RESUMO
Objectives: To evaluate the tumor-infiltrating PD-1 positive lymphocytes and regulatory T cells (Treg) as prognosis predic-tors of metastatic renal cell carcinoma (mRCC), and investigate the expression of PD-1 and Treg cells in mRCC and elucidate their corre-lation with clinicopathological parameters and prognosis. Methods: A total of 269 mRCC patients from June 2007 to June 2017 in Zhongshan Hospital, Fudan University, were included in the study. The expression of PD-1 and Tregs in mRCC samples were detected by immunohistochemistry. The relationship between the expression of PD-1 and Tregs was analyzed. Results: PD-1 positive expression in mRCC was 31.60% (85/269) and it was positively correlated with the tumor Fuhrman grade and negatively correlated with progno-sis. Tumor infiltration of Tregs in mRCC was 36.80% (99/269), and it was also positively correlated with the tumor Fuhrman grade and negatively correlated with prognosis. Univariate analysis showed that PD-1 positive lymphocytes and high Treg infiltration numbers were negatively correlated with overall survival (OS) and progression free survival (PFS) rates. Thus, PD-1 positive lymphocytes and high Treg infiltration numbers are independent prognostic indicators of OS and PFS and when combined, they can render a better pre-diction for prognosis. Conclusions: Intra-tumoral infiltration of PD-1 positive lymphocytes and Tregs can be used as significant prognos-tic indicators of mRCC, and the combined predictive effect is better than the individual predictive effect. Therefore, evaluating the number of PD-1 positive lymphocytes or infiltrating Tregs in mRCC is helpful in clinically estimating mRCC prognosis in patients.