The aim of this study is to verify the status and the clinical significance of BRAF and NRAS mutations in patients of one of the university hospitals in Korea.

Polymerase chain reaction (PCR) amplification and direct sequencing were performed for the analysis of melanoma samples (n=22) for the detection of mutations in exon 15 of the BRAF gene, and exons 2 and 3 of the NRAS gene in genomic DNA. Mutations of the BRAF gene were correlated with the clinicopathologic features of patients and the BRAF mutation status was compared in 18 paired primary and metastatic tumors.

Incidence of somatic mutations within the BRAF and NRAS genes was 27.3% (6/22) and 0% (0/22), respectively. Age, gender, Breslow thickness, and ulceration did not show correlation with BRAF mutations. Among 18 patients with metastasis, BRAF mutation was detected in 22.2% of cases (4/18), and all four cases with BRAF mutations were identified in metastatic lymph node tissues. BRAF mutations were only found in lymph node metastases, which was statistically significant (28.6% vs 0%, P<0.01).

The incidence of BRAF mutation is as low as in other Asian reports and the NRAS mutation was not found in patients of our institute.