
Genetic Testing
Understanding Chromosomal Changes in CLL/SLL Cells1
CLL/SLL cells can have chromosomal deletions (part of a chromosome lost or deleted), gene mutations (change), or a combination of both.
Chromosomal deletions1
- Parts of a chromosome can be lost (deleted) during cell division. Chromosomal deletions are named “del” for “deletion” followed by the name of the missing piece.
Gene mutations1
- Genes can become mutated (changed). Some mutations may cause cancer, but not all mutations are dangerous.
Gene mutations and chromosomal deletions can affect how CLL/SLL progresses and may help doctors develop your treatment plan.
How will my doctor know of chromosomal abnormalities in my CLL/SLL cells?1,2
One of the tests known to search for chromosomal deletions is FISH. FISH stands for “fluorescence in situ hybridization.” A different lab test, called DNA sequencing, examines CLL/SLL cells for gene mutations. It can identify the mutational status of IGHV (immunoglobulin heavy-chain variable region gene) and other genes.
What might my test results mean?1,3
Your test results may help you and your doctor better understand your disease. Up to 50% of patients with CLL/SLL have a sign of high-risk disease that can inform how their disease will progress. To learn more about genetic testing, contact your doctor.
Some genetic risk factors for CLL/SLL include:
Del 17p2,4,5
- This chromosomal deletion indicates that CLL/SLL may be more aggressive compared to people with a complete chromosome.
- Among people with CLL/SLL who have not had any treatment, about 3% to 10% have the 17p chromosome deletion. Del 17p can become more common as CLL progresses.
Del 11q2,3
- Another chromosomal deletion that can mean that CLL/SLL may be more aggressive than in people with a complete chromosome.
- About 1 in 5 people with CLL have 11q deletion.
Unmutated IGHV2,4,6
- The unmutated immunoglobulin heavy-chain variable region (IGHV) gene is a risk factor linked to more aggressive disease.
- Approximately 40% to 50% of people with CLL have unmutated IGHV.
References: 1. National Comprehensive Cancer Network. NCCN Guidelines for Patients®: Chronic lymphocytic leukemia. V1.2023. ©National Comprehensive Cancer Network, Inc. 2022. All rights reserved. 2. Leukemia and Lymphoma Society. The CLL Guide: Information for patients and caregivers. Chronic lymphocytic leukemia. Revised 2017. Accessed August 18, 2022. https://www.lls.org/sites/default/files/2021-07/PS34_CLL_Booklet_2021.pdf 3. Döhner H, Stilgenbauer S, James MR, et al. 11q deletions identify a new subset of B-cell chronic lymphocytic leukemia characterized by extensive nodal involvement and inferior prognosis. Blood. 1997;89(7):2516-2522. 4. Lee J, Wang Y.L. Prognostic and predictive molecular biomarkers in chronic lymphocytic leukemia. J Mol Diagn. 2020; 22 (9): 1114-1125. 5. Schnaiter A, Stilgenbauer S. 17p deletion in chronic lymphocytic leukemia: risk stratification and therapeutic approach. Hematol Oncol Clin North Am. 2013;27(2):289-301. 6. Kröber A, Seiler T, Benner A, et al. VH mutation status, CD38 expression level, genomic aberrations, and survival in chronic lymphocytic leukemia. Blood. 2002;100:1410-1416.