PPP5C encodes protein phosphatase 5 (PP5), a serine/threonine protein phosphatase with dual function as both a phosphatase and co-chaperone 1. The enzyme exhibits unique self-inhibitory regulation through low basal activity that is activated by various cellular signals 1. PPP5C functions as a catalytic phosphatase by coordinating with active-site metal ions and dephosphorylating diverse substrates including kinases, nuclear receptors, and signaling proteins 2. The protein regulates multiple cellular processes including cell cycle progression, apoptosis, and signaling pathways such as Wnt signaling through dephosphorylation of Dvl2 3. PPP5C is highly expressed in several cancer types including prostate, bladder, and ovarian cancers, where it promotes cell proliferation and survival 456. In prostate cancer, PPP5C regulates JNK and ERK1/2 phosphorylation to promote cell survival 4. The gene shows intolerance to loss-of-function variants, and de novo variants cause severe developmental phenotypes including microcephaly, seizures, and developmental delay, suggesting haploinsufficiency 7. PPP5C also participates in glucocorticoid-responsive gene networks in brain tissue, contributing to stress response mechanisms 8. Its dual phosphatase-chaperone function makes PPP5C an emerging therapeutic target for cancer treatment 1.