Role of p53 Expression in the Progression of Gastric Cancer in the Indian Population

ABSTRACT Introduction: Gastric carcinogenesis frequently affects tumor suppressor TP53 gene, resulting in increased expression of p53 protein and mutations towards later stages of Gastric Carcinoma. Objectives: To analyze p53 protein expression in different stages of gastric cancer to determine if it could be used as a biomarker to allow targeted screening of high risk groups with intestinal metaplasia. Methods: We retrieved 101 formalin fixed paraffin embedded tissue blocks of histopathology proven Gastric Carcinoma specimens and conducted an immunohistochemical study on a subset of 25 cases. Tumor sections were taken with adjacent normal mucosa. p53 expression was evaluated using immunohistochemical markers. With the observations from the study, analysis of p53 expression in different areas of the mucosa was done. Result: Thirteen carcinoma cases (52%) expressed p53 protein with a majority of eight (66.7%) cases showing intensity 3. Normal and metaplastic mucosa did not express p53 protein. In dysplastic mucosa, seven (28%) cases showed p53 expression with intensity ranging from 1 to 3. On comparing the data after excluding the p53 negative regions of normal and metaplastic mucosa, there was no difference with statistical significance. Conclusion: p53 expression is negative in normal and metaplastic gastric mucosa but shows expression in dysplastic and cancer cells. Thus, TP53 mutation is most likely an event towards later stages of carcinogenesis. We are dubious on the ability of p53 to be used as an authentic screening tool at the metaplastic stage to predict progression to carcinoma