcinoma in situ (DCIS) is thought to be a precursor lesion to invasive ductal carcinoma and sometimes occurs in combination with invasive disease. However, the majority of DCIS lesions do not progress to invasive disease. To date no molecular markers have been identified that associate with the potential for development to invasive disease. Our work has sought to identify molecular markers that can be used to determine the likelihood of DCIS being associated with invasive disease. Identification of such markers could be of direct therapeutic benefit, since patients with a high likelihood of associated or subsequent invasive disease could be managed more aggressively.

Methods: We have compiled matched pairs, consisting of patients that have recurred with DCIS, compared to those who have DCIS plus invasive disease. Laser-capture microdissection was used to isolate in situ and invasive components of the latter, and in situ components of the former. We analyzed these samples by parallel cDNA-mediated Annealing, Selection, Extension, and Ligation (DASL) analysis of transcription, and DNA copy number analysis by resequencing. In addition, exome capture deep re-sequencing has been conducted on multiple cored in situ versus invasive components of DCIS from the same tumor sample.

Results: Gene expression analysis revealed candidate genes that were specific to DCIS and others that were expressed only in the adjacent invasive component of the tissue. These genes are currently being evaluated to identify interesting candidates. Additionally, we characterized the gene expression signatures from tumors that recurred as DCIS only, to the DCIS component of those tumors that recurred with adjacent invasive disease. We identified genes that were differentially expressed between these data sets.

The DNA copy number analysis of laser-captured samples indicated a single dominant clone in each DCIS. In contrast to previously reported observations, the profiles of invasive versus non-invasive lesions differ significantly from one another. Observations of non-invasive versus invasive components of adjacent disease in two of the pairs indicate that the profile of the invasive lesions differ from that of the non-invasive component, however the profiles share many individual features.

Discussion: Our data identify differences between in situ and neighboring invasive tumor that may mark features associated with progression. Integration of the copy number and transcription profiling datasets will reveal the extent to which genomic alterations drive changes in gene expression. Identification of markers that distinguish indolent and aggressive subsets of DCIS that can be used to predict an association with invasive disease has the potential for near term clinical utility and may identify therapeutic targets for aggressive DCIS.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-14-01.

Abstract PD02-01: Her2 expression measured by AQUA analysis on BCIRG-005 and BCIRG-006 predicts the benefit of Herceptin therapy

Introduction: There have been disparate results reported in breast cancer testing for HER2 assessment as measured by protein expression or DNA amplification, yet both tests are routinely used to prescribe the drug Herceptin (trastuzumab, Genentech, So San Francisco, CA). Typically, immunohistochemistry (IHC) staining intensity of 3+ or FISH copy ratio of ≥2.0 are used to establish the cutoff between a negative and a positive result. However, it is unclear whether positivity is correlated with differential response to therapy. We used Automated Quantitative Analysis (AQUA) and a fluorescent immunohistochemical assay to measure HER2 expression in cases scored by central laboratory FISH and also receiving Herceptin therapy. The intentions of the study were two-fold: first, to provide further validation of the AQUA technology as applied to the clinical measurement of HER2 expression in breast cancer and second, to examine the potential of drug response stratification within those patients that are considered positive.

Methods: AQUA fluorescence IHC staining was performed on a multi-cohort tissue microarray (TMA) set. The assay was constructed in the Genoptix CLIA laboratory per ASCO/CAP guidelines and with a cutpoint that was validated against IHC (with FISH reflex). The trial specimens tested were from the BCIRG-005/006 studies. BCIRG-005 had n=1544 cases all assessed as FISH- while the 006 cohort had n=1477 cases all assessed as FISH+. Disease free survival (DFS) was used as the variable in subsequent modeling and analysis.

Results: The BCIRG 005 and 006 cohorts, examined in aggregate, allowed for an initial examination of agreement relationships between HER2 levels as assessed by AQUA scoring and HER2 levels as assessed by central lab FISH. Results indicated a 77% negative agreement, a 97% positive agreement and an 87% overall concordance agreement for a total of n=3021 cases. Additional Cox modeling of the patients that were enrolled as FISH+ and stratified for those who did or did not receive Herceptin treatment demonstrated a significant overall hazard ratio (HR = 0.75, CI=0.60,0.93) and when stratified for response to Herceptin, cases determined to be positive by AQUA showed significant benefit from treatment (HR = 0.66, CI = 0.52,0.85) in contrast to those who were scored as negative by AQUA that did demonstrate benefit from therapy (HR = 1.19, CI=0.71,1.97).

