METTL1 and hepatoblastoma: Our group has previously reported that many genetic variants of genes encoding RNA m6A and m7G methyltransferase, demethylase, and m6A-reading proteins confer hepatoblastoma susceptibility, including METTL3 [10], METTL4 [9], AlkB homolog 5 (ALKBH5) [28], FTO [29], YTHDC1 [30], YTHDF1 [14], WTAP [15], WDR4 [13], and METTL1 [11].