L’immunohistochimie (clone VE1) est une méthode économique, spécifique et sensible pour détecter la présence d’une mutation BRAFV600E dans le mélanome

Abstract

Determination of BRAF mutation status is mandatory in the management of patients with inoperable stage IIIC or stage IV melanoma. Currently, molecular biology (MB) has been validated for detecting the presence of BRAF mutations. To compare the sensitivity, specificity and cost of immunohistochemistry (IHC) (clone VE1) versus BM methods (qPCR and Sanger sequencing). All the samples for which BRAF mutation status was requested between March 2013 and February 2015 at the cellular and molecular analysis laboratory of the Angers Hospital were included retrospectively and consecutively. The IHC (clone VE1) and BM analyses were performed with the same formalin-fixed paraffin embedded tumour samples. The cost of these two methods was determined on the basis of the cost for the French Health Insurance. Two hundred and seven samples were subjected to a determination of BRAF mutational status in IHC and BM. Only one sample was discordant between these two methods (positive in IHC, negative in BM). The sensitivity and specificity of the IHC was 100% and 99.25% respectively. The ratio of the cost of IHC/BM testing was 1:2.1. IHC (clone VE1) is a specific, sensitive and economic method for determining BRAFV600E mutation status. Nevertheless, this method must be validated in order to be integrated into a decisional algorithm, alongside BM methods, to determine whether targeted BRAF-inhibitor therapy is indicated.