CEACAM5 and neoplasm: In summary, our results support the conclusion that CEA has better diagnostic efficacy in GC, PC, GBC and CRC patients, and its expression level is related to tumor stage and metastasis; that CA199 and CA125 have better diagnostic efficacy in PC patients, but poor diagnostic efficacy for GC, EC, GBC and CRC; and that CA724 is expressed at a higher level in CRC patients but has low diagnostic efficacy.