Clinical outcome and pathological features associated with NRAS mutation in cutaneous melanoma

Summary The effect of NRAS mutations on the pathological features and clinical outcomes in patients with cutaneous melanoma was compared with that of tumors containing BRAF V600E mutations and tumors wild type for both (WT). Clinical outcome data were obtained from a prospective cohort of 249 patients. Mutations involving NRAS and BRAF V600E were detected by PCR and were sequence verified. Cox proportional hazards regression was performed to relate NRAS and BRAF mutations to clinical outcome. Seventy‐five percentage of NRAS mutations occurred in tumors >1 mm thick ( BRAF V600E 40%, WT 34%); 75% of NRAS mutations had >1 mitosis/mm 2 ( BRAF V600E 40%, WT 55%). When compared to WT, multivariate analysis of melanoma‐specific survival (MSS) identified NRAS mutations as an adverse prognostic factor [hazard ratio (HR) 2.96; P = 0.04] but not BRAF V600E mutations (HR 1.73; P = 0.23). NRAS mutations were associated with thicker tumors and higher rates of mitosis when compared to BRAF V600E and WT melanoma and independently of this, with shorter MSS.