Abstract 3227: Intratumor diversity of surface marker expressions on tissue infiltrating lymphocytes in renal cell carcinoma patients

Introduction and Objectives: Renal cell carcinoma (RCC) is considered as an immunogenic tumor and several immune checkpoint inhibitors including anti PD-1 antibody has been reported to have impressive antitumor responses. Immunotherapy is believed to overcome tumor heterogeneity as previously reported in RCC patients. However, there were no reports whether there was intra-tumor diversity of surface marker expressions which could combine the new immune checkpoint inhibitors though the existence of polyclonal expansion of T lymphocytes in RCC were reported. Here, we investigated the surface marker expressions of tumor tissue infiltrating lymphocytes (TIL) and classified them based on their functional populations. Moreover, we explored the presence of intra-tumor diversity of surface marker expressions of TILs in each individual. Material and Methods: We extracted 70 sites 46 patients underwent surgical resection (clear cell RCC; 40, non-clear cell RCC; 6). Each TIL was characterized based on functional T cell populations (naïve T cell, effector T cell, regulatory T cell, Activated T cell, Exhausted T cell) using seven surface marker expressions (CD4, CD8, CD45RA, PD-1, Tim3, ICOS, CD25) measured by flow cytometry. Then we classified and examined the presence of intra-tumor diversity using 36 TILs from 12 patients by clustering analysis. Finally, all of TILs were classified and we examined both the validity and the clinical importance of its classification. Statistical analysis was performed using SPSS ver. 20.0. Results: Firstly, 36 TILs could be classified into three groups. Although 28 TILs of 10 patients were classified into the same group within each individual, 8 TILs of 2 patients (16.7%) were classified into different groups within each individual and those patients had intra-tumor diversity of surface marker expressions of TILs. Secondly, 70 TILs including previous ones were classified into three groups and 2 patients were consistently classified into different groups within each individual and this classification could be validated. Finally, we analyzed the correlation between this classification and clinical features to show the clinical importance of this classification. The presence of lymphovascular invasion was significantly correlated with this classification by both univariate (p = 0.002) and multivariate analysis (OR: 0.093, 95%CI: 0.016 - 0.533, p = 0.008). Conclusions: This study showed the presence of intra-tumor diversity of surface mark