Studies investigating the association between p53 codon 72 polymorphism and gastric cancer risk report conflicting results. The objective of this study was to quantitatively summarize the evidence for such a relationship. Two investigators independently searched the Medline and Embase databases. This meta-analysis included 12 case-control studies, which included 1,665 gastric cancer cases and 2,358 controls. The combined results based on all studies showed that there was no significant difference in genotype distribution [Arg/Arg odds ratio (OR) 5 0.96, 95% confidence interval (CI) 5 0.79, 1.16; Pro/Pro (OR 5 1.21, 95% CI 5 0.92, 1.58); Pro/Arg (OR 5 0.95, 95% CI 5 0.79, 1.14)] between gastric cancer and noncancer patients. When stratifying for race, results were similar except that patients with gastric cancer had a significantly lower frequency of Arg/Arg (OR 5 0.84, 95% CI 5 0.72, 0.99) than noncancer patients among Asians. Stratified the various studies by the location, stage, Lauren's classification, and histological differentiation of gastric cancer, we found that (i) patients with cardia gastric cancer had a significantly higher frequency of Pro/Pro (OR 5 3.20, 95% CI 5 1.46,7.01) than those with noncardia gastric cancer among Asians; (ii) patients with advanced (stage III/IV) gastric cancer had a significantly higher frequency of Arg/ Arg (OR 5 1.48, 95% CI 5 1.01, 2.16) than those with early (stage I/II) gastric cancer among Asians; (iii) patients with poor differentiation had a significantly lower frequency of Pro/Pro (OR 5 0.13, 95% CI 5 0.03, 0.64) than those with well differentiation among Caucasians. This meta-analysis suggests that the p53 codon 72 polymorphism may be associated with gastric cancer among Asians, and that difference in genotype distribution may be associated with the location, stage, and histological differentiation of gastric cancer. ' 2007 Wiley-Liss, Inc.Key words: gastric cancer; p53 codon 72; gene polymorphism; meta-analysis Gastric cancer, the second leading cause of death from cancer throughout the world, is an important health problem. A 2005 analysis of the worldwide incidence of and mortality from cancer showed that 934,000 cases of gastric cancer occurred in 2002 and that 700,000 patients die annually of this disease. 1 Despite the overall decline in gastric cancer rates in most of the Western World, gastric cancer remains a serious fatal disease throughout much of the rest of the world. Thirty-eight percent of worldwide cases occur in China, where it remains the most common cancer in both sexes as it is elsewhere in Eastern Asia. 2 Conversely, the incidence rates of adenocarcinomas of the proximal stomach and distal esophagus have been increasing, particularly in the Western World. 3 Gastric carcinogenesis is a complex, multistep and multifactorial process, in which many factors are implicated. The majority of gastric cancers are thought to be caused by environmental factors that result in damage to the mucosa and that inhibit its ability to repair itself. This response...