Western blot assay showed that MG53 transfected group had much lower levels of RAC1, p-JNK, p-ERK and p-P38 (Fig. 6F), which was in consistence with our in vitro data and it further verified that MG53 inhibited the tumorigenesis of HCC through its effective inhibition of RAC1-MAPK signaling pathway. This evidence concerns the gene RAC1 and hepatocellular carcinoma.