Abstract 4639: Single-cell immunoprofiling and spatial analysis of hormone receptor subtypes in HER2+ and HER2low breast tumors using multiplexed immunofluorescence

Background: Breast cancer is characterized by distinct molecular subtypes based on expression of estrogen and progesterone hormone receptors (ER and PR), and epidermal growth factor receptor 2 (HER2). To investigate presence and location of distinct immune cell populations on single cell level we utilized the multiplexed immunofluorescence (mIF) platform MultiOmyx to investigate the tumor immune microenvironment (TME) in HER2+ breast cancer. We have built on growing data implicating distinct immunophenotypes in the breast cancer TME with breast cancer outcomes by profiling 1) prevalence; 2 location (e.g. intratumoral, stromal); 3) phenotype (e.g. activated, exhausted) of infiltrating immune cells.

Methods: We optimized a custom 26-marker MultiOmyx panel interrogating HER2 IF expression, HER2 signaling, and immune markers. This mIF platform leverages serial IF image capture to allow concurrent profiling of all 26 markers on a pathologic section at single cell resolution. We applied the 26-marker panel to a tissue microarray of 208 unique patients with matched tumor/normal tissue cores (1-4 cores/patient; total 333 tumor and 307 normal cores). HER2-positive was defined via ASCO/CAP guidelines; HER2-low was defined as HER2 immunohistochemistry (IHC) 1+/2+ but HER2 in-situ hybridization (ISH) negative.

Results: The 208 unique tumors profiled included 88.9% (185/208) HER2-positive and 11.1% (23/208) HER2-low; 62.5% (130/208) hormone receptor (HR) positive and 37.5% (78/208) HR negative. Median follow-up from diagnosis was 143 months. Among HER2-positive patients, 98.9% (n=183/185) received HER2-directed therapy in the (neo)adjuvant or metastatic setting or were diagnosed prior to FDA approval of trastuzumab for early stage disease. In sum, from 1166 regions of interest in 640 total cores, a total of 1,076,700 single cells were profiled via the 26-marker panel. Tumors categorized based on HR and HER2 reflected distinct immunophenotype. Relative to HR+HER2low, HR-HER2low tumors had a significant increase in the density of T cells (CD3) and tumor-associated macrophages (TAMs) (CD68). The increase in T cells was observed for T helper (CD3+CD4+), T regulatory (CD3+CD4+FoxP3+), as well as T cytotoxic cells (CD3+CD8+). Observed increases in pro-tumorigenic M2 TAM density (CD68+CD163+) were observed for both HR negative subtypes when compared to HR+HER2+ and HR+HER2low groups, indicating a negative correlation between M2 TAM infiltration and ER/PR status. HER2low tumors had significantly lower tumor PDL1+ than HER2+ tumors. Additionally, 18 of the 208 patients with equal distribution across the hormone-receptor subtypes underwent whole slide multiplexed analysis to perform a deeper spatial analysis.

Conclusions: In a large, clinically annotated cohort of breast cancers distinct immunophenotypes are evident among HR and HER2+ subsets.

Citation Format: Anna Juncker-Jensen, David Tallman, Harry Nunns, Heather Lefebvre, Karen Yamamoto, Katharine A. Collier, Mark Vater, Ava Strahan, Ava Willoughby, Olivia Bouchard, Madison Kingsbury, Mathew Cherian, Ashley C. Pariser, Preeti K. Sudheendra, Bhuvaneswari Ramaswamy, Margaret Gatti-Mays, Ainura Kyshtoobayeva, Zaibo Li, Daniel G. Stover. Single-cell immunoprofiling and spatial analysis of hormone receptor subtypes in HER2+ and HER2low breast tumors using multiplexed immunofluorescence. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4639.

Abstract 855: Spatial analytics of the tumor microenvironment on double stained immunohistochemistry images using deep learning

Spatial locations of immune cells in the tumor microenvironment (TME) have been shown to correlate with clinical outcome in different cancers. A worse patient outcome has been reported in oral squamous cancer for individuals with an increased number of Tregs within 30 µm of CD8+ cells [1]. Likewise, the spatial relationship between CD8+ and PD-L1+ cells has become an area of interest as a possible indication for the response to PD-L1-inhibition. It was recently shown in a retrospective study that the combined assessment of CD8 and PD-L1 in NSCLC tumors outperformed CD8 or PD-L1 alone as prognostic markers for predicting treatment with immune checkpoint inhibitors [2].

As reported in these cases, quantifying spatial relationships between two biomarkers can provide clinical and/or biological insights. Spatial analytics of the TME requires accurate cell segmentation and classification. To that end, NeoGenomics have developed an IHC assay for combined CD8 and 22C3/PD-L1 staining, as well as a deep learning pipeline to automatically identify, segment, and classify CD8+ and PD-L1+ cells from whole slide IHC images. We see a 95% concordance of the number of CD8+ and PD-L1+ cells detected in our double stained IHC assay with serial sections stained either for CD8 or PD-L1 alone.

