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

BACKGROUND

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

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

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

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

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

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

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

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

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

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

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

Background

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

Patients and Methods

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

Results

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

Conclusions

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Background

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

Methods

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

Results

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

Conclusions

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

BACKGROUND

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

DESIGN

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

CONCLUSIONS

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

BACKGROUND

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

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

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

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

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

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

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

Disease Free Survival

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Introduction:

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

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

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

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

Abstract P6-04-04: Hypoxia Is Associated with Somatic Loss of BRCA1 Protein and Pathway Activity in Triple Negative Breast Cancer

Background: Triple negative breast cancer (TNBC) has loss of BRCA1 activity either through germline mutation, epigenetic modification or negative transcriptional regulators. Yale investigators have demonstrated that tumor hypoxia leads to loss of critical DNA repair activities, including BRCA1, RAD-51 and γ-H2AX (Bindra RS, et al. Cancer Res 2005;65(24): 11597-604). This study was designed to explore the relationship of BRCA1 loss and hypoxia using Carbonic Anhydrase IX (CA-IX), a downstream target of hypoxia-induced factor 1a (HIF-1a), an accepted surrogate biomarker for tumor hypoxia, in TNBC. Methods: Two cohorts of breast tumors from Yale archival materials were studied. The first consisted of 660, unselected breast tumors, the second a cohort of 130 TNBC, both with long term clinical followup. Automated Quantitative Analysis (AQUA) was used to detect the intensity of BRCA1 and CAIX within specific subcellular compartments. CA-IX antibody M75 was provided by the J Zavada lab (1:10000), BRCA1 monoclonal antibody M110 (Ab-1) was purchased from Calbiochem (1:1000). The 130 TNBC cohort was also subjected to whole genome expression analysis. In brief, tissue core biopsies from tumor blocks were subjected to nucleic acid extraction using RecoverAll Total Nucleic Acid Isolation kit (Applied Biosystems) and 600ng total RNA were processed by the Keck Microarray Facility for the Illumina DASL platform. Statistical analysis of gene expression data was carried out in Bioconductor/R software. A set of relevant signatures was selected by enrichment analysis of modules identified by principal component analysis. Signature scores were computed as Pearson correlation between the signature vector of gene contributions and each sample's expression profile for these genes. Results: In the cohort of 660 specimens, 22 were found to have high CA-IX expression score (above cut-off value of 10). Cut-off was based on known positive cell lines and corresponding AQUA scores, as well as visual confirmation of positivity. A negative correlation (Rho=-0.6, p=0.0165) of BRCA1 nuclear protein with CA-IX level was found and this data was reproducible on a duplicate array. Of note, 14 out of 22 hypoxic breast tumors were from triple negative breast cancers (TNBC) (p=0.0034). In the triple negative cohort, CAIX staining was positive in 20 % of cases (n=15/75) and in these samples it was associated with the 2002 van ‘t Veer BRCA1 mutant signature (Rho=0.51). Positive CAIX staining was also associated with worse outcome (p=0.046) as was CAIX mRNA expression (p=0.02).

Conclusions: In human breast tumors BRCA1 nuclear expression is negatively correlated with tumor hypoxia, measured by CAIX. A subset of TNBC has higher levels of hypoxia and BRCA1 signatures. This data suggests that CAIX may be a useful biomarker for BRCA1 loss, and possibly for response to PARP inhibitor therapy. This will be evaluated in our recently completed trial of BSI-201+Irinotecan.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-04-04.

