Expression of multidrug resistance gene product (P-glycoprotein) in transitional cell carcinomas of the upper urinary tract.

We assessed the expression of P-glycoprotein, the product of the multidrug resistance gene, in 107 specimens from patients with transitional cell carcinoma of the upper urinary tract, using an immunohistochemical method with a polyclonal antibody. P-glycoprotein was expressed in 28 of 107 (26%) specimens. While P-glycoprotein expression was not related to the grade or stage of these tumors, the incidence of P-glycoprotein in specimens with tumors which coexisted in renal pelvic and ureter is significantly higher than those with either renal pelvic or ureter tumor alone. In the patients with advanced upper urinary tract tumor who had adjuvant chemotherapy including at least one P-glycoprotein-transported drug (mdr regimen), overall survival of patients with P-glycoprotein-positive tumor was significantly shorter than that of patients with negative tumor. This pilot study demonstrates that P-glycoprotein can be expressed in one fourth of transitional cell carcinomas of the upper urinary tract and that P-glycoprotein expression serves as a prognostic indicator in patients with these tumors who are treated with mdr regimens.