KLB and bladder transitional cell carcinoma: Alpha-Klotho (KLα) and beta-Klotho (KLβ) have recently been reported to correlate with cancer prognosis in some malignancies and we previously reported the association between KLα, KLβ, and urothelial carcinoma of the bladder (UCB), indicating that KLβ acts as a tumor promoter.