Conclusions: Analysis of the cases in this study originally determined to be HER2+ by FISH indicates that AQUA may improve predictions of which patients will benefit from Herceptin therapy.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD02-01.

Association between the nuclear to cytoplasmic ratio of p27 and the efficacy of adjuvant polychemotherapy in early breast cancer

BACKGROUND

The purpose of this study was to evaluate the prognostic and predictive value of p27 expression in patients with early breast cancer.

PATIENTS AND METHODS

Quantitative immunofluorescence assays for p27 were done on a tissue microarray that included 823 samples from patients randomized between anthracycline-based chemotherapy and no chemotherapy. Quantification of p27 was done using the AQUA® system (HistoRx, Inc., Branford, CT). Both p27 nuclear expression and the nuclear to cytoplasmic ratio were assessed.

RESULTS

Nuclear p27 expression was not predictive for the efficacy of anthracycline-based chemotherapy [adjusted P=0.18 for disease-free survival (DFS)] nor prognostic [95% confidence interval (CI) 0.99-1.01, P=0.49]. However, p27 nuclear/cytoplasmic ratio was predictive for the efficacy of adjuvant chemotherapy (adjusted P=0.016 DFS). The adjusted hazard ratio (HR) for relapse associated with adjuvant chemotherapy was 0.56 (95% CI 0.37-0.84, P=0.005) and 1.06 (95% CI 0.76-1.47, P=0.74) for patients with high and low nuclear/cytoplasmic ratio, respectively. p27 N/C ratio was prognostic in patients treated with chemotherapy (HR for relapse or death for a 1 unit increase in p27 N/C ratio was 0.30, 95% CI 0.12-0.77) but not in the untreated arm (HR for relapse or death was 1.27, 95% CI 0.58-2.8).

CONCLUSIONS

This study did not confirm the role of p27 nuclear expression as a prognostic parameter. However, the p27 nuclear/cytoplasmic ratio was predictive in patients treated with anthracycline-based chemotherapy.

P1-06-24: Nuclear Localization of Stat5a Predicts Response to Antiestrogen Therapy and Prognosis of Clinical Breast Cancer Outcome

Nuclear-localized and tyrosine-phosphorylated Stat5 has been reported as a favorable prognostic marker and predictor of response to antiestrogen therapy in breast cancer. Phospho-Stat5 antibodies do not distinguish between phosphorylated Stat5a and the closely related Stat5b, but Stat5a is considered more critical for normal mammary development than Stat5b. The purpose of this study was to determine whether levels of nuclear-localized Stat5a protein (Nuc-Stat5a) were prognostic of clinical outcome or predictive of antiestrogen response. Stat5a was detected by traditional diaminobenzidine-chromogen immunohistochemistry (IHC) and pathologist scoring or by quantitative immunofluorescence in five archival cohorts of breast cancer. Levels of nuclear-localized Stat5a (Nuc-Stat5a) were evaluated by pathologist scoring of whole tissue sections detected by IHC or automated quantitative analysis (AQUA) of immunofluorescently-labeled tissue microarrays. Levels of Nuc-Stat5a were reduced in invasive breast cancer tissues and lymph node metastases compared to normal tissue and ductal carcinoma in situ when quantified by AQUA (Material I; n=180). Tissues from patients not treated with adjuvant therapy or treated with antiestrogen monotherapy were analyzed according to Nuc-Stat5a status for breast cancer-specific survival (CSS) and time to recurrence (TTR) using univariate and multivariate statistical models, adjusting for clinical features including tumor grade, size, lymph node and ER, PR and Her2 status. In two prognostic cohorts of node-negative breast cancer patients, low expression of Nuc-Stat5a, detected by standard IHC (Material II; n=223) or quantitative analysis (Material III; n=198), was prognostic of poor breast cancer outcome as measured by univariate and multivariate CSS (Material II/III) and TTR (Material II). CSS and TTR analysis of two independent materials of tumors from patients treated with antiestrogen monotherapy and analyzed by standard IHC (Material IV; n=73) or quantitative immunofluorescence (Material V; n=97) indicated that patients whose tumors expressed low levels of Nuc-Stat5a were at a greater than 4-fold risk of antiestrogen therapy failure when adjusted for hormone receptor status and clinical features (multivariate CSS: Material IV HR=4.3 (1.2,15.6), p=0.03; Material V HR=5.0 (1.87,13.06), p=0.001). In conclusion, loss of Nuc-Stat5a is a promising independent marker of poor breast cancer prognosis in node-negative, non-adjuvant treated breast cancer patients. Additionally, Nuc-Stat5a may be a useful clinical tool to predict tumor response to antiestrogen therapy.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-06-24.

