Disseminated melanoma, preclinical therapeutic studies, clinical trials, and patient treatment

Disseminated malignant melanoma is a very resistant tumor to therapy. Mechanisms of resistance to chemotherapy may be due to glutathione reductase and O6 alkyltransferase, two enzymes especially able to detoxify from alkylation. An interesting model is represented by dacarbazine in the treatment of melanoma with nitrosourea derivatives. Cytokines may come to play an increasing role in the combination with chemotherapy; interferon-alpha and interleukin-2, for example, seem to potentiate the action of chemotherapy in well-designed clinical protocols. Moreover, tumor necrosis factor-alpha was shown to be active in combination therapy with interferon-gamma and chemotherapy when administered by isolation perfusion. Targeting with monoclonal antibodies or melanocyte-stimulating hormone-alpha conjugated to cytotoxic agents represents a promising area. The discovery of a gene, designated MAGE1, coding for a peptide presented by HLA-A1 and able to specifically activate cytotoxic T lymphocytes may represent a unique approach to specific active immunotherapy for melanoma. The interference with integrins and adhesion molecules may play a role in the prevention of metastases. Some preclinical models seem to validate this approach. Current treatment of disseminated malignant melanoma involves chemotherapy often associated with other cytotoxic agents or cytokines, which may potentiate the antitumor effect. Other therapeutic issues reviewed concern targeting and immunotherapy. This review ends with a survey of biologic factors that may constitute new approaches to melanoma therapy.