KL and breast cancer: In humans, α-Klotho deficiency or functional variants of α-Klotho are associated with the development of vascular calcification (11, 17), atherosclerosis (18), diabetes (19), hypertension (20), chronic kidney disease (21), osteoporosis (22), anemia (23), and various cancers such as hepatocellular carcinoma (24), breast cancer (25), gastric cancer (26), and renal cell carcinoma (27).