In this study, using online database, we analyzed the prognostic role of five m6A modulators in breast cancer, especially in TNBC, the sub-type with the worst prognosis and the greatest potential for metastasis, and found that METTL3 is the most critical in TNBC, that METTL3 occurred at low expression in TNBC, and was a protective factor of DMSF. The gene discussed is METTL3; the disease is breast cancer.