The serum concentration of IL-26, CEA, CA19-9, CA125, CA72-4, and ferritin was measured by ELISA in 100 patients with benign gastric diseases and 302 GC patients, including stages I (n = 75), II (n = 73), III (n = 125) and IV (n = 29) [111]. Here, CEACAM5 is linked to gastric cancer.