The skin immune system and the challenge of tumour immunosurveillance.

The Skin Immune System (SIS) is a relatively new concept central to the issue of cutaneous tumour surveillance. The Langerhans cell (LC) is a key component of SIS. Skin cancer causing agents such as ultraviolet B (UV-B) irradiation and chemical carcinogens like dimethylbenz(a)anthracene (DMBA) alter LC function, resulting in immunosuppression and the promotional phase of tumour development. Once tumours, such as melanoma, are established they may show evidence of tumour regression due to immune reaction but frequently escape immune attack and metastasise. This article explores our knowledge of LC and SIS in these responses. For tumour immunosurveillance to be an effective reality at the clinical level, experiments are required to provide a more precise base for immunotherapy.