NM23 EXPRESSION IN METASTASIS OF MALIGNANT-MELANOMA IS A PREDICTIVE PROGNOSTIC PARAMETER CORRELATED WITH SURVIVAL

The management of patients presenting with metastatic malignant melano ma (MM) is hampered by the substantial variability in survival of thes e patients and the lack of prognostic markers. In the search for a rel iable predictive parameter, we have investigated the expression of the nm23 gene, considered to be a major regulator of the metastatic proce ss. We have analysed by Northern blot the nm23 mRNA level in tumour ti ssue obtained from metastases of 20 stage II and ten stage III patient s with MM. Normal human tissues and benign naevi were simultaneously e xamined. The level of nm23 expression was highly heterogeneous in MM m etastases, with a mean value which was higher than the mean level in n ormal tissues and naevi. Correlative study was focused on the overall survival following resection of the metastasis in which nm23 Northern blot analysis was performed. Patients displaying higher nm23 expressio n in metastatic tissue (above the mean level) tended to have a longer survival than others (P = 0.08), and this difference was significant f or patients presenting with isolated regional lymph node involvement ( P = 0.035). The time from biopsy of the primary MM to the appearance o f the first lymph node metastasis also showed a positive correlation w ith the nm23 mRNA level in this metastasis. The present study is not o nly in accordance with previous reports showing that the nm23 gene may be implicated in MM progression, but also suggests the reliable value of nm23 expression as a prognostic marker for patients presenting wit h metastatic MM.