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Custom pyrosequencing assay to detect short BRAF deletions in Langerhans cell histiocytic lesions
  1. Fanélie Jouenne1,2,
  2. Aurélie Sadoux1,3,
  3. Gwenaël Lorillon4,
  4. Baptiste Louveau1,3,
  5. Emmanuelle Bugnet4,
  6. Veronique Meignin5,
  7. Samia Mourah1,2,
  8. Abdellatif Tazi2,4
  1. 1Pharmacogenomics Department, Hôpital Saint-Louis, Assistance Publique-Hôpitaux de Paris, Paris, Île-de-France, France
  2. 2INSERM U976, Université de Paris, Paris, Île-de-France, France
  3. 3INSERM U976, INSERM, Paris, Île-de-France, France
  4. 4National Reference Centre for Histiocytoses, Pulmonology Department, Hôpital Saint-Louis, Assistance Publique-Hôpitaux de Paris, Paris, Île-de-France, France
  5. 5Pathology Department, Hôpital Saint-Louis, Assistance Publique-Hôpitaux de Paris, Paris, Île-de-France, France
  1. Correspondence to Professor Abdellatif Tazi, National Reference Centre for Histiocytoses, Pulmonology Department, Hopital Saint-Louis, Paris, Île-de-France, France; abdellatif.tazi{at}


Langerhans cell histiocytosis (LCH) is a rare inflammatory myeloid neoplastic disease driven by activating mutations in the mitogen-activating protein kinase signalling pathway, including the BRAFV600E mutation and BRAF deletions (BRAFdel). Next-generation sequencing and whole exome sequencing (WES) are valuable and powerful approaches for BRAFdel identification, but these techniques are costly and time consuming. Pyrosequencing is an alternative method that has the potential to rapidly and reliably identify gene deletions. We developed a custom pyrosequencing assay to detect the exon-12 BRAFdel in 18 biopsies from adult patients with LCH, which were all genotyped in parallel using Sanger sequencing and WES. A BRAFdel was detected in 7/18 (39%), 6/18 (33%) and 3/18 (17%) LCH lesions using WES, pyrosequencing and Sanger, respectively, with good concordance between the WES and pyrosequencing results (Kappa-coefficient=0.88). Therefore, our pyrosequencing assay is reliable and useful for detecting BRAFdel, particularly in BRAFV600E-negative LCH lesions, for which targeted treatment is indicated.

  • genetics
  • neoplasms
  • molecular biology

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  • FJ and AS are joint first authors.

  • Handling editor Runjan Chetty.

  • Contributors FJ and SM interpreted the data, drafted the manuscript and revised the manuscript. VM analysed and interpreted the histological findings. EB managed the clinical database. GL managed the sample acquisition and collected the clinical data. AS performed the molecular analysis. BL analysed the data. SM and AT designed the research, analysed the data, interpreted the data and revised the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests GL declares travel accommodations from Vitalaire and Chiesi. SM declares advisory roles for Roche and Biocartis. AT declares speaker fees from Chiesi and travel accommodations from Boehringer Ingelheim, Astrazeneca, and Vitalaire.

  • Patient consent for publication Not required.

  • Ethics approval The present study was performed in accordance with the Helsinki Declaration and was approved by the INSERM Institutional Review Board and Ethics Committee in Paris no 13-130, France.

  • Provenance and peer review Not commissioned; internally peer reviewed.

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