EXPRESSION OF BCL-2 IN TESTICULAR-CARCINOMA - CORRELATION WITH TUMOR PROGRESSION AND MDR1 PGP/

BACKGROUND. The expression of bcl-2 has been studied extensively in a variety of human tumors. However, there is a lack of clinical data reg arding its expression in germ cell testicular tumors (GCTTs). METHODS. In this study, the authors screened 70 patients with GCTTs for bcl-2 expression using immunohistochemistry (IHC) and the streptavidin-bioti n-alkaline phosphatase method. This expression was also correlated wit h the metastatic behavior, clinical stages, and multidrug resistance g ene product protein (MDR1/Pgp) immunostaining of GCTTs. RESULTS. Overa ll, 41 carcinomas (58%) stained positively with anti-bcl-2 monoclonal antibody. According to histologic type, these lesions with positive st aining included 11 of 26 seminomas (42.3%) and 30 of 44 nonseminomatou s germ cell testicular tumors (NSGCTs) (68%). The incidence of bcl-2 i mmunostaining was higher (P = 0.05, two-tailed Fisher's exact test) am ong NSGCTs than among seminomas. The expression of bcl-2 was more prev alent among tumors from patients with metastases than among tumors fro m metastasis free patients (P = 0.000). There was a significant differ ence between the three stages of disease in the expression of bcl-2 (c hi(2) = 0.000), i.e., bcl-2 expression was clearly dominant among tumo rs at advanced stages. A significant association between bcl-2 and Pgp immunostaining was established (P = 0.004). CONCLUSIONS, These findin gs revealed that bcl-2 expression occurs in GCTTs. Furthermore, they s uggest that bcl-2 is associated with a more advanced malignant phenoty pe of this tumor. (C) 1998 American Cancer Society.