RASSF4 (Ras association domain family member 4) functions as a tumor suppressor gene that regulates apoptosis and cell cycle progression through multiple signaling pathways. The protein acts as a key regulator of the Hippo pathway, interacting with MST1 to inhibit YAP nuclear translocation, thereby suppressing cell proliferation and tumor growth 1. RASSF4 promotes apoptosis through activation of the Chk2-p53 signaling axis, stabilizing p53 and facilitating stress-induced apoptosis in response to genotoxic agents 2. The gene is frequently downregulated through epigenetic mechanisms in various cancers, including colorectal cancer 3, non-small cell lung cancer 4, and gastric cancer 2. In acute myeloid leukemia, RASSF4 expression is negatively regulated by GATA2, and its downregulation contributes to chemotherapy resistance by modulating the MDM2-p53 pathway 5. RASSF4 also plays a protective role in metabolic dysfunction-associated steatotic liver disease by preventing hepatic steatosis and fibrosis 1. Clinically, reduced RASSF4 expression correlates with advanced tumor stage, poor prognosis, and decreased overall survival in multiple cancer types, establishing it as both a prognostic biomarker and potential therapeutic target.