NCCN Guidelines for Patients® | Chronic Lymphocytic Leukemia
17 NCCN Guidelines for Patients ® : Chronic Lymphocytic Leukemia, 2018 2 Treatment planning Blood tests Blood tests Blood tests are used to diagnose CLL as discussed in Part 1. For those people who need treatment, they may help doctors with treatment options. They are also used for at least three other reasons. First, blood tests can be used to know the outlook (prognosis) of a person with CLL; these tests are called prognostic markers. This means that they may help predict how fast the CLL may progress to needing treatment, or how long a treatment response may last. However, this is only an estimation from a study of groups of patients with similar prognostic markers; each person can be different. Prognosis is also likely to be different with the newer medications used for treatment. Second, some blood tests are used to know the extent (stage) of cancer. How staging is related to starting treatment is discussed at the end of this chapter. Third, blood tests can help to find other diseases including those related to CLL. It’s important to treat all illnesses. Blood tests for CLL may include: Genetic tests FISH test. It is very common for CLL cells to have abnormal chromosomes. In CLL cells, chromosomes that commonly have defects include chromosomes 11, 12, 13, and 17. FISH is a test that is used to search for abnormal chromosomes and genes. FISH is sometimes used for diagnosis as described in Part 1 but also for prognosis. It can be done using either blood or bone marrow cells. It is a helpful test but not essential for treatment planning. Missing (deleted) parts of chromosomes 11 or 17 are signs of a poor prognosis. A good prognosis is linked to deleted parts of chromosome 13, if it is the only abnormal chromosome. Trisomy is when there are three copies of a chromosome in a cell instead of the normal two. Trisomy 12 is linked to neither a poor nor a good prognosis. Karyotype. A karyotype is a picture of the chromosomes in cells. It shows if there is a defect in the size, shape, and number of chromosomes. A blood or bone marrow sample can be used. Chemicals are added to the sample to start cell growth. For CLL, a chemical called CPG should be used. A “complex karyotype” is linked to a poorer prognosis. A complex karyotype is when there are 3 or more unrelated defects in chromosomes that occur in more than one cell. The presence of a complex karyotype may affect your treatment options. Read Part 4 for more information. DNA sequencing. DNA sequencing is a lab test of blood or marrow that is used to look for mutations in genes. A DNA sequencing test reveals the order of the chemicals that make up DNA. Certain gene mutations (abnormal changes) may be found with DNA sequencing. For CLL, DNA sequencing is used to test for mutations in the IGHV ( i mmunoglobulin h eavy- c hain v ariable) region and TP53 genes. Immunoglobulins are Y-shaped proteins that help fight germs. In Part 1, they were described by their other name—antibodies. Normal antibodies are made of two heavy chain proteins and two light chain proteins. See Figure 6 on page 18. IGHV region genes in B-cells contain instructions for making the heavy chain protein. These genes may or may not be mutated in people with CLL. Prognosis is good if IGHV is mutated. TP53 is the gene that makes a protein that signals for either the repair or destruction of damaged cells. Thus, it helps to prevent tumors from forming. DNA sequencing can be used to learn if this gene is mutated. If mutated, prognosis is poor.