No evidence for c-erbB-2 overexpression in gastric carcinogenesis.

Abstract

Conflicting data on c-erbB-2 overexpression in gastric carcinomas can be found in the literature with regard to overall prevalence, prognostic significance and the histological type according to Lauren. The majority of these studies have focused on advanced gastric carcinomas whereas data on c-erbB-2 overexpression in early gastric carcinomas, especially of Caucasian origin, are relatively sparse. We therefore examined a series of Caucasian early gastric carcinomas to assess overall c-erbB-2 overexpression and to correlate c-erbB-2 overexpression, if any, with the type of growth pattern and the Lauren type. Forty-five paraffin-embedded gastrectomy specimens from early carcinomas were examined for the presence of chronic active gastritis, chronic atrophic gastritis, subtypes of intestinal metaplasia and dysplasia. The Lauren type and the type of growth pattern were reassessed for all early carcinomas. c-erbB-2 overexpression was assessed with monoclonal antibody 3B5 and polyclonal antibody A485. Complete absence of c-erbB-2 overexpression was observed in chronic active gastritis, chronic atrophic gastritis, subtypes of intestinal metaplasia, and dysplasia. Moreover, c-erbB-2 overexpression was found absent in both intestinal-type (n = 20) and diffuse-type early gastric carcinomas (n = 25), irrespective of growth type. c-erbB-2 overexpression does not play a role in the progression from normal to neoplastic gastric mucosa and should be considered as a late event in gastric carcinogenesis. Moreover, c-erbB-2 overexpression does not discriminate between intestinal and diffuse type early gastric carcinomas of Caucasian origin. Finally, it appears that mechanisms other than c-erbB-2 overexpression underlie the reported differences in biological behaviour of early gastric carcinomas with different types of growth pattern.