Chronic Lymphocytic Leukemia IGHV Somatic Hypermutation Detection by Targeted Capture Next-Generation Sequencing

Area of Science:

• Oncology
• Genetics
• Molecular Biology

Background:

• Somatic hypermutation (SHM) status of the immunoglobulin heavy variable (IGHV) gene is critical for chronic lymphocytic leukemia (CLL) prognosis and treatment.
• Current methods like Sanger sequencing for IGHV SHM detection are low-throughput and lack multiplexing capabilities.

Purpose of the Study:

• To design and validate a DNA targeted capture approach for detecting IGHV SHM status.
• To integrate IGHV SHM detection into a next-generation sequencing (NGS) panel for comprehensive CLL prognostication.

Main Methods:

• Developed a DNA targeted capture assay as a submodule of an NGS panel.
• The panel includes probes for IGHV SHM and other key CLL-associated genes (e.g., TP53, NOTCH1).
• Input FASTQ files and output reports follow European Research Initiative on CLL guidelines.

Main Results:

• Validated the NGS panel on 35 CLL patient samples, achieving 100% sensitivity and specificity compared to Sanger sequencing for IGHV SHM status in 33 samples.
• The panel successfully identified IGHV SHM status in 34 out of 35 patients.
• Demonstrated the panel's ability to be combined with other targeted capture panels for detecting SNVs, indels, and copy number variants (e.g., TP53 copy loss).

Conclusions:

• A targeted capture approach enables efficient IGHV SHM detection within broader sequencing panels.
• This integrated molecular assay facilitates comprehensive prognostication for CLL patients.
• The method offers a high-throughput, reliable alternative for IGHV SHM analysis in CLL diagnostics.