Abstract P5-08-16: Local immunologic environment related with tumor infiltrating lymphocytes (TIL) and PD-1/PD-L1 expression in early stage breast cancer

Abstract

Abstract Purpose: Recent studies have shown that local immune environment revealed with programmed death 1(PD-1)/programmed death ligand 1(PD-L1) and tumor infiltrating lymphocytes(TIL) affects the tumor-growth and prognosis. In this study, we evaluated the tumor local immune environments using immunohistological staining for analysis of PD-1/PD-L1 expression and TIL of tumor local in operable early-stage breast cancer. Method: A total of 100 surgical specimens of stageI-III invasive breast carcinoma paraffinembedded between 1995 and 2005 were analyzed. Immunohistological staining for PD-1, PD-L1, PTEN, CD3, CD8, and CD163 were performed by the conventional PAP method. In addition, intratumoral and intrastromal TILs and macrophages were simultaneously stained by anti-CD3, CD8, CD163 antibodies and measured by 'Win ROOF' computer software (version 5.7, Mitani Corporation, Japan). Results: Intratumoral PD-1 expressed significantly higher in triple negative breast cancer (TNBC) compared to other subtype BC (p=0.0094), intratumoral and intrastromal CD3+ lymphocytes and CD163+ macrophages were also significantly higher in TNBC, respectively (CD3: p=0.0002; 0.0139 and CD163: p=0.0043; 0.0270). PTEN loss was also more frequently observed in TNBC (p=0.0475). In addition, after a median 5-year follow-up, patients of luminal A subtype with lower PD-L1 and PTEN expression showed better disease free survival (DFS) with a significant difference (p=0.0148, p=0.0475). Conclusion: Local expression of PD-1/PD-L1 antigens on tumor cells, CD3+ lymphocytes, CD163+ macrophages infiltration singnificantly increased in early-stage TNBC. PTEN expression on tumor local might be associated with DFS in patients with early-stage BC. Citation Format: Okabe M, Toh U, Iwakuma N, Mishima M, Kawahara A, Kage M, Itoh K, Akagi Y. Local immunologic environment related with tumor infiltrating lymphocytes (TIL) and PD-1/PD-L1 expression in early stage breast cancer. [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 P5-08-16.