We integrated our previously-reported cell segmentation and classification workflow used for MultiOmyx data (multiplexed IF images) [3] with Indica HALO to analyze whole slide IHC images double stained using two distinct chromogens. In this study, we performed IHC double staining and cell classification analysis on a CD8 - PD-L1 assay in NSCLC tumors. In addition to cell segmentation and classification image outputs, we also generate cell-level and slide-level tables with various cell morphological information, phenotype counts and densities, and biomarker intensity values that can be used to automatically define H-score measures for each biomarker. Additionally, advanced spatial analytics is performed to calculate the average distance between cells of various phenotypes, and spatial clustering patterns of different phenotypes in the TME (i.e. CD8+ and PD-L1+ cells). These analyses enable investigation of numerous complex cell interactions in TMEs.

NeoGenomics quantitative double stained IHC assay is compatible with any two biomarkers of interest even if they are expressed on the same cell as long as the sub-cellular localization of the markers is different. The combination of double staining for CD8 and PD-L1, and quantifying spatial relationships between the two biomarkers is capable of providing the needed context to guide treatment decisions.

References

1. Feng Z et al., JCI Insight. 2017 Jul 20:e93652

2. Steele KE et al., J Immunother Cancer 2018;6:20

3. Nagy ML et al., AACR Annual Meeting 2018; April 14-18, 2018; Chicago, IL

Citation Format: Mate L. Nagy, Anna Juncker-Jensen, Harry Nunns, Ben Ovadia, Ainura Kyshtoobayeva, Karen Yamamoto, Qingyan Au, Josette William Ragheb. Spatial analytics of the tumor microenvironment on double stained immunohistochemistry images using deep learning [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 855.

Abstract 3420: Integrative tumor profiling beyond panel sequencing

Introduction: Targeted cancer therapies rely on the identification of biomarkers specific to the tumors. Next generation sequencing (NGS) based genomic profiling has informed clinical decision making by identifying somatic alterations such as single nucleotide variants (SNVs), small insertion and deletion mutations (indels), structural variations, tumor mutation burden (TMB), and microsatellite instability (MSI) status. Here, we describe an integrative approach to characterize the genomic complexity of solid tumors using whole genome sequencing (WGS), whole exome sequencing (WES), whole transcriptome sequencing (RNAseq), and tumor only panel sequencing.

Methods: We report on WES for 84 paired tumor normal samples in a variety of tumor types including breast, colon, head and neck, melanoma, cervical, thyroid, glioblastoma, lung, pancreatic, prostate, appendiceal, cholangiocarcinoma, and kidney. A subset of these samples were also sequenced with high depth tumor only gene panel. WGS and RNAseq data were included in the analysis for additional 14 tumor normal pairs. Somatic alteration assessments included SNV, indels, MSI status, TMB, mutational signatures, copy number variations, gene fusions and structural variations.

Results: Analysis using tumor normal WES and RNAseq identified both clinically relevant genes as well as mutational processes. We found a high percentage of germline mutations were misidentified as somatic variants using tumor only panels, further highlighting the importance of paired tumor normal sequencing. In some cases, the putative driver gene or the variant in a cancer gene identified by WES was not included in panel sequencing. For example, mutations in FOXA1 gene were recently implicated as clinically relevant resistance and metastasis marker. Exome wide mutational signature analysis also identified BRCA (Cosmic sig 3) signature in tumors with no alterations in BRCA1/2 genes. WGS analysis and fusion gene detection revealed novel fusion genes as well as important structural alterations. Examples include a novel BRAF fusion in a cholangiocarcinoma devoid of other known driver mutations, a novel NTRK3 fusion partner in a glioblastoma tumor, and numerous tandem duplications in an ovarian cancer.

Conclusion: In contrast to tumor only gene panels, tumor and matched normal whole exome assay examines the entire coding portion of the genome without the limitations of a predefined gene list. This allows for detection of mutations in recently identified cancer drivers, ability to reliably distinguish somatic variants from clonal hematopoiesis or other germline variants, calculate genome wide mutational patterns including TMB, MSI, and identify the underlying mutational processes such as genomic signatures. The addition of WGS sequencing allows the identification of clinically relevant genomic rearrangements and novel structural variations.

Citation Format: Corine K. Lau, Alena S. Harley, Paul Choppa, Janine Cooc, Ainura Kyshtoobayeva, Natalia Jun, Mark Dayrit, Wayne Delport, Mark Saldivar, Yop Jun, Raaj Trivedi, Alexandra E. Gylfe, Travis R. Lacey, Ezra Cohen, Kenneth Bloom, Eve Shinbrot. Integrative tumor profiling beyond panel sequencing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3420.

Abstract P3-05-06: Automated analysis of Her2 FISH using combined Immunofluorescence and FISH signals

Introduction: Qualifying patients for Her2 targeted therapy is currently done by detecting Her2 protein overexpression or gene amplification using immunohistochemistry and/or FISH. We have recently developed a method for detecting both signals on the same tissue section allowing direct correlation of protein expression and gene copy number on a cell by cell basis. Accurate assessment of Her2 gene copy number is critical and can pose a challenge due to tumor heterogeneity. This paper reports the accuracy of a proprietary FISH dot counting algorithm on a cell-by-cell basis, potentially allowing analysis of thousands instead of dozens of tumor cells.

