Correlation between oestrogen receptor (ERα) and Ki-67 receptor expression in canine genital neoplasms by immunohistochemistry

Abstract

The objective of the current study involved assessment of correlation between the expression of oestrogen receptor (ERα) and Ki-67 by immunohistochemistry, in the genital borne neoplasms in 12 postpubertal bitches between 2 to 12 years of age, presented at University Veterinary Hospitals, Kokkalai and Mannuthy. The age group of 5-8 years had the highest incidence of neoplasia (50.00 %) in comparison with other groups. Episiotomy was performed for extraluminal tumours while local excision performed in all intraluminal tumours except canine transmissible venereal tumour (CTVT). A chemotherapeutic regimen involving intravenous infusion of vincristine sulphate at 0.025 mg/kg was administered to bitches with CTVT and squamous cell carcinoma (SCC) until complete remission of the neoplasm. The tumours were histopathologically confirmed as myofibroma (n=6), CTVT (n= 3), leiomyoma (n = 1), SCC (n = 1) and fibroma (n = 1). Immunohistochemical staining of the neoplastic tissues was performed to evaluate ERα and Ki-67 expression status which could aid in estimating the malignancy potential and influence of ERα on the same. Spearman’s rank correlation between the immunohistochemical scores for the expression of ERα and Ki-67 in these tumours was highly significant (p<0.01). The correlation between ERα and Ki-67 had a significant negative correlation (p < 0.05). In conclusion, the study suggests that higher expression of Ki-67 of a neoplasm coupled with lower expression of ERα bears evidence to a malignant process.

Keywords

• canine
• genital neoplasms
• immunohistochemistry
• erα
• ki-67