Prevalence and Prognostic Significance of PIK3CA Mutation and CNV Status and Phosphorylated AKT Expression in Patients With Cervical Cancer Treated With Primary Surgery

Currently, there are limited and conflicting reports on the prognostic utility of PIK3CA and associated pathway markers for cervical cancers treated with primary surgical management. Moreover, current studies are lacking complete characterization of adjuvant treatment with RT and/or chemotherapy. We aimed to document the prevalence, clinicopathologic, adjuvant treatment details, and prognostic value of PI3K/AKT pathway mutations and copy number variation and phosphorylated AKT status in patients with cervical cancers treated with primary surgery. A clinicopathologic review was performed on a retrospective cohort of 185 patients with cervical cancer, treated with primary surgery at a single tertiary institution. Next-generation sequencing and digital PCR was used to determine PI3K/AKT pathway mutational status and PIK3CA copy number variation, respectively, and fluorescent immunohistochemistry measured phosphorylated AKT expression. In all, 179 of 185 (96.8%) of tumors were successfully sequenced; 48 (26.8%) were positive for PI3K/AKT pathway mutations-the majority (n=37, 77.1%) PIK3CA mutations. PIK3CA mutation was associated with pathologically positive lymph nodes [12 (32%) vs. 22 (16%); P =0.022] and indication for postoperative chemoradiotherapy [17 (45.9%) vs. 32 (22.5%); P =0.004]. On multivariable analysis, PIK3CA status was not associated with overall survival ( P =0.103) or progression-free survival ( P =0.240) at 5 yrs, nor was PIK3CA copy number variation status. phosphorylated AKT ≤ median significantly predicted for progression-free survival [multivariable hazard ratio 0.39 (0.17-0.89; P =0.025)] but not overall survival ( P =0.087). The correlation of PIK3CA with pathologic positive lymph node status yet lack of association with survival outcomes may be due to the use of adjuvant postoperative therapy. PIK3CA assessment before radical hysterectomy may help identify patients with a higher risk of node-positive disease.

Combining TMEM Doorway Score and MenaCalc Score Improves the Prediction of Distant Recurrence Risk in HR+/HER2- Breast Cancer Patients

PURPOSE

to develop several digital pathology-based machine vision algorithms for combining TMEM and MenaCalc scores and determine if a combination of these biomarkers improves the ability to predict development of distant metastasis over and above that of either biomarker alone.

METHODS

This retrospective study included a subset of 130 patients (65 patients with no recurrence and 65 patients with a recurrence at 5 years) from the Calgary Tamoxifen cohort of breast cancer patients. Patients had confirmed invasive breast cancer and received adjuvant tamoxifen therapy. Of the 130 patients, 86 cases were suitable for analysis in this study. Sequential sections of formalin-fixed paraffin-embedded patient samples were stained for TMEM doorways (immunohistochemistry triple staining) and MenaCalc (immunofluorescence staining). Stained sections were imaged, aligned, and then scored for TMEM doorways and MenaCalc. Different ways of combining TMEM doorway and MenaCalc scores were evaluated and compared to identify the best performing combined marker by using the restricted mean survival time (RMST) difference method.

RESULTS

the best performing combined marker gave an RMST difference of 5.27 years (95% CI: 1.71-8.37), compared to 3.56 years (95% CI: 0.95-6.1) for the associated standalone TMEM doorway analysis and 2.94 years (95% CI: 0.25-5.87) for the associated standalone MenaCalc analysis.

CONCLUSIONS

combining TMEM doorway and MenaCalc scores as a new biomarker improves prognostication over that observed with TMEM doorway or MenaCalc Score alone in this cohort of 86 patients.

Survival in Women with De Novo Metastatic Breast Cancer: A Comparison of Real-World Evidence from a Publicly-Funded Canadian Province and the United States by Insurance Status

Metastatic breast cancer (MBC) patient outcomes may vary according to distinct health care payers and different countries. We compared 291 Alberta (AB), Canada and 9429 US patients < 65 with de novo MBC diagnosed from 2010 through 2014. Data were extracted from the provincial Breast Data Mart and from the National Cancer Institute's SEER program. US patients were divided by insurance status (US privately insured, US Medicaid or US uninsured). Kaplan-Meier and log-rank analyses were used to assess differences in OS and hazard ratios (HR) were estimated using Cox models. Multivariate models were adjusted for age, surgical status, and biomarker profile. No difference in OS was noted between AB and US patients (HR = 0.92 (0.77-1.10), p = 0.365). Median OS was not reached for the US privately insured and AB groups, and was 11 months and 8 months for the US Medicaid and US uninsured groups, respectively. The 3-year OS rates were comparable between US privately insured and AB groups (53.28% (51.95-54.59) and 55.54% (49.49-61.16), respectively). Both groups had improved survival (p < 0.001) relative to the US Medicaid and US uninsured groups [39.32% (37.25-41.37) and 40.53% (36.20-44.81)]. Our study suggests that a universal health care system is not inferior to a private insurance-based model for de novo MBC.

Computational approaches to support comparative analysis of multiparametric tests: Modelling versus Training

Multiparametric assays for risk stratification are widely used in the management of breast cancer, with applications being developed for a number of other cancer settings. Recent data from multiple sources suggests that different tests may provide different risk estimates at the individual patient level. There is an increasing need for robust methods to support cost effective comparisons of test performance in multiple settings. The derivation of similar risk classifications using genes comprising the following multi-parametric tests Oncotype DX^® (Genomic Health.), Prosigna^™ (NanoString Technologies, Inc.), MammaPrint^® (Agendia Inc.) was performed using different computational approaches. Results were compared to the actual test results. Two widely used approaches were applied, firstly computational “modelling” of test results using published algorithms and secondly a “training” approach which used reference results from the commercially supplied tests. We demonstrate the potential for errors to arise when using a “modelling” approach without reference to real world test results. Simultaneously we show that a “training” approach can provide a highly cost-effective solution to the development of real-world comparisons between different multigene signatures. Comparisons between existing multiparametric tests is challenging, and evidence on discordance between tests in risk stratification presents further dilemmas. We present an approach, modelled in breast cancer, which can provide health care providers and researchers with the potential to perform robust and meaningful comparisons between multigene tests in a cost-effective manner. We demonstrate that whilst viable estimates of gene signatures can be derived from modelling approaches, in our study using a training approach allowed a close approximation to true signature results.

PIK3CA mutation and CNV status and post-chemoradiotherapy survival in patients with cervical cancer

PURPOSE

This study aimed to describe the prognostic value of PI3K/AKT pathway mutations in a large cohort of patients with cervical cancer.

