BackgroundThis study investigated the correlation of programmed death 1 (PD-1) and T cell immunoglobulin and ITIM domain (TIGIT) with clinicopathological characteristics of renal cell carcinoma (RCC) and explored the biological roles of both proteins in the development, metastasis, and invasion of RCC.Material/MethodsThe expressions of PD-1 and TIGIT were detected in the RCC and adjacent normal tissues, and their correlation with the clinicopathological characteristics of RCC, relationship between PD-1 and TIGIT in RCC, and the correlation of PD-1 and TIGIT expression with distance of adjacent normal tissues to RCC were further evaluated.ResultsTIGIT and PD-1 expression was detectable in the immune cells of peripheral blood mononuclear cells and lymphoid tumor infiltrating lymphocytes, and TIGIT expression was significantly higher than PD-1 expression in the same sample. Cells with transparent cytoplasm were diffuse, and several cells showed dark nuclear staining with mild atypia; the interstitium was rich in blood vessels and had mild fibrous hyperplasia, and immunofluorescence staining showed cells were positive for TIGIT. The expression of PD-1 and TIGIT was significantly different between RCC and adjacent normal tissues (P<0.05). Positive PD-1 expression was closely related to tumor size and Fuhrman grade (P<0.05). The expression of TIGIT and PD-1 was related to the distance of adjacent normal tissues to RCC (P<0.05).ConclusionsThe activation of PD-1 and TIGIT may exert negative regulatory effects and inhibit the immune response to cancer cells, resulting in immune escape of cancer cells. Both PD-1 and TIGIT may serve as potential targets for the treatment of RCC.