BCL-2 IMMUNOREACTIVITY IN PROSTATE TUMORIGENESIS IN RELATION TO PROSTATIC INTRAEPITHELIAL NEOPLASIA, GRADE, HORMONAL STATUS, METASTATIC GROWTH AND SURVIVAL

The Bcl-2 protein prolongs cell survival by overriding apoptosis. To e xplore the role of Bcl-2 in prostate tumorigenesis, immunoreactivity f or Bcl-2 was examined in untreated and androgen-deprived tumours and l ymph node metastasis. Following the transurethral resection, 150 untre ated patients were maintained under surveillance until death or for a minimum of 11 years, and castration was performed at symptomatic progr ession. The Bcl-2 index (BI) was defined as the percentage of immunore active cells in a tumour. The mean BI was 12 in the untreated tumours, and BT was significantly higher in high-grade tumours, mean BI 17, th an in low-grade tumours, mean BI 6. There was no correlation between B I and stage or metastatic disease, nor did BI predict cancer-specific survival. In 16 androgen-deprived, but non-relapsed tumours, the mean BI was 54, at a mean time of 22 months after castration, indicating a permanent in crease of Bcl-2 protein expression after androgen withdra wal. In six patients, tissues from the prostate tumour and obturator l ymph node metastasis were available. Four primary tumours immunostaine d for Bcl-2, but only one metastasis stained. Foci of high grade prost atic intraepithelial neoplasia (PIN) were present in 44 of the 150 unt reated tumours. All PIN foci were intensely immunoreactive for Bcl-2, and mean BI was 79, suggesting that Bcl-2 protein expression is associ ated with early prostate tumorigenesis.