EXPERIMENTAL DESIGN

Patients with pre-treatment archival specimens, diagnosed with FIGO stages IB-IVA cervical cancer between 1998 and 2014 and treated with radical, curative intent chemoradiotherapy (CRT) at a single center were identified. Mutational status was determined by next generation sequencing and PIK3CA copy number (CNV) was assessed by digital PCR.

RESULTS

190 patients with available pre-treatment tumor specimens were identified. Median OS and PFS were 57.4 and 46.0 months, respectively. A total of 161 tumors were successfully sequenced; 60 (37.3%) had PI3K/AKT pathway mutations, with 50 (30.1%) having PIK3CA hotspot mutations. PIK3CA CNV gain was noted in 79 (59.2%) of the 154 successfully analyzed. On univariate analysis, PIK3CA mutation was associated with poor OS (HR 1.73; 95% CI: 1.03-2.92; p = .037) but not PFS (HR 1.38; 0.84-2.28; p = .204). Absence of any PI3K/AKT pathway mutation was associated with improved OS (HR 1.68; 1.01-2.81; p = .046) but not PFS (HR 1.50; 0.93-2.43; p = .202). Associations were not maintained when adjusting for clinical factors. On univariate analysis, PIK3CA mutation positive, CNV normal tumors were associated with poorer OS (HR 2.55; 1.18-5.50; p = .017) and trend to worse PFS (HR 1.87; 0.90-3.83; p = .094) when compared to those with CNV gain and wildtype PIK3CA.

CONCLUSIONS

PI3K/AKT pathway mutations are common in cervical cancer. Consideration of PIK3CA mutational status with CNV status may be important in predicting outcome in cervical cancer patients.

Abstract P3-06-10: Temozolomide & vorinostat as a targeted therapy strategy for triple negative breast cancer

Approximately 15% of newly diagnosed breast cancers (BC) are classified as triple negative (TNBC), which have a worse prognosis than hormonal receptor-positive BCs. Standard treatment for TNBC includes cytotoxic chemotherapies that are associated with significant toxicities. Currently the only targeted therapy (PARP inhibition) exists for the 10% of TNBC patients who have germline BRCA mutations. There is an ongoing unmet need for TNBC that may include targeted strategies to improve outcomes.

The alkylating agent temozolomide (TMZ) is an oral chemotherapy drug used in the treatment of glioblastomas. The therapeutic benefit of TMZ largely depends on cells not being able to fully repair the DNA damage it causes. O6-methylguanine-DNA methyltransferase (MGMT) is normally expressed and able to repair damage caused by TMZ; however, MGMT is often silenced by promoter methylation in many tumours (mMGMT), and such tumours show a better response to TMZ than those with unmethylated promoters (uMGMT). MGMT has been shown to be methylated in up to 50% of TNBC, suggesting TMZ may be a targeted treatment option. Additionally, studies in other tumour sites suggest that adding an HDAC inhibitor (HDACi) to TMZ can increase response and early phase trials have shown this combination is well tolerated.

We have previously shown cytotoxicity with TMZ in mMGMT TNBC cell lines and now hypothesize that the addition of HDAC inhibition to TMZ will have synergistic effects. Using in vitro models, we explored the efficacy of Vorinostat (HDACi) alone and in combination with TMZ and/or cisplatin utilizing TNBC cell lines: HTB132 (uMGMT) and HTB26 (mMGMT). Cytotoxicity assays were utilized to determine median effective dose (EC50) for each treatment and then we performed EC50 synergy testing. Percent viability was calculated as the absorbance ratio of treated/untreated cells X 100. The EC50 was then determined by calculating the intercept of the log effect vs log RV dose.

We found that Cisplatin and HDAC inhibition showed similar cytotoxicities in both cell lines. The addition of cisplatin to either TMZ or HDACi increased cytotoxicity compared to either treatment alone in the mMGMT cell line HTB26; however, the addition of cisplatin to TMZ in the uMGMT cell line showed the greatest cytotoxicity. Interestingly, we also saw an increase in cytotoxicity when cells were treated with the combination TMZ and HDACi, regardless of methylation status of the MGMT promotor. Finally, the triple combination therapy did not increase cytotoxicity.

Although HDAC inhibition showed cytotoxicity regardless of methylation status of the MGMT promotor; it was increased by the combination with TMZ in both cell lines evaluated. Further, the addition of cisplatin to TMZ did not improve cytotoxicity in the mMGMT cell line but did increase cytotoxicity in the uMGMT cell line. There appears to be no benefit to triple therapy in either cell line. We are currently evaluating these combinations in a xenograft murine model to provide pre-clinical support for a Phase II funded clinical trial in TNBC patients.

Citation Format: Elizabeth N Kornaga, Ailian Yang, Kathy Gratton, Zhong Qiao Shi, Nancy A Nixon, Gloria Roldan Urgoiti, Don G Morris. Temozolomide & vorinostat as a targeted therapy strategy for triple negative breast cancer [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 P3-06-10.

Identification of Distinct Prognostic Groups: Implications for Patient Selection to Targeted Therapies Among Anti-Endocrine Therapy–Resistant Early Breast Cancers

PURPOSE

Hormone receptor–positive breast cancer remains an ongoing therapeutic challenge, despite optimal anti-endocrine therapies. In this study, we assessed the prognostic ability of genomic signatures to identify patients at risk for recurrence after endocrine therapy. Analysis was performed on the basis of an a priori hypothesis related to molecular pathways, which might predict response to existing targeted therapies.

PATIENTS AND METHODS

A subset of patients from the Tamoxifen Versus Exemestane Adjuvant Multinational trial ( ClinicalTrials.gov identifiers: NCT00279448 and NCT00032136, and NCT00036270) pathology cohort were analyzed to determine the prognostic ability of mutational and copy number aberration biomarkers that represent the cyclin D/cyclin-dependent kinase (CCND/CDK), fibroblast growth factor receptor/fibroblast growth factor (FGFR/FGF), and phosphatidylinositol 3-kinase/protein kinase B (PI3K/ATK) pathways to inform the potential choice of additional therapies to standard endocrine treatment. Copy number analysis and targeted sequencing was performed. Pathways were identified as aberrant if there were copy number aberrations and/or mutations in any of the predetermined pathway genes: CCND1/CCND2/CCND3/CDK4/CDK6, FGFR1/FGFR2/FGFR2/FGFR4, and AKT1/AKT2/PIK3CA/PTEN.

RESULTS

The 390 of 420 samples that passed quality control were analyzed for distant metastasis–free survival between groups. Patients with no changes in the CCND/CDK pathway experienced a better distant metastasis–free survival (hazard ratio, 1.94; 95% CI, 1.45 to 2.61; P < .001) than those who possessed aberrations. In the FGFR/FGF and PI3K/AKT pathways, a similar outcome was observed (hazard ratio, 1.43 [95% CI, 1.07 to 1.92; P = .017] and 1.34 [95% CI, 1.00 to 1.81; P = .053], respectively).