Abstract P3-10-26: Quantitative Protein and Gene Expression Biomarkers of Tamoxifen and Letrozole Recurrence in the NCIC CTG MA.17 Cohort

Background: The MA.17 study showed that extended adjuvant endocrine therapy with letrozole (LET) after completing 5 years of tamoxifen (TAM) markedly reduced the risk of recurrence in women with ER+ early stage breast cancer and improved overall survival in women presenting with node +ve disease. The HOXB 13:IL17BR gene expression ratio (signature) has been shown to predict outcome in breast cancer patients treated with adjuvant tamoxifen monotherapy and provides additional information beyond that from known positive (ER and PR) and negative (Her-1 and Her-2) predictors of responsiveness to tamoxifen in node-ve women. We report a case control evaluation of the Breast Cancer Index (BCI; bioTheranostics, Inc.), which combines the HOXB13 and IL17BR twogene and the molecular grade index (MGI) gene expression signatures, with respect to distinguishing which patients are at risk of late recurrences and who would respond to extended endocrine therapy with LET. The prognostic and predictive utility of quantitative immunofluorescence of ER, PR, Her-2, tumor aromatase, COX-2, GATA3 and Nat1 in the TAM-PLACEBO and the TAM-LET cohorts will also be evaluated and compared to results derived by standard immunohistochemistry. Methods: FFPE tumor blocks were collected from patients who experienced a breast cancer recurrence up to unblinding of MA.17. Controls were matched 2:1 for age, tumor size, lymph node status, and prior chemotherapy, and were all disease free for longer than cases. All cases were reviewed for standard histopathology by two independent pathologists. RNA was extracted, amplified, converted to cDNA and subjected to RT-PCR with primers and probes to HOXB13, IL17BR, BUB1A, CENPA, NEK2, RACGAP1 and RRM2. ER, PR HER1, HER2, COX2, Aromatase, GATA3 and NAT1 will be analyzed by routine IHC techniques and by immunoflourescent Automated Quantitative Analysis (AQuA).

Results: 105 cases and 210 matched controls are available for evaluation. All sections are under review and tissue microarrays have been performed on all cases and controls. Detailed results on the BCI and ER, PR, Her-2 will be available at the SABCS.

Discussion: MA.17 has shown that extended adjuvant endocrine therapy after tamoxifen is effective at preventing disease recurrence given for an additional 5 years. Numerous clinical trials are exploring whether extending AIs will show this benefit, and there is an increasing need to improve the therapeutic index by distinguishing those at risk from those who are not. It is also important to determine which patients will benefit from the therapy and which will recur without benefit. The latter patients could be triaged to clinical trials of novel therapies to overcome endocrine resistance. This study will help to define these issues and pave the way for more effective selection of specific patients for adjuvant endocrine strategies.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-10-26.

Growth factor receptor-bound protein-7 (Grb7) as a prognostic marker and therapeutic target in breast cancer

BACKGROUND

Growth factor receptor-bound protein-7 (Grb7) is an adapter-type signaling protein recruited to various tyrosine kinases, including HER2/neu. Grb7-specific inhibitors are in early development. As with other targeted therapies, response to therapy might be associated with target expression.

MATERIALS AND METHODS

Tissue microarrays containing 638 primary breast cancer specimens with 15-year patient follow-up were employed to assess Grb7 expression using our Automated QUantitative Analysis method; cytokeratin defines pixels as breast cancer (tumor mask) within the histospot, and Grb7 expression within the mask is measured with Cy5-conjugated antibodies.

RESULTS

High Grb7 expression was strongly associated with decreased survival in the entire cohort and in the node-positive subset (P = 0.0034 and P = 0.0019, respectively). On multivariable analysis, it remained an independent prognostic marker (P = 0.01). High Grb7 was strongly associated with high HER2/neu, and coexpression of these molecules was associated with worse prognosis than HER2/neu overexpression alone.

CONCLUSIONS

High Grb7 defines a subset of breast cancer patients with decreased survival, indicating that Grb7 might be a valuable prognostic marker and drug target. Coexpression with HER2/neu indicates that cotargeting these molecules might be an effective approach for treating HER2/neu-positive breast cancers. Future studies using Grb7-targeting agents should include assessment of Grb7 levels.