PD05-03: Impact of Quantitative Measurement of HER2, HER3, HER4, EGFR, ER and PTEN Protein Expression on Benefit to Adjuvant Trastuzumab in Early-Stage HER2+ Breast Cancer Patients in NCCTG N9831

Background: Prediction of benefit from trastuzumab in patients (pts) with HER2+ breast cancer remains an important goal. We sought to investigate the predictive value of quantitative measurement of HER2, HER3, HER4, EGFR, ER and PTEN protein expression on the benefit of trastuzumab in the phase III HER2+ adjuvant N9831 study for pts randomized to chemotherapy alone (Arm A) or chemotherapy with sequential (Arm B) or concurrent trastuzumab (Arm C).

Methods: For each marker, we evaluated quantitative expression, relationship with demographic data, and association with disease-free survival (DFS) of pts. Freshly cut tissue microarray slides with up to three-fold redundancy per specimen from the N9831 cohort were treated identically using the AQUA (Camp, et al; Nat Med 2002, JCO 2008) method of quantitative immunofluorescence for each marker. HER2 was tested with CB11 (mouse monoclonal, Biocare, Inc.) and preliminary results were available for 698 of nearly 1400 pt specimens to be tested. The minimum value per pt was used in statistical analysis. Specimens were classified with high versus low expression based on a median value cutpoint for each marker. Median follow-up was 7.0 yrs.

Results: Quantitative HER2 was compared with centrally performed HER2 testing by IHC and FISH. Median quantitative HER2 via AQUA was 10,017 units for the HER2 IHC 3+ group (n=607) versus 1058, 831, and 970 for the HER2 IHC 2+ (n=68), 1+ (n=11), and 0 (n=11) groups, respectively. The Spearman correlation between quantitative HER2 and FISH HER2/CEP17 ratio was 0.32 (p&lt;0.001). High quantitative HER2 was associated with lower percentage of hormone receptor positivity (48% vs 59%, chi-sq p=0.003) but not associated with age, race, nodal positivity, tumor histology, grade, or size. High HER2 did not impact DFS in any arm of the study (See Table). Data for additional HER2 testing, HER3, HER4, EGFR, ER and PTEN are in process and will be ready by September, 2011.

Conclusions: Similar to results based on standard HER2 testing by IHC and FISH in N9831, quantitative HER2 did not impact benefit from adjuvant trastuzumab. Results for additional markers will be presented. Our complete quantitative results for a second epitope on HER2, HER3, HER4, ER and EGFR will be the first report of these markers in a large patient cohort in the adjuvant setting.

Disease Free Survival

P1-07-03: Preanalytical Variables Affect Protein Expression in Formalin Fixed Paraffin Embedded Tissue – Assessment of Intrinsic Controls To Define Tissue Quality for Immunohistochemical Analysis

Background: Recently it has been shown that biospecimen handling and pre-analytical variables can dramatically affect biomarker assays of protein expression in tumor tissue. Phospho-proteins and even labile unmodified proteins have been suggested to show significant loss of expression due to prolonged time to formalin fixation. Here we assess 4 clinically relevant proteins (ER, PR, HER2 and Ki67) and 20 other proteins for changes as a function to the key preanalytic variables of ischemic time. The ultimate goal of our effort is to find a method to monitor the degradative effect of these variables by construction of a Tissue Quality Index (TQI).

Materials and Methods: Two different breast cancer cohorts were used in order to analyze the biomarkers and their change according to time to formalin fixation. The first cohort consists of 93 breast cancer specimens in 2 fold redundancy on a TMA with cell lines and controls. The time to formalin fixation for each breast cancer specimen was recorded and ranges from 25 to 415 minutes. The second cohort consists of 25 matched pairs of breast cancer biopsies and resections. The time to formalin fixation for the biopsies is minimal while the time to fixation for the resections, though not recorded, averages between 1 and 3 hours. Protein expression was measured using the AQUA method of quantitative immunofluorescence.

