Serum CXCL12 levels in patients with esophageal cancer were measured at 1.27 ng/ml compared to 0.86 ng/ml in healthy controls [79], while gastric cancer tumors were approximately 3618 ng/ml compared to 1715 ng/ml in the non-cancer control group [80]. This evidence concerns the gene CXCL12 and esophageal cancer.