RAB18 and hepatocellular carcinoma: Our results agreed with the previous study in HCC which showed that Rab18 was directly targeted and down-regulated at protein levels by miR-429 in HCC cells, but whether the expression of Rab18 was also regulated at transcriptional levels in NSCLC cells just like that by hepatitis B virus X protein stimulation in HCC cells remain to be investigated [23].