Abstract P4-04-05: Differential mRNA expression patterns in breast tumors with high vs. low quantity of stromal tumor–Infiltrating lymphocytes
Authors: Moyer AM , Boughey JC , Kalari KR , Suman VJ , McLaughlin SA , Moreno-Aspitia A , Northfelt DW , Gray RJ , Sinnwell JP , Carlson EE , Dockter TJ , Jones KN , Felten SJ , Conners AL , Wieben ED , Ingle JN , Wang L , Weinshilboum RM , Visscher DW , Goetz MP 
Published: May 2016

Background: Tumor-infiltrating lymphocytes (TIL) have prognostic and potentially predictive significance in the (neo)adjuvant treatment of high-risk breast cancer. However, quantitative TIL measurement is not routinely performed. It is unclear why some tumors attract large quantities of TIL while others do not. We sought to confirm the association between TIL and pathologic complete response rate (pCR) and to further use next generation sequencing (NGS) to identify genes and gene pathways associated with the presence/absence of TIL.

Methods: We studied 140 women with high risk stage I-III breast cancer, enrolled in the Breast Cancer Genome Guided Therapy Study (BEAUTY), obtaining serial biopsies for DNA/RNA sequencing and MRI imaging to assess response to neoadjuvant chemotherapy (NAC) with taxane (+/- trastuzumab+/-pertuzumab for HER2+ disease) followed by AC or (F)EC. Diagnostic pre-NAC core needle biopsies and surgical resection specimens post-NAC were available from 110 patients. Stromal TIL were semi-quantitated on a scale of 1-4 (with 1: ≤10/hpf, 2: subtle infiltrate &gt;10/hpf, 3: moderate infiltrate readily visible at low power magnification, 4: dense infiltrate with innumerable lymphocytes). For this analysis, low TIL was defined as scores of 1-2 vs. high defined as 3-4. Using pre-NAC biopsies, RNAseq was performed using the Illumina HiSeq2000 and the Mayo Analysis Pipeline for RNAseq (MAP-Rseq) for quality control, sequence alignment, and gene counts. The quantity of TIL was associated with transcripts across the transcriptome after conditional quantile normalization. Differentially expressed genes were obtained using EdgeR analysis, using a false discovery rate of 0.05, and pathways were evaluated using GAGE methods.

Results: The pCR and residual cancer burden (RCB)-0/I rates by stromal TIL status within each molecular subtype are presented in the table. A diverse spectrum of 1344 genes with differential expression between tumors with high vs. low stromal TIL was identified. The genes with &gt;2.0-fold change (FC) and p&lt;1e-09 included S100A7 (4.49 FC), LCN2 (2.48 FC), and ART3 (2.82 FC) (genes known to be involved in immune regulation), as well as TDRD1 (2.71 FC) (a gene related to ERG [ETS-related gene] expression). In addition, the "regulation of actin cytoskeleton" pathway was upregulated in tumors with high TIL, while the "Hedgehog signaling" and "Wnt signaling" pathways were downregulated.

Molecular SubtypeStromal TILspCR rate n (%)RCB-0/I rateLuminal AHigh------Luminal ALow0/9 (0%)0/9 (0%)Luminal BHigh1/9 (11.1%)1/8 (12.5%)Luminal BLow3/24 (12.5%)6/23 (26.1%)ER+/HER2+High3/9 (33.3%)4/9 (44.4%)ER+/HER2+Low1/6 (16.7%)1/6 (16.7%)ER-/HER2+High8/9 (88.9%)7/7 (100%)ER-/HER2+Low4/8 (50.0%)6/8 (75.0%)Triple NegativeHigh10/19 (52.6%)13/19 (68.4%)Triple NegativeLow7/14 (50.0%)9/13 (69.2%)

Conclusions: We identified genes and gene pathways associated with high TIL expression in breast tumors prior to NAC that provide insight into the interactions between TIL and tumors. TIL can be easily semi-quantitated on H&E and along with these novel biomarkers, may contribute to the personalization of breast cancer therapy.

Citation Format: Moyer AM, Boughey JC, Kalari KR, Suman VJ, McLaughlin SA, Moreno-Aspitia A, Northfelt DW, Gray RJ, Sinnwell JP, Carlson EE, Dockter TJ, Jones KN, Felten SJ, Conners AL, Wieben ED, Ingle JN, Wang L, Weinshilboum RM, Visscher DW, Goetz MP. Differential mRNA expression patterns in breast tumors with high vs. low quantity of stromal tumor–Infiltrating lymphocytes. [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 P4-04-05.