[Lung resistance protein analysis in testicular cancer].

Germ cell testicular cancers are well-curable neoplasms, because total remission can be achieved in about 80% of the cases. However, 15-20% of the patients die due to drug resistance (DR). A number of mechanisms of the multidrug resistance phenotype are known, including MDR/P-glycoprotein (P-gp) and the so-called multidrug resistance associated protein (MRP). Lung Resistance Protein (LRP) is an ATP dependent membrane transporter protein associated with MDR. In our present work we studied the expression of LRP in testicular cancers. LRP expression was determined by immunohistochemistry (IH), Western blot (WB) and RT-PCR techniques. Clinical resistance was defined in accordance with the clinical oncologic rules. In 29 (41%) of 70 primary testicular tumours and in 22 (63%) of 35 cases, elevated LRP levels were established by IH and WB, respectively. In the latter 63%, the LRP mRNA levels were elevated as well. Six cases of the 15 seminomas and 23 cases of the nonseminomatous germ cell tumours (NSGCT) proved to be positive. No relationship was demonstrated between LRP expression and the stage of the disease. Despite the LRP positivity of 6 tumour samples, all of the seminomas proved sensitive. Of the 39 sensitive NSGCT, 27 cases were LRP-negative, whereas 11 tumour samples of 16 patients belonging to the resistant group proved LRP-positive (p=0.04). The authors concluded that the expression of LRP is responsible for clinical drug resistance in non-seminomatous testicular cancer patients.