Lack of an association of programmed cell death-1 PD1.3 polymorphism with risk of hepatocellular carcinoma susceptibility in Turkish population: A case-control study

AimThe programmed cell death-1 (PD-1) is a potent immunoregulatory molecule which is responsible for the negative regulation of T-cell activation and peripheral tolerance. Recently, overexpression of PD-1 has been reported to contribute to immune system evasion and poor survival of hepatocellular carcinoma (HCC). A common single nucleotide polymorphism in intron 4 of PD-1 gene called PD-1.3 has been reported to influence PD-1 expression, but its association with HCC has yet to be investigated. The aim of the present study was to investigate whether this polymorphism could be involved in the risk of HCC susceptibility.MethodsThe genotype frequency of PD-1.3 polymorphism was determined by using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method in 236 subjects with HCC and 236 cancer-free control subjects matched on age, gender, smoking and alcohol status.ResultsNo statistically significant differences were found in the genotype distributions of the PD-1.3 polymorphism among HCC and cancer-free control subjects (P = 0.22).ConclusionOur results demonstrate for the first time that the PD-1.3 polymorphism has not been in any major role in genetic susceptibility to hepatocellular carcinogenesis, at least in the population studied here. Independent studies are needed to validate our findings in a larger series, as well as in patients of different ethnic origins.

► PD-1 is a member of the CD28/B7 superfamily of costimulatory molecules. ► PD-1 is responsible for the negative regulation of T-cell activation. ► We investigated the association of PD-1.3 polymorphism and risk of HCC. ► PD-1.3 polymorphism may not be a genetic susceptibility factor for HCC.