Characterizing the Immune Phenotype of Tumor Infiltrating Lymphocytes in Renal Cell Carcinoma

Cancer immunotherapy has advanced with the introduction of anti-PD-1 therapy. Anti-PD-1 therapy blocks the inhibitory immune checkpoint receptor PD-1, and allows T cells to regain their cytotoxic potentials in response to cancerous cells. Amongst the cytotoxic lymphocytes other than T cells, natural killer (NK) cells have not been fully explored regarding anti-PD-1 treatment. With this in mind, our aim was to characterize the immunophenotype of the immune cells in patients diagnosed with renal cell carcinoma (RCC), and separate their corresponding tumor infiltrating lymphocytes (TILs). Altogether, we analyzed the immunophenotype of the T and NK cells and RCC tumor cells from 13 RCC patients using flow cytometry. In addition, we tested the function of NK cells against RCC cells using various cell line models (NK-92 and RCC cell lines), and monitored the cytotoxicity in real time using a cell impedance assay. Based on the results, we suggest that patients diagnosed with RCC possess unique immune profiles depending on the individual, but also share characteristics regarding the tumor. In addition, NK cells have the potential to activate a cytotoxic response to RCC cells. By phenotyping the TILs, potential novel biomarkers for immuno-oncological (IO) therapy could be detected, which could aid in determining which patients would most likely benefit from immunological therapies such as anti-PD-1 treatment.