Molecular bases for sensitivity to figitumumab (CP-751,871) in NSCLC

8091

Background: Signaling of Insulin like Growth Factors (IGFs) through the IGF type 1 receptor (IGF-IR) induces tumor resistance to cancer therapy. Bioavailability of IGFs is regulated by IGF-binding proteins (IGFBP), of which IGFBP3 is the most abundant. Figitumumab (F) (CP-751,871), a specific IGF-IR inhibitor, has shown phase 2 activity in NSCLC in some histologies (i.e., squamous cell and adenocarcinoma) but not others (i.e, large cell or NOS tumors). Methods: Protein expression of members of the IGF-IR pathway, EGFR and differentiation markers was determined in core biopsies from 230 NSCLC pts, including 52 pts enrolled in F trials. Plasma concentration of IGF-1 and related proteins was determined in 159 NSCLC pts in F trials. Gene expression profiling was conducted in 35 NSCLC cell lines treated with F. Results: Squamous NSCLC had the highest IGF-IR expression (p=0.057). An association with better outcome was seen for E-cadherin expression (HR =0.62, 0.46–0.82 95% CI, p=0.005) and clustering by E-cadherin levels revealed a strong correlation between IGF-IR and EGFR expression in the high E-cadherin group (p<0.001). This subset included 73% of the squamous cell tumors investigated (N=44). Plasma levels of free IGF-1 (fIGF-1) were low and not predictive of response in squamous cell. In contrast, pts with adenocarcinoma had high plasma fIGF-1 levels (p=0.06) that correlated with vimentin expression (Rho=0.732, p=0.06), and both fIGF-1 and vimentin were predictive of F clinical benefit (p=0.03). Large cell/NOS NSCLC expressed the highest levels of vimentin (p<0.001) but had low E-cadherin and IGF-IR expression and low fIGF-1 plasma levels. Analysis of anchorage independent growth in NSCLC cell lines confirmed that F activity is independently associated to IGF-IR overexpression (p=0.02) and IGFBP3 under-expression (p=0.009). Conclusions: IGF-IR overexpression and increased free IGFs/low IGFBP are key independent mechanisms of sensitivity to F in NSCLC of squamous and adenocarcinoma cell histologies.

[Table: see text]

[Table: see text]

Association of constitutively activated hepatocyte growth factor receptor (Met) with resistance to a dual EGFR/Her2 inhibitor in non-small-cell lung cancer cells

There is a pressing need to identify new drug targets and novel approaches for treatment of non-small-cell lung carcinoma (NSCLC). Members of the epidermal growth factor receptor (EGFR) and Met receptor families have been identified as important molecular targets for NSCLC. Two EGFR tyrosine kinase inhibitors (TKIs; erlotinib and gefitinib) are in current clinical use, but a majority of patients do not respond to these targeted therapies. We used receptor TK (RTK) capture arrays to identify receptors active in NSCLC cell lines. As Met and ErbBs were active, we explored the potential therapeutic advantage of combined targeting of Met with ErbB receptor family inhibitors for treatment of NSCLC. We found that Met physically interacts with both EGFR and Her2 in a NSCLC cell line with overexpression/overactivation of Met. Combined use of a dual EGFR/Her2 inhibitor with a Met inhibitor yields maximal growth inhibition compared with the use of EGFR and/or Met inhibitors. This suggests that simultaneous inhibition of multiple RTKs may be needed to effectively abrogate tumour cell growth. Phosphoproteomic analysis by RTK capture arrays may be a valuable tool for identifying the subset of tumours with functional receptor activation, regardless of mechanism.

Multiplexed AQUA-based assessment of SWOG 9313 shows prognostic value of continuous ER, PR and HER2 assessment

