Preoperative CEA was recognized as an independent prognostic factor for CRC (19, 20), while postoperative CEA was more important in the monitoring of recurrence and metastasis, and the postoperative CEA levels increased 2-6 months before the diagnosis of recurrence in 18%-75% of the recurrent CRC cases (10, 21, 22). The gene discussed is CEACAM5; the disease is colorectal carcinoma.