Among the m6A RNA methylation regulators, the writers METTL3 and METTL14 were reported as suppressor genes in GBM but oncogenes in acute myelocytic leukemia (AML) and hepatocellular carcinoma [15,26]; the reader YTHDF2 promotes cancer cell proliferation in pancreatic cancer [36]; the eraser ALKBH5 functions as an oncogene in both GBM and breast cancer [4,37]; and the eraser FTO is an oncogene in AML and glioma [4,28]. Here, METTL3 is linked to breast cancer.