Thompson, E. Aubrey

Abstract Background: Growing evidence supports the critical role of preexisting immune response in triple negative breast cancer (TNBC). However, there are limitations with current evaluation approaches: inability to functionally assess the type of immune infiltration with traditional pathologic evaluation and loss of spatial distribution in conventional high-plex gene or protein expression analyses from the whole tumor section. Here, we report the initial analysis of immune protein expression as a function of spatial distribution and clinical outcomes in TNBC samples. Methods: NanoString GeoMxTM Digital Spatial Profiling (DSP) was used to quantify 39 immune-related proteins in stromal and tumor segments from 44 TNBC samples from the FinXX trial. Samples were matched for patient characteristics, treatment arm (capecitabine vs. 5-fluorouracil), and outcome based on recurrence-free survival (RFS) with 22 samples from patients who recurred and 22 samples from patients with durable RFS. Regions of interest (ROIs) were selected based on expression of cytokeratin (tumor), CD45 (leukocytes), or CD68 (macrophages). Each ROI was segmented into tumor (pancytokeratin-positive area) and stroma (pancytokeratin-negative/nuclear SYTO13-positive area). The general linear model was used for statistical analysis of differential expression with RFS as a categorical variable (recur yes or no). Results: A total of 950 tumor and stroma segments were included in this initial analysis. In both tumor and stroma segments, over-expression of T cell activation markers (CD137, GITR) was associated with better outcome, whereas T cell markers (CD3, CD4, CD8) were not significantly associated with outcome. In tumor segments alone, improved outcome was significantly associated with increased protein expression [> 2-fold change (FC) at p<0.001] of CD56, PD-L2, HLA-DR, CD137, GITR, and CD40. In CD45-enriched stroma, improved outcome was associated with elevated expression (FC>2.0, p<0.001) of PD-L2; whereas durable RFS was associated with elevated PD-L2 and IDO1 expression in CD68-enriched stroma. In contrast, macrophage/dendritic cell markers CD68 and CD11c were not associated with outcome. In tumor cells adjacent to CD45-enriched stroma, durable RFS was associated with increased abundance (FC>2.0, p<0.001) of PD-L2, CD56, CD27, GITR, CD20, HLA-DR, and IDO1. Similarly, in tumor segment associated with CD68-enriched stroma, proteins associated with RFS included PD-L2, HLA-DR, CD56, GITR, and CD137. Among 39 immune function proteins, only elevated CTLA4 expression in CD68-enriched stroma was associated with recurrence (FC=0.55, p<0.001), whereas tumor-segment CTLA4 was associated with RFS. Conclusions: Using an in-depth analysis to precisely quantify the abundance of multiple immune function proteins in a spatially defined manner, we observed that PD-L2, IDO1, and T cell activation markers were robustly associated with durable RFS in both tumor and stromal segments. In contrast, MHC components (HLA-DR, beta-2-microglobulin), B cell markers (CD20), and NK cell markers (CD56) were strongly associated with favorable outcome in tumor but not in stromal segments. Our study highlights the conclusion that the immune landscape of TNBC is far too complex to be encompassed by any single molecular marker, and more detailed analyses of the DSP data reported here are ongoing with a view towards using quantitative multiplex analyses to refine our understanding of how therapeutic outcome is influenced by interactions among immune cells and between immune and tumor cells. Acknowledgements: Supported by the Breast Cancer Research Foundation (BCRF18-161), Bankhead Coley (6BC05 Florida Department of Health), 26.2 with Donna Foundation, US National Cancer Institute (CA15083), and the Canadian Cancer Center Citation Format: Saranya Chumsri, Douglas Hinerfeld, Jennifer M. Kachergus, Yaohua Ma, Heather A Brauer, Sarah Warren, Xue Wang, Torsten O. Nielsen, Karama Asleh, Heikki Joensuu, Edith A. Perez, E. A. Thompson. Digital spatial mapping of the immune landscape of triple negative breast cancer reveals novel features of immune-tumor cell interaction [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 PD5-06.

