EXPRESSION OF BCL-6 PROTEIN IN NORMAL SKIN AND EPIDERMAL NEOPLASMS

Bcl-6 protein is a recently identified novel transcription factor whos e deregulated expression is associated with diffuse large B cell lymph omas. It was recently shown by us that the protein is located in germi nal center B cells and their neoplastic counterparts. In the present s tudy, the expression of bcl-6 protein on normal epidermis, benign, and malignant tumors originating from epidermal cells, and squamous cell carcinoma (SCC) cell lines are investigated. With the use of immunohis tochemistry, bcl-6 protein was shown to stain intensely on normal pric kle cells, but none to only slightly on epidermal basal cells. Papillo mas and keratoacanthomas copied their normal counterparts in the mode of expression. Various levels of expression were found on seborrheic k eratoses, while the expression level on basal cell epitheliomas was lo w. Peculiarly, eccrine poromas and undifferentiated spindle-shaped bas al cell epitheliomas were totally unstained, Squamous cell carcinomas showed a variety of expression levels, while two undifferentiated spin dle-shaped carcinomas and one undifferentiated SCC cell line remained unstained. These results suggest that the expression of bcl-6 protein may be associated with morphological differentiation In normal and neo plastic epidermal cells.