METTL3 and cancer: It has also been shown that by investigating the copy number variation (CNV) status of 23 m6A methylation-related genes (MRGs) in the cancer genome atlas (TCGA) of BCa patients, 24.51% of the 411 TCGA BCa patients had mutations in these 23 genes, with METTL3 mutations being the most frequent, indicating that METTL3 is one of the key m6A MRGs in BCa and is related to BCa survival (119).