Nevertheless, preoperative serum CEA was not associated with MLM in the univariable logistic regression analysis, which might be because serum CEA levels are influenced by several factors 28,29, including tumor size, tumor CEA contents, CEA production rates, tumor location, and the rate of CEA elimination 29-31, and their results contradict the suggestion that CEA levels increase with more advancing stages of CRC. The gene discussed is CEACAM5; the disease is colorectal carcinoma.