Abstract: Translesion DNA synthesis is a kind of post-replication repair process, which mainly involves DNA polymerase kappa, eta and zeta. Translesion synthesis is a tolerance mechanism of DNA damage inside the cell, in which DNA polymerase zeta plays an important role. DNA polymerase zeta is mainly composed of subunits Rev7 and Rev3, and play the main role of participate in the damage repair in cell metabolism. Rev7 (also known as MAD2L2) is a multifunctional protein that can be combined with a variety of proteins to participate in DNA damage repair, cell cycle regulation, gene expression and carcinogenesis, which is also involved in the process of controlling the prognosis of various adverse tumors.