This may be due to following reasons: (a) CEA data in our study were non-normally distributed data, and Wilcoxon test, instead of unpaired Student’s t-test, was used to compare the two groups; (b) our data were obtained within 1 week before operation, which may be different from Alotaibi’s study, for which a data collection time-frame is not indicated; and (c) our study enrolled RC patients rather than CRC patients. The gene discussed is CEACAM5; the disease is colorectal carcinoma.