Dados do Trabalho

Título

Prognostic biomarker immunohistochemical evaluation in canine testicular tumor – preliminary results from an animal model of cancer research

Introdução

Testicular neoplasms have high incidence in domestic dogs. Man can also be affected by this group of neoplasms. Seminoma originates from seminiferous tubule germinal epithelium. Cryptorchidism is a risk factor and prognosis is good after orchiectomy. However, metastatic disease is reported in both species.
Ezrin is a protein involved in cell adhesion and tissue invasion. Its elevated expression in tumoral cells is implicated in cellular invasiveness and metastatic events.

Objetivo

To evaluate Ezrin immunohistochemical (IHC) expression in testicular seminoma in dogs as a translational study to human seminomas. Ezrin may be implicated in advanced, metastatic tumors in both species, granting prognostic value from an animal model of spontaneous disease in men.

Métodos

Study approved by UFF Ethics Committee in Animal Use (protocol 6334231122). Ten formalin-fixed paraffin-embedded samples diagnosed as canine diffuse seminoma were selected and revised from UFF Veterinary Pathological Anatomy Laboratory (LAPV-UFF) archives. Tissue sections were submitted to IHC analysis for primary anti-Ezrin antibody (mouse monoclonal, Santa Cruz,1:500 µL) by streptavidin-biotin-peroxidase method. Revelation system used was diaminobenzidine (DAB) and Harris hematoxylin as counterstaining. Positive control was included according to manufacturer. Primary antibody was replaced by the same Ig isotype as negative control.
IHC staining was evaluated considering intensity (absent - 0, weak - 1, moderate - 2, or strong - 3) and percentage of positive cells (1-25%= 1; 26-50%= 2; 51-75%= 3; 76-100%= 4) as previously described. Results were evaluated by descriptive statistical tools.

Resultados

Of 10 evaluated samples, five (50%) belonged to dogs of no specific breed followed by three (30%) Poodle and one (10%) Chow Chow and Labrador Retriever breed each. Age average was 10,8 years old, comprising old dogs. Human seminoma is more common in young adult males but its frequency in both species is very similar, besides histopathological features, enabling translational studies.
Nine samples (90%) presented positive brown cytoplasmic anti-ezrin immunostaining. Ezrin cytoplasmic immunostaining is described in other neoplasms, whether in dogs or men.
Ezrin immunomarking intensity was variable among samples. Three cases presented weak intensity, in four cases it was moderate and in two cases it was strong. Increased ezrin expression is considered a poor prognostic factor in a variety of human cancers but studies regarding seminoma whether in dog or man are scarce.
Regarding percentage of positive cells, three cases presented grade 1, one case was grade 2 and another one grade 3, with four cases presenting grade 4. Ezrin interacts with actin filaments and plasma membrane, in cell adhesion and signaling transduction, cellular events implicated in metastatic process.

Conclusões

Ezrin expression was observed in canine seminomas, varying in intensity and cell positivity percentual. Due to its role in metastatic events, ezrin has been studied as a potential molecule for target therapy. Its expression and role in canine seminomas can help elucidate ezrin implication in tumor progression through translational studies using the dog as an animal model for research in human testicular cancer.

Palavras-chave

testicular neoplasia; prognostic biomarker; animal model of research

Financiador do resumo

This study was funded/financed in part by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and FAPERJ—Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro.