CCND1 and neoplasm: Therefore, HBx, especially the HBx-deletion mutant HBx-d382, is involved in regulating CyclinD1 expression through an HBx-mediated miR-338-3p down-regulation mechanism, suggesting that miR-338-3p plays a tumor suppressor role in the development of HBx- and HBx-d382 deletion-mutant–mediated HCC.