Association Between Polymorphisms in Genes Encoding PD-1/PD-L1 Molecules and Clinicopathological Features in Clear Cell Renal Cell Carcinoma

The PD-1/PD-L1 axis is crucial for immune regulation and homeostasis, but cancer cells can exploit this pathway to evade immune surveillance. PD-1, a key immune checkpoint receptor, interacts with its ligands PD-L1 and PD-L2 to modulate immune responses within the tumor microenvironment. We hypothesized that single nucleotide polymorphisms (SNPs) in the PDCD1 and CD274 genes, encoding PD-1 and PD-L1, are associated with clinicopathological features, PD-L1 immunohistochemical expression, and clinical outcomes in clear cell renal cell carcinoma (ccRCC). We analyzed four SNPs using TaqMan allelic discrimination assays in 238 ccRCC cases: rs11568821 and rs7603052 (PDCD1), and rs4143815 and rs17718883 (CD274). The rs7603052 polymorphism in PDCD1 and rs17718883 in CD274 were significantly associated (p = 0.033 and p = 0.043 respectively) with PD-L1 expression in tumor-infiltrating immune cells (TIICs). Specifically, the C allele of rs7603052 and the CC genotype of rs17718883 correlated with PD-L1 positivity in TIICs. Additionally, the C allele of rs4143815 in CD274 was associated with PD-L1 positivity in tumor cells (p = 0.039). Notably, rs17718883 in CD274 was associated with ccRCC patient prognosis: carriers of the T allele, particularly those with the CT genotype, demonstrated improved overall survival compared to CC genotype carriers (p < 0.001). These findings suggest that PDCD1 and CD274 polymorphisms may serve as potential predictive and prognostic biomarkers in ccRCC.