Abstract PO008: Stromal Tumor Infiltrating Lymphocytes (sTILs) as a putative prognostic marker to identify a responsive subset of TNBC in an Indian Breast Cancer Cohort

Abstract

Abstract Objectives: Prognostic significance of stromal tumor infiltrating lymphocytes; sTILs is evaluated to identify a responsive subset of TNBC in an Indian cohort of breast cancer patients. Methods: A retrospective cohort of breast cancer patients from a single onco-surgeon breast cancer clinic treated with uniform treatment strategy across is evaluated for sTILs. FFPE tissue of primary tumor of invasive breast carcinoma are collected with ethical approvals. Tumor sections blinded for subtypes are stained with H&E and scored for sTILs by a pathologist following Immuno-Oncology TILs working groups scoring guidelines. Results: Analysis of 144 primary breast tumors for sTILs scores re-enforces significantly higher infiltration in TNBC tumors than HER2+ve and ER+ve tumors. Higher sTILs scores co-relate with gradually incremental pathological response to therapy specifically in TNBC subset and with better disease-free survival outcomes. Within TNBC, older and post-menopausal patients harbor higher scores of sTILs. Conclusion: Despite a small cohort of breast cancer patients, TNBC subtype reflected significantly higher scores of sTILs with better response to therapy and disease-free outcomes as compared to other breast cancer subtypes. A larger number of breast cancer patients from an Indian cohort will strengthen the findings to establish sTILs as a marker to identify a responsive subset of TNBC. Citation Format: Madhura Kulkarni, Pooja M. Vaid, Anirudha Puntambekar Puntambekar, Rituja A. Banale, Ruhi Reddy, Rohini Unde, Namrata Namewar, Devaki Kelkar, L.S. Shashidhara, C.B. Koppiker. Stromal Tumor Infiltrating Lymphocytes (sTILs) as a putative prognostic marker to identify a responsive subset of TNBC in an Indian Breast Cancer Cohort [abstract]. In: Proceedings of the AACR Virtual Special Conference on the Evolving Tumor Microenvironment in Cancer Progression: Mechanisms and Emerging Therapeutic Opportunities; in association with the Tumor Microenvironment (TME) Working Group; 2021 Jan 11-12. Philadelphia (PA): AACR; Cancer Res 2021;81(5 Suppl):Abstract nr PO008.