PPP1R12B (protein phosphatase 1 regulatory subunit 12B) is a regulatory subunit of protein phosphatase 1 that modulates PP1 catalytic activity and substrate specificity 1. The protein regulates myosin phosphatase activity and augments calcium sensitivity of the contractile apparatus, with roles in muscle contraction regulation and cytoskeletal organization 2. PPP1R12B undergoes insulin-stimulated phosphorylation at multiple sites (particularly serine 29, serine 504, and serine 645/threonine 646), suggesting involvement in insulin signaling pathways 1. In cancer biology, PPP1R12B functions as a tumor suppressor. The PEAK1-PPP1R12B axis inhibits colorectal cancer growth and metastasis by suppressing the Grb2/PI3K/Akt signaling pathway 3, while microRNA-4463-mediated suppression of PPP1R12B promotes colon cancer cell proliferation and migration 4. PPP1R12B is downregulated in Wilms' tumor and associated with poor patient survival 5. Beyond cancer, PPP1R12B serves as a diagnostic biomarker for abdominal aortic aneurysm (AAA), where its downregulation may be mediated by N6-methyladenosine modification and correlates with AAA severity 6. Additionally, PPP1R12B is dysregulated in pelvic organ prolapse and diabetes mellitus, emerging as a key diagnostic gene in metabolic and connective tissue pathologies 78.