Abstract #704

Introduction: HER2 is expressed at high levels due to gene amplification in about 15% of breast cancer cases and it has been shown to be a poor prognostic marker. However, HER2 is also expressed in normal breast duct tissue, albeit a much lower levels. We hypothesized that continuous analysis of expression using AQUA will provide prognostic information beyond that attainable with conventional methods.&#x2028; Methods: A tissue microarray was made from 2123 cases of the 3122 patients accrued to SWOG 9313, in which sequential doxorubicin and cyclophosphamide (A-C) was compared to combination AC. A multiplexed assessment of HER2 and estrogen receptor (ER) was performed on the same slide using the immunofluoresence-based AQUA® method of automated quantitative analysis. Reproducibility and fidelity of multiplexing were determined for each marker by regression analysis.&#x2028; Results: As expected, both ER and PR were significantly predictive of disease-free survival (DFS) when both are tested as continuous variables, both adjusted for node status, tumor size, treatment and menopausal status (p-values 0.005 and &lt;0.001, respectively). HER2, measured as a continuous variable showed a bi-phasic effect. It has been previously reported (Camp et al, Cancer Research 2003, 63;1445) that both the high and low expressers of HER2 have worse outcome (low levels are equivalent to that seen in normal breast ducts). Splitting the SWOG cohort by deciles shows that both the top and bottom decile have worse DFS than the middle 80% (log rank p=0.012). Also, modeling the hazard ratio as a function of concentration shows a U-shape relationship showing both high and low HER2 expression is associated with poorer DFS.&#x2028; Conclusions: The AQUA method provides a reproducible method of continuous measurement of ER, and HER2 on the same slide. In this cohort both ER and PR as continuous variable are highly prognostic, as expected, but multiplexing with HER2 did not affect outcome. Quantitative analysis demonstrated that both low and high levels of HER2 expression were associated with poor outcome. Studies are ongoing to determine the significance of this observation with respect to biological classifications of breast cancer and relationships with breast cancer therapies.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 704.

Predictive value of p27 for the benefit of adjuvant anthracycline-based chemotherapy in early breast cancer

Abstract #6063

Background: p27 is a cyclin-dependent kinase (cdk) inhibitor that plays a role in cell cycle regulation. The expression of this protein, assessed by immunohistochemistry (IHC), has prognostic value for overall survival in breast cancer patients (Porter P.L., J Natl Cancer Inst., 2007). Based on this, we hypothesized that p27 could be a predictive factor for the efficacy of adjuvant anthracycline (A)-based chemotherapy in early breast cancer.&#x2028; Methods: Tumor samples from 823 patients, included at Institut Gustave Roussy (IGR) in two randomized trials comparing an A-based chemotherapy with no adjuvant treatment, were used to construct a tissue microarray. We previously reported predictive values of ER, Her2 expression and molecular subclassification using the same tissue array (Conforti R., Ann Oncol., 2007). Nuclear and cytoplasmic expression of p27 was assessed by the AQUA system. A p27 ratio of nuclear and cytoplasmic expression (p27 N/C ratio) was calculated for each tumor sample. The prognostic and predictive value of the continuous value of p27 N/C ratio was assessed by a Cox regression model adjusted for treatment, age, tumor grade, stage and ER expression (IHC) and stratified by trial.&#x2028; Results: p27 was assessable in 715 primary tumors. The p27 N/C ratio was significantly different according to the molecular subclasses (p=0.001) and was higher in Her2- versus Her2+ and in EGFR+ versus EGFR- tumors (p=0.0075 and p&lt;0.0001 respectively). There was an almost significant interaction between p27 N/C ratio and disease-free survival in the adjusted Cox model (p=0.052). The adjusted hazard ratios (HR) of relapse or death of a unit increase in p27 N/C ratio was HR = 1.27 (95% CI = [0.58-2.81], p = 0.55) in the control arm and HR = 0.30 (95% CI = [0.12-0.77], p= 0.01) in the A-arm. For overall survival, the adjusted interaction p-value was equal to 0.08. The adjusted HR of death of a unit increase in p27 N/C ratio was HR=1.67 (95% CI = [0.61-1.73], p=0.32) in the control arm and HR=0.32 (95% CI = [0.10-0.99], p=0.05) in the A-arm.&#x2028; Conclusion: p27 N/C ratio, determined by the AQUA system, was borderline predictive for the efficacy of adjuvant A-based chemotherapy. However, this study is hampered by a relatively low number of events, a low dose of anthracycline, and multi-hypotheses testing (overall 20 biomarkers tested in different studies).

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6063.

