Dados do Resumo

Título

GRANULOSA CELL TUMOR AND VIMENTIN EXPRESSION IN BITCHES: PRELIMINARY EVALUATION IN AN ANIMAL MODEL.

Introdução

Granulosa cell tumor (GCT) is the most common sex-cord-stromal tumor affecting female dogs, despite ovarian tumors rarity. GCT in women comprises 2-3% of all ovarian tumors and the adult type is more frequent, occurring in premenopausal women. Likewise, GCT is more frequent in old bitches. In both species, GCT can be active, leading to hyperestrogenism. Vimentin is a cytoplasmic filament expressed in many cells, including GCs. It is overexpressed and implicated in tumor invasion and prognosis.

Objetivo

To preliminarily investigate vimentin immunohistochemical expression in granulosa cell tumors diagnosed in ovarian samples retrieved from UFF Veterinary Pathological Anatomy Laboratory archive, from spayed bitches, evaluating female dogs as an animal model of this disease in woman.

Métodos

UFF Ethics Committee in Animal Use approval n. 1972030724. Eight formalin-fixed paraffin embedded canine ovarian GCT samples were histopathologically revaluated and processed through streptavidin-biotin-peroxidase immunohistochemical technique and analyzed under optical microscopy by two researchers. Age of included bitches was recorded when available. Sections were incubated overnight with anti-vimentin primary antibody (mouse monoclonal, Dako) and diaminobenzidine (DAB) was used as chromogen. GCT were classified regarding structural pattern (follicular, cystic or trabecular) and Call Exner body identification in HE sections. Vimentin expression was graded by semi-quantitative scale as absent, weak, moderate or strong, according to intensity of brown immunostained tumoral cells. Vimentin immunolocalization was identified as cytoplasmic, membrane or membrane-cytoplasmic, according to immunostained cellular site. Results were evaluated by descriptive statistics tools.

Resultados

Only age of three bitches included in this study was available (9,11 and 13 y) with the remaining not informed, but all adult dogs (over 1 y). Despite this lack of information, GCT occurred in old bitches, in parallel to adult GCT in premenopausal or early postmenopausal women (Sahin, Saini). GCT histopathological pattern observed were trabecular (62%, 5/8) and follicular (38%, 3/8) ones. No cystic pattern was identified. Call-Exner body was found in two samples (20%, 2/8), not obligatorily present as in women GCT (Guleria). Concerning vimentin immunoexpression, all samples were positive, with more than 90% of tumoral cells with brown (DAB) immunostaining, as reported in GCT in women (Qian). Regarding intensity, 75% (6/8) of analyzed samples were strongly immunostained for vimentin while 25% (2/8) presented moderate immunostaining. Vimentin immunostaining location was predominantly cytoplasmic but some tumoral cells also presented membrane and perinuclear immunomarking.

Conclusões

Vimentin was overexpressed in evaluated canine GCT samples, similarly to GCT in women. Vimentin cytoplasmic predominant pattern highlights its cytoskeleton function regarding cell format, migration and invasion, enabling further studies regarding prognosis. GCT occurred in old bitches resembling adult GCT in postmenopausal women, enabling translational studies in canine animal model.

Financiador do resumo

This study was funded/financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001 and FAPERJ—Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro.

Palavras Chave

granulosa cell tumor; immunohistochemical marker; animal model