Recent retrospective cohort analysis of 15,330 patients with PC and diabetes showed that use of DPP-4 inhibitors only (n = 441) (HR 0.77; 95% CI: 0.64–0.93) and in combination with metformin (n = 820) (HR 0.80; 95% CI: 0.68–0.94) had a significant overall survival (OS) benefit compared to the reference group (not on either DPP4 inhibitors or metformin). This evidence concerns the gene DPP4 and diabetes mellitus.