As our study showed equivocal findings, this is very important data, as unlike other tumor types (colorectal, lung, head, and neck) which showed survival benefit with DPP4 inhibitors both in single and multi-center retrospective analyses as well as on large-scale SEER-Medicare database queries, there is a discrepancy in the findings regarding the impact on survival of DPP4 inhibitors in prostate cancer. This evidence concerns the gene DPP4 and prostate cancer.