Basal cell carcinoma: expression of apoptosis suppressing protein BCL-2

ABSTRACT

The Bcl-2 protein increases cell longevity by inhibiting apoptosis [programed cell death]. The aim of the study is to evaluate the expression and possible role of Bcl-2 in basal cell carcinoma [BCC]. Twenty two patients with 24 lesions [BCCs] were included in the study. After excision with safety margins, routine paraffin section of formalin-fixed BCCs were labeled with anti-Bcl-2 monoclonal antibodies using a biotin-avidin immunoperoxidase procedure. Apoptotic cells were counted in ten high power fields [HPFs] of each section. The results were compared with those in ten age and sex matched controls. Excision with reconstructive procedures was done with a safety margin [5mm]. Simple undermining and advancement was done in 8 patients, post-auricular full thickness skin graft in 7 patients, local flaps [V-Y advancement flap, rotation flap] in 9 patients. In normal skin samples, Bcl-2 was only expressed by the basal keratinocytes in one of ten [10%] samples. The mean apoptotic index [AI] was 0.5 cells/10 HPFs. In BCC, Bcl-2 was expressed by tumor cells in 21/24 cases [87.5%] with apoptotic index AI ranging between 2-11 cells/10 HPFs with a mean 4.94 +/- 1.2 cells [statistically highly significant]. Bcl-2 over-expression in the majority of BCCs may be the initial factor that predisposes to malignant transformation of keratinocytes by inhibiting apoptosis