Results: ER alpha, PR, HER2 and Ki67 were each analyzed on the time to fixation array with 2 different antibodies commonly used in the clinical setting. Correlation of AQUA scores of these markers with time to formalin fixation revealed a trend towards loss of protein expression as a linear function of time to fixation without reaching statistical significance. Analysis of these 4 proteins on the matched pairs of biopsies and resections showed that tumor heterogeneity predominated over the effects of ischemic time. Toward identification of markers for a TQI, 20 biomarkers were analyzed on the time to fixation array. Both HIF1alpha and AKAP13 show a significant increase as a function of time to fixation, whereas pMAPK, histone 4 and pTyrosine 4G10 revealed a significant loss of expression. These trends were confirmed in the matched pair validation set with the execption of histone 4. A TQI is being built from these variables.

Conclusions: Ischemic time is a critical pre-analytical variable that impacts measurement of protein expression in tumor tissue. The 4 standard markers used clinically in breast cancer appear to show only moderate effects that appear less critical to measurement accuracy than the issue of tumor heterogeneity. We identified 4 proteins which show a significant change with increasing time to formalin fixation and should allow construction of a TQI for assessment of pre-analytic antigenic degradation.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-07-03.

PD05-04: Quantitative Measurement of Antigen Degradation in NCCTG N9831 Tissue Microarrays

Background: Unstained recuts from formalin-fixed paraffin-embedded tissues are commonly collected for cooperative group studies. There is concern among pathologists that improper storage conditions can lead to antigen degradation. In an effort to quantify this effect, we compared the expression of HER1 and HER2 on two sets of identical cohort tissue microarrays (TMAs) from the N9831 HER2+ adjuvant phase III trial (NCT00005970; www.clinicaltrials.gov); one freshly cut set (cut April 18, 2011) and a second set stored at 4 degrees for over two years (cut between Nov, 2007 and Jan, 2008).

Methods: The two sets of TMA slides containing 1580 tumor samples from the N9831 cohort were treated identically using the AQUA method of quantitative immunofluorescence. HER1 was tested with D38B1 (rabbit monoclonal, Cell Signaling Technology, Inc.) and HER2 with CB11 (mouse monoclonal, Biocare, Inc.) on tumors from 695 patients (712 specimens) in the fresh TMAs and 779 patients (800 specimens) in the old TMAs in up to three-fold redundancy per specimen.

Results: Frequency distributions of the expression of HER2 revealed bimodality in the fresh TMAs compared to an attenuated distribution of the old cases. The average score of the entire cohort was significantly lower in old TMAs compared to fresh cuts (paired t-test, p&lt;0.0001). Linear regression of the average HER2 scores from new TMAs versus the average scores from old TMAs showed a slope term of 0.52, which is statistically significantly different from the hypothetical value of 1 (p&lt;0.0001). Regressions between any two fresh slides showed slopes close to 1.0. Similar results were seen for HER1, but fewer positive cases made the changes less dramatic.

Conclusions: The storage condition of tissue slides is a critical pre-analytical variable that can dramatically lower the score of HER1 and HER2, artificially. Thus, studies done on inadequately stored slides, either whole sections or TMAs, must be interpreted with caution. Tissue collection and analysis of biomarkers for cooperative group studies should not include unstained recuts, but rather, entire blocks or large cores from tissue blocks.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD05-04.

Abstract PD10-09: Causes for False-Negative Estrogen Receptor (ER) Classification in Breast Cancer

Background. Determination of Estrogen Receptor (ER) status by standard immunohistochemistry (IHC) methods is subject to variation from pre-analytic factors as well as subjectivity in measurement and interpretation. Studies have estimated a 10-20% false-negative rate in current U.S. clinical practice, suggesting significant potential under-treatment. In efforts to standardize the assay and reduce this false-negative rate, new ASCO/CAP guidelines have recently been issued, which decreased the threshold for ER positivity from 10% of nuclei “positive", to 1%. However, these guidelines fail to define what threshold of staining intensity should be considered a “positive” nuclei, and instead they use the phrase “of any intensity”. Here, we address the issue of the intensity of an IHC stain, and attempt to show that the threshold for positivity is variable, and is a cause for false-negative ER classification.

