The presence of beta2 microglobulin on the membrane of the keratinocyte in premalignant skin disorders.

Beta2 Microglobulin, the invariable light chain of the histocompatibility antigen, has proved to be absent on the cell surface of basal cell carcinoma. In actinically damaged skin and in patients with a past history of arsenic ingestion changes can be observed on the epidermal cell membrane which can predict malignancy before cell dysregulation is visible. The epidermis in the basal cell naevus syndrome behaves in this respect as normal epidermis and the spontaneous tumour growth cannot be explained by a predisposing defect in the HLA-antigens of the epidermal cell surface.