There was a significant difference in serum Klotho levels between cancer patients [median (IQR):95.53 (71.72, 125.45) ug/g creatinine] and non‐case group [median (IQR): 99.06 (76.73, 131.18) ug/g creatinine] (p = 0.0001) (Figure S1A), even the distribution of serum Klotho by tertiles did not differ between cancer and non‐case group (p = 0.4343) (Figure S1B). Here, KL is linked to cancer.