4567 Background: Trials combining anti-PDL1 and anti-VEGF therapies for clear cell renal cell carcinoma (ccRCC) are underway; however the relationship between the expression of PDL1 and genes in the VEGF pathway is poorly understood. Using the Affymetrix platform, we observed an inverse association between the expression of PDL1 and key genes in the VEGF pathway. Herein, we validate this inverse association using an independent set of 100 primary ccRCC tumors. Methods: From our registry database we sampled 100 ccRCC tumors with varying PDL1 protein expression (0%-100%) determined by immunohistochemistry (IHC). We extracted RNA from FFPE slides and performed RT-PCR to quantify gene expression of PDL1, VEGF, VEGFR1, and VEGFR2. All genes were normalized to the POLR2a gene. We evaluated the association of PDL1 protein expression and VEGF gene expression using Spearman rank correlation. In addition, we employed a linear mixed effects model to compare the fold-change in expression of VEGF genes between PDL1 low (0-5%, n=68) and PDL1 high (>5%, n=32) tumors. Results: As expected, PDL1 protein expression positively correlates with PDL1 geneexpression (corr=0.42, p<0.001). Validating our array data, PDL1 protein expression inversely correlates with expression of key VEGF genes: VEGF (corr=-0.23, p=0.01), VEGFR1 (corr=-0.34, p<0.001), and VEGFR2 (corr=-0.23, p=0.01). In our dichotomized analysis, we noted significantly higher expression of VEGF genes in the PDL1 low compared to the PDL1 high group: VEGF (fold change=1.82, p<0.001), VEGFR1 (FC=2.63, p<0.001), and VEGFR2 (FC=2.13, p=0.001). Conclusions: We independently validate an inverse association between the expression of PDL1 and key genes in the VEGF pathway in primary ccRCC. If validated further in larger studies, the existence of an immune evasive and an angiogenic phenotype within ccRCC could inform current clinical trials targeting these two pathways. Ultimately, whether VEGF signaling affects PDL1 expression, or whether angiogenic or immune evasive phenotypes predict response to anti-PDL1, anti-VEGF, or a combination of the two therapies remains unclear.

1037 Background: Folate receptor alpha (FRA the product of the FOLR1 gene) has been identified as a potential prognostic and therapeutic target in a number of cancers. A correlation has been shown between intense expression of FRA in breast tumors and poor prognosis, yet little is known about FOLR1/FRA expression across clinically relevant breast cancer subtypes. Methods: 131 breast cancer tumors including 4 benign, 33 ER+, 26 HER2+, and 68 triple negative (TN) were constructed into tissue microarrays (TMAs). FRA expression was analyzed by immunohistochemistry (IHC) using a high affinity FRA antibody. Tumor membrane staining intensity was scored by a pathologist as negative (0), weak (1+), moderate (2+) and strong (3+). The percent of cells within each tissue core stained at each intensity was recorded to calculate an H-score. The H-score is a weighted score that captured both the proportion of positive staining and intensity for each tumor. H-score values can range from zero (no membrane staining) to a maximum of 300 (100% membrane staining at 3+). H-scores for each patient sample were averaged over 3 TMA cores. The mean H-scores for each tumor subtype and the percentage of 3+ staining in >30% of tumor cells were compared by a Mann-Whitney test. The distribution of FOLR1 mRNA was completed using a TCGA RNA-seq dataset from 691 breast tumors classified as ER+, HER2+ and TN. FOLR1 levels of TN versus ER+ and HER2+ were compared by a Mann-Whitney test. Results: The mean H-score for the benign tumors was 0, ER+ (13.31), HER2+ (39.36), TN (119.02). The median H-score for the benign tumors was 0, ER+ (0), HER2+ (7.5), TN (127.5). The TN tumors mean and median H scores were significantly higher than benign, ER+ or HER2+ (p<0.001). The largest percentage of 3+ staining in >30% of tumor cells was observed in TN tumors (36.7%) and lowest in ER+ tumors (0%) (p<0.001). TN tumors had significantly higher levels of FOLR1 mRNA compared to ER+ and HER2+ subtypes (p<0.0001). Conclusions: Our data indicate that expression of FRA is highly prevalent in TN tumors and is supported by FOLR1 mRNA levels. Anti-FRA therapy may represent an important therapeutic intervention in TNBC who to this point have no active targeted treatment options.

