SIRT6 levels of serum from gastric cancer patients (n = 22, 65.27 ± 12.50 years old, 40.9% females) and healthy controls (n = 22, 63.50 ± 10.77 years old, 45.4% females) were measured to evaluate the correlation between circulating SIRT6 levels and cancer cachexia development. This evidence concerns the gene SIRT6 and cancer.