Moreover, in chronic myeloid leukemia (CML), the activity of A-to-I writer ADAR1 has been proven to hinder let-7 miRNAs’ biogenesis, enhancing the replicative capacity of leukemia stem cells and promoting cancer progression [178]; meanwhile, in colon and lung cancer, the downregulation of the m7G writer METTL1 interferes with the methylation and maturation of the same miRNA family, resulting in the enhanced migration of cancer cells [122]. This evidence concerns the gene METTL1 and cancer.