Dpp4 Genetic Variants Influence Baseline Prostate-specific Antigen Levels: the J-micc Study

Prostate specific antigen (PSA) testing plays a major role in prostate cancer screening; however, the low positive predictive value of PSA testing leads to many unnecessary biopsies. Genetic background is one of factors that could cause it. That's why an association between genetic background and PSA levels should be elucidated. This study aimed to investigate whether DPP4 genetic variants are associated with baseline PSA levels. A cross-sectional study was performed on 2,074 Japanese men aged between 35 and 69 in the Shizuoka area from the Japan Multi-institutional Collaborative Cohort (J-MICC) Study. Three DPP4 tagging single nucleotide polymorphisms (SNPs) were selected for genotyping: rs3788979 (A/G), rs7608798 (T/C), and rs2268889 (A/G). Higher mean serum PSA levels were significantly associated with an increase in the number of the rs7608798 C allele (p for trend = 0.02). A stratified analysis by age groups demonstrated that PSA levels had positive significant trends with the numbers of the minor alleles of rs3788979 or rs7608798 in the oldest group (men aged between 60 and 69) (p for trend=0.004 for rs3788979 and p for trend=0.001 for rs7608798). Haplotype analysis showed that the C-A (rs7608798-rs2268889) haplotype was significantly associated with increased PSA levels (p=0.006), compared with the most common haplotype, T-A. In summary, our study suggests that DPP4 genetic variants influence baseline PSA levels, especially in men aged between 60 and 69.