CEACAM5 and neoplasm: Fourth, tumor markers such as carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA) levels are affected by cholangitis and obstructive jaundice, and thus show insufficient diagnostic ability9.Therefore, a novel target that facilitates a high-precision early diagnosis and intensive treatment, besides curative resection, of GBC is needed.