Uniformly positive (&gt;80%) HER2 expression maximizes sensitivity and specificity for prediction of response to trastuzumab in CALGB 9840

Abstract #6046

Purpose: The recent ACO/CAP guidelines revised the cut-point for HER2 expression by immunohistochemistry (IHC) from 10% up to 30%. Recently we showed that heterogeneity of expression is a function of the assessed biomarker and, for HER2, &gt;80% area of expression was most prognostic and predictive. Here we test this hypothesis in CALGB 9840, a prospective cooperative group clinical trial of Paclitaxel (P) and Trastuzumab (T).&#x2028; Experimental Design: Tissue from 274 cases selected from cases with available slides from the TH arm were first scored by pathologists as 0-3+, but then again scored to assess percentage of tissue staining with prospectively chosen cut points of &gt;10%, &gt;30% or &gt;80%. Response was assessed by modified RECIST criteria, including complete and partial response. Stable disease and progressive disease were considered non-response.&#x2028; Results: Amongst the 176 cases treated with P+T there were 90 (52%) responses (PR+CR), 3 cases were unevaluable for response. In the subset of cases treated with T, there was inconsistent differences in the &gt;10% vs the &gt;30% categories but the &gt;80% category was uniformly statistically significantly predictive of response. Receiver Operator Characteristic (ROC) curves constructed to assess prediction of response showed areas under the curves (AUC) of 0.59 for IHC and 0.60 for FISH suggesting both are failed tests for defining an optimal cut-point. However, selecting only the cases scored as 3+ shows an AUC of 0.72 and the optimal cut-point is for the test is at 95% positive 3+ HER2 staining. This modification of the cut-point would have denied T to 6 of the 49 patients who responded to therapy in the 3+ group. However, there were also 41 (of 86) patients in the 0,1+ and 2+ groups that responded to therapy, raising the possibility that the response in those 6 patients may have been unrelated to T therapy.&#x2028; Conclusions: When using clinical outcome to assess the value of the current tests for prediction of response to T, ROC curves suggest that both the old and new HER2 tests fail at defining an optimal cut-point. However, using only strongly positive cases (3+), an acceptable test can be achieved which is maximized at 95% area of expression. This cut-point, while statistically rigorous, is limited by the fact that the patients were treated with both P and T. This result suggests a similar analysis is warranted on a larger cohort of T treated patients, perhaps in the adjuvant or neoadjuvant setting. The availability of other options for HER2 amplified cases (ie lapatinib) and the increased use of T in the adjuvant setting warrant optimization of tests for the best possible patient selection.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6046.

HSP90 as a marker of progression in melanoma

BACKGROUND

HSP90 chaperones molecules critical for cell survival and malignant progression, including mutated B-raf. HSP90-targeting agents are in clinical trials. No large studies have been conducted on expression of HSP90 in melanomas.

MATERIALS AND METHODS

Tissue microarrays containing 414 nevi, 198 primary and 270 metastatic melanomas were assessed using our automated quantitative analysis (AQUA) method of in situ protein measurement; we use S-100 to define pixels as melanocytes (tumor mask) within the array spot, and measure HSP90 expression within the mask using Cy5-conjugated antibodies.

RESULTS

HSP90 expression was higher in melanomas than nevi (P < 0.0001) and higher in metastatic than primary specimens (P < 0.0001). No association was seen between high HSP90 expression and survival in the primary or metastatic patient subsets. In primary melanomas, high HSP90 expression was associated with higher Clark level (P = 0.0167) and increased Breslow depth (P < 0.0001).

CONCLUSIONS

HSP90 expression was significantly higher in tumors than nevi and was associated with disease progression, indicating that it might be a valuable drug target in melanoma, as well as a useful diagnostic marker. Prospective studies are needed to confirm the diagnostic role of HSP90, as well as the predictive role of HSP90 expression in patients treated with HSP90 inhibitors.

