Our results showed that PCa patients with the DPP4 rs7608798 AG+GG genotype or rs2268889 TC+CC genotype had a higher risk of developing an advanced clinical primary tumour (cT) stage (adjusted odds ratio (AOR): 1.680, 95% confidence interval (CI): 1.062–2.659, p = 0.025; AOR: 1.693, 95% CI: 1.092–2.624, p = 0.018). Here, DPP4 is linked to posterior cortical atrophy.