Androgen and Estrogen Receptor Expression in Different Types of Perianal Gland Tumors in Male Dogs

SIMPLE SUMMARY: The immunohistochemical evaluation of the steroid hormone receptors expression in neoplastic cells is a widely used diagnostic method in human medicine especially for the selection of appropriate therapy in case of breast cancers. The authors made an attempt to demonstrate prognostic and predictive value of determination of sex hormone receptors in canine perianal gland tumors. Perianal adenomas, epitheliomas and carcinomas occur mainly in older male dogs. Although surgery is the most commonly used procedure, the risk of complications related to general anesthesia and the anatomical location of the tumor adjacent to the anus makes a dilemma. The performed studies indicate that perianal gland tumors in dogs with a high expression of androgen and estrogen receptors may show a potentially greater sensitivity to hormone therapy in contrast to tumors showing low or no expression. Moreover, it was noticed that the expression of the receptors was significantly lower in neoplasms with high histological malignancy grade compared to benign tumors. Diversified expression of androgen and estrogen receptors depending on the histological type can be used for further clinical studies aimed at developing diagnostic and prognostic schemes providing the selection of therapy in the case of perianal gland tumors in dogs. ABSTRACT: Perianal gland tumors are modified sebaceous glands present in the skin of the perianal region in the dog. Hormonal stimulation may induce hyperplasia of the perianal glands or their neoplastic progression. The presence of androgen (AR) and estrogen (ER) receptors have been demonstrated both in normal perianal glands as well as in perianal tumors. The aim of the study was an immunohistochemical assessment of the expression of estrogen and androgen receptors in perianal gland tumors in dogs as an applicatory marker for antihormonal treatment. Biopsy samples of perianal masses were collected from 41 male dogs. A histopathological examination revealed 24 adenomas, 12 epitheliomas and five carcinomas. The immunohistochemical staining showed a mainly nuclear expression of AR and ER in the neoplastic cells. Both the androgen and estrogen receptors were expressed in adenoma, epithelioma and carcinoma cases; however, the highest expression of the receptors was stated in the adenoma and epithelioma. In the case of the carcinoma, the expression of sex hormone receptors was very weak. The differences of the number of cells expressing AR and ER as well as the observed differentiated intensity of staining in the studies demonstrated that the determination of the expression of the sex hormone receptors may be useful to elaborate a diagnostic and therapeutic algorithm.