MOLECULAR MARKERS OF MUCOSA HARBORING GASTRIC ADENOMAS

Context Gastric adenoma is a precursor lesion of the adenocarcinoma. Objective To characterize gastric adenomas according to the mucin immunoexpression and to evaluate the immunoexpression of p53, p16ink4a, BCL-2, cyclin D, Ki-67, in the adenoma and in the gastric mucosa harboring adenoma. Methods Forty gastric specimens from 20 patients were classified as intestinal (MUC2 - goblet cell mucin) or foveolar (MUC5AC - gastric-foveolar mucin) adenomas. Immunohistochemistry was performed using streptavidin-biotin-complex method. Results Twelve (60%) patients were men. The mean age was 67.9 ± 12.9 years-old. Intestinal adenomas were detected in 13 (65%) patients and gastric type in 7 (35%). Low-grade dysplasia was present in 13 (65%) of the adenomas, high-grade in 3 (15%), and adenocarcinoma within the polyp in 4 (20%). Six (30%) patients had synchronous adenocarcinoma. p53 immunoexpression was observed in 6/20 (30%) of adenomas, and in 2/6 (33.3%) of synchronous tumors. There was an association between p53 immunoexpression and intestinal type of adenoma/tumor, P = 0.04. There was no association between p16ink4a, Bcl-2, cyclin D and Ki-67 and adenoma clinicopathological characteristics. Conclusion Immunohistochemistry may be useful to classify the adenomas subtypes and may define the pathway of adenoma to carcinoma sequence