Carcinoembryonic antigen (CEA), an important broad-spectrum tumor biomarker, is used as an efficient prognostic indicator in the early clinical diagnosis and disease prevention of pancreatic cancer [1,2], colorectal cancer [3,4], breast cancer [5,6], lung cancer [7,8], and gastric cancer [9,10,11]. Here, CEACAM5 is linked to gastric cancer.