Additionally, circRNAs in exosomes derived from HCC cells, specifically circGSE1, act on the miR-324-5p/transforming growth factor beta receptor 1 (TGFBR1)/SMAD family member 3 (Smad3) axis to induce expansion of regulatory Tregs and facilitate immune evasion of HCC cells (Huang et al., 2022). Here, SMAD3 is linked to hepatocellular carcinoma.