PRDM2 (PR/SET domain 2), also known as RIZ, is a histone methyltransferase that catalyzes lysine-9 methylation of histone H3 1. The gene produces two major isoforms through alternative splicing: RIZ1 (PR-domain positive) and RIZ2 (PR-domain negative), which differ functionally in their ability to regulate transcription 1. PRDM2 functions as a DNA-binding transcription factor with zinc-finger domains that mediate protein-DNA interactions and may activate genes like HMOX1 2. At the mechanistic level, PRDM2 regulates gene expression through epigenetic modifications and transcriptional control, with distinct isoforms showing differential effects on T lymphocyte differentiation and activation 3. Disease relevance is substantial: an imbalance between RIZ1 and RIZ2 isoforms is implicated in multiple malignancies, where the PR-positive RIZ1 is typically lost or downregulated while RIZ2 remains elevated in cancer cells 1. PRDM2 promoter methylation suppresses expression in lung cancer, and demethylating agents can restore expression and inhibit cancer cell growth 4. Mutations and deletions in PRDM2 occur frequently in hepatocellular carcinoma 5, and hypoxia-induced alternative splicing of PRDM2 produces frameshift mutations promoting tumor adaptation 6. Clinically, PRDM2 variants associate with polycystic ovary syndrome subtypes 7, suggesting diagnostic and therapeutic potential across multiple disease contexts.