Studio immunoistochimico dell'espressione della glicoproteina p nel mastocitoma cutaneo canino in funzione del grado istologico

Canine cutaneous mast cell tumor represents a malignant neoplasm which frequently needs a combination of surgical and chemotherapeutical treatment approach. One of the most frustrating aspect is the development of multidrug resistance (MDR) due to the expression of MDR1 gene codifing P-glycoprotein (Pgp). The aim of this study was to determine and describe the pattern of expression of Pgp and find out any relations with the histologic grade of canine mast cell tumor to suggest routine evaluation for Pgp expression as an MDR marker. Tissue sections from 42 cases of canine mast cell tumor were submitted to our laboratory, classified and graded according to WHO diagnostic criteria. Immunohistochemical staining was performed using mouse monoclonal antibody C494 and the positive reaction was evaluated in 10 areas hpf. Statistical analysis of data was performed to evaluate the results. Our results indicate a direct relation between Pgp expression and histologic grade of canine mast cell tumor. Future follow up study after chemotherapy protocol would be extremely useful to suggest a routine immunohistochemical evaluation for Pgp as a MDR marker.