Bcl-2 expression in breast cancer is down-regulated by trans-arterial administration of chemotherapeutic agents

Bcl-2 is one of the cytoplasmic oncoproteins, and has been shown to suppres s apoptotic cell death. In this study, we investigated the relationship bet ween Bcl-2 expression and effects of chemotherapeutic agents on human breas t cancer cells. We examined 26 surgically resected breast tumors with preop erative trans-arterial administration of chemotherapeutic agents and 30 con trol cases using immunohistochemical methods. In all 26 cases in the chemot herapy group, the breast cancer cells were focally degenerated to various d egrees, associated with inflammation and stromal desmoplastic changes. Bcl- 2 expression was found in 46% (12/26) of the chemotherapy group and in 67% (20/30) of controls. Of the 12 Bcl-2-positive cases in the chemotherapy gro up, 5 were diffusely positive [Bcl-2(2+)] and 7 were focally positive [Bcl- 2(+)]. Of the 20 Bcl-2-positive cases in the control group, 18 were diffuse ly positive and 2 were focally positive. We speculate that Bcl-2 expression was down-regulated by transarterial administration of chemotherapeutic age nts and was associated with apoptosis and degeneration of breast cancer cel ls.