Method: Automatic FISH signal counts were compared to manual counts of 888 cells selected from 19 invasive ductal breast carcinoma samples exhibiting varying degrees of Her2 expression collected between June 2011 and March 2012. Tissue sections (4 µm) were mounted on positively charged slides, baked and processed through deparaffinization, rehydration and antigen retrieval, then stained for immunofluorescence (IF) using Cy5 labeled Her2 and Cy3 labeled cytokeratin antibodies, counterstained with DAPI, and imaged using InCell 2000 analyzer with GE-proprietary acquisition and processing software. Images were collected at 10x magnification and digitally stitched to span the entire tissue section. A pathologist then selected separate tumor and adjacent normal epithelium regions for subsequent imaging at 40x magnification. Slides were subsequently processed for FISH by pepsin digestion and then subjected to FISH by using PathVysion kit (Abbott Molecular, Des Plaines, IL). After hybridization and subsequent high stringency washes, samples were DAPI stained and mounted for microscopy. Samples were imaged at 40x at the same regions recorded for 40x IF acquisition, using filtersets appropriate for FISH fluorophores and DAPI.

A proprietary automated processing algorithm was used to analyze combined IF and FISH signals and derive case specific Her2 score from the tumor and/or adjacent normal epithelium. Cell-level dot counting accuracy was assessed using two metrics comparing automated counts to manual counts: cell classification agreement, where a normal cell was defined as having 3 or less Her2 and Cep17 dots; and dot-counting match, where a difference of more than 20% in absolute counts was considered an error.

Result: Our automatic results gave an overall cell-by-cell classification agreement of 88% (range 71% to 98% by case). Combining classification agreement and counting match, our algorithm gave an overall accuracy of 81% (range 63% to 97% by case). Restricting to tumor tissues (as judged by pathologist review of IF) classification agreement and accuracy were 84% and 72%, respectively.

Conclusion: The observed variability in algorithm performance between the different cases was due to the fact that error root causes were case dependent. For instance, the main cause of over-counting errors was image noise and artifacts. On the other hand, the main cause of under-counting was low image contrast, especially in highly amplified cases. These results are an early indication of the promise of automatic dot counting applied to breast cancer slides multiplexed for Her2 IF and FISH.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-05-06.

Abstract P2-10-04: The Mammostrat Test is an Effective Tool to Stratify Patient Samples Previously Characterized as Intermediate by the Oncotype Dx Test

Mammostrat is a well validated, 5-antibody immunohistochemistry (IHC) based assay initially developed to assess the risk of recurrence in patients with early stage estrogen receptor (ER) positive breast cancer. Recent data from the TEAM trial demonstrated that Mammostrat predicted distant relapse free survival (DRFS) for both exemestane and tamoxifen-exemestane treated patients irrespective of nodal status and chemotherapy. OncoType Dx® is a recurrence assay frequently used by oncologists to aid in the selection of early stage breast cancer patients who may benefit from adjuvant chemotherapy. It is currently unclear whether patients whose tumors demonstrate an intermediate risk score should receive chemotherapy. We sought to determine if tumors with intermediate OncoType Dx® scores would be clearly classified as high or low risk with the Mammostrat assay.

Formalin fixed paraffin embedded tissue blocks were retrieved from 143 patients whose tumor were previously assessed as intermediate with the OncoType Dx® assay (Genomic Health, Redwood City, Ca). Six serial 5 micron sections were cut from the tissue block. One section was stained with H&E and the remaining five sections were stained with the Mammostrat antibodies, NDRG1 (AGI-3-3-12E clone, Clarient, Aliso Viejo, CA), TRMT2A (AGI-2-33-12E clone, Clarient, Aliso Viejo, Ca), P53 (D07 clone, Dako, Carpenteria, CA), CEACAM (S0235 08/28/06 clone, Clarient, Aliso Viejo, CA)and SLC7A5 (AGI-1-108-2E clone, Clarient, Aliso Viejo, CA). Slides were reviewed by a single pathologist (KJB) using previously published Mammostrat criteria and a risk score of low, moderate or high was generated.

Of the 143 tumors, 62 (43%) were classified as low risk, 51 (36%) were classified as high risk and 30 (21%) were classified as moderate risk. Thus, 113 (79%) cases were defined as either low risk or high risk by the Mammostrat assay.

The Mammostrat assay reclassified 79% of OncoType Dx® intermediate tumors into a clear high risk or low risk category. Based on data from the TEAM trial, node negative patients categorized as low risk by Mammostrat had a 5 year DRFS of 96%, while data from the NSABP-B20 trial showed that patients categorized as high risk by the Mammostrat assay derived a significant benefit from adjuvant chemotherapy. Mammostrat may be an effective tool to aid oncologists and patients in treatment decisions when Oncotype Dx® classifies a tumor as intermediate risk.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-10-04.

Abstract P3-05-05: HER2 Expression and Gene copy analysis by Immunofluorescence and Fluorescence in situ Hybridization, on a Single formalin-fixed paraffin-embedded tissue section

Introduction: Breast cancer is the most common cancer for women worldwide. HER2 expression and gene copy number are important when determining eligibility for adjuvant therapy and/or chemotherapy medications. One challenging issue for breast cancer testing is intratumoral heterogeneity of HER2 gene amplification. Intratumoral heterogeneity can make it difficult to localize target cells of interest. Serial tissue sections used for independent H&E, IHC and FISH stains also increase the difficulty to localize targets due to cellular truncation. We have developed a system to assess both HER2 expression and gene copy number on the same cell.

