KL and malignant colon neoplasm: Previous studies have detected both cytoplasmic and membrane-bound Klotho by immunofluorescence staining from human kidney, parathyroid gland, peripheral blood, peritoneal monocytes, cardiomyocytes, colon cancer tissues, and several human tissue-derived cells.48 We show here for the first time, the presence of both gene and protein expression of endogenous Klotho in human bone tissue.