bcl-2 protein expression in aggressive and non-aggressive basal cell carcinomas

Area of Science:

• Oncology
• Dermatopathology
• Molecular Biology

Background:

• The anti-apoptotic gene bcl-2 promotes cell viability but not proliferation.
• High bcl-2 expression typically correlates with favorable outcomes in epithelial tumors.
• Bcl-2 immunoreactivity in basal cell carcinomas (BCCs) shows conflicting reports, ranging from 67-100% positivity.

Purpose of the Study:

• To investigate the bcl-2 protein immunoprofile in clinically non-aggressive (NA-BCCs) and aggressive BCCs (A-BCCs).
• To determine if bcl-2 protein expression can predict BCC aggressiveness.
• To evaluate bcl-2 expression in recurrent BCCs.

Main Methods:

• Immunohistochemical analysis of bcl-2 protein expression in 50 NA-BCCs and 25 A-BCCs.
• Scoring of bcl-2 expression based on the percentage of positive cells (0-4+ scale).
• Evaluation of bcl-2 expression in initial and recurrent A-BCCs.

Main Results:

• All BCCs showed bcl-2 positivity, but low bcl-2 labeling was significantly associated with A-BCCs (p < 0.01).
• NA-BCCs, including nodular and superficial subtypes, exhibited high bcl-2 labeling.
• Aggressive BCCs, particularly infiltrative subtypes and their recurrences, consistently showed low bcl-2 labeling (1+ or 2+).

Conclusions:

• Differential bcl-2 expression highlights the heterogeneity among BCC subtypes.
• Superficial and nodular BCCs are indolent with high bcl-2, while aggressive BCCs are infiltrative with low bcl-2.
• Low bcl-2 labeling in recurrent BCCs indicates a more aggressive growth pattern.