E2F1 and ovarian cancer: NSUN2 is aberrantly upregulated in ovarian cancer and promotes the malignancy of ovarian cancer through regulating the expression of the oncogenic driver E2F transcription factor 1 (E2F1) in an m5C-dependent manner, and E2F1 facilitates the transcription of NSUN2 as well as MYBL2 and RAD54L.