Background The antibody Ki-67 is a reliable and easy tool to accurately assess the growth fraction of neoplasms in humans and animals, and it has been used to predict the clinical outcome. and epitheliomas of the perianal glands the computer-assisted counting and the manual counting gave similar results; however, just the computer-assisted picture analysis was effective to predict the perianal gland carcinoma recurrence. Summary Since there have been significant variations in the real amount of Ki-67-positive nuclei, this marker became effective in assisting the classification of perianal gland neoplasms also to refine the analysis criteria, in those samples with high variation in morphology/area specifically. Also, higher Ki-67 index relates to recurrence in instances of perianal gland carcinomas. Further, the computer-assisted picture analysis became an easy and reliable solution to measure the Ki-67 index in perianal gland neoplasms. Keywords: Cell proliferation, Computer-assisted picture analysis, Canines, Immunohistochemistry, MIB-1 Background Perianal glands, also called circumanal glands (by their area) and hepatoid glands (by their histological similarity with hepatocytes), are modified sebaceous glands within perianal pores and skin  primarily. Tumors of perianal glands are normal in aged and intact man canines. They happen sometimes buy Triphendiol (NV-196) in females and hardly ever in neutered men [2,3]. The causes of these neoplasms are unknown; however, gonadal hormones appear to interfere with perianal gland cell proliferation [1,3]. The possible influence of testosterone in perianal gland neoplasms is indicated by the high prevalence of benign tumor regression (up to 95%) after male neutering [1-4]. Adenoma is a common lesion in dogs and, besides hyperplasia, accounts for 8-10% of all canine skin tumors . Adenomas generally retain the lobular architecture, presenting well-differentiated hepatoid cells and a single buy Triphendiol (NV-196) peripheral layer of basaloid reserve cells . Some adenomas contain focal areas of pleomorphism that may suggest malignant transformation . Several authors have grouped perianal gland epitheliomas with perianal gland adenomas [4,6], but the World Health Organization classified adenomas and epitheliomas in different categories . Walder and Gross  classified the epitheliomas as low-grade perianal gland carcinomas. buy Triphendiol (NV-196) Distinction between adenomas and epitheliomas is easy when the basaloid reserve cells are organized in sheets, islands or trabeculae, together with moderate-low to moderate-high mitosis index, without atypia . Perianal gland carcinomas are uncommon canine malignant neoplasms and occur almost exclusively in a perianal location. Well-differentiated carcinomas are clinically indistinguishable from adenomas. They are characterized by nodular formation. On the other hand, poorly differentiated carcinomas are poorly circumscribed and usually ulcerated . The cells in well-differentiated carcinomas maintain the hepatoid morphology, forming solid islands and tightly packed trabaculae with a scarcity of collagen. The maturation patterns from reserve cells to hepatoid cells are disorganized and reserve cells are increased in number . The distinction between perianal adenoma and carcinoma is often difficult: both may have poorly preserved lobulation and intermingling of germinal cells with mature hepatoid cells . The Ki-67 antigen is expressed in G1, S, G2, and M phases of the cell cycle, but not in G0, and thus Ki-67 distinguishes between proliferating and quiescent cells . Ki-67 expression is usually estimated as percentage of immunostained cells, with nuclear staining being the most common criterion for proliferative index . Ki-67 can be managed and controlled firmly, implying a simple part in cell proliferation . Further, the principal antibody anti-human Ki-67 (clone MIB-1) continues to be extensively found in studies to look for the prognosis of various kinds canine neoplasms [12-14]. Even though the morphological design of perianal gland neoplasms, when noticed using hematoxylin and eosin stain (HE), is meant to allow a precise analysis, occasionally, the event of focal pleomorphism in epitheliomas and adenomas can recommend malignant change, and bring about recurrence. Therefore, the purpose of this research was to research the immunohistochemical design of Ki-67 staining in regular and neoplastic canine perianal glands to be able to evaluate the feasible usage of this proliferation marker as an ancillary solution to determine perianal tumor analysis and prognosis. Strategies buy Triphendiol (NV-196) Ethics This research was authorized by the Institutional Ethics and Pet Welfare Committee (Comiss?o de tica zero Uso de Animais – CEUA, UNESP, approach number 02214-2011). Cells examples Forty-two canine perianal gland neoplasms had been retrieved through the archives of an exclusive practice lab of veterinary pathology (VETPAT C Campinas C S?o Paulo- Brazil). The owners had been asked and approached to response a questionnaire concerning recognition from the pets, advancement of the entire case, and recurrence. The specimens had been re-evaluated by two pathologists. All specimens had been removed during LEPR medical procedures, set in 10% natural buffer formalin, inlayed in paraffin, and consecutive areas were used.