CONCLUSION

We show that aberrations of genes in these pathways are independently linked to a higher risk of relapse after endocrine treatment. Improvement of the clinical management of early breast cancers could be made by identifying those for whom current endocrine therapies are sufficient, thus reducing unnecessary treatment, and secondly, by identifying those who are at high risk for recurrence and linking molecular features that drive these cancers to treatment with targeted therapies.

Abstract P2-08-13: Survival in women with de novo metastatic breast cancer: Comparison of real-world evidence from publicly-funded Canadian province and the United States by insurance status

Background: Access to cancer screening, diagnosis and treatment in the United States (US) is affected by insurance status; whereas, access within a publicly-funded health care system is similar across the whole population. The aim of this study was to compare overall survival (OS) of de novo stage IV (metastatic) breast cancer (BC) pts in a Canadian province and in the US according to insurance status.

Methods: All female pts 18-64 yrs of age diagnosed with de novo stage IV BC from Jan 1, 2010 through Dec 31, 2014 with available biomarker information were included. Pts diagnosed by death certificate or autopsy and pts ≥ 65 yrs were excluded due to unreliable insurance status classification in the US SEER database. The Alberta cohort (AB) was obtained from the Alberta Health Services CancerControl Breast Data Mart (BDM), a repository of information on all pts diagnosed with their first BC diagnosis from Jan 1, 2004 onwards in the province of Alberta, Canada. The U.S. cohort was obtained from the US Surveillance, Epidemiology, and End Results (SEER) program cancer database. A total of 9,604 pts from the SEER database and 294 pts from the BDM were analyzed. OS was evaluated over a 2 yr period and median and 2 yr OS were estimated. Unadjusted associations were compared using the log-rank test, and hazard ratios (HR) were estimated using the Cox proportional hazards model with US insured set as reference group.

Results: Comparison of AB and US cohorts showed no differences based on age group (18-49 vs 50-64), yr of diagnosis or receipt of primary surgery. The AB cohort had a higher incidence of hormone receptor positive (HR+), similar frequency of HER2+, and a lower incidence of triple negative (TN) BC relative to the US cohort: HR+ 60.5% vs 56.4%; HER2+ 30.6% vs 28.8%; and TN 8.8% vs 14.8%, respectively [p=0.017]. The distribution of HR+, HER2+ and TN BC was consistent between the SEER insured, Medicaid and uninsured groups. AB cohort estimated 2 yr OS was 70.1%, similar to the insured group of 66.0% and significantly better than the Medicaid or uninsured pts [53.2% and 50.9%; p&lt;0.0001]. Subgroup analysis based on biomarker status, surgery and age group showed similar results. Adjusting for these variables, AB OS remained similar to the insured group [HR=0.92 (0.74-1.15) p=0.474] with worse OS noted in the Medicaid and uninsured populations [HR=1.44 (1.32-1.56) and HR=1.53 (1.33-1.77) p&lt;0.001, respectively].

 HR+HER2+TNNo SurgerySurgery18-4950-64InsuredReference Group: HR=1.00AB0.92 (0.68-1.24) p=0.5841.15 (0.76-1.72) p=0.5090.84 (0.49-1.42) p=0.5070.91 (0.71-1.17) p=0.4660.71 (0.45-1.11) p=0.1330.84 (0.56-1.27) p=0.4080.87 (0.67-1.12) p=0.284Medicaid1.43 (1.27-1.61) p&lt;0.0011.57 (1.32-1.87) p&lt;0.0011.37 (1.18-1.60) p&lt;0.0011.46 (1.33-1.59) p&lt;0.0011.55 (1.33-1.81) p&lt;0.0011.75 (1.52-2.00) p&lt;0.0011.47 (1.34-1.61) p&lt;0.001Uninsured1.76 (1.44-2.15) p&lt;0.0011.64 (1.20-2.22) p&lt;0.0011.56 (1.20-2.05) p=0.0011.56 (1.34-1.80) p&lt;0.0011.59 (1.16-2.18) p=0.0041.76 (1.35-2.29) p&lt;0.0011.67 (1.43-1.94) p&lt;0.001

Conclusion: OS in women with de novo stage IV BC in AB was similar to US insured. AB and US insured experienced superior OS compared with US Medicaid and uninsured.

Citation Format: Kornaga EN, Matutino AR, Pereira AA, Verma S, Lupichuk S. Survival in women with de novo metastatic breast cancer: Comparison of real-world evidence from publicly-funded Canadian province and the United States by insurance status [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 P2-08-13.

An international multicenter study to evaluate reproducibility of automated scoring for assessment of Ki67 in breast cancer

The nuclear proliferation biomarker Ki67 has potential prognostic, predictive, and monitoring roles in breast cancer. Unacceptable between-laboratory variability has limited its clinical value. The International Ki67 in Breast Cancer Working Group investigated whether Ki67 immunohistochemistry can be analytically validated and standardized across laboratories using automated machine-based scoring. Sets of pre-stained core-cut biopsy sections of 30 breast tumors were circulated to 14 laboratories for scanning and automated assessment of the average and maximum percentage of tumor cells positive for Ki67. Seven unique scanners and 10 software platforms were involved in this study. Pre-specified analyses included evaluation of reproducibility between all laboratories (primary) as well as among those using scanners from a single vendor (secondary). The primary reproducibility metric was intraclass correlation coefficient between laboratories, with success considered to be intraclass correlation coefficient >0.80. Intraclass correlation coefficient for automated average scores across 16 operators was 0.83 (95% credible interval: 0.73-0.91) and intraclass correlation coefficient for maximum scores across 10 operators was 0.63 (95% credible interval: 0.44-0.80). For the laboratories using scanners from a single vendor (8 score sets), intraclass correlation coefficient for average automated scores was 0.89 (95% credible interval: 0.81-0.96), which was similar to the intraclass correlation coefficient of 0.87 (95% credible interval: 0.81-0.93) achieved using these same slides in a prior visual-reading reproducibility study. Automated machine assessment of average Ki67 has the potential to achieve between-laboratory reproducibility similar to that for a rigorously standardized pathologist-based visual assessment of Ki67. The observed intraclass correlation coefficient was worse for maximum compared to average scoring methods, suggesting that maximum score methods may be suboptimal for consistent measurement of proliferation. Automated average scoring methods show promise for assessment of Ki67 scoring, but requires further standardization and subsequent clinical validation.