Assessment of PI3 kinase as a druggable target in melanoma

8521

Background: PI3 (phosphatidylinositol-3) kinase is central to a major intracellular signal transduction pathway that influences numerous cellular functions, including growth, differentiation and survival. Drugs that target PI3 kinase have demonstrated preclinical activity, and are undergoing further development. The PI3 kinase inhibitor, SF1126 is expected to enter clinical trials in 2007. The hallmarks for a valuable drug target include differential expression between normal and malignant cells and an association with disease progression. PI3 kinase expression has not been thoroughly evaluated in melanoma. We sought to determine the expression and prognostic value of PI3 kinase in a large cohort of primary and metastatic melanomas and to compare the expression with that of benign nevi. Methods: Tissue microarrays containing 548 melanomas and 540 benign nevi were employed to assess PI3 kinase expression. We used a novel method of in situ automated quantitative analysis (AQUA) of protein levels. We applied S100 conjugated to Cy3 to identify a melanoma tumor mask within a histospot, and measured PI3 kinase expression levels using Cy5 conjugated antibodies within the mask. Continuous AQUA scores were correlated with clinical and pathological variables. Results: PI3 kinase expression was higher in melanomas than in nevi by unpaired t-tests (p < 0.0001), and was significantly higher in metastatic than in primary specimens (p < 0.0001). High PI3 kinase scores were associated with Clark levels of IV-V (p = 0.0126), Breslow thickness > 2mm (p = 0.044) and absence of tumor infiltrating lymphocytes (p = 0.014). High PI3 kinase expression strongly correlated with decreased survival by Cox univariate analysis (p = 0.0024), but was not independent of disease stage. Conclusions: PI3 kinase expression is remarkably higher in malignant melanocytes than in benign nevi. Moreover, high PI3 kinase expression is associated with disease aggression, making PI3 kinase an attractive drug target for melanoma. This is the first large study assessing PI3 kinase levels in melanoma in a quantitative fashion. Assessment of the association between PI3 kinase levels and response to therapy is warranted.

No significant financial relationships to disclose.

VEGF, VEGFR1, and VEGFR2 expression in melanoma

8520

Background: Metastatic melanoma is a chemoresistant disease with poor prognosis. Angiogenesis plays a role in progression and metastasis of melanoma. Identifying angiogenic molecules that are differentially expressed between benign and malignant tissues may enable us to create an assay to predict sensitivity to antiangiogenic agents, thus guiding selection of patients for treatment. VEGF signals through its receptor VEGFR1/flt-1 (R1) but is thought to mediate most of its angiogenic and proliferative effects through VEGFR2/flk-1/kdr (R2). In smaller melanoma studies, VEGF, R2 and less commonly R1 expression was associated with disease aggression. We characterized VEGF, R1, and R2 expression on a cohort of 540 nevi and 548 melanomas. Methods: We stained tissue microarrays to assess VEGF, R1, and R2 expression by automated quantitative analysis (AQUA), an objective method for analysis of protein levels. We used S100 to define pixels as melanoma (tumor mask) within the array spot, and measured intensity of VEGF, R1, and R2 expression using Cy5 conjugated antibodies within the mask. Results: VEGF, R1, and R2 expression was significantly higher in melanomas than in nevi by unpaired t-tests (p<0.0001). VEGF and R2 expression was higher in metastatic than primary specimens (p<0.0001). Differential expression of R1 between metastatic and primary specimens was less pronounced (p=0.0158). R2 expression correlated with Breslow depth > 2 mm (p=0.0129). Cox univariate analysis revealed an association between decreased survival and expression of VEGF (p= 0.0488) and R2 (p=0.0035); however, this was not independent of disease stage. Conclusions: VEGF, R1, and R2 expression is higher in malignant melanocytes than in their benign counterparts and higher in metastatic than primary specimens. This association with disease aggression underscores the importance of these proteins as therapeutic targets. Differential expression of R2 was found to be more significant than R1, supporting the belief that VEGF mediates its effects through R2 in malignancy. To our knowledge, this is the largest study to examine the VEGF pathway in melanoma. Future clinical trials of antiangiogenic agents in melanoma should include correlative serum and tissue assays of VEGF, R1, and R2 as biomarkers of response to therapy.

