RESUMO
Various doses of 17beta-estradiol (E2) were administered subcutaneously to inbred female Sprague-Dawley (SD) rats once at birth. At 50 days after birth, rats in all the groups were given 10 mg of 7, 12-dimethylbenz[a]anthracene (DMBA). In the 1000 microg group, the incidence and number of mammary carcinomas were markedly low, while in the 10 microg group, a large number of mammary carcinomas was noted. Corpora lutea were observed in all rats in the control, 0.1, 1, 10 and 100 microg groups at 50 days old; however, no corpora lutea were observed in any rat in the 1000 mg group at age 50 days and at sacrifice. Observation of the whole-mount specimens showed a low number of terminal end buds (TEBs) in the 1000 microg group and a high number in the 10 microg group. It is suggested that neonatal administration of E2 affects the gonadotropin-secreting system, resulting in a decrease of progesterone, which is thought to influence the progression of mammary carcinomas induced by DMBA. Moreover, neonatal administration of E2 directly affects the mammary glands, and it is suggested that E2 may promote differentiation of TEBs resulting in inhibitory effects on the initiation of mammary carcinomas.
Assuntos
9,10-Dimetil-1,2-benzantraceno/toxicidade , Carcinógenos/toxicidade , Estradiol/farmacologia , Neoplasias Mamárias Experimentais/patologia , Animais , Animais Recém-Nascidos , Relação Dose-Resposta a Droga , Estradiol/administração & dosagem , Feminino , Neoplasias Mamárias Experimentais/induzido quimicamente , RatosRESUMO
A solid mass arising from the mammary gland was found in a 7-year-old female cynomolgus monkey. Histologically, the mass consisted of 2 components: spindle-shaped or ovoid sarcomatous cells and squamous epithelial cells. Metastatic nodules noted in the lung, liver and the gallbladder had the same histological features as the mammary mass. Immunohistochemistry revealed that the sarcomatous cells were positive for alpha-smooth muscle actin (alpha-SMA), vimentin, calponin, S-100 protein, epithelial membranous antigen (EMA), cytokeratin (large spectrum) and cytokeratin 14 (CK 14) in the cytoplasm, and p53, erbB-2 and progesterone receptor in the nuclei, but negative for desmin and estrogen receptor. The squamous epithelial cells were positive for EMA, cytokeratin (large spectrum) and CK 14, but negative for the rest. Both sarcomatous and squamous epithelial components were negative for glial fibrillary acidic protein (GFAP). Based on histological and immunohistochemical features, the present case was diagnosed as a malignant myoepithelioma with a squamous epithelial component in the mammary gland with distant metastases.