Low Ki67/high ATM protein expression in malignant tumors predicts favorable prognosis in a retrospective study of early stage hormone receptor positive breast cancer

Introduction

This study was designed to investigate the combined influence of ATM and Ki67 on clinical outcome in early stage hormone receptor positive breast cancer (ES-HPBC), particularly in patients with smaller tumors (< 4 cm) and fewer than four positive lymph nodes.

Methods

532 formalin-fixed paraffin-embedded specimens of resected primary breast tumors were used to construct a tissue microarray. Samples from 297 patients were suitable for final statistical analysis. We detected ATM and Ki67 proteins using fluorescence and brightfield immunohistochemistry respectively, and quantified their expression with digital image analysis. Data on expression levels were subsequently correlated with clinical outcome.

Results

Remarkably, ATM expression was useful to stratify the low Ki67 group into subgroups with better or poorer prognosis. Specifically, in the low Ki67 subgroup defined as having smaller tumors and no positive nodes, patients with high ATM expression showed better outcome than those with low ATM, with estimated survival rates of 96% and 89% respectively at 15 years follow up (p = 0.04). Similarly, low-Ki67 patients with smaller tumors, 1-3 positive nodes and high ATM also had significantly better outcomes than their low ATM counterparts, with estimated survival rates of 88% and 46% respectively (p = 0.03) at 15 years follow up. Multivariable analysis indicated that the combination of high ATM and low Ki67 is prognostic of improved survival, independent of tumor size, grade, and lymph node status (p = 0.02).

Conclusions

These data suggest that the prognostic value of Ki67 can be improved by analyzing ATM expression in ES-HPBC.

Abstract P3-07-08: Temozolomide as a targeted therapy strategy for triple negative breast cancer

BACKGROUND:

Approximately 15% of newly diagnosed breast cancers are classified as triple negative (TNBC). TNBCs are considered more aggressive and have a worse prognosis as no targeted therapies are currently available. These tumors are routinely treated with chemotherapy agents with only modest proven efficacy.

Temozolomide (TMZ) is an oral chemotherapy agent commonly used for the treatment of brain tumors and melanoma. TMZ is an alkylating agent, and its therapeutic benefit depends on its ability to alkylate/methylate DNA, most commonly at the N-7 or O-6 positions of guanine residues. This process leads to DNA damage and subsequently triggers cell death. Cells that express the enzyme O6-Methylguanine-DNA Methyltransferase (MGMT) are able to repair damage caused by TMZ. Tumors that lack expression of MGMT, owing to methylation of the gene promoter, demonstrate a better response to TMZ treatment as a result of synthetic lethality.

It was first reported in 2012 that TNBCs were more likely to be MGMT methylated, which was confirmed by another group that reported up to 64% of wild-type BRCA1 TNBC exhibited MGMT gene methylation. In 2013 it was found that basal-like breast cancers were more likely to be MGMT methylated and linked to larger tumor size. Together these findings suggest that a sub-population of TNBCs lack MGMT expression, due to promoter methylation.

Currently, TMZ is not a treatment option for breast cancers given the modest efficacy of TMZ noted in breast cancer clinical trials; however, most of these trials have focused on using this agent to either treat or prevent brain metastases, due to TMZs ability to cross the blood-brain barrier. Importantly, none of these trials investigated MGMT expression or specifically TNBC populations.

We hypothesize that TMZ may be a viable and efficacious treatment option for TNBCs that lack MGMT expression, due to promoter methylation.

METHODS:

We analyzed 12 archival specimens and 4 TNBC cell lines (HTB132, HTB26, HTB126 and HCC1806) for MGMT expression using a qRT-PCR clinical assay available from Calgary Laboratory Services. Additionally, we also looked at MGMT protein expression in the cell lines using Western Blot analysis to confirm the qRT-PCR results. Finally, we performed an in vitro assay with TNBC cell lines to determine cytotoxicity of TMZ.

RESULTS:

Analysis of the archival specimens found that 33% of samples analyzed had MGMT promoter methylation by qRT-PCR. Additionally, we found that HTB26 and HTB126 cell lines showed MGMT promoter methylation by qRT-pCR analysis. Western Blot analysis confirmed lack of MGMT expression in these two cell lines, and also identified another cell line (HCC1806) lacking MGMT protein that was classified as unmethylated by the qRT-PCR clinical assay. Moreover, our in vitro assay found that two cell lines (HTB26 and HCC1806) showed a noticeable response to treatment with TMZ. Interestingly, HTB126 did not show response to TMZ, suggesting that there may be another putative resistance pathway.

CONCLUSIONS:

Preliminary findings suggest that TMZ may be a viable targeted treatment option for TNBCs. Currently, we are investigating drug response using in vivo mouse models, as well as investigating synergistic combination therapy options.

Citation Format: Kornaga EN, Gratton K, Shi Q, Yang A, Nixon NA, Roldan Urgoiti G, Morris DG. Temozolomide as a targeted therapy strategy for triple negative 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 P3-07-08.

Impact of tumoral carbonic anhydrase IX and Ki-67 expression on survival in oral squamous cell carcinoma patients

Oral squamous cell carcinoma (OSCC) is the most commonly diagnosed type of head and neck cancer, accounting for ~300,000 new cases worldwide annually. Carbonic anhydrase IX (CAIX) and Ki-67 have been associated with reduced disease-specific survival (DSS) in patients with OSCC. We previously proposed a combined CAIX and Ki-67 signature of 'functional hypoxia' and sought to replicate this association in a larger independent cohort of patients with OSCC at the Fred Hutchinson Cancer Research Center (FHCRC) in Seattle. The study population included patients with incident primary OSCC treated at the University of Washington Medical Center and the Harborview Medical Center in Seattle between December 2003 and February 2012. Archived tumor blocks were obtained with tissue samples from 189 patients, and triplicate 0.6 mm cores were assembled into tissue microarrays (TMAs). Fluorescence immunohistochemistry and AQUAnalysis® were used to quantify the expression of tumoral CAIX (tCAIX) and stromal CAIX (sCAIX) and tumoral Ki-67 for each TMA core. Hazard ratios for DSS were calculated using Cox proportional hazards analysis. High tCAIX and sCAIX expression levels were associated with reduced DSS (aHR=1.003, 95% CI:1.00-1.01 and aHR=1.010, 95% CI:1.001-1.019, per AQUA score unit, respectively). Ki-67 expression was not associated with survival (aHR=1.01, 95% CI:0.99-1.02) in the FHCRC cohort. DSS for patients with high sCAIX and low Ki-67 did not differ from that of other patient groups. Elevated tCAIX was associated with reduced DSS as a continuous and as a dichotomized (75%) variable. sCAIX was associated with DSS as a continuous variable but not when dichotomized (75%). However, the previously proposed 'functional hypoxia' signature was not replicated in the current FHCRC study. The failure to replicate our prior observation of poorer survival in patients with combined high sCAIX and low tumoral Ki-67 was likely due to the absence of an association between tumoral Ki-67 and DSS in this cohort. However, the association between DSS and tCAIX and sCAIX supports a role for CAIX in OSCC clinical outcomes.

