Relationship between p53 expression and gastric cancers in cardia and antrum

Background: The mutations in p53 gene and accumulation of p53 protein are the most common genetic events in gastric carcinomas. The present study was conducted to compare the frequency of p53 gene overexpression in a consecutive series of adenocarcinomas arising from the cardia and the antrum. This study also evaluates the associations of this gene expression with demographic and clinicopathologic findings (age, sex, histology, and grade of tumor). Methods: Retrospective analysis was performed on 111 patients with gastric cancer who had undergone upper gastrointestinal endoscopies in 5th Azar Medical Center (northeastern, Iran), during 1998-2005. The series comprised of 25 patients with cardia adenocarcinoma and 86 patients with antral adenocarcinoma. p53 alteration (nuclear p53 overexpression) was detected by immunohistochemistry. Results: Nuclear p53 overexpression was found in 14 (56%) out of the 25 and 27 (31.3%) out of the 86 patients with cardia and antral adenocarcinomas, respectively. p53 gene overexpression was significantly more frequent in adenocarcinomas of the cardia than the antrum. There were no differences in the clinicopathologic characteristics of the tumors between p53-positive and p53-negative cases in both types of the cancer. Conclusion: This study shows that p53 alterations correlate well with gastric location, and they are more frequent in adenocarcinoma of the cardia than the antrum. This result reinforce the hypothesis that the cancers of the lower esophagus and upper stomach have distinct epidemiologic, pathogenesis, and molecular characteristics from that observed in cancers of the lower part of the stomach