Method: Immunofluorescence (IF) and Fluorescence in situ Hybridization (FISH) were performed on tissue sections from 19 patients with invasive ductal breast carcinoma. Cases were selected based on prior HER2 FISH results (HER2:Chromosome 17 = ratio) representing unamplified (<2.0), amplified (≥2.0) and equivocal (1.8–2.2). Samples were collected from June 2011 – February 2012. Tissue sections were cut at 4uM from formalin-fixed paraffin-embedded tissue blocks. Slides were stained with antibodies for HER2 (Clone #D8F12, Cell Signaling, Danvers, MA), cytokeratin (Clone #AE1, eBioscience, San Diego, CA) and Pan cytokeratin (Clone #PCK-26, Sigma-Aldrich, St. Louis, MO). The whole tissue imaging was performed on the In-Cell (GE Healthcare, Chalfont St. Giles, UK) at 10X. Proprietary software developed by GRC (GE Global Research, Niskayuna, NY) controlled the hardware and performed numerous algorithmic functions. Regions of Interest (ROI) were selected by a pathologist on a whole tissue image and coordinates were recorded by the software. The slides were then imaged at 40x using the previously recorded ROI's. The same slides were stained with the PathVysion HER2/CEP17 FISH kit (Abbott Molecular, Des Plaines, IL). Slides were registered to the previous IF scan using recorded coordinates and tissue morphology recognition algorithms. The sections were imaged for FISH at 40X using the previous ROI selections. Cases were assessed for successful protein and genetic expression using proprietary visualization tools for combined analysis.

Results: We evaluated a total of 22 breast cancer cases with 19 cases detecting both protein and gene expression. Of the three cases that could not be evaluated the rationale is as follows: tissue damage incurred during imaging, insufficient focus during the FISH imaging portion, and poor signal to noise of the FISH dots.

Conclusion: The reported incidence of intratumoral HER2 amplification heterogeneity is as high as 30%. The challenges associated with tumor heterogeneity may benefit from a standardize analysis method. Using integrated images generated by this system, pathologist is able to select the appropriate cells for HER2 copy number enumeration based on the expression level of HER2 protein, in the same cell, allowing rapid identification of intratumoral heterogeneity.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-05-05.

Fixation time does not affect the expression of estrogen receptor

The purpose of this pilot study was to determine the impact of the length of fixation in 10% buffered formalin on the expression of estrogen receptor by immunohistochemical analysis. We studied tissue samples from 10 invasive breast cancer cases after fixation for 1, 3, 6, and 9 to 10 hours. The tissue was processed immediately after fixation, resembling routine practice. Then the 40 blocks were incubated with antiestrogen receptors SP1, 6F11, and 1D5. The stained slides were reviewed and scored. We found no significant difference in the intensity of the stain or the percentage of cells stained regardless of the time in fixation or the antibody used. Fixation times between 1 and 9 hours in 10% formalin do not seem to have an impact on the expression of estrogen receptor by immunohistochemical analysis, at least in these high-expressing tumors.

A Multi-Method Analysis of c-erbB2/HER2 in FFPE Tissue: Correlation of a Novel and Rapid In Situ Hybridization Procedure, HER2 CISH and IHC

Background: Overexpression of HER2/neu gene or protein is found in 20% to 30% of breast carcinomas and is predictive of response to treatment by trastuzumab. Methods such as FISH or CISH determine gene amplification status, however, amplified genes may or may not be all transcribed at equivalent levels. Recently, a new c-erbB-2 probe for rapid in situ hybridization (rapid ISH) has been designed. This probe consists of 2 fragments of single-stranded DNA with lengths of 672 and 1143 nucleotides that are targeted against mRNA sequences transcribed from the HER2/neu gene. The extended probe sequence confers increased specificity, sensitivity and speed of reaction with the target mRNA. In this study, the correlation of the Rapid ISH method to FDA approved IHC and CISH methods and a method employing a rabbit monoclonal antibody is assessed. Equivocal IHC cases (IHC 2+) will also be validated.Methods: Two TMA blocks (98 cases: 2 cores/case) of FFPE cases of invasive breast carcinomas were used. Blocks were previously scored by IHC. IHC was assessed by Dako HercepTest®, and a rabbit monoclonal antibody [EP1045Y]; and two ISH methods, a c-erbB-2 probe, and HER2 CISH. All cores were assessed for IHC 0, 1+, 2+ and 3+ staining and ISH was scored as positive, or negative, according to the FDA approved interpretation scheme. Rapid ISH is scored as negative or positive.Results: IHC scores 0 and 1+ were considered negative. IHC 2+ scores were considered negative or positive after confirmation by CISH, and 3+ scores were positive. ISH was scored negative or positive. In a 98 case study, there was a 94% (92/98) concordance between HER2 CISH and IHC, 92% (90/98) concordance between Rapid ISH and IHC; and HER2 CISH and Rapid ISH showed a 98% (96/98) concordance. In one case a 1+ IHC score by HercepTest was determined to be positive by CISH and Rapid ISH.Score01+2+3+HercepTest® (%)41.0%20.5%10.3%28.2%c-erbB-2/HER2 RbMab (%)39.8%15.3%11.2%33.7%c-erbB-2/HER2 RISH Probe + (%)1.0%1.0%1.0%38.8%HER2 CISH + (%)0.0%2.0%1.0%36.7%Table 1: Correlation of c-erbB-2/HER2 by IHC, Gene Amplification (CISH) and mRNA (Rapid ISH) on TMA. Total 98 cases (*except HercepTest® which had 39 cases).Conclusion: c-erbB2 protein was assessed by IHC using the HercepTest®, HER2 gene amplification was quantified using HER2 CISH and HER2 mRNA transcription was determined using a chromogenic single stranded DNA probe (Rapid ISH). A 95% correlation was achieved between the two IHC methods (HercepTest® and a rabbit monoclonal antibody). Concordance between HER2 CISH and Rapid ISH methods was 98%. The rabbit monoclonal antibody IHC method achieved a 94% correlation with HER2 CISH compared to 95% for HercepTest®. In conclusion, this study demonstrates the high concordance between Rapid ISH and the common methods (IHC, FISH/CISH) for assessment of c-erbB2 or HER2/neu status in breast cancer. Based upon these results, it may be proposed that Rapid ISH or HER2 CISH be used in the primary screening of HER2 status.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6009.

