The most frequently reported alteration of multidrug-resistant cells is overexpression of a 170 kD glycoprotein (P-glycoprotein or P-170) encoding by the MDR1 gene family. Expression of the multidrug-resistance gene product P-glycoprotein was screened in 55 untreated human germ cell testicular tumors using monoclonal antibody (C219) and immunoenzyme staining. In samples out of 17 seminomatous germ cell testicular tumors (SGCT) 2 seminomas, and out of 38 non-seminomatous tumors (NSGCT) 20 carcinomas (15 teratomas, 4 embryonal carcinomas, 1 with Yolk sac differentiation and 1 embryonal rhabdomyosarcoma) showed high expression of P-glycoprotein. NSGCT-s, which are more refractory than seminomas to anticancer chemotherapy, frequently expressed P-glycoprotein. These immunohistochemically detected elevated P-170 expressions were correlated by the overexpression of MDR1 mRNA gene sequences. A relationship between clinical resistance and P-glycoprotein expression seems thus to exist in 4 teratomas 3 embryonal carcinomas, and 1 seminomas. A significant correlation (p < 0.02) between P-170 expression and clinical drug resistance in stage II-III germ cell testicular tumors could be demonstrated. The results suggest that a multidrug resistant phenotype may also occur and P-glycoprotein might contribute to drug resistance in testicular tumors.
|Translated title of the contribution||Multidrug resistance of testicular cancers. (Detection of P-glycoprotein and MDR1 gene expression and their clinical connection)|
|Number of pages||7|
|Publication status||Published - jan. 1 1995|
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