marrow. Children receive sedation or special medicine to make them sleep during this procedure. The sample that is obtained is sent for several tests, including immuno-phenotyping, cytogenetics, and fluorescent in situ hybridization (FISH).
Immuno-Phenotyping A sample from the bone marrow aspirate will show whether your child has T-cell or B-cell leukemia.
Cytogenetics A sample from the bone marrow aspirate will show chromosome changes in the leukemia cells. Some leukemia cells will “swap” some of their genetic pieces from one chromosome to another. This is called a translocation . Certain translocations help predict the prognosis and risk group for children with leukemia. Results from this test may not be available for 1–2 weeks. Fluorescent in Situ Hybridization (FISH) FISH is a test that uses special fluorescent dyes that only attach to specific parts of chromosomes. The test can be used to look for specific changes in chromosomes in the leukemia cell. Results from this test may not be available for 1–2 weeks. Lumbar Puncture (Spinal Tap) Leukemia cells can hide in the spinal fluid, so a spinal tap is done to look for these cells. A needle is carefully inserted into the spinal canal to obtain a sample of cerebrospinal fluid to look for leukemia cells. Additionally, a lumbar (or lower back) puncture will be performed periodically throughout leukemia treatment to place chemo- therapy drugs into the central nervous system to prevent or treat leukemia in the spinal fluid. Chest X Ray A chest X ray can help detect a mass or enlargement in the chest or lymph nodes in the chest, often seen in T-cell leukemia. Testicular Biopsy This test will be done if your doctor thinks that leukemia may be in the testicles. Typically, testicular involvement is suspected if there is a painless enlargement of the testicle. To obtain the biopsy, a needle is inserted into the testes to remove a small sample of tissue that will be examined under a microscope to look for leukemia cells. This is done in the operating room while your child is asleep. Only a small percentage of boys have testicular disease at initial diagnosis. Imaging Tests Imaging studies such as computerized tomography (CT) scans, magnetic resonance imaging (MRI), or ultrasound tests may be done to help determine if the cancer has spread to other parts of the body, such as the brain.
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