A recent study showed that DPP-4 inhibitors were thought to be primarily responsible for modulating the activity of a range of peptides, such as GLP-1 and glucose-dependent insulinotropic polypeptide, thereby inhibiting or promoting the risk of cancers, including PCa.[12] Moreover, Wesley et al found that DPP-4 inhibits the malignant phenotype of prostate cancer cells by blocking bFGF signaling pathway.[13] However, the role between incretin-based drugs and prostate cancer in real populations has not yet been fully demonstrated. This evidence concerns the gene DPP4 and prostate cancer.