METTL14 plays a complex role in malignant tumors: low levels of METTL14 expression are found in hepatocellular carcinoma [13], colorectal cancer [14, 16, 17], bladder cancer [15], gastric cancer [18], childhood ETV6/RUNX1-positive acute lymphoblastic leukemia [19], and papillary thyroid carcinoma [20], where METTL14 functions as a tumor suppressor [13–18], whereas levels of METTL14 expression are high in pancreatic cancer [21, 22] and acute myeloid leukemia [23], where this protein functions as a tumor promoter. This evidence concerns the gene METTL14 and urinary bladder cancer.