Variant allele frequencies of BRAF mutations in adult histiocytoses. (A) Frequencies of patients with BRAF mutations in the different types of histiocytoses. (B) Distribution of the histiocytoses according to their VAF. For instance, the numbers of cases with VAF 0 to 1%, 1 to 2% and 2 to 3% were 8, 10 and 11 respectively. (C) VAF values in the main types of histiocytoses. (D) Correlation of VAF with the percentage of histiocytes (i.e., all the histiocytes identified by histology among all cells present within the tissue). Whatever the method used, the correlation of VAF with the percentage of histiocytes was low: R2 was 0.15 and 0.01 in pyrosequencing and pddPCR respectively.