Genetic Testing
Understanding Chromosomal Changes in Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (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.
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.
Genes can become mutated. Some mutations may cause cancer, but not all mutations are dangerous.
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. 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.
Genetic testing can give your doctor important information about how your condition may progress over time. It can also help inform treatment decisions. Tests are done using blood, bone marrow, or tissue samples. One of the tests that searches 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.
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 predict how their disease might progress. To learn more about genetic testing, contact your doctor.
Some genetic risk factors for CLL/SLL include:
CLL/SLL may be more aggressive in people with this chromosomal deletion compared to those 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.
Another chromosomal deletion that can mean that CLL/SLL may be more aggressive in people who have the deletion than in those with a complete chromosome.
About 1 in 5 people with CLL have 11q deletion.
The unmutated IGHV gene is a risk factor linked to more aggressive diseases.
Approximately 40% of people with CLL have unmutated IGHV.
Del 17p1,3,4
CLL/SLL may be more aggressive in people with this chromosomal deletion compared to those 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 11q1,2
Another chromosomal deletion that can mean that CLL/SLL may be more aggressive in people who have the deletion than in those with a complete chromosome.
About 1 in 5 people with CLL have 11q deletion.
Unmutated IGHV 1,3,5
The unmutated IGHV gene is a risk factor linked to more aggressive diseases.
Approximately 40% of people with CLL have unmutated IGHV.
References: 1. Leukemia and Lymphoma Society. Chronic Lymphocytic Leukemia. Revised June 2021. Accessed January 15, 2025. https://www.lls.org/sites/default/files/2021-07/PS34_CLL_Booklet_2021.pdf 2. 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. 3. Lee J, Wang YL. Prognostic and predictive molecular biomarkers in chronic lymphocytic leukemia. J Mol Diagn. 2020;22(9): 1114-1125. 4. 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. 5. 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.