FEN1 and neoplasm: Multiple studies have noted that compared with normal cells, HLA/MHC, as one of the most important phenotypic changes in the immune escape process of tumor cells, is downregulated or absent in a variety of tumor cells and is closely related to the poor prognosis of patients.38 Our data also proved that the expression of HLA-DR decreased in OSCC (Fig. 5), suggesting that downregulating FEN1 can improve the immunogenicity in OSCC.