Anemia, leukocytosis and thrombocytosis as prognostic factors in patients with cervical cancer treated with radical chemoradiotherapy: A retrospective cohort study

Introduction

Anemia has long been associated with poor prognosis in patients with cervical cancer. Recently, additional hematologic parameters have emerged as potential indicators of worse outcome in this patient group. In a cohort of cervical cancer patients treated with chemoradiotherapy (CRT) and brachytherapy, we report on the prognostic significance of hematologic parameters including anemia, leukocytosis, neutrophil to lymphocyte ratio (NLR), and thrombocytosis, the effect of combining anemia with other hematologic parameters, and the effect of changes in hemoglobin levels during treatment.

Materials and methods

Two-hundred fifty-seven cervical cancer patients were retrospectively identified from a single cancer institution’s database. Hematologic parameters were categorized as: anemia (hemoglobin ≤115 g/L), leukocytosis (white blood cell count >10 × 10⁹/L), thrombocytosis (platelets >400 × 10⁹/L), and NLR (ratio >5). The association between clinical factors and hematologic parameters on progression-free survival (PFS) and overall survival (OS) were assessed at 5 years.

Results

At 5 years, both pre-treatment anemia (PFS: 60% vs 34%, p < 0.0001; OS: 68% vs 41%, p < 0.0001) and on-treatment anemia (PFS: 62% vs 40%, p < 0.0001; OS: 70% vs 48%, p < 0.0001) were significantly associated with worse survival. This adverse effect on 5-year PFS and OS was increased in patients with both pre-treatment anemia and leukocytosis (PFS: 72% vs 42%, p < 0.0001; OS: 68% vs 37%, p < 0.0001) and pre-treatment anemia and elevated NLR (PFS: 61% vs 30%, p < 0.0001; OS: 68% vs 37%, p < 0.0001). Five-year PFS (50% vs 31%) and OS (60% vs 36%) was better in patients whose pre-treatment anemia improved to normal hemoglobin levels on treatment vs those patients who were anemic both pre- and on-treatment.

Conclusion

Pre-treatment and on-treatment anemia were significant, independent predictors of worse PFS and OS. Anemia and other hematologic parameters remain prognostic markers for cervical cancer patients. Improvement in PFS and OS was seen in patients with normalization of hemoglobin.

Identification of the SUMO E3 ligase PIAS1 as a potential survival biomarker in breast cancer

Metastasis is the ultimate cause of breast cancer related mortality. Epithelial-mesenchymal transition (EMT) is thought to play a crucial role in the metastatic potential of breast cancer. Growing evidence has implicated the SUMO E3 ligase PIAS1 in the regulation of EMT in mammary epithelial cells and breast cancer metastasis. However, the relevance of PIAS1 in human cancer and mechanisms by which PIAS1 might regulate breast cancer metastasis remain to be elucidated. Using tissue-microarray analysis (TMA), we report that the protein abundance and subcellular localization of PIAS1 correlate with disease specific overall survival of a cohort of breast cancer patients. In mechanistic studies, we find that PIAS1 acts via sumoylation of the transcriptional regulator SnoN to suppress invasive growth of MDA-MB-231 human breast cancer cell-derived organoids. Our studies thus identify the SUMO E3 ligase PIAS1 as a prognostic biomarker in breast cancer, and suggest a potential role for the PIAS1-SnoN sumoylation pathway in controlling breast cancer metastasis.

Expression of PD-L1 and presence of CD8-positive T cells in pre-treatment specimens of locally advanced cervical cancer

Several of the cancer immunotherapies under investigation or in clinical use target the programmed death-ligand 1/programmed death-1 (PD-L1/PD-1) signaling axis. PD-L1 expression in tumor samples has been used as a predictive marker for response to these therapeutics, and may also have independent prognostic utility when assessed along with immune cell markers. Our objectives were to assess the expression of PD-L1 in tumor specimens from a uniformly treated patient cohort with locally advanced cervical cancer, and to determine its prognostic significance along with the density of tumor-infiltrating T cells. We identified 120 patients with locally advanced cervical cancer treated with radical chemoradiotherapy, and built tissue microarrays from their formalin-fixed, paraffin-embedded pre-treatment biopsies. We used conventional brightfield and fluorescence immunohistochemistry to detect PD-L1, and quantified protein expression using both manual pathologist scoring and automated software analysis. We also evaluated the effect of PD-L1 expression in tumors, along with the presence and density of intra-tumoral CD8⁺ T cells, on patient survival outcomes. Approximately 96% of the tumor samples expressed PD-L1, as determined using quantitative software analysis. Neither expression of PD-L1 nor density of CD8⁺ T cells was associated with progression-free or overall survival. However, there was a trend towards worse progression-free survival in patients whose tumors expressed PD-L1 but lacked CD8⁺ T cells (hazard ratio=0.43 (0.18-1.01), P=0.053). Nevertheless, the high percentage of cervical cancer tumor samples expressing PD-L1 suggests that anti-PD-L1 or anti-PD-1 therapies are potential treatment options for this patient population.

Abstract P6-09-20: Clinical utility of PgR with various cutpoints using 3 commercial assays relative to 15yr survival

Introduction:

Hormone receptors ER and PgR are routinely assessed by pathologists using immunohistochemical (IHC) assays to guide treatment decisions. Patients who are hormone receptor positive are offered hormonal therapy, such as tamoxifen, which improves survival. Although both ER and PgR are evaluated, ER is primarily utilized for patient management as the clinical utility of PgR has not been clearly established according to CAP/ASCO guidelines. Notably, a meta-analysis by the Early Breast Cancer Trialists' Collaborative Group reported that PgR status was not significantly predictive of response to adjuvant tamoxifen, suggesting that PgR may not have a role in breast cancer management. More recently, the level of PgR expression has been hypothesized to be important in predicting response to endocrine therapy, where high PgR levels are more indicative of estrogen-dependent tumors, and thus more sensitive to hormonal treatment.

In this study, we evaluate PgR expression using the current cut-point (Allred&gt;2), as well as an optimized cut-point (Allred&gt;5 to identify PgR high tumors), with regards to 15yr disease-free survival (DFS) and disease-specific overall survival (DSOS) using three commercially available ready-to-use (RTU) IHC assays from Dako, Leica and Ventana in an ER+ cohort.

