AR and prostate cancer: While the exact mechanism of interplay between the AR and DPP4 inhibitors is still in question, it is important to note that the Russo et al. study, which suggested a potential resistance mechanism, is the only such study to date to posit such a hypothesis, while the Shah et al. SEER-Medicare study found the opposite, reporting that patients with prostate cancer on DPP4 inhibitors had superior survival outcomes [5].