Evaluación pronóstica de la reacción inmunohistoquímica del Ki- 67 en neoplasias mamarias de caninos (Canis lupus familiaris)

Abstract

The present study was designed to determine the prognostic value of the Ki-67 proliferation index in canine mammary neoplasms and its relationship with the histological degree of malignancy. The retrospective study was carried out at the Laboratories of the Technical University of Ambato, with 20 tumor samples obtained by incisional and excisional biopsies from female canine patients who attended the Veterinary Center, framed from May 2023 - May 2024. Of the twenty samples, 75% were obtained from entire females and 25% from sterilized females. The neoplasms were classified according to their histopathological degree of malignancy and compared with an immunohistochemical study that included a cell count to determine the Ki-67 proliferation index. All cases evaluated were malignant neoplasms, the histopathological grading showed the following distribution: 55% grade I (11T), 40% grade II (8T), 5% grade III (1T). Regarding the Ki-67 proliferation index, the MIB-1 antibody was used, which has proven to be one of the most used with this antigen due to its high specificity, the result was expressed as a percentage of positive cells: on a scale of 1-9%, 10 patients entered corresponding to 50%, from 10-30% there were 9 patients representing 45% and >30%, 1 patient representing 5%. When relating the Ki- 67 proliferation index with the histological grade of malignancy, a statistically significant response was obtained (P = 0.0078) which indicates that the higher the histopathological grade, the higher the Ki-67 index. These results suggest that, when performing a histopathological study, it should be complemented with an immunohistochemical study of Ki-67 to have a better diagnosis and to know the prognosis of each patient to apply an appropriate treatment.