Measurement of c-myc oncogene expression provides an accurate prognostic marker for acral lentiginous melanoma

Acral lentiginous melanoma is a particularly aggressive tumour with a worse prognosis than other varieties of primary cutaneous melanoma. In order to study the biology of this disease, the activity of the c-myc oncogene was s tudied in tumours from 45 patients using flow cytometry. High levels of onc oprotein were found in all tumours and exceeded that documented in other va rieties of cutaneous melanoma. Survival analysis with stratification of pat ients according to oncogene activity provided a useful prognostic marker wi th shorter disease free interval (Log-Rank test, chi(2) = 16.7, P < 0.0001) and overall survival (Log-Rank test, chi(2) = 8.9, P = 0.002) in tumours w ith high oncoprotein levels. Multivariate analysis revealed c-myc oncogene expression to be more accurate in predicting clinical outcome than all exis ting clinicopathological parameters including the Breslow depth (Cox's prop ortional hazards model, P = 0.0011). This study provides biological evidenc e to explain the aggressive behaviour of acral melanoma and supports the ap plication of oncogene measurement as an accurate prognostic marker.