METTL1 and breast cancer: METTL 1, also known as tRNA (guanine-N7)-methyltransferase, catalyzes 7-methylguanosine (m7G) modification on human tRNA, particularly at position 46 within the tRNA variable loop, by forming a complex with WD repeat domain 4.72 Ying et al. 73 found that METTL1-mediated m7G tRNA modification regulates the translation of epidermal growth factor receptor (EGFR) and EGF-containing fibulin-like extracellular matrix protein 1 (EFEMP1), promoting BC progression through the METTL1-m7G-EGFR/EFEMP1 axis.