On the contrary, DPP4 expression in both 22Rv1 and C4-2 was reduced after treatment with midostarin (<i>p</i> < 0.05).<h4>Conclusion</h4>Our study establishes DPP4 as a multifaceted pan-cancer biomarker with prognostic significance and immunotherapeutic implications, particularly in prostate cancer. This evidence concerns the gene DPP4 and prostate cancer.