[Table: see text]

Automated quantitative analysis of DCC tumor suppressor protein in ovarian cancer tissue microarray shows association with β-catenin levels and outcome in patients with epithelial ovarian cancer

BACKGROUND

The deleted in colorectal cancer (DCC) protein, the product of DCC tumor suppressor gene, is frequently altered in cancer. Preclinical data demonstrate that DCC regulates beta-catenin levels. Here, we sought to determine the association of DCC with beta-catenin protein levels, clinicopathological parameters and patient outcome in ovarian cancer using a method of in situ compartmentalized protein analysis.

METHODS

A tissue array composed of 150 advanced-stage ovarian cancers, treated with surgical debulking and platinum-paclitaxel (Taxol) combination chemotherapy, was constructed. For evaluation of protein expression, we used an immunofluorescence-based method of automated in situ quantitative measurement of protein analysis (AQUA).

RESULTS

One hundred and twelve patients (74%) had sufficient tissue for AQUA. The median follow-up time for the entire cohort was 33 months. Patients with low nuclear DCC expression had a 3-year progression-free survival (PFS) rate of 0% compared with 33% of those with high DCC expression (P = 0.0067). In multivariate analysis, low nuclear DCC expression level retained its prognostic significance for PFS. Between DCC and beta-catenin, a significant relationship was found, where tumors with low DCC had low beta-catenin and vice versa (P = 0.003).

CONCLUSIONS

Low nuclear DCC levels predict for poor patient outcome in epithelial ovarian cancer. DCC may exert its antitumor function, in part, through regulation of beta-catenin levels.

AQUA and FISH analysis of HER-2/neu expression and amplification in a small cell lung carcinoma tissue microarray

AIMS

Most small cell lung carcinoma (SCLC) patients have metastatic disease at the time of diagnosis and are faced with poor prognosis and limited treatment options. Reports of HER-2/neu gene amplification and overexpression in this malignancy have raised the possibility of applying targeted immunotherapy with trastuzumab, the monoclonal antibody used to treat metastatic breast cancer. However, a review of the studies measuring HER-2/neu gene amplification and protein expression in SCLC reveals discordant results. The aim of the present study was to re-examine HER-2/neu expression in SCLC in relation to gene copy number using the new, highly sensitive, immunofluorescence automated quantitative analysis (AQUA) technology.

METHODS AND RESULTS

Fluorescence in situ hybridization (FISH) was used to measure HER-2/neu gene copy number and amplification status and AQUA was used to measure protein expression in a series of 23 SCLC tumours on a tissue microarray. None of the 17 SCLC specimens assessable by FISH exhibited HER-2/neu gene amplification as defined by a HER-2/neu/chromosome 17 ratio = or > 2. Twelve of 17 (70.1%) SCLC samples were polysomic for chromosome 17 with corresponding increases in HER-2/neu gene copy numbers. Intermediate levels of protein expression corresponding to AQUA scores in the range of 4-24 were detected in all 23 specimens. High protein expression levels corresponding to AQUA scores up to 83, observed previously in association with gene amplification and poor prognosis in breast cancer cases, were not detected in the present study. No statistically significant association was observed between absolute chromosome 17 or HER-2/neu gene copy numbers and protein expression levels in tumour cells (P > 0.45).

CONCLUSIONS

The lack of gene amplification and robust HER-2/neu protein expression in SCLC tumour cells in this series does not suggest a prominent role for the HER-2/neu gene in SCLC tumour progression and does not support the general applicability of targeted immunotherapy with trastuzumab to this malignancy.

