SMAD4 and hepatocellular carcinoma: Exosomal miR-210 secreted by hepatocellular carcinoma (HCC) cells is transferred into ECs, where it directly downregulates the expression of Sma and Mad-related protein 4 (SMAD4) and signal transducer and activator of transcription 6 (STAT6), thereby promoting angiogenesis and driving tumor vasculature formation [105].