MACC1 (metastasis-associated in colon cancer 1) functions primarily as a transcriptional activator of the MET receptor tyrosine kinase, serving as a key regulator of HGF-MET signaling pathways 1. The protein promotes cellular motility, invasion, and proliferation in vitro, and drives tumor growth and metastasis in vivo through its transcriptional control of MET expression 1. MACC1's mechanism involves binding to the MET gene promoter and activating transcription, subsequently enhancing hepatocyte growth factor/MET signaling cascades that facilitate cancer progression 1. Additional regulatory mechanisms include interactions with GIPC1, which functions both as a protein binding partner and transcription factor for MACC1, creating a feedback loop that amplifies metastatic potential 2. MACC1 overexpression demonstrates strong clinical significance as a prognostic biomarker across multiple solid tumor types. Meta-analyses reveal that high MACC1 expression correlates with poor overall survival (HR 2.11), reduced relapse-free survival (HR 2.22), and decreased disease-free survival (HR 2.94) 3. In hepatocellular carcinoma specifically, MACC1 overexpression associates with aggressive tumor characteristics including vascular invasion, capsule invasion, and metastasis 4. Furthermore, MACC1 expression influences chemotherapy sensitivity, with MACC1 silencing enhancing apoptosis and increasing sensitivity to cisplatin treatment 5.