Methods:

The Calgary tamoxifen breast cancer cohort (Calgary cohort) is a TMA series that includes 532 patients diagnosed with primary breast cancer (1985-2000) who received tamoxifen treatment regardless of hormone receptor status. All RTU assays followed vendor recommended protocols. Specific details regarding the cohort and IHC assays have been previously described (Kornaga et al. Mod Path 2016). All analyses were performed using Stata 12, and multivariate models were adjusted for age, grade, size, lymph node and HER2 status. ER status was defined by the corresponding vendor specific IHC assay.

Results:

Multivariate models looking at DFS are presented in Table 1. None of the assays were significant when the clinical cut-point was used; however, when the optimized cut-point was investigated, all assays found high expression of PgR was significantly associated with improved DFS. Table 2 presents the multivariate models looking at DSOS. Similarly, PgR was not found to be associated with improved DSOS using the current cut-point. When the optimized cut-point was examined, Dako and Leica assays were significantly associated with improved DSOS: The Ventana assay did not reach significance.

Table 1 PgR15YR DFS CutpointHR95% CIp-valueDako&gt;20.830.40-1.730.624Dako&gt;50.560.35-0.910.020Leica&gt;21.130.45-2.830.792Leica&gt;50.520.30-0.890.017Ventana&gt;20.730.32-1.670.460Ventana&gt;50.570.34-0.970.037

Table 2 PgR15YR DSOS CutpointHR95% CIp-valueDako&gt;20.740.33-1.650.464Dako&gt;50.550.32-0.950.031Leica&gt;20.880.35-2.220.780Leica&gt;50.440.24-0.790.006Ventana&gt;20.590.25-1.370.218Ventana&gt;50.630.35-1.150.134

Conclusions:

High PgR expression (Allred&gt;5) is associated with improved 15yr DFS and DSOS in a tamoxifen-treated cohort, where PgR positivity defined using current guidelines is not associated with improved DFS or DSOS. Additionally, differences were noted between the vendor RTU assays with regards to DSOS.

Citation Format: Kornaga EN, Paterson AHG, Feng X, Morris DG, Magliocco AM, Klimowicz AC. Clinical utility of PgR with various cutpoints using 3 commercial assays relative to 15yr survival [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 P6-09-20.

Expression of DNA damage response proteins in cervical cancer patients treated with radical chemoradiotherapy

OBJECTIVE

The management of locally advanced cervical cancer has improved significantly with the advent of cisplatin-based chemoradiotherapy (CRT) as the primary treatment regimen. Nevertheless, a significant proportion of patients fail to respond or relapse on this treatment and have a very poor prognosis. Our goal was to determine the prognostic value of a panel of proteins involved in detection and repair of DNA damage.

METHODS

We performed fluorescence immunohistochemistry, and used software analysis to assess expression of DNA damage response proteins ATM, DNA-PKcs, PARP-1, Ku70 and Ku86 in 117 pre-treatment specimens from patients with locally advanced cervical cancer. We compared expression to clinicopathologic correlates to determine prognostic significance.

RESULTS

Five-year progression-free survival was significantly lower in the low expressors than in high expressors of ATM (35% vs. 58%, p=0.044) and PARP-1 (24% vs. 61%, p=0.003), and showed a trend to significance for DNA-PKcs (30% vs. 60%, p=0.050). Low expression of the same proteins also correlated significantly with lower overall survival. In multivariable analysis, adjusted for FIGO stage and tumor size, low ATM and PARP-1 expression was significantly associated with both poorer progression-free and overall survival. Pairwise analyses indicated that expression levels of these proteins were correlated.

CONCLUSIONS

Expression of DNA damage response proteins in cervical cancer is associated with outcome in patients treated with CRT. Immunohistochemical analysis of these proteins may be useful in guiding treatment decisions in such patients.

Significance of Co-expression of Epidermal Growth Factor Receptor and Ki67 on Clinical Outcome in Patients With Anal Cancer Treated With Chemoradiotherapy: An Analysis of NRG Oncology RTOG 9811

PURPOSE

To measure co-expression of EGFR and Ki67 proteins in pretreatment tumor biopsies of anal cancer patients enrolled on NRG Oncology RTOG 9811, a phase III trial comparing 5-fluorouracil/mitomycin-C/radiation therapy (Arm A) versus 5-fluorouracil/cisplatin/radiation therapy (Arm B), and to correlate expression with clinical outcome.

METHODS AND MATERIALS

EGFR and Ki67 co-expression was measured after constructing a tissue microarray using fluorescence immunohistochemistry and automated quantitative image analysis. The Ki67 score within EGFR high versus low areas (Ki67ratio in EGFR_high:low) in each tumor core was analyzed at the median, quartiles, and as a continuous variable. Associations between the tumor markers and clinical endpoints (overall and disease-free survival, locoregional and colostomy failure, and distant metastases) were explored.

RESULTS

A total of 282 pretreatment tumors were analyzed from NRG Oncology RTOG 9811. Of evaluated specimens, 183 (65%, n=89, Arm A; n=94, Arm B) were eligible and analyzable. There were no significant differences in baseline characteristics or outcomes between analyzable and unanalyzable patient cases. Median follow-up was 6.0 years. On multivariate analysis, after adjusting for gender, patients with Ki67ratio in EGFR_high:low ≥median had worse overall survival (hazard ratio 2.41, 95% confidence interval 1.38-4.19, P=.0019). After adjusting for N stage and largest tumor dimension, patients with Ki67ratio in EGFR_high:low ≥ median had a higher risk of a disease-free failure (hazard ratio 1.85, 95% confidence interval 1.18-2.92, P=.0078). Technical validation with an independent anal cancer patient cohort was performed and shows a very similar biomarker score distribution.

CONCLUSIONS

High Ki67ratio in EGFR_high:low is associated with worse clinical outcome in this subset of patients with anal cancer treated with chemoradiation on NRG Oncology RTOG 9811. Evaluation within a clinical trial will be required to determine whether patients with these tumor characteristics may specifically benefit from an EGFR-targeted therapeutic agent.

