Molecular Markers of Mucosa Harboring Gastric Adenomas

Abstract

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.

Molecular Alterations in Gastric Preneoplastic Lesions and Early Gastric Cancer

“…With immunohistochemical staining, we can distinguish the different types. Intestinaltype gastric adenomas show MUC2 and/or CDX2 expression, whereas the foveolar type is characterized by strong/diffuse MUC5AC positivity, weak/focal MUC6 immunostaining, and an absence of MUC2 or CDX2 expression [28,29].…”

“…Low-grade lesions mostly feature diffuse MUC6 expression, with a surface coating of MUC5AC. About 10% of pyloric gland adenomas display focal expression of MUC2 and/or CDX2 [28,29].…”

“…Oxyntic gland adenoma is a benign epithelial neoplasm composed of columnar cells with differentiation to chief cells, parietal cells, or both, characterized by a high rate of progression to adenocarcinoma. The predominant cell type is represented by immature chief cells, which are positive for MUC6 [28,29].…”