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Microsatellite instability in hyperplastic and adenomatous polyps of the stomach
Author(s) -
Nogueira Ana M. M. F.,
Carneiro Fátima,
Seruca Raquel,
Cirnes Luis,
Veiga Isabel,
Machado José C.,
SobrinhoSimões Manuel
Publication year - 1999
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/(sici)1097-0142(19991101)86:9<1649::aid-cncr5>3.0.co;2-n
Subject(s) - hyperplastic polyp , microsatellite instability , malignant transformation , adenomatous polyps , pathology , immunohistochemistry , medicine , neoplastic transformation , stomach , carcinoma , cancer , colorectal cancer , gastroenterology , biology , carcinogenesis , microsatellite , colonoscopy , gene , allele , genetics
BACKGROUND Few studies have focused on the presence and significance of microsatellite instability (MSI) in gastric polyps, and the results on record are conflicting. The aim of the current study was to address this issue, taking into consideration the 2 main types of gastric polyps, the coexistence of foci of malignant transformation, and the expression of p53 and ERBB‐2. METHODS Six hyperplastic polyps, 10 adenomatous polyps, and 4 adenomatous polyps displaying foci of malignant transformation (intestinal‐type carcinoma) were studied for MSI. The authors analyzed a mononucleotide repeat microsatellite (BAT‐26) and 5 dinucleotide repeats in microdissected formalin fixed, paraffin embedded tissue sections that were representative of the lesions. Expression of p53 and ERBB‐2 were evaluated by immunohistochemistry. RESULTS BAT‐26 positivity was detected in 1 of 6 hyperplastic polyps (16.7%) and in 2 of 10 adenomas (20%) without malignant transformation. In the 4 adenomatous polyps with carcinomatous foci, BAT‐26 positivity was detected in 2 cases (50%) in both (adenomatous and carcinomatous) components of the lesions. p53 immunoreactivity was observed in 6 adenomatous polyps, 2 of them with malignant transformation. Overexpression of the ERBB‐2 protein was detected in 1 adenomatous polyp with malignant transformation. CONCLUSIONS Replication error (RER+) phenotype occurs in both hyperplastic and adenomatous polyps of the stomach. The highest frequency is observed in adenomatous polyps with carcinomatous foci, suggesting that MSI may play a role in the process of malignant transformation in this setting. No significant association was observed between RER+ phenotype and overexpression of p53 or ERBB‐2 proteins. Cancer 1999;86:1649–56. © 1999 American Cancer Society.