FOXK2 and bladder transitional cell carcinoma: Significant up‐regulation of FOXK2 was observed in prostate adenocarcinoma (PRAD), uterine corpus endometrial carcinoma (UCEC), bladder urothelial carcinoma (BLCA), colorectal cancer (CRC), pancreatic ductal adenocarcinoma (PDAC), and stomach adenocarcinoma (STAD), while no such increase was found in lung cancer (lung adenocarcinoma [LUAD], lung squamous cell carcinoma [LUSC]) or thyroid carcinoma (THCA) tumor and adjacent tissues.