520 Background: There is considerable interest in developing HER2 testing criteria for adjuvant H. We used the 21-gene assay to examine the relationship of HER2 mRNA to benefit from H. Methods: N9831 compared adjuvant chemotherapy AC-T to concurrent chemotherapy-trastuzumab AC-TH in stage I-III HER2+ breast cancer. Recurrence Score (RS) and HER2 mRNA expression were determined by Oncotype DX (neg<10.7, equiv 10.7 to <11.5, and pos ≥11.5 log2 expression units). Cox regression was used to assess the association of HER2 expression with H benefit for distant recurrence. Results: Median follow-up: 7.4 yrs. Of 1,940 total pts, 901 had consent and sufficient tissue. HER2 by RT-PCR was neg in 130 (14%), equiv in 85 (9%), and pos in 686 (76%) pts. Concordance between HER2 assessments was 95% for RT-PCR vs central IHC (>10% + cells = +), 91% for RT-PCR vs central FISH (≥2.0 = pos) and 94% for central IHC vs central FISH. In the primary analysis, the association of HER2 expression with H benefit was marginally non-significant (P=0.057). In hormone receptor pos pts (local IHC) the association was significant (P=0.002). The association was nonlinear with the greatest estimated benefit at lower and higher HER2 mRNA expression levels. The observed treatment benefit in low HER2 pts was not due to imbalance between arms in RS and individual gene expression values. Conclusions: Concordance among HER2 assessments by central IHC, FISH, and RT-PCR was high. Association of HER2 mRNA expression with H benefit was marginally non-significant. A consistent benefit of trastuzumab irrespective of mHER2 levels was observed in the pts with either IHC+ or FISH+ tumors. Benefit was observed in pts with high HER2 by RT-PCR but also observed for the small groups of pts with negative results by quantitative RT-PCR or FISH (Table). Plausible mechanisms for this observation will be discussed. [Table: see text]

AbstractImmune checkpoint inhibitor therapies targeting PD‐1/PD‐L1 are now the standard of care in oncology across several hematologic and solid tumor types, including triple negative breast cancer (TNBC). Patients with metastatic or locally advanced TNBC with PD‐L1 expression on immune cells occupying ≥1% of tumor area demonstrated survival benefit with the addition of atezolizumab to nab‐paclitaxel. However, concerns regarding variability between immunohistochemical PD‐L1 assay performance and inter‐reader reproducibility have been raised. High tumor‐infiltrating lymphocytes (TILs) have also been associated with response to PD‐1/PD‐L1 inhibitors in patients with breast cancer (BC). TILs can be easily assessed on hematoxylin and eosin–stained slides and have shown reliable inter‐reader reproducibility. As an established prognostic factor in early stage TNBC, TILs are soon anticipated to be reported in daily practice in many pathology laboratories worldwide. Because TILs and PD‐L1 are parts of an immunological spectrum in BC, we propose the systematic implementation of combined PD‐L1 and TIL analyses as a more comprehensive immuno‐oncological biomarker for patient selection for PD‐1/PD‐L1 inhibition‐based therapy in patients with BC. Although practical and regulatory considerations differ by jurisdiction, the pathology community has the responsibility to patients to implement assays that lead to optimal patient selection. We propose herewith a risk‐management framework that may help mitigate the risks of suboptimal patient selection for immuno‐therapeutic approaches in clinical trials and daily practice based on combined TILs/PD‐L1 assessment in BC. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Abstract Purpose: Recent studies have demonstrated a benefit of adjuvant capecitabine in early breast cancer, particularly in patients with triple-negative breast cancer (TNBC). However, TNBC is heterogeneous and more precise predictive biomarkers are needed. Experimental Design: Tumor tissues collected from TNBC patients in the FinXX trial, randomized to adjuvant anthracycline–taxane–based chemotherapy with or without capecitabine, were analyzed using a 770-gene panel targeting multiple biological mechanisms and additional 30-custom genes related to capecitabine metabolism. Hypothesis-generating exploratory analyses were performed to assess biomarker expression in relation to treatment effect using the Cox regression model and interaction tests adjusted for multiplicity. Results: One hundred eleven TNBC samples were evaluable (57 without capecitabine and 54 with capecitabine). The median follow-up was 10.2 years. Multivariate analysis showed significant improvement in recurrence-free survival (RFS) favoring capecitabine in four biologically important genes and metagenes, including cytotoxic cells [hazard ratio (HR) = 0.38; 95% confidence intervals (CI), 0.16–0.86, P-interaction = 0.01], endothelial (HR = 0.67; 95% CI, 0.20–2.22, P-interaction = 0.02), mast cells (HR = 0.78; 95% CI, 0.49–1.27, P-interaction = 0.04), and PDL2 (HR = 0.31; 95% CI, 0.12–0.81, P-interaction = 0.03). Furthermore, we identified 38 single genes that were significantly associated with capecitabine benefit, and these were dominated by immune response pathway and enzymes involved in activating capecitabine to fluorouracil, including TYMP. However, these results were not significant when adjusted for multiple testing. Conclusions: Genes and metagenes related to antitumor immunity, immune response, and capecitabine activation could identify TNBC patients who are more likely to benefit from adjuvant capecitabine. Given the reduced power to observe significant findings when correcting for multiplicity, our findings provide the basis for future hypothesis-testing validation studies on larger clinical trials.

