YAF2 (YY1-associated factor 2) is a zinc finger protein that functions as a multifaceted transcriptional regulator with dual roles in both oncogenic suppression and cell survival. Structurally, YAF2 contains an N-terminal C2-X10-C2 zinc finger domain 1 and functions as a component of Polycomb repressive complexes, bridging YY1 interaction with PRC1 to enable PcG recruitment to chr12 2. YAF2 demonstrates opposing effects on MYC family proteins: it inhibits MYC-mediated transactivation while enhancing MYCN-dependent activation, suggesting isoform-specific or context-dependent regulation. At the cellular level, YAF2 exhibits anti-apoptotic activity through multiple mechanisms. Phosphorylated YAF2 stabilizes FANK1 protein by inhibiting its proteasomal degradation, suppressing tumor cell apoptosis 3, and acts as a caspase-8 inhibitor essential for embryonic survival 4. Additionally, YAF2 promotes TP53-mediated genotoxic stress responses by stabilizing PDCD5 protein and preventing its ubiquitin-dependent degradation 5. Clinically, elevated YAF2 expression in non-small cell lung cancer correlates with poor prognosis, increased metastasis, and cisplatin resistance via AKT/p38 MAPK pathway activation 6. YAF2 represents a potential therapeutic target for cancer treatment, as miR-139-5p-mediated YAF2 suppression sensitizes cancer cells to chemotherapy and reduces invasive capacity.