Methods. Quantitative Immunofluorescence (QIF) using the AQUA method was performed on an Index tissue microarray (TMA) that contains 31 patient controls spanning the range of ER expression (including a number of patients with subtle levels of ER clustered around the threshold for detection) and a series of cell lines. Using recombinant ER protein, and a series of conversions from western blots to cell lines to TMAs, we defined a threshold of detection at 2pg/µg total protein. We then analyzed the Index TMA on a case-by-case basis, comparing QIF to IHC done by routine protocol in two labs at Yale University (Research Histology and the CLIA-certified lab), as well as an Index TMA stained with standard methods but with omission of the hematoxylin counterstain. We also performed a similar analysis (QIF vs. IHC) for a large retrospective Yale cohort (YTMA 49) in order to further compare the variability in threshold for positivity.

Results. We found 19 of 31 patients in the Index TMA to be ER positive by QIF. The first 3 of these 19 (lowest amounts of ER just above the threshold), appeared negative by IHC performed in both Yale laboratories. However, when IHC was performed without hematoxylin counterstain, the low levels of ER were visible above background in all 3 cases. Furthermore, when this series was examined in stains from different labs, the threshold for positivity (above the hematoxylin stain) varied. Preliminary assessment of the large cohort suggests a similar result, that is 1) the threshold for positivity is obscured by hematoxylin and 2) the threshold for positivity varies as a function of the lab in which the array was stained. Conclusions. Using an Index TMA, we have found that subtle levels of ER are detectable by QIF, but not by routine IHC tests (DAB staining). Our data suggests that between 5 and 20 percent of cases may be misclassified due to low levels of ER obscured by the hematoxylin counterstain. Furthermore, the extent of this problem is variable between labs. Studies are underway to define the role of heterogeneity versus intensity, and to determine the predictive implications of ER expression near the threshold.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD10-09.

Abstract P3-10-16: Quantitative Subtractive Immunofluorescence To Develop a Surrogate for Mena Inv(asive) Isoform Is Associated with Poor Outcome in Breast Cancer

Introduction:

Previous work has shown that the inv isoform of Mena, an actin binding protein, is associated with invasion at the cellular level and metastasis in the context of the microenvironment in both animal models and humans (Robinson, B.D. et al. Clin Cancer Res 15, 2433-2441 (2009). However, the prognostic value for metastasis of MenaINV itself is unknown because there is no antibody that directly recognizes this isoform. Here we describe a method to assess a surrogate for MenaINV by measuring total Mena and subtracting the levels of the 11a (non-invasive) isoform. Method: Total Mena and Mena11a were measured in two independent retrospective breast cancer cohorts with 20 year follow-up using tissue microarray and quantitative immunofluorescence (AQUA) technology in a previously described multiplexed mode. AQUA scores for each marker were converted into z scores followed by subtraction of Mena 11a (noninvasive form of Mena) from total Mena (invasive and non-invasive) = Mena(inv) surrogate. This was calculated for each patient and correlated with clinical and pathological characteristics as well as disease-free survival in both cohorts.

Results: In the older Yale cohort, Kaplan Meier analysis dividing the Mena(inv) surrogate by quartiles suggested collapse of the top three quartiles followed by comparison to the fourth quartile (log rank p= 0.0003, n=501). The 4th quartile was also significant in node positive (log rank p=0.0047, n=267) and estrogen negative (ER) patient subgroups (log rank p=0.0003, n=234). Cox multivariate analysis showed Mena(inv) was independent of age, tumor size, nuclear grade, nodal status, ER, PR, Her2 (HR=0.636, 95% CI=0.47-0.86, p=0.0038, n=420). The newer Yale cohort showed similar results, but that cohort also had data on local vs. distant recurrence. The relative risk of distant recurrence in this cohort is 2.56 (p=0.011) for patients with high Mena (inv) compared to 1.96 (p=0.055) for any recurrence.

Conclusions: High Mena (inv) surrogate shows prognostic value for poor survival in two independent breast cancer cohorts with some suggestion of preferential prognostic value for distant recurrence.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-10-16.