Reciprocal regulation of RhoA and RhoC characterizes the EMT and identifies RhoC as a prognostic marker of colon carcinoma

Understanding how RhoC expression and activation are regulated is essential for deciphering its contribution to tumorigenesis. Here, we report that RhoC expression and activation are induced by the epithelial to mesenchymal transition (EMT) of colon carcinoma. Using LIM 1863 colon cancer cells, RhoC protein expression and subsequent activation were detected coincident with the loss of E-cadherin and acquisition of mesenchymal characteristics. Several Ets-1 binding sites were identified in the RhoC promoter, and evidence was obtained using chromatin immunoprecipitation that Ets-1 can regulate RhoC expression during the EMT. Interestingly, a marked decrease in RhoA activation associated with the EMT was observed that corresponds to the increase in RhoC expression. Use of shRNA established that RhoA inhibits and RhoC promotes post-EMT cell migration, demonstrating functional significance for their coordinate regulation. To assess the importance of RhoC expression in colon cancer, immunohistochemistry was performed on 566 colorectal tumors with known clinical outcome. The level of RhoC ranged from no expression to high expression, and statistical analysis revealed that elevated RhoC expression correlates with poor outcome as well as aberrant expression and localization of E-cadherin. These data provide one mechanism for how RhoC expression is regulated in colon carcinoma and substantiate its utility as a prognostic marker.

β-Catenin Functions Mainly as an Adhesion Molecule in Patients with Squamous Cell Cancer of the Head and Neck

BACKGROUND

beta-catenin, depending on subcellular localization, plays a dual role in carcinogenesis: as a signaling factor (in the nucleus) and as an adhesion molecule (in cell membrane). In this study, we sought to determine the role of beta-catenin in head and neck carcinogenesis.

METHODS

First, we studied the incidence of mutations of beta-catenin in a cohort of 60 head and neck squamous cell cancers (HNSCC). We subsequently evaluated the protein expression levels of beta-catenin in a cohort of oropharyngeal squamous cell cancer tissue microarray using a novel in situ method of quantitative protein analysis and correlated those with cyclin D1 levels and clinical and pathologic data.

RESULTS

The mean follow-up time for survivors was 45 months and for all patients was 35 months. We found no mutations in the cohort of 60 HNSCC. beta-catenin displayed primarily membranous expression pattern. Patients with high tumor-node-metastasis stage were more likely to have high expression of beta-catenin (P = 0.040). Patients with low beta-catenin expression had a local recurrence rate of 79% compared with 29% for patients with high beta-catenin tumors (P = 0.0021). Univariate Cox regression revealed a hazard ratio for low beta-catenin tumors of 3.6 (P = 0.004). Kaplan-Meier analysis showed that patients with low beta-catenin expressing tumors trended toward worse 5-year disease-free survival (P = 0.06). In multivariate analysis, only beta-catenin expression status was an independent prognostic factor (P = 0.044) for local recurrence. Tumors with high beta-catenin had low cyclin D1 and vice versa (P = 0.007).

CONCLUSIONS

The absence of activating beta-catenin mutations combined with the inverse correlation between beta-catenin levels with cyclin D1 levels and outcome suggest that beta-catenin mainly functions as an adhesion and not signaling molecule in HNSCC.

Prognostic significance of p16 protein levels in oropharyngeal squamous cell cancer

PURPOSE

Functional inactivation of p16 is an early and frequent event in head and neck squamous cell cancers. In this study, we sought to determine whether p16 expression is of prognostic importance in oropharyngeal squamous cell carcinoma.

EXPERIMENTAL DESIGN

p16 protein expression was evaluated by immunohistochemistry in a tissue microarray composed of 123 oropharyngeal squamous cell cancers with a mean patient follow-up time of 33 months.

RESULTS

p16 overexpression was associated with more advanced Tumor-Node-Metastasis stage and higher histologic grade. Despite this association with unfavorable features, p16 overexpression was associated with decreased 5-year local recurrence rates (11 versus 53%) and increased 5-year disease-free survival (62 versus 19%) and overall survival (60 versus 21%). In multivariate analysis, p16 expression status remained an independent prognostic factor for local recurrence, disease-free survival, and overall survival.

CONCLUSIONS

In patients with oropharyngeal squamous cell carcinoma, overexpression of p16 as determined by immunohistochemistry is associated with significantly improved prognosis and lower local recurrence rates.