DNMT1 and cholangiocarcinoma: In cholangiocarcinoma, miR-148a and miR-152 target DNMT1; reduced expression of these miRNAs contributes to increased DNMT1 activity, which affects transcription of the tumor suppressor genes Ras association domain family member 1 (RASSF1A) and cyclin-dependent kinase inhibitor 2A (p16INK4a) [34].