PGM5 (phosphoglucomutase 5) is a structural protein with dual roles in cellular junctions and cancer regulation. Originally characterized as a component of adherens-type cell-cell and cell-matrix junctions that positively regulates myofibril maturation and sarcomere organization 1, PGM5 lacks phosphoglucomutase enzymatic activity despite its name. Recently, PGM5 has emerged as a tumor suppressor across multiple cancer types. PGM5 expression is significantly downregulated in prostate cancer, with low expression correlating with poor prognosis and high Gleason scores; overexpression represses cancer cell proliferation and migration 2. The PGM5 antisense transcript PGM5-AS1 functions as a competing endogenous RNA (ceRNA) that inhibits cancer progression in bladder, colorectal, cervical, and esophageal cancers through distinct microRNA-sponging mechanisms 3, 4, 5, 6. In colorectal cancer, PGM5-AS1 shows diagnostic potential, with combined testing improving early-stage cancer detection 7. Beyond cancer, PGM5 transcripts are expressed in the placenta where their expression is dysregulated in pregnancy complications like fetal growth restriction and preeclampsia, suggesting roles in placental development 8. These findings position PGM5 as both a structural organizer of muscle and epithelial tissues and an important tumor suppressor with clinical biomarker potential.