METTL1 enhances the translation of GADD45A and RB1 through an m7G dependent, codon-specific mechanism that increases tRNA-m7G levels, thereby inducing G2/M arrest and suppressing breast cancer cell proliferation while increasing the antitumor efficacy of CDK4/6 inhibitors such as abemaciclib. Here, CDK4 is linked to breast carcinoma.