Loss of alpha-dystroglycan expression in cutaneous melanocytic lesions

The dystroglycan complex (DG) is an important glycoprotein complex linking the epithelial cell cytoskeleton to the basement membrane, originally characterized in muscle and in genetic muscle diseases.1 DG has been shown to be involved in skin morphogenesis and in epithelial carcinogenesis, modulating cell differentiation and adhesion, assembly of the epithelial basement membrane and interactions with the extracellular matrix (ECM).2 DG comprises an alpha (α-DG) and a beta (β-DG)-subunits, with the α-DG-subunit being the extracellular, functional part of the complex and binding several ECM components (laminin, perlecan). Loss of α-DG function has been reported in many epithelial- and neural-derived tumours, demonstrating a correlation with tumour grading, progression and clinical outcome measures.3 In the skin, DG is localized at the dermo-epidermal junction and is produced by epidermal keratinocytes and dermal fibroblasts.4 Tissue expression of the α-DG subunit has not been previously characterized in cutaneous melanocytic nevi and in malignant melanoma. We report the expression profile of α-DG in tissue samples of melanocytic tumours, from benign melanocytic nevi to melanoma