Use of oncogene expression as an independent prognostic marker for primary melanoma

For 25 years, the Breslow depth of primary tumors has remained the most accurate prognostic test of survival for primary melanoma. However a number of studies have indicated that outcome for intermediate-thickness melanomas (0.75-2.49 mm) is often at variance with that predicted by the Breslow depth. This study investigated c-myc oncogene expression in 92 primary tumors of intermediate thickness using flow cytometry. Oncoprotein expression was detected in 87 tumors (95%) with a median positivity of 48% (range, 0%-96%). Survival analysis performed using the Kaplan-Meier method revealed a significant association between oncoprotein positivity and clinical outcome (p < 0.01, log-rank test). Multifactorial analysis of survival using Cox's proportional hazards model revealed c-myc oncoprotein to be an independent prognostic marker more accurate than all other clinicopathological parameters including the Breslow depth (chi(2) = 9.68, p< 0.01). Estimation of c-myc oncoprotein is therefore recommended as a powerful prognostic marker for intermediate-thickness primary melanoma.