Proto-oncogene HER-2 in normal, dysplastic and tumorous feline mammary glands: an immunohistochemical and chromogenic in situ hybridization study.
BACKGROUND
Feline mammary carcinoma has been proposed as a natural model of highly aggressive, hormone-independent human breast cancer. To further explore the utility of the model by adding new similarities between the two diseases, we have analyzed the oncogene HER-2 status at both the protein and the gene levels.


METHODS
Formalin-fixed, paraffin-embedded tissue samples from 30 invasive carcinomas, 7 benign lesions and two normal mammary glands were analyzed. Tumour features with prognostic value were recorded. The expression of protein HER-2 was analyzed by immunohistochemistry and the number of gene copies by means of DNA chromogenic in situ hybridization.


RESULTS
Immunohistochemical HER-2 protein overexpression was found in 40% of feline mammary carcinomas, a percentage higher to that observed in human breast carcinoma. As in women, feline tumours with HER-2 protein overexpression had pathological features of high malignancy. However, amplification of HER-2 was detected in 16% of carcinomas with protein overexpression, a percentage much lower than that observed in their human counterpart.


CONCLUSIONS
Feline mammary carcinoma would be a suitable natural model of that subset of human breast carcinomas with HER-2 protein overexpression without gene amplification.
Ordás
Javier
J
Departamento de Anatomía Patológica Comparada, Facultad de Veterinaria, Universidad de Córdoba, Campus Universitario de Rabanales, Carretera de Madrid- Cádiz Km 396 14014 Córdoba, Spain. jordas@jccm.es
Millán
Yolanda
Y
Dios
Rafaela
R
Reymundo
Carlos
C
de Las Mulas
Juana Martín
JM
D000818:Animals; D002415:Cats; D005260:Female; D005456:Fluorescent Dyes; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008321:Mammary Glands, Animal / Q000737:chemistry* / Q000378:metabolism / Q000473:pathology; D015674:Mammary Neoplasms, Animal / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D000090063:Proto-Oncogene Mas; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*
D005456:Fluorescent Dyes; D000090063:Proto-Oncogene Mas; D018719:Erb-b2 Receptor Tyrosine Kinases; C000715470:MAS1 protein, human