bcl-2 and MIB-1 Expression in Basal Cell Carcinoma

Lee, Bong Kil; Lee, Won Woo; Lee, Sung Kyung

Abstract

BACKGROUND: bcl-2 is a newly characterized proto-oncogen that has been shown to suppress programmed cell death(apoptosis), which is involved in tumorigenesis, and its expression has been demonstrated within tumor cells in a variety of neoplasms.
OBJECTIVE
We examined whether there are differences in bcl-2 expression in basal cell carcinoma and several epidermal keratinocytic tumors. In addition, we evaluated bcl-2 expression according to histological types of basal cell carcinoma as well as the interaction of expression of bcl-2 and MIB-1 protein in BCC subtypes.
METHODS
Routine paraffin sections of formalin-fixed sixty tissues(20 BCC, 10 Bowen disease, 10 keratoacanthoma, and 20 SCC) were labelled with anti-bcl-2 monoclonal antibody and MIB-1 using a labelled streptavidin-biotin complex.
RESULTS
1. Twenty cases of basal cell carcinoma were examined and all expressed cytoplasmic bcl-2. Three out of 20 cases of squamous cell carcinoma were focally positive. None of the 10 Bowen disease cases and the 10 keratoacanthoma cases expressed bcl-2. 2. In BCC, bcl-2 immunoreactivity was great in the superficical subtypes which had an indolent growth variant, moderate in the circumscribed types, and weak in the infiltrative types which had aggressive growth variants. 3. Evaluation of the distribution of bcl-2 immunoreactive categories and MIB-1 grades revealed a negative correlation tendency, but no statistical significance.
CONCLUSION
Our results suggest the presence of a protection mechanism from apoptosis mediated by bcl-2 protein involved in the neoplastic growth mechanism of BCC. In addition, the observed findings in the expression pattern of bcl-2 and MIB-1 in the BCC subtypes may be due to interaction between bcl-2 and other apoptotic-related oncogens.