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 regarding 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-biotin-alkaline phosphatase method. This expression was also correlated with the metastatic behavior, clinical stages, and multidrug resistance gene product protein (MDR1/Pgp) immunostaining of GCTTs. RESULTS Overall, 41 carcinomas (58%) stained positively with anti-bcl-2 monoclonal antibody. According to histologic type, these lesions with positive staining included 11 of 26 seminomas (42.3%) and 30 of 44 nonseminomatous germ cell testicular tumors (NSGCTs) (68%). The incidence of bcl-2 immunostaining was higher (P = 0.05, two-tailed Fisher's exact test) among NSGCTs than among seminomas. The expression of bcl-2 was more prevalent among tumors from patients with metastases than among tumors from metastasis free patients (P = 0.000). There was a significant difference between the three stages of disease in the expression of bcl-2 (χ2 = 0.000), i.e., bcl-2 expression was clearly dominant among tumors at advanced stages. A significant association between bcl-2 and Pgp immunostaining was established (P = 0.004). CONCLUSIONS These findings revealed that bcl-2 expression occurs in GCTTs. Furthermore, they suggest that bcl-2 is associated with a more advanced malignant phenotype of this tumor. Cancer 1998;83:331-336. © 1998 American Cancer Society.