Xu et al. [45] by investigating the miR-21 molecular mechanisms involved in supporting hepatocellular carcinoma HEPG2 cell proliferation, reported by immunohistochemistry staining on 14 tumor samples, the miR-21 expression inversely correlated with MKK3 staining in tumor tissues, which expression was strikingly repressed when compared to relative adjacent non-tumor tissues [45]. This evidence concerns the gene MAP2K3 and neoplasm.