MNU-Induced Rat Mammary Carcinomas: Immunohistology and Estrogen Receptor Expression

• Type: Article in International Scientific Journal
• Date: 2013

Authors

R. Soares Maia (Author) Other; A. I. Faustino Rocha (Author) Other; C.I. Teixeira Guedes (Author) Other; J. Pinho Oliveira (Author) Other; D. Talhada (Author) Other; A. Rema (Author) Other; F. Faria (Author) Other; M. Ginja (Author) Other; R. Ferreira (Author) Other; R. M. Gil da Costa (Author) FEUP; P. A. Oliveira (Author) Other; C. Lopes (Author) Other

Journal

Title: Journal of Environmental Pathology, Toxicology and Oncology

Vol. 32 No. 2

Pages: 157-163

ISSN: 0731-8898

Publisher: Begell House

Indexing

ISI Web of Knowledge - 2 Citations

Scopus - 2 Citations

Associated Projects

UI0511 - PROJECTO ESTRATÉGICO - UI 511 - 2013-2014

Other information

Authenticus ID: P-006-FG3

DOI: 10.1615/jenvironpatholtoxicoloncol.2013007541

Abstract (EN): Environmental exposure to nitrosamines is associated with the development of cancer in a variety of target organs. One such carcinogen, N-methyl-N-nitrosurea (MNU), has long been used to induce mammary tumors in rats, which provide a useful model to study mammary carcinogenesis. However, some poorly clarified issues remain, such as the lack of a clear description of morphological patterns of tumors and the distribution and role of estrogen receptors (ERs) during tumor progression, as tumors overexpressing ERs show aparadoxical tendency to recur after ovariectomy. Mammary carcinomas were induced in Sprague-Dawley rats using MNU. The tumors were studied histologically and distribution of smooth muscle actin and ERs was studied immunohistochemically. All tumors presented both an epithelial and a myoepithelial component, demonstrated by immunohistochemical detection of smooth muscle actin. Tumors showed distinct histological patterns: well-differentiated papillary and adenoid areas and poorly differentiated solid and spindle-cell foci. Overexpression of ERs (>75% of labelled cells vs. 0-75% in control tissue) occurred in papillary and adenoid areas but not in solid and spindle-cell foci. Poorly differentiated tumor foci are likely to represent a more advanced, estrogen-independent phase in cancer progression and constitute the basis for tumor recurrence after ovariectomy.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7