PURPOSE Recent trials have shown potential benefit of extended adjuvant endocrine therapy and relatively high risk of recurrence (RoR) after 5 years in hormone receptor-positive (HR+) human epidermal growth factor receptor 2–negative (HER2−) breast cancer. Although risk of late relapse in HR+ HER2− breast cancer is fairly well defined, the risk in HER2-positive (HER2+) breast cancer treated with adjuvant trastuzumab-based chemotherapy remains largely unknown. METHODS We included 3,177 patients with HER2+ breast cancer treated with adjuvant chemotherapy alone or with trastuzumab from the North Central Cancer Treatment Group N9831 (ClinicalTrials.gov identifier: NCT00005970 ) and National Surgical Adjuvant Breast and Bowel Project B-31 (ClinicalTrials.gov identifier: NCT00004067 ) trials. RESULTS Overall, HR+ breast cancer was significantly associated with improved recurrence-free survival (RFS) during the first 5 years (hazard ratio, 0.65; 95% CI, 0.56 to 0.77; P < .001). Among patients treated with trastuzumab, cumulative hazard for RFS was lower in patients with HR+ HER2+ breast cancer during the first 5 years (10.96% v 17.48%; hazard ratio, 0.60; 95% CI, 0.45 to 0.79; P < .001). However, there was no significant difference in RFS based on HR status during years 5 to 10 (hazard ratio, 1.32; 95% CI, 0.93 to 1.88; P = .12). A comparable degree of trastuzumab benefit was observed in HR+ and HR− breast cancers ( P for interaction = .87). Furthermore, we observed low RoR in years 5 to 10 among patients with HR+ HER2+ breast cancer: 3.23% in patients without lymph node involvement (N0) and 6.39% in patients with involvement of one to three lymph nodes (N1). CONCLUSION The benefit of adjuvant trastuzumab persists for a long time. A distinct pattern of recurrence was observed between HR+ and HR− HER2+ disease but with similar degree of benefit from adjuvant trastuzumab. RoR in years 5 to 10 in HR+ HER2+ breast cancer is low, particularly in patients with N0 or N1 disease.

3142 Background: Recent studies have demonstrated a benefit of adjuvant capecitabine, particularly in triple negative breast cancer (TNBC) patients with residual disease after neoadjuvant chemotherapy. However, biomarkers to predict which patients are more likely to benefit from capecitabine are needed. Methods: The nanoString Breast Cancer 360 (BC360) and PanCancer Immunoncology (IO360) panels were used to quantify mRNA expression in TNBC samples in the FinXX trial. FinXX is a phase III trial which randomized high risk patients to receive either 3 cycles of docetaxel followed by 3 cycles of cyclophosphamide, epirubicin, and fluorouracil (Arm A: T+CEF) vs. 3 cycles of docetaxel plus capecitabine followed by 3 cycles of cyclophosphamide, epirubicin, and capecitabine (Arm B: TX+CEX). Gene signature scores were analyzed using prespecified algorithms developed by nanoString. Digital Spatial Profiling was carried out using GeoMX platform. Results: A total of 111 TNBC patients in FinXX trial were included (57 in Arm A and 54 in Arm B) with 10.2 years median follow up. There were 7 cancer- and immune-related gene signatures identified by BC360 and IO360 panels that were significantly associated with improved recurrent free survival favoring an addition of capecitabine. These include cytotoxic cell signature (HR 0.37, 95%CI 0.15-0.92, p 0.03), endothelial signature (HR 0.18, 95%CI 0.04-0.83, p 0.03), mast cell signature (HR 0.43, 95%CI 0.21-0.88, p 0.02), PDL2 gene (HR 0.29, 95%CI 0.09-0.99, p 0.05), immunoproteasome (HR 0.34, 95%CI 0.13-0.89, p 0.02), exhausted CD8 (HR 0.29, 95%CI 0.09-0.97, p 0.04), and PD1 (HR 0.44, 95%CI 0.20-1.02, p 0.05). Conclusions: Analysis of RNA abundance signatures strongly suggests that there are important immune features that are associated with benefit from capecitabine in TNBC. However, analysis of RNA extracted from whole tumor sections lacks spatial discrimination. We anticipate that a more detailed, spatially-defined analysis of protein abundance, using the novel NanoString GeoMX platform, will provide more insights and define specific immune features associated with improved outcome. Additional results of GeoMX will be reported at the meeting. Clinical trial information: NCT00114816.

