m6A levels are decreased in immortalized and oncogenically transformed human mammary epithelial cells. The levels of METTL3 are descresed and ALKBH5 are increased. Overexpression of METTL3 and METTL14 and knockdown of ALKBH5 results in increased proliferation and migaration of immortalized cells. m6A levels may be downregulated in immortalized cells. Hypoxia increased m6A levels throgh mechanisms that are independent of METTL3, METTL14 and ALKBH5 expression levels. Increases of m6A levels in hypoxia are regulated by HIF.