Programmed death protein 1 (PD-1) expression in tumor-infiltrating inflammatory cells may be indicative of unfavorable survival outcomes in patients with clear cell renal cell carcinoma (ccRCC), according to a study published in In Vivo.
“Programmed death ligand-1 (PD-L1) and PD-1 expression levels in many tumors and their correlation with prognosis have been actively studied. However, studies on PD-1 expression and its prognostic value in ccRCC are limited and controversial,” the researchers wrote.
They collected data on 166 patients with ccRCC treated between 2000 and 2009 at a single institution. Representative paraffin blocks of ccRCC specimens were used to create tissue microarray blocks. PD-L1 and PD-1 expression in tumor and inflammatory cells were assessed by two pathologists.
Upon univariate analysis, significant correlations were observed between PD-1 expression in tumor-infiltrating inflammatory cells and unfavorable disease-free survival (DFS; P<0.001) and disease-specific survival (DSS; P=0.002) in the univariate analysis. Multivariate analysis yielded a significant relationship between PD-1 expression and unfavorable DFS (P=0.025).
“PD-1 expression in tumor-infiltrating inflammatory cells serves as an independent prognostic factor for unfavorable DSS in patients with ccRCC,” the study authors wrote in their conclusion.