Clinical, histological and genetic study of malignant melanoma in Koreans

Abstract

Background: Melanomas at different sites with different levels of sun exposure are found to have genetic alterations such as BRAF, NRAS, KIT, and GNAQ/11 mutations. We designed this study to analyze the mutation status of primary tumors in Korean melanoma patients and identify the correlation between the mutations status and clinicopathological features of melanoma.Methods: Patients diagnosed with malignant melanoma from 2005 to 2012, 188 in number, at Yonsei University Health System, were enrolled for this study.Results: The most common type was acral type (n=89, 47.3%) followed by non-chronic sun damage induced type (Non-CSD type) (n=32, 17%) and mucosal type (n=31, 16.5%). The overall incidence of somatic mutation was 17.6% in the BRAF gene, 12.6% in NRAS, and KIT amplification was 28.6%. GNAQ/11 mutation in the uveal type was 66.6%. Of the non-CSD type, 41.9% had the BRAF mutation while 35.8% of the acral type had KIT amplification. BRAF (P < 0.01) mutation was associated with advanced stage at diagnosis and was correlated to poor prognosis of the patients compared to wild-type patients.Conclusion: In conclusion, the mutation status between Korean melanomas and Caucasian melanomas are similar, but the proportion of the subtypes is distinguishable. In this study, BRAF mutation status was identified as an independent prognostic factor in Korean melanoma patients.