Detection of chromothripsis-like patterns with a custom array platform for chronic lymphocytic leukemia

Area of Science:

• Genomics
• Oncology
• Molecular Diagnostics

Background:

• Chronic lymphocytic leukemia (CLL) exhibits a variable clinical course.
• Chromosomal alterations in CLL are linked to prognosis and treatment decisions.
• Current diagnostic methods like 4-marker fluorescence in situ hybridization (FISH) have limitations.

Purpose of the Study:

• To develop and validate a targeted genome-wide array for comprehensive abnormality detection in CLL.
• To overcome the limitations of existing diagnostic tools for CLL.
• To provide a robust tool for risk stratification and guiding therapy in CLL patients.

Main Methods:

• A targeted genome-wide array (qChip®Hemo) was designed with high-density probes for commonly altered CLL loci.
• DNA from 180 CLL patients was hybridized to the array.
• Array findings were compared with conventional FISH analysis.

Main Results:

• The array detected copy number alterations (CNAs) in 86% of CLL cases.
• High concordance between array and FISH was observed (84% sensitivity, 100% specificity), with discrepancies identifying subclonal alterations.
• Specific chromosomal losses (11q, 17p), genomic complexity, and chromothripsis were significantly associated with clinical outcomes.

Conclusions:

• The validated targeted array is a practical tool for diagnosing CLL, detecting relevant CNAs, genomic complexity, and chromothripsis in a single experiment.
• This array offers advantages over FISH by identifying a broader range of abnormalities, including those not covered by standard FISH panels.
• The array can effectively stratify CLL patients for routine diagnostics and clinical trials, enabling risk-adapted therapy.