A systematic comparison of three commercial estrogen receptor assays in a single clinical outcome breast cancer cohort

Breast cancers are routinely assessed for estrogen receptor status using immunohistochemical assays to assist in patient prognosis and clinical management. Specific assays vary between laboratories, and several antibodies have been validated and recommended for clinical use. As numerous factors can influence assay performance, many laboratories have opted for ready-to-use assays using automated stainers to improve reproducibility and consistency. Three commonly used autostainer vendors-Dako, Leica, and Ventana-all offer such estrogen receptor assays; however, they have never been directly compared. Here, we present a systematic comparison of three platform-specific estrogen receptor ready-to-use assays using a retrospective, tamoxifen-treated, breast cancer cohort from patients who were treated in Calgary, Alberta, Canada from 1985 to 2000. We found all assays showed good intra-observer agreement. Inter-observer pathological scoring showed some variability: Ventana had the strongest agreement followed closely by Dako, whereas Leica only showed substantial agreement. We also analyzed each estrogen receptor assay with respect to 5-year disease-free survival, and found that all performed similarly in univariate and multivariate models. Determination of measures of test performance found that the Leica assay had a lower negative predictive value than Dako or Ventana, compared with the original ligand-binding assay, while other measures-sensitivity, specificity, positive predictive value, and accuracy-were comparable between the three ready-to-use assays. When comparing against disease-free survival, the difference in negative predictive value between the vendor assays were not as extreme, but Dako and Ventana still performed slightly better than Leica. Despite some discordance, we found that all ready-to-use assays were comparable with or superior to the ligand-binding assay, endorsing their continued use. Our analysis also allowed for exploration of estrogen receptor-negative, progesterone receptor-positive cases, and we discovered that this phenotype was not consistent across the assays, suggesting this might be an artifact.

Abstract P5-07-07: Fluorescence quantitative image analysis of HER2 evaluation against current clinical HER2 assays in breast cancer testing

BACKGROUND: Presently, therapy for treatment of breast cancer is based on the evaluation of formalin fixed, paraffin embedded (FFPE) pathological specimens using a combination of immunohistochemistry (IHC) and gene copy assessment by in-situ hybridization (-ISH) techniques, following current testing guidelines from the American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP). Patients with specimens found to have marked overexpression and amplification of the human epidermal receptor 2 (HER2) are approved for treatment with trastuzumab. While IHC and –ISH assays represent the current clinical standard, these assays are subject to pre-analytical variation, which could lead to false negative results. There are novel laboratory technologies which may improve the accuracy of HER2 measurements and lead to improved patient selection for therapy.

AIM: In this comparative study, we assessed the utility of testing HER2 expression by the fluorescence IHC using AQUA® - a novel computer assisted platform to enable quantitative assessment of protein expression in FFPE tissue specimens – against current clinical assays (IHC and –ISH).

METHODS: Local cases from 2008-2010 clinically evaluated for HER2 were identified for further pathological review. FFPE tissue specimens were retrieved from a total of 207 cases with sufficient tumor present, and placed into a tissue microarray (TMA). TMA sections underwent assessment for IHC HER2 (Clone 4B5, Ventana), HER2/Chromosome 17 gene copy number (Inform HER2 dual-ISH DNA Probe Cocktail Assay, Ventana), and fluorescence IHC (Clone SP3, Thermo Fisher).

RESULTS: HER2 results were available for 142 patients for IHC, and 134 patients for dual–ISH and fluorescence IHC. A comparison of the current clinical methods revealed 11 discordant cases. The average median fluorescence IHC cytoplasmic HER2 expression (cAQUA) was found to be 225.65, (70.65-419.95). HER2 cAQUA was strongly correlated with dual-ISH, and cases with low level amplification had low cAQUA expression. There were cases having high cAQUA expression that did not show amplification by dual-ISH. Only a few amplfied cases demonstrated low cAQUA expression. Dichotomizing cAQUA at the 256 showed an improvement of the receiver operating characteristic compared to the clinical HER2 IHC assay (cAQUA=0.903, p&lt;0.001; IHC=0.833, p=0.006).

CONCLUSIONS: Measurement of HER2 expression using human interpretation can be imprecise as there is still some discordance between HER2 IHC and dual-ISH assays. Evaluation of HER2 protein expression using the novel AQUA assay showed correlation with IHC and dual-ISH, and AQUA may present a more precise way to quantify HER2 protein expression. HER2 cAQUA used a different antibody clone than the clinical IHC assay; however, previous studies have shown strong correlation between these two antibodies. The AQUA assay may identify a previously unrecognized group of breast cancers with elevated HER2 expression. The significance of this finding requires further investigation, particularly in regards with cAQUA HER2 serving as a marker for response to anti-HER2 therapy.

Citation Format: Kornaga EN, Feng X, Klimowicz AC, Dean ML, Guggisberg N, Morris DG, Magliocco AM. Fluorescence quantitative image analysis of HER2 evaluation against current clinical HER2 assays in breast cancer testing. [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 P5-07-07.

Abstract P5-10-16: Evaluation of RT-qPCR and luminex-based methodolgies in HER2 breast cancer testing

*Co-First Authors

Background: Currently, patients diagnosed with breast carcinoma undergo HER2 testing to direct clinical treatment decisions. At present, immunohistochemical (IHC) and in-situ hybridization methodologies are employed in the clinical setting to ascertain HER2 status. While these tests represent the current standard, their interpretation and variability of results with respect to HER2 prognostic and predictive value remains an outstanding issue.

Aim: In this comparative study we assessed the utility of testing HER2 gene expression by RT-qPCR and the Luminex Quantigene® Plex 2.0 (Affymetrix) methodology against the clinically accepted IHC assay.

Methods: Local cases from 2008-2010 that were clinically evaluated for HER2 were identified and underwent further pathologist review. In cases where there was sufficient tumor, formalin fixed paraffin embedded samples were retrieved. A total of 207 cases were identified which met selection criteria. Tumour sections were stained for HER2 and scored 0-3, following ASCO/CAP guidelines. For molecular assessment total RNA was extracted from tumours and those samples with sufficient RNA yield and quality were assessed for Her2 transcript level expression by RT-qPCR (n=129) and Luminex Quantigene® Plex 2.0 assays (n=166).

Results: Results for RT-qPCR are relative to two normal breast calibrator samples and reported as the mean relative quantification (RQ) value. For HER2 IHC negative cases (0/1+), the mean score was 0.13 (0.004-1.84, SD ±0.22); equivocal cases (2+), mean score was 0.19 (0.007-0.72, SD ±0.18); and positive cases (3+), mean score was 1.51 (0.03-6.78, SD ±1.61). Student’s t-test was performed to compare the means between groups and results are as follows: negative vs. equivocal p=0.17; equivocal vs. positive p=0.0002; and negative vs. positive p&lt;0.0001. Luminex methodology is reported as the normalized mean fluorescence intensity (nMFI) for each group. For HER2 IHC negative cases (0/1+), the mean score was 0.28 (0.01-1.19, SD ±0.23); equivocal cases (2+), mean score was 0.42 (0.10-1.23, SD ±0.27); and positive cases (3+), mean score was 4.74 (0.1-9.09, SD ±2.5). Student’s t-test to compare the means between groups was again utilized, and results are as follows: negative vs. equivocal p=0.0036; equivocal vs. positive p&lt; 0.0001; and negative vs. positive p&lt; 0.0001.Conclusions: Results demonstrate that both RT-qPCR and Luminex Quantigene® Plex 2.0 methods are able to discern strong positive HER2 cases (IHC 3+) from negative HER2 (IHC 0/1+). For cases with moderate IHC staining (2+), the Luminex-based assay was found to perform better than RT-qPCR. For each reporting group, the range of HER2 gene expression values were observed to overlap; thus no distinct cut point could be assigned. While the results from this pilot study are promising, the adoption of molecular methods for HER2 diagnostic testing will require further rigorous investigation before any clinical considerations can be made.

