Pilot evaluation of optical genome mapping in chronic lymphocytic leukemia: complementing FISH analysis

Area of Science:

• Genomics
• Cytogenetics
• Oncology

Background:

• Chronic lymphocytic leukemia (CLL) exhibits clinical heterogeneity due to genomic alterations.
• Fluorescence in situ hybridization (FISH) is standard but limited to predefined loci.
• Optical genome mapping (OGM) provides a genome-wide view for structural variant identification.

Purpose of the Study:

• Compare FISH and OGM findings in CLL patients.
• Evaluate OGM's potential for detecting additional or cryptic genomic alterations.
• Assess the impact of OGM findings on prognosis and therapeutic decisions.

Main Methods:

• Analyzed 20 treatment-naive CLL patients using both FISH and OGM.
• Compared structural variants (SVs), copy number variations (CNVs), and chromosomal abnormalities.
• Evaluated concordance/discordance and clinical relevance of OGM-specific alterations.

Main Results:

• OGM identified 22 SVs, 32 CNVs, and 8 aneuploidies in 18 patients.
• FISH was negative in 3 patients, but OGM detected abnormalities.
• OGM revealed additional chromosomal abnormalities missed by FISH in 3/5 patients with initially negative FISH results.

Conclusions:

• OGM identified chromosomal abnormalities beyond the scope of standard FISH panels.
• These findings highlight OGM's potential to refine prognostic models in CLL.
• OGM serves as a valuable adjunct to conventional cytogenetic assessments in CLL.