CDKN1A and hepatocellular carcinoma: Cui et al. reported that exosomal miR-224 promotes cell proliferation by targeting glycine N-methyltransferase.202 In addition, exosomal miR-93 can stimulate proliferation and invasion of HCC by suppressing TIMP2/TP53INP1/CDKN1A.203 Moreover, HCC cell-derived exosomal miR-665 promotes tumor cell proliferation by targeting MAPK/ERK signal pathway.204 Studies report that serum exosomal miR-1247-3p is implicated in lung metastasis in HCC patients.