Melanocytes in human skin express bcl-2 protein

Abstract

The bcl-2 gene was initially identified through its participation in the translocation 14:18 in B-cell lymphomas of follicular center cell origin. This classic translocation juxtaposes the transcriptionally active immunoglobulin heavy-chain locus on chromosome 14 to the bcl-2 gene on chromosome 18, resulting in overexpression of bcl-2 protein. The oncogene bcl-2 is thought to prolong cell survival through interference with programmed cell death. To date, bcl-2 expression has been reported in normal lymphoid, hemopoietic, neural, breast and prostatic tissues. Since melanocytes are neural crest derivatives and have an extended life-span, our objective was to determine whether the bcl-2 protein is expressed in human melanocytes. We analyzed normal skin biopsies for bcl-2 expression using standard immunohistochemistry. As hypothesized, dendritic cells in the basal epidermal layer stained strongly for bcl-2. The distribution and morphology of these cells was typical for melanocytes. Additionally, eccrine sweat glands, lymphocytes and the dermal papilla of hair follicles demonstrated bcl-2 positivity. We believe this to be the first report of bcl-2 expression in normal melanocytes.