Frequency of BRAF Mutation and Clinical Relevance for Primary Melanomas

BACKGROUND: This study was conducted to clarify the frequency of the BRAF mutation in primary melanomas and its correlation with clinicopathologic parameters. METHODS: We analyzed the frequency of BRAF mutation in patients with primary cutaneous melanoma (n=58) or non-cutaneous one (n=27) by performing dual priming oligonucleotide-based multiplex real-time polymerase chain reaction to isolate and to purify the DNA from the formalin-fixed and paraffin-embedded tumors. RESULTS: The BRAF mutation was found in 17.2% (10/58) of patients with primary cutaneous melanoma and 11.1% (3/27) of those with non-cutaneous melanoma. The frequency of BRAF mutation was not correlated with any clinicopathologic parameters with the exception of the patient age. The frequency of the BRAF mutation was significantly higher in patients younger than 60 years as compared with those older than 60 years (p=0.005). CONCLUSIONS: Compared with previous reports, our results showed that the frequency of the BRAF mutation was relatively lower in patients with primary cutaneous melanoma. Besides, our results also showed that the frequency of the BRAF mutation had an inverse correlation with the age. Further studies are warranted to exclude methodological bias, to elucidate the difference in the frequency of the BRAF mutation from the previous reports from a Caucasian population and to provide an improved understanding of the molecular pathogenesis of malignant melanoma.