PCNA and cervical squamous intraepithelial neoplasia: The results showed 5 common KEGG pathways in the N-CIN group (p < 0.01), namely, DNA mismatch repair (PCNA [20], EXO1 [21], POLD1, MSH6, and LIG1), the cell cycle (MCM3, MCM5 [22], CDC6, MCM6 [23], CHEK2, PKMYT1, CDC7, RBL1, WEE1, CCNA2 [24], and TTK), DNA replication (PCNA, POLD1, DNA2, MCM3, MCM5, PRIM2, POLE2, MCM6, LIG1, RNAEH2A, and PRIM1), cysteine and methionine metabolism (LDHC), and nucleoside exception repair (PCNA, POLD1, POLE2, and LIG1).