METTL1 and urinary bladder carcinoma: Our previous study showed that the level of METTL1 is dramatically increased in bladder cancer (BC) tissues, and high expression of this marker was found to be associated with BC invasion.[15] In humans, the METTL1/WDR4 complex catalyzes the formation of 7‐methylguanosine (m7G) at the 46th position of the tRNA variable loop.