P-glycoprotein expression in primary and metastatic transitional cell carcinoma of the bladder
Antineoplastic Combined Chemotherapy Protocols
Carcinoma, Transitional Cell
Urinary Bladder Neoplasms
The data show that an increase in the proportion of cells expressing P-glycoprotein occurs after exposure to a combination chemotherapy program containing drugs known to select for P-glycoprotein expression in vitro. The observation of increased immunoreactive endothelial cells suggests transactivation of the MDR1 in these cells. While data are preliminary, P-glycoprotein expression in capillary endothelial cells may contribute to drug resistance. Taken together, these mechanisms may contribute to therapeutic failure in patients with bladder tumors treated with chemotherapy.