[Molecular markers associated to prognosis of melanoma]

Melanoma prognosis is based on histological criteria such as tumor thickness (measured by Breslow index), level of invasion (Clarck's level), presence of ulceration and number of mitoses per mm2. However, these parameters do not provide a precise prognosis in all cases: thin melanomas may develop metastases and thick melanomas may remain focalized for many years. For these reasons, the search for other prognostic factors is still ongoing. Many molecules play a part in the invasiveness and metastatic dissemination of melanoma have now been identified. Expression of these molecules has been studied in primary melanoma and correlated with prognosis. An increase in the number of cells positive for Ki67 (detected by Mib1), cycline A, cycline D, p35, MMp-2, beta1 and beta3 integrins, osteonectin, the presence of an intense inflammatory infiltrate and capillary invasion are considered as factors of poor prognosis as well as the decrease in p16, p27, Melan A and nm23. The significance of CD44 modifications is still controversial. Only a small number of these different proteins has a prognostic value independent of tumor thickness. These results need to be confirmed on larger series of patients. Additional hope is given to new techniques such as the analysis of the genes implied in tumor progression by microarray technique in such a way as to provide a molecular map of each tumor.