Pathomorphological and immunohistochemical study of selected markers of tumour cell proliferation in equine sarcoids.

The research article explores the characteristics of tumor cells and connective tissue in horse skin tumors, known as sarcoids. It uses various investigative techniques and tackles factors like horse breed and tumor type. Also, it assesses the relationship between specific markers and cell proliferation and recurrence.

Study Design and Samples

• The study utilised a variety of methods for investigation, including histopathology, which involves studying the microscopic structure of diseased tissue, and immunohistochemistry, which involves the use of antibodies to detect specific antigens in a tissue section.
• Analysis was conducted on 50 sarcoids, skin tumors from horses, collected from 36 horses. The tumors were further categorized into different types, namely occult, verrucous, fibroblastic, and mixed, based on their clinical appearances.

Patient Demographics

• The tumors were majorly located in the girth, neck, head, and legs region, with girth being the highest (30%).
• The average age at first clinical examination of the horses was 5.7 years, and the sarcoids were majorly found in mares (61%) compared to geldings and stallions.
• The majority of the horses were of the Wielkopolska breed or a mixed breed with the Wielkopolska breed, and most of them were bay in color (80%).

Findings and Observations

• The study found variability in the presence of characteristic microscopic features, however, it was not sufficient to differentiate the clinical types based on histopathology alone.
• Analysis of the expression of PCNA, a marker for cell proliferation, was not indicative of the clinical type of sarcoid but was useful in determining the tumor’s biological activity and chances of recurrence.
• Despite testing, the study failed to find a relationship between AgNORs, another marker of cellular proliferation, and cell proliferation.
• One significant discovery was the presence of p53 positive cells in the epidermal and fibroblastic portions of the tumors. p53 is a protein that prevents cell proliferation, and its presence was noted in the recurring sarcoids.
• The staining for cytokeratin, an intermediate filament in epithelial cells, and vimentin, another intermediate filament in connective tissue cells, was found to aid the diagnosis of the tumor.
• The immunohistochemical studies of PCNA and p53 carry significant prognostic value.