Citation Format: Elizabeth N Kornaga, John B McIntyre, Alexander C Klimowicz, Natalia Guggisberg, Don G Morris, Anthony M Magliocco. Evaluation of RT-qPCR and luminex-based methodolgies in HER2 breast cancer testing [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P5-10-16.

Abstract P1-07-10: Comparison of three commercial ER/PR assays on a single clinical outcome series

Introduction: Adjuvant tamoxifen is the standard therapy for early stage hormone receptor+ breast cancers (BC). Estrogen receptor (ER) and progesterone receptor (PR) analysis is routinely performed by immunohistochemical (IHC) testing on BC specimens to assist in determining hormone receptor status and patient treatment. ER/PR IHC methodologies and guidelines have recently come under review. Many clinical laboratories have opted to use platform specific, ready-to-use (RTU) ER/PR assays provided by three companies: Dako, Leica and Ventana. While each of these companies are using antibodies that were validated on BC clinical outcome series, these platform specific RTU assays have never been directly compared using the same clinical outcome series. We present a systematic comparison of the three platform specific RTU ER/PR assays, using a retrospective BC cohort, to evaluate the concordance and reproducibility of the RTU ER/PR assays, and to assess the ability of the RTU ER assays to predict tamoxifen response.

Methods: The Calgary Tamoxifen Cohort is a retrospective database containing demographic, clinical and pathological data for 820 BC patients diagnosed between 1985–2000 at the Tom Baker Cancer Centre (Calgary, Canada). Formalin-fixed paraffin-embedded tissue blocks were available for 511 patients, and replicate 0.6mm cores were taken and built into tissue microarrays (TMAs). The TMAs were stained using the platform specific assays on the DakoLink Plus, Ventana BenchMark Ultra, or Bond-III Leica autostainers. Slides were manually scored by the Allred method.

Results: Ventana and Dako had the best concordance for ER (κ=0.90). Substantial agreement was seen for ER staining between Leica and Ventana (κ=0.79), and Dako and Leica (κ=0.66). Agreement was more consistent between the three platforms for PR staining (κ=0.78–0.82). Inter-observer reproducibility was evaluated for all three platforms between three observers: Dako ER (κ=0.80–0.92) and PR (κ=0.69–0.90); Leica ER (κ=0.67–0.83) and PR (κ=0.70–0.89); Ventana ER (κ=0.88–1.00) and PR (κ=0.78–0.94). TMAs were rescored and intra-observer agreement was calculated: Dako ER (κ=1.00) and PR (κ=0.98); Leica ER (κ=0.91) and PR (κ=0.94); Ventana ER (κ=1.00) and PR (κ=0.94). ER Allred scores were dichotomized using current standards and univariate analysis for 5-year disease free survival was performed. All platforms achieved significance with the logrank test and hazard ratio (HR) estimates (p &lt; 0.0001). Cox models were also run to adjust for lymph node status, grade, size and HER2 status. ER status determined by Dako [HR=0.37(0.19–0.74), p = 0.005] and Ventana [HR=0.40(0.18–0.87), p = 0.021] maintained significance, while ER status determined by Leica [HR=0.61(0.31–1.20), p = 0.154] did not.

Conclusions: Concordance between RTU assays demonstrated more variation for ER than PR. All assays showed substantial agreement for inter- and intra- observer reproducibility. Although ER RTU assays from all vendors performed as expected in univariate analysis, multivariate models demonstrated differences. Dako and Ventana appeared equivalent in the multivariate analysis, each providing prognostic information, whereas Leica did not achieve independence in this analysis.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-07-10.

Abstract P3-10-35: Using Automated Image Analysis To Validate Ki67 as a Clinical Prognostic Biomarker for Estrogen-Receptor Positive Breast Cancers

Background: Ki67, an indicator of proliferation, has been shown to be a useful prognostic and predictive marker for breast cancer. Ki67 can be used to identify two distinct estrogen-receptor positive subtypes: luminal A and luminal B. Luminal A breast cancers have been identified as having a lower proliferation and better outcome compared to luminal B. Furthermore, early clinical trials suggest that Ki67 may be useful in identifying a subset of patients that are sensitive to adjuvant docetaxel treatment. Currently, only estrogen-receptor (ER), progesterone-receptor (PR), and human epidermal growth-factor (HER2) are routinely performed. We have optimized and validated an immunohistochemical (IHC) Ki67 assay and automated computerized image analysis platform for routine clinical testing. Materials and Methods: Immunohistochemical staining was quantitatively assessed using the ACIS® III platform on a cohort (N=761) of tamoxifen treated patients who were diagnosed with breast cancer in Calgary between 1990 and 2001. Tissue microarrays were constructed using three 0.6 mm cores. Ki67 results were available for 510 patients, 461 of which are ER/PR positive and HER2 negative. Staining was performed using the DAKO FLEX ready-to-use system. The percent nuclear area positive was calculated using ACIS III and the maximum value was used in statistical analysis

Results: X-tile statistical software was used to identify an optimal Ki67 cut point to distinguish differential overall survival in node negative ER positive cancers of 18.75%. This cut point was then used to categorize the 461 ER/PR positive and HER2 negative breast cancers into luminal A (407; 88.3%) or luminal B (54; 11.7%) subtypes. The 8-year breast cancer specific survival was 85.2% (95% CI = 81.3% - 89.1%) for luminal A and 53.6% (95% CI = 39.3% - 67.9%) for luminal B (P&lt;0.0001). Cox regression showed a hazard ratio of 1.63 (95% CI = 0.99 — 2.67, p=0.055), adjusting for age, tumor size, grade and lymph node status. Discussion: Quantification of Ki67 expression using automated image analysis can be used clinically to distinguish luminal A from luminal B in ER/PR positive and HER2 negative breast cancers. The purpose of this project was to develop a reliable Ki67 assay that can be easily adopted by other testing centers. Using a ready-to-use IHC system — such as DAKO FLEX — allows for consistent results between other clinical laboratories. Additionally, using an automated, quantitative imaging system — such as the ACIS® III — reduces inter-observer variation that can occur by human visual assessment.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-10-35.