Biological factors, tumor growth kinetics, and survival after metastasectomy for pulmonary melanoma

INTRODUCTION

Approximately 23% of melanoma patients will eventually develop pulmonary metastases and have a median survival of only about 7-11 months. Because pulmonary metastasectomy can improve this statistic, we investigated clinicopathologic features and biological correlates that might be used to identify surgical candidates.

METHODS

Archived operative specimens and clinical records were retrieved for 20 melanoma patients who underwent resection of isolated pulmonary metastases at the John Wayne Cancer Institute, Saint John's Health Center. Five-year postmetastasectomy survival (PMS) rate was correlated with age, number of pulmonary metastases, tumor doubling time (TDT), tumor necrosis, and immunohistochemical expressions of four biological markers: Ki-67, glucose transporter-1 (Glut-1), caspase-3, and CD31.

RESULTS

Median TDT was 61 days. On multivariate analysis, TDT (P = 0.008), Glut-1 intensity (P = 0.04), and CD31 expression (P = 0.004) were the significant predictors of PMS. Age, number of pulmonary metastases, tumor necrosis, and expression of Ki-67 or caspase-3 did not significantly impact survival. Median TDT was 56 days with Glut-1 expression versus 165 days without Glut-1 expression (P = 0.002), and Glut-1 staining intensity independently affected TDT (P = 0.012).

CONCLUSIONS

Surgical resection may be preferable to toxic systemic therapies in melanoma patients whose isolated pulmonary metastases have a long TDT (> or = 61 days) and no biopsy evidence of Glut-1 expression.

Inability of immunohistochemistry to predict clinical outcomes of endometrial cancer patients

INTRODUCTION

Despite optimal surgery, some patients with early endometrial carcinoma develop recurrence and die of disease. A number of immunohistochemical (IHC)-identified cell products (markers) have been proposed as predictors of recurrence. This study characterizes a large series of endometrial carcinomas with previously described markers as well as markers that have not been investigated in endometrial carcinoma.

PATIENTS AND METHODS

Women who had undergone surgery for endometrial carcinoma were identified and specimens accessed. Tissue blocks were evaluated for ten IHC markers. Results were correlated with last known clinical status.

RESULTS

Mean follow-up was 43 months; complete data were available on 117 patients. Two women died of other causes; of the remaining 115, eight died of disease and six were alive with recurrence at last follow-up (12%). Vascular endothelial growth factor staining independently predicted recurrence and death. However, in multivariate analyses, only FIGO stage predicted outcome.

DISCUSSION

Our goal was to identify markers to predict which women with endometrial carcinoma were likely to have disease recurrence. We evaluated cell-cycle regulatory proteins, growth factors, hormone receptors, and angiogenic factors, but did not identify any marker that independently predicted outcome in multivariate analysis. This may reflect the few negative outcomes in our population.

β-Catenin regulates the gene of MMP-26, a novel matrix metalloproteinase expressed both in carcinomas and normal epithelial cells

There are several unorthodox features, which distinguish the non-redundant and unique novel matrix metalloproteinase-26 (MMP-26) (an enzyme that has recently evolved and does not exist in rodents but is present in humans) from other members of the MMP superfamily. This report describes our recent efforts to gain a better understanding of the mechanisms which restrict expression of MMP-26 to certain cell/tissue types. We examined transcriptional regulation of the human MMP-26 gene in normal and malignant cells. The AP-1 and Tcf-4 sites of the MMP-26 promoter appear most potent in regulating the expression of the MMP-26-luciferase chimera in HEK293 embryonic kidney and MCF7 breast carcinoma cells. Key regulators of the Wnt pathway (beta-catenin and lymphoid enhancer-binding factor/T-cell factor with which beta-catenin associates) enhanced the transcriptional activity of MMP-26 suggesting that the MMP-26 gene is a likely target of the Wnt pathway. Immunostaining, gene arrays and reverse-transcriptase polymerase chain reaction (RT-PCR) confirm the presence of MMP-26 in normal cells, including the apical epithelial conjunctiva cells of the human eye, as well as in malignant cells of epithelial origin. MMP-26 predominantly accumulates in its proenzyme form in the intracellular milieu of the transfected breast carcinoma MCF7 cells. This study brings us a step forward towards a better understanding of the unconventional role, regulation and functions of epithelial cell MMP-26 in physiological conditions and in neoplasms.

