Abstract: The POLι(Pol iota) gene product participates in the bypass of DNA lesions. It encodes DNA polymerase ι(pol iota) that plays an important role in translesion DNA synthesis. Recently, POLι is found to be connected with the generation and development of some tumors. We summarize the gene location, construction, biological function, and molecular properties of DNA polymerase ιand address its connection with tumor susceptibility.