BCL-2 EXPRESSION IN PRIMARY MALIGNANCIES OF THE SKIN

Background and Design: Basal cell carcinoma (BCC), squamous cell carci noma (SCC), and malignant melanoma (MM) are the three most common mali gnant neoplasms that arise in the skin. Deregulation of oncogene funct ion not infrequently leads to an increased rate of cellular proliferat ion. However, the expansion of malignant cells can also occur if progr ammed cell death is inhibited. The oncogene bcl-2 participates in the regulation of apoptosis (programmed cell death). In view of this, we d etermined the presence and possible role of bcl-2 in primary cutaneous malignancies. Routine paraffin sections of formalin-fixed BCCs, SCCs, MMs (primary and metastatic), actinic keratoses, and SCCs in situ wer e labeled with anti-bcl-2 monoclonal antibody using a biotin-avidin-im munoperoxidase procedure. Results: Twenty-three BCCs were examined and all expressed cytoplasmic bcl-2. Two of 20 SCCs were positive. One of these had patchy, diffuse staining, and the other stained in only sma ll foci. None of eight SCCs in situ and none of eight actinic keratose s expressed bcl-2. Sixteen of 18 MMs expressed bcl-2. Conclusions: The bcl-2 gene product has been found to inhibit apoptosis. Our prelimina ry results suggest that the expression of bcl-2 is present quite consi stently in BCCs and MMs, but not in SCCs or precursor lesions. The exp ression (or lack thereof) of bcl-2 may reflect the difference in the r egulation of cell turnover between these tumors, or histogenetic diffe rences.