Abstract 738: Correlation between tumor infiltrating lymphocytes and CCL5 gene expression in chemotherapy-resistant triple negative breast cancer

Abstract

Background: The presence of tumor infiltrating lymphocytes (TILs) have been associated with a better outcome in triple negative breast cancer (TNBC). In the other hand, we have found that CCL5, a chemokine involved in the recruitment of immune cells to the tumor microenvironment is an independent prognostic marker for distant-recurrence free survival (DFRS) in TNBC. The aim of this work was to evaluate the relationship between these two immunological prognostic markers in chemotherapy-resistant TNBC. Material and Methods: We evaluated a retrospective cohort (n = 74) of TNBC patients with residual disease after neoadjuvante chemotherapy. Residual tumors were profiled with Nanostring for genes previously related to TNBC aggressiveness. Gene expression values for CCL5 were log2 transformed and median centered. TIL count was performed according to the methods published by Salgado et al (2015). Values of TILs count were log2 transformed (values with 0% were removed from the cohort; n = 1). Spearman's rank correlation analysis and proportional hazards regression was used to investigate the relationship and impact in the outcome between these two markers. Results: The median TIL count was 10% (interquartile range: 21.25). A total of 59.5% of cases had TILs <15%. There was a significant correlation between TILs and CCL5 (ñ = 0.345, P = 0.032). In univariate analysis (as continuous variable), TILs (HR = 0.968 per unit of change; 95%IC: 0.946-0.990; P = 0.006) and CCL5 (HR = 0.95 per unit of change; 95%IC: 0.635-0.996; P = 0.046) were both associated with outcome. After adjusting to CCL5 expression, TIL's count, was the only significant marker with a P-value = 0.007 (HR = 0.702 per unit of change; 95%IC: 0.54-0.909), in contrast to CCL5 (HR = 0.925, CI95%:0.717-1,194; P-value = 0.550). Conclusions: TILs and CCL5 gene expression are significantly correlated in chemotherapy-resistant TNBC. However, although CCL5 expression is strongly associated with the progression of BC, particularly TNBC, TIL assessment remains the stronger and more significant prognostic immunological marker. Citation Format: Joseph A. Pinto, Zaida D. Morante, Roberto Salgado, Nadezhda Cardenas, Jhajaira Araujo, Jaime Ponce, Franco Doimi, Justin Balko, Henry Gomez. Correlation between tumor infiltrating lymphocytes and CCL5 gene expression in chemotherapy-resistant triple negative breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 738.