Correlation of dynamic contrast enhancement MRI parameters with microvessel density and VEGF for assessment of angiogenesis in breast cancer

PURPOSE

To investigate the association between parameters obtained from dynamic contrast enhanced MRI (DCE-MRI) of breast cancer using different analysis approaches, as well as their correlation with angiogenesis biomarkers (vascular endothelial growth factor and vessel density).

MATERIALS AND METHODS

DCE-MRI results were obtained from 105 patients with breast cancer (108 lesions). Three analysis methods were applied: 1) whole tumor analysis, 2) regional hot-spot analysis, and 3) intratumor pixel-by-pixel analysis. Early enhancement intensities and fitted pharmacokinetic parameters were studied. Paraffin blocks of 71 surgically resected specimens were analyzed by immunohistochemical staining to measure microvessel counts (with CD31) and vascular endothelial growth factor (VEGF) expression levels.

RESULTS

MRI parameters obtained from the three analysis methods showed significant correlations (P < 0.0001), but a substantial dispersion from the linear regression line was noted (r = 0.72-0.97). The entire region of interest (ROI) vs. pixel population analyses had a significantly higher association compared to the entire ROI vs. hot-spot analyses. Cancer specimens with high VEGF expression had significantly higher CD31 microvessel densities than did specimens with low VEGF levels (P < 0.005). No significant association was found between MRI parameters obtained from the three analysis strategies and IHC based measurements of angiogenesis.

CONCLUSION

A consistent analysis strategy was important in the DCE-MRI study. In this series, none of these strategies yielded results for MRI based quantitation of tumor vascularity that were associated with IHC based measurements. Therefore, different analyses could not account for the lack of association.

In vitro chemoresistance and biomarker profiles are unique for histologic subtypes of epithelial ovarian cancer

OBJECTIVES

To determine whether there is a relationship between histologic subtype of epithelial ovarian cancer and chemoresistance, we evaluated ovarian carcinomas of six histologic subtypes and correlated histology with in vitro drug response. Biomarker profiles (p53, Her-2 neu, and EGFR) were also evaluated to determine if their expression patterns were associated with histology.

METHODS

In vitro drug response profiles for different histologic subsets of epithelial ovarian carcinomas exposed to standard relevant chemotherapy agents were determined in the Extreme Drug Resistance assay (EDR). Immunohistochemistry techniques were employed to determine biomarker expression.

RESULTS

Of 5195 referred serial cases of epithelial ovarian cancer, there were 2660 papillary serous, 303 endometrioid, 142 mucinous, 102 clear cell, 952 undifferentiated carcinomas, and 42 tumors of low malignant potential. For the samples as a whole, the incidences of extreme drug resistance to the tested chemotherapeutic agents were cisplatin 10%, carboplatin 16%, cyclophosphamide 16%, doxorubicin 40%, gemcitabine 21%, paclitaxel 22%, and topotecan 13%. When compared to papillary serous tumors, mucinous tumors were more frequently resistant to cisplatin (10% vs. 18%) but less frequently resistant to topotecan (13% vs. 5%) and doxorubicin (42% vs. 16%). Endometrioid tumors were less resistant to cisplatin (10% vs. 6%) and doxorubicin (42% vs. 20%). Clear cell and undifferentiated tumors had the lowest rates of EDR to paclitaxel (13% and 18%) and cyclophosphamide (7% and 11%), while borderline tumors showed high rates of EDR to these agents (52% and 63%, respectively). With respect to biomarker profiles, mP53 was detected in 46%, Her-2 neu in 16%, and EGFR in 30% of the cases evaluated. As compared to all other subtypes, clear cell carcinomas had significantly higher Her-2 neu expression (19%). Relative to papillary serous carcinomas, borderline tumors exhibited significantly lower rates of mP53 expression (60% vs.17%).

CONCLUSIONS

We found significant differences in the frequencies of extreme drug resistance to chemotherapeutic agents and biomarker expression among histologic subtypes of epithelial ovarian cancer. The data collected in this investigation may provide a guide for stratification of patients entering clinical trials based on histology and biomarker expression.

Inability of immunohistochemistry to predict clinical outcomes of endometrial cancer patients

Introduction

Despite optimal surgery, some patients with early endometrial carcinoma develop recurrence and die of disease. A number of immunohistochemical (IHC)-identified cell products (markers) have been proposed as predictors of recurrence. This study characterizes a large series of endometrial carcinomas with previously described markers as well as markers that have not been investigated in endometrial carcinoma.

