TET1 and cancer: Since FOXA1 functions as a transcriptional promoter in multiple kinds of cancers and TET1 functions as a DNA methylhydroxylase to decrease the methylation level of various gene promoters and enhance their transcription [20, 21], we predicted that hsa_circ_0007919 binds to FOXA1 and TET1 to promote the transcription of LIG1.