According to the X-tile program, 18 nodes were defined as the optimal minimum node for CEA-elevated colon cancer patients in the SEER set (< 18 nodes vs. ≥ 18 nodes: log-rank P <  0.001), with the maximum Chi-square value 88.5 (Fig. 1). Here, CEACAM5 is linked to malignant colon neoplasm.