The Dual Role of in Tumorigenesis: Mechanisms and Epigenetic Targeting Strategies.

RASSF4 is a key member of the Ras-associated domain family (RASSF) that exhibits dual functionality in tumorigenesis, playing critical yet context-dependent roles in various malignancies. Its expression is epigenetically regulated through promoter hypermethylation, histone modifications, and microRNAs including miR-155 and miR-196a-5p, which directly target its 3' untranslated region. In most cancers, such as non-small cell lung cancer (NSCLC) and gastric adenocarcinoma (GAC), RASSF4 acts as a tumor suppressor by inhibiting the RAS/MAPK pathway while activating the Hippo signaling cascade, ultimately inducing cell cycle arrest and apoptosis. Conversely, in aRMS, RASSF4 is upregulated by the PAX3-FOXO1 fusion oncoprotein and promotes tumor growth through MST1 inhibition and subsequent YAP activation. This review systematically analyzes current evidence regarding RASSF4's complex regulatory mechanisms and clinical significance. We propose targeted therapeutic strategies including epigenetic reactivation, gene intervention, and combination therapies. Furthermore, we identify RASSF4 as a promising diagnostic biomarker and therapeutic target based on integrated mechanistic and clinical evidence. Future research should focus on elucidating context-dependent regulatory switches, developing targeted delivery systems, and validating clinical utility through prospective trials.