Abstract Background: Recent studies have demonstrated a benefit of adjuvant capecitabine in early stage breast cancer, particularly in patients with residual disease after neoadjuvant chemotherapy. Subset analyses suggest that patients with triple negative breast cancer (TNBC) may be more likely to benefit with capecitabine in this setting. However, more precise biomarkers to predict which patients are most likely to benefit from capecitabine are needed. Methods: The NanoString Breast Cancer 360TM (BC360) panel was used to quantify mRNA expression in FFPE tissue samples from patients with TNBC in the FinXX trial. Gene signature scores were analyzed using prespecified algorithms developed by NanoString. 30 additional custom genes related to capecitabine metabolism and function were added. Patients in FinXX trial were randomized to receive either 3 cycles of docetaxel followed by 3 cycles of cyclophosphamide, epirubicin, and fluorouracil (T+CEF) or 3 cycles of docetaxel plus capecitabine followed by 3 cycles of cyclophosphamide, epirubicin, and capecitabine (TX+CEX). Cox proportional hazard ratio (HR) was used to determine the association of each gene signature with recurrence free survival (RFS). Results: A total of 111 samples from patients with TNBC in the FinXX trial were available for gene expression analysis. 57 patients were treated with T+CEF and 54 patients were treated with TX+CEX. The median age was 52 years and median follow up was 10.2 years. Consistent with the previous analysis of the FinXX trial, patients with TNBC had nonsignificant but favorable RFS with capecitabine (HR 0.60, 95% CI 0.27-1.3, p 0.2). Among 39 individual genes and metagene signatures generated with the BC360 panel, there were 4 gene signatures significantly associated with improved RFS favoring an addition of capecitabine with TX+CEX compared to T+CEF. These were the cytotoxic cell signature (HR 0.37, 95%CI 0.15-0.92, p 0.03), endothelial signature (HR 0.18, 95%CI 0.04-0.83, p 0.03), mast cell signature (HR 0.43, 95%CI 0.21-0.88, p 0.02), and PDL2 gene (HR 0.29, 95%CI 0.09-0.99, p 0.05). PAM50 intrinsic subtype was not predictive of capecitabine benefit within this TNBC subset. Moreover, we identified additional individual 12 genes that were significantly associated with capecitabine benefit (p-FDR&lt;0.05). Among these genes, high expression of CES1, which encodes an enzyme that activates capecitabine, was significantly associated with improved RFS when treated with capecitabine (HR 0.71, 95%CI 0.32-1.61 with p-interaction=0.04). Conclusion: Our analyses demonstrated potential predictive individual genes and metagene signatures that may be used to identify TNBC patients who are more likely to benefit from adjuvant capecitabine. Interestingly, several gene signatures related to immune response and genes related to capecitabine activation were associated with improved outcome in TNBC patients treated with capecitabine in the FinXX trial. While these findings are compatible with basic science reports, future studies are needed to validate the significance of these gene signatures as predictive biomarkers for capecitabine benefit. Citation Format: Chumsri S, Asleh K, Brauer HA, Mashadi-Hossein A, Lauttia LS, Lindman H, Nielsen TO, Joensuu H, Thompson EA. Predictive gene signatures of adjuvant capecitabine benefit in triple negative breast cancer in the FinXX trial [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 P3-11-05.

Abstract Purpose: Young age has been shown to be an independent predictor of poor outcome in breast cancer. In HER2-positive breast cancer, the effects of aging remain largely unknown. Experimental Design: A total of 4,547 patients were included [3,132 from North Central Cancer Treatment Group (NCCTG) N9831 and 1,415 from National Surgical Adjuvant Breast and Bowel Project (NSABP) B-31]. Pathologic stromal tumor-infiltrating lymphocyte (sTIL) and molecular tumor infiltrating lymphocyte (mTIL) signatures were evaluated. Results: In NCCTG N9831, comparable benefit of trastuzumab was observed in all patients [age ≤ 40; HR, 0.43; 95% confidence interval (CI), 0.28–0.66; P &lt; 0.001; and age &gt; 40; HR, 0.56; 95% CI, 0.45–0.69; P &lt; 0.001]. Similar results were observed in NSABP B-31 (age ≤ 40; HR, 0.45; 95% CI, 0.29–0.68; P &lt; 0.001; and age &gt; 40; HR, 0.42; 95% CI, 0.33–0.54; P &lt; 0.001). Among patients who received chemotherapy alone, younger age was associated with poor outcome in the hormone receptor–positive subset, but not the hormone receptor–negative subset, in both trials. Although there was no association between sTILs and age, a small, but significant increase in mTIL CD45 and some immune subset signatures were observed. Among patients who received chemotherapy alone, patients over 40 years of age with lymphocyte-predominant breast cancer had excellent outcome, with 95% remaining recurrence free at 15 years. Conclusions: Among patients treated with trastuzumab, there was no significant difference in outcome related to age. Our study suggests that trastuzumab can negate the poor prognosis associated with young age.