RESUMO
One established mechanism of multidrug resistance [MDR] in cancer chemotherapy is elevated expression of permeability-glycoprotein [Pgp], that functions as an efflux pump which excretes lipophilic chemotherapeutic drugs from cancer cells. The expression of Pgp by immunohistochemistry was examined in tissue specimens taken from 60 patients with head and neck squamous cell carcinomas using a monoclonal antibody, which is specific to human MDR1 gene product. The results showed that 80% of the tumors were stained by Pgp antibody with a statistically significant correlation between the degree of expression of Pgp and the degree of differentiation. The results showed also a wide variation in Pgp expression and high expression of Pgp in more undifferentiated tumors. So, Pgp can be used as a marker for diagnostic and prognostic value in the head and neck cancer