Analysis of BRAF gene mutations in 80 patients with malignant melanoma in Xinjiang Uygur Autonomous Region

Objective To assess the relationship between BRAF gene mutations and clinical phenotype of malignant melanoma.Methods Tissue specimens were collected from the lesions of 80 patients with malignant melanoma,and from the normal skin of 30 patients with trauma in the Department of Plastic Surgery or General Surgery,and subjected to paraffin embedding and DNA extraction.PCR was performed to amplify the exon 11 and 15 of BRAF gene followed by DNA sequencing.Chi-square test and Fisher's exact test were carried out to assess the relationship between BRAF gene mutations and clinical phenotypes of malignant melanoma.Results BRAF gene mutations were found in 19 (23.8％) of the 80 malignant melanoma specimens.Among the 19 mutationpositive specimens,17 (88.2％) carried mutations in exon 15 of BRAF gene with V600E as the most frequent (88.2％,15/17) mutation type,and 2 (10.5％) carried mutations in exon 11.No mutation was found in any of the normal skin tissue specimens.The average age at onset was 57.5 years in these patients.The frequency of BRAF gene mutation was significantly higher in patients younger than 60 years than in those older than 60 years (37.1％ vs.13.3％,x2=6.613,P ＜ 0.05).A significant difference was observed in the frequency of BRAF gene mutation among tissue specimens of mueosal,acral and non-aeral malignant melanoma (18.2％ (4/21) vs.14.7％(5/34) vs.41.7％ (10/24),x2=6.167,P ＜ 0.05).There was no significant association between BRAF gene mutation and gender,race or lymph node metastasis (all P ＞ 0.05).Conclusions BRAF gene is a hot spot for mutations in patients with malignant melanoma in Xinjiang Uygur Autonomous Region,with V600E point mutation in exon 15 as the most frequent mutation type.BRAF gene mutations appear to be closely correlated with the age at onset of and lesional sites in,but uncorrelated with gender and race of or lymph node metastasis in,patients with malignant melanoma. Key words: Melanoma;  Genes, BRAF;  Mutation;  XINJIANG