Objective To explore the clinical significance of expression of CEA mRNA and serum CEA and the related proteins in colorectal cancer (CRC). Methods Blood samples were collected from 370 CRC patients and 350 controls. CEA mRNA was determined by RT-PCR and levels of CEA, CA19-9, CA242, and CA724 were examined with chemiluminescence. Results The positive rate of jointly detecting serum CEA, CA19-9, CA242, and CA724 was significantly higher than CEA mRNA expressions (P