Patients and methods

Women who had undergone surgery for endometrial carcinoma were identified and specimens accessed. Tissue blocks were evaluated for ten IHC markers. Results were correlated with last known clinical status.

Results

Mean follow-up was 43 months; complete data were available on 117 patients. Two women died of other causes; of the remaining 115, eight died of disease and six were alive with recurrence at last follow-up (12%). Vascular endothelial growth factor staining independently predicted recurrence and death. However, in multivariate analyses, only FIGO stage predicted outcome.

Discussion

Our goal was to identify markers to predict which women with endometrial carcinoma were likely to have disease recurrence. We evaluated cell-cycle regulatory proteins, growth factors, hormone receptors, and angiogenic factors, but did not identify any marker that independently predicted outcome in multivariate analysis. This may reflect the few negative outcomes in our population.

Ki-67 and p53 expression in minimal deviation melanomas as compared with other nevomelanocytic lesions

Minimal deviation melanoma is a controversial entity encompassing a heterogeneous group of lesions cytologically in the spectrum between recognized subtypes of nevi and conventional "primary configuration" melanomas and reported to have a better prognosis than the latter. To evaluate the distinctiveness of minimal deviation melanoma, Ki-67 proliferation rates and p53 expression in minimal deviation melanomas were compared with those in compound nevi, Spitz nevi, and vertical growth phase superficial spreading malignant melanoma. Twelve examples of each lesion were immunostained with antibodies to the Ki-67 and p53 proteins and evaluated by a pathologist who was blind to the diagnoses. The mean Ki-67 (MIB-1) proliferation rates for the compound nevi, Spitz nevi, minimal deviation melanomas, and superficial spreading malignant melanomas were 0, 3%, 13%, and 25%, respectively. The mean Ki-67 proliferation rate was statistically greater in the minimal deviation melanomas than in the compound nevi or the Spitz nevi (P <.05), but the proliferation rates in the two melanoma subtypes were not statistically significant (P =.08). The mean p53 values for these lesions were 0, 9%, 9%, and 26%, respectively; the latter two were statistically different (P <.01). Based on these Ki-67 and p53 immunophenotypes, minimal deviation melanoma may represent a distinct entity.

Independent association of angiogenesis index with outcome in prostate cancer

New molecular factors have been characterized that are associated with the prognosis of prostate carcinoma patients, including p53 status and angiogenesis. We reported recently that mutant p53 (mp53) was associated with decreased expression of an endogenous inhibitor of angiogenesis, thrombospondin-1 (TSP-1), and increased microvessel density in melanoma and breast cancer. In this study, we performed a similar analysis on primary prostate carcinoma to determine whether these factors were associated with each other or patient outcomes. Paraffin-embedded specimens of 98 cases of primary prostate carcinoma were obtained and examined to confirm tissue diagnosis and Gleason scores. Carcinoma-specific levels of p53, TSP-1, and tumor angiogenesis were determined using semiquantitative immunohistochemistry (IHC) methods. Acquisition of mp53 was significantly associated with decreased TSP-1 (P = 0.002) and increased angiogenesis (P < 0.0001). An angiogenesis index integrating mp53, TSP-1, and angiogenesis (CD31) scores was found to be an independent predictor of survival in univariate and multivariate analyses that included Gleason score, clinical stage, and patient age. Further validation of the angiogenesis index in prostate carcinoma may provide a new tool to stratify patient risk.

Analysis of p53, p21WAF1, and TGF-beta1 in human ductal adenocarcinoma of the pancreas: TGF-beta1 protein expression predicts longer survival

Loss of p53 and p21WAF1 expression have previously been reported in pancreatic adenocarcinoma. Despite these findings in several reports of oncogene and tumor suppressor gene alterations in pancreatic cancer, the clinical significance of these changes is still poorly understood. In an attempt to detect molecular prognostic markers for pancreatic carcinoma, we studied the immunohistochemical expression of p53, p21WAF1, and TGF-beta1 proteins in 42 pancreatic adenocarcinomas of the ductal type. The results were correlated with clinicopathologic findings to identify the markers with prognostic significance. p53 nuclear immunoreactivity was seen in 20 (48%) of the cases, and it was strong to moderate in 14 (33%) of them. p21WAF1 cytoplasmic positivity was found in 16 (38%) of the tumors, with 72% staining strong to moderate. TGF-beta1 stained the cytoplasm of the tumor cells in 13 (31%). Of the p53-negative cases, 12 (54%) exhibited p21WAF1 expression. In 3 (30%) of cases, TGF-beta1 reactivity was seen in the absence of p53 and p21WAF1 p53 positivity identified tumors of higher grade, but did not correlate with stage or survival. TGF-beta1 expression, however, identified low-grade tumors and patients with longer survival. No correlation was found between the expression of any of these molecular markers and smoking history. We report a significant correlation between TGF-beta1 reactivity and low-grade tumors and between TGF-beta1 and better survival. This is a novel finding pointing to TGF-beta1 as a possible new stage-independent predictor of tumor survival in pancreatic ductal adenocarcinoma. In agreement with others, we also found p53 mutation in 20 (48%) of the tumors.

