Expression of lamins depends on epidermal differentiation and transformation.

Abstract

It has been suggested that A- and B-type lamins, proteins of the nuclear lamina, play important roles in the morphogenesis of the nucleus and cellular differentiation. To investigate the expression of these nuclear proteins in normal skin and some keratinocytic tumours of the skin. We examined by means of immunohistochemistry the expression of lamins in normal skin and some keratinocytic tumours of the skin, such as squamous cell carcinoma (SCC), basal cell carcinoma (BCC), Bowen's disease, solar keratosis, keratoacanthoma and seborrhoeic keratosis. In normal skin, A-type lamin was expressed in all epidermal cells, but the expression level of B-type lamins diminished from basal cells to granular cells. In keratinocytic tumours, the expression of A-type lamin was reduced, especially in BCCs, Bowen's disease and poorly differentiated SCCs. B-type lamins were reduced and exhibited heterogeneous expression patterns in most well-differentiated SCCs and keratoacanthomas. Antibodies against B-type lamins stained only peripheral cells of the lobules in keratoacanthomas, while no regular staining patterns were seen in well-differentiated SCCs. Lamin expression depends on the differentiation and transformation of the human skin. This finding should be useful for the diagnosis of keratinocytic tumours.