METTL3 and breast cancer: M6A methylation writer METTL3 was discovered playing an oncogenic role in carcinogenesis, such as colorectal carcinoma (11), bladder cancer (12), breast cancer (13), etc. METTL3 mRNA and protein are expressed abundantly in AML cells, and their depletion induces cell differentiation and apoptosis and delays leukemia progression (14).