Melanin content and downregulation of glutathione S-transferase contribute to the action of L-buthionine-S-sulfoximine on human melanoma

L-buthionine-S,R-sulfoximine (L-S,R-BSO) was enriched for the active L-buthionine-S-sulfoximine (L-S-BSO) diastereomer. Comparative analysis was performed to determine if this enriched form possessed an increased capacity to deplete glutathione (GSH), and to inhibit the proliferation of tumor cell lines and fresh human tumor samples. Increased activity was observed for the enriched preparation of L-S-BSO in direct proportion to its increased L-S-diastereomeric percentage. Significant antitumor activity towards melanoma, breast and ovarian carcinoma specimens was noted, with the greatest activity directed against malignant melanoma. The activity of BSO on melanoma specimens was found to be correlated with their melanin content, suggesting that free radicals generated during melanin synthesis may become cytotoxic after GSH-dependent scavenging has been eliminated by BSO treatment. The antimelanoma activity of melphalan and BCNU were found to be significantly enhanced in combination with L-S-BSO. With respect to the mechanism of L-S-BSO synergy with alkylators, L-S-BSO treatment of M14 and ZAZ human melanoma cell lines resulted in decreased GSH levels and glutathione S-transferase (GST) activity. Western and Northern blot analyses indicated that GST-mu was the predominant isozyme downregulated after L-S-BSO treatment. Both M14 and ZAZ cell lines selected for resistance to L-S-BSO also showed decreased levels of GST-mu expression. However, in drug free media GST enzyme activity returned to pre-treatment levels without altering the BSO-resistance status of the cell lines. We conclude that L-S-BSO may be an active agent in the treatment of melanoma, and that it may enhance alkylator activity on melanoma through depletion of GSH and down-regulation of GST expression. Purified L-S-BSO should be explored clinically as an active agent for the treatment of melanoma.

Levels of multidrug resistance (MDR1) P-glycoprotein expression by human breast cancer correlate with in vitro resistance to taxol and doxorubicin

To determine whether multidrug resistance (MDR1) P-glycoprotein (Pgp) expression correlated with clinical MDR1-related drug resistance, we established a protocol for quantitative measurement of Pgp expression and in vitro drug resistance in doxorubicin resistant MCF7 breast cancer cell lines and 359 freshly resected specimens of breast carcinoma. Pgp expression was detected with 4E3, UIC2, and JSB-1 monoclonal antibodies using flow cytometry and immunohistochemistry (IHC). Pgp function was determined using PSC833 in a drug resistance-reversal assay and with a three-dimensional agarose-based extreme drug resistance assay. MCF7 calibrator cell lines expressed Pgp, which was functional and in proportion to the degree of drug resistance. Flow cytometry, UIC2 shift assays, IHC scores, and determination of absorbance products by image analysis were all highly correlated (r > 0.9). Overall Pgp expression increased from 11% in untreated patients to 30% in patients who had previously received chemotherapy. Compared with Pgp-negative tumors, a significant increase in doxorubicin and Taxol resistance was seen for breast cancers that expressed Pgp, regardless of prior treatment. A strong correlation between the degree of Pgp expression and in vitro resistance to Taxol and doxorubicin (but not to 5-fluorouracil) was found when either IHC scores or image analysis-based methods were used to quantify Pgp expression (n = 185, P < 0.0001). The degree of Pgp expression strongly correlated with the degree of drug resistance in the clinical specimens studied. These data suggest that (a) Pgp contributes to clinical MDR1-related drug resistance, and (b) both intrinsic and acquired expression of Pgp in breast cancer may contribute in part to therapeutic failure and relapse.

Selective and synergistic activity of L-S,R-buthionine sulfoximine on malignant melanoma is accompanied by decreased expression of glutathione-S-transferase

L-buthionine-S,R-sulfoximine (BSO) selectivley inhibits glutathione (GSH) synthesis. Malignant melanoma may be uniquely dependent on GSH and its linked enzymes, glutathione S-transferase (GST) and GSH-peroxidase, for metabolism of reactive orthoquinones and peroxides produced during melanin synthesis. We compared the in vitro effects of BSO on melanoma cell lines and fresh melanoma specimens (n = 118) with breast and ovarian cell lines and solid tumors (n = 244). IC50 values (microM) for BSO on melanoma, breast and ovarian tumor specimens were 1.9, 8.6, and 29, respectively. The IC90 for melanoma was 25.5 microM, a level 20-fold lower than steady state levels achieved clinically. The sensitivity of individual specimens of melanoma correlated with their melanin content (r = 0.63). BSO synergistically enhanced BCNU activity against melanoma cell lines and human tumors. We followed GSH levels, GST enzyme activity, GST isoenzyme profiles and mRNA levels after BSO. BSO (50 microM) treatment for 48 hr resulted in a 95% decrease in ZAZ and M14 melanoma cell line GSH levels, and a 60% decrease in GST enzyme activity. GST-mu protein and mRNA levels were significantly reduced in both cell lines. GST-pi expression was unaffected. These data suggest that BSO action on melanoma may be related to GSH depletion, diminishing the capacity to scavenge toxic metabolites produced during melanin synthesis. We report here for the first time that BSO enhancement of alkylator action may be related in part to down regulation of GST. BSO may be a clinically useful adjunct in the treatment of malignant melanoma.