In contrast to the tumor-friendly role of galectin-9, results obtained from mouse models in vivo and in vitro indicated that galectin-9 can promote tumor cell apoptosis, including in chronic myelogenous leukemia cells [49], malignant melanomas [50,51], gallbladder carcinomas [52], HCCs [53], cholangiocarcinomas [54] and gastric cancer cells [55]. This evidence concerns the gene LGALS9 and gastric cancer.