Melanoma tumor tissue ( in particular regressive areas) present a lymphocytic infiltrate with an anti-tumoral specificity. The aim of the study is to analyse at different stages of the disease, tumor samples and to characterise the cellular infiltrate in situ ( in particular T lymphocytes, NK cells and macrophages), the role of inhibitor receptors on in situ immunosuppression, and potential modulation by medical treatments such as dacarbazine.