Since NKX6.3 is expressed in post-mitotic differentiated migrant cells of gastric units and loss of heterozygosity at chromosome 8p11 has been frequently detected [7, 8], we hypothesized that alteration of the NKX6.3 gene may lead to abnormal differentiation and homeostatic imbalance of gastric mucosal epithelium and may eventually cause gastric cancer. This evidence concerns the gene NKX6-3 and gastric cancer.