SIRT1 and rectal cancer: In addition, the expression level of SIRT1 was significantly correlated with tumor markers such as CA724, CEA, and CA125 in gastric cancer patients, and CEA and CA199 in colon and rectal cancer patients (p < 0.05), suggesting that SIRT1 may not only be a new target for cancer therapy, but also an important tool for clinical use in cancer diagnosis.