Reliable one-step assessment of IGHV mutational status and gene mutations in Chronic Lymphocytic Leukemia by capture-based high throughput sequencing

Abstract

Proper management of chronic lymphocytic leukemia (CLL) patients requiring therapy relies on two important prognostic and theranostic molecular features: respectively, the mutational status of tumoral cells immunoglobulin heavy chain variable domain (IGHV) and the characteristics of TP53. Both these (immuno)genetic analyses require multiple time-consuming amplification and sequencing techniques by Sanger or HTS. The capture-HTS technology, allowing to select regions of interest, represents an attractive alternative and has already been applied for the detection of clonality in lymphoproliferative disorders. Here, a single-step capture design was developed to concomitantly investigate for IGHV and TP53. This was applied to a training retrospective (n=14) and a validation prospective (n=91) cohorts of CLL patients. The training cohort demonstrated the robustness of the method by comparison with the classical Sanger sequencing technology (100% identical results) for the IGHV mutational status. This consistency was confirmed for the first 59 patients of the validation cohort. Overall, the IGHV status of whole population (n=103) was accurately identified. Simultaneously, deletion or mutations of TP53 were identified from the same capture-library and HTS-sequencing run for each patient. This novel approach provides, in a single assay, useful answers about the molecular landscape of CLL patients, allowing for a documented choice of therapy.