Although there was no direct evidence to prove that miR-21 was responsible for HBV infection or replication, some studies showed that miR-21 was essential in the HBV x protein (HBx) induced non-tumor to tumor transformation (27, 31, 33), mechanically through phosphatase and tensin homolog/phosphoinositide 3-kinase/protein kinase B (PTEN/PI3k/Akt) signaling pathway (34). Here, REG1A is linked to neoplasm.