OGG1 and esophageal cancer: In an effort to resolve this ambiguity, we have performed a meta-analysis to determine the role of OGG1 Ser326Cys polymorphism on the risk for UADT cancer and GI cancer which includes different independent case control studies on head and neck cancer, gastric cancer, colorectal cancer, pancreatic cancer, gallbladder cancer and esophageal cancer.