There were also significant differences in the serum levels of CEA between patients with colorectal cancer and control subjects (P = 0.02); the mean serum concentration was 18.3±100.8 ng/mL in patients with colorectal carcinoma and 1.9±1.8 ng/mL in control subjects (Figure S2B). This evidence concerns the gene CEACAM5 and colorectal cancer.