BCR-ABL1 Genetic Test

A BCR-ABL1 genetic test uses a sample of blood or bone marrow to look for an abnormal gene called BCR-ABL1. This abnormal gene is involved in certain types of blood cancer. It's found in: Most people who have chronic myeloid leukemia (CML), which is also called chronic granulocytic leukemia or chronic myeloid leukemia; Some people who have certain types of acute lymphoblastic leukemia (ALL); Some people with acute myeloid leukemia (AML), but very rarely; The abnormal BCR-ABL1 gene is made when two separate genes merge together and become one gene.

Genes are short sections of DNA. DNA is made of long strands of material that carry information that controls what you look like and how your body works. DNA is packaged into structures in your cells called chromosomes.

Normally, most of your cells have the same set of 23 pairs of chromosomes. The abnormal BCR-ABL1 gene is formed when pieces of chromosomes 9 and 22 break off and trade places. The broken piece of chromosome 9 includes part of the ABL1 gene.

It attaches (fuses) to part of the BCR gene on chromosome 22. This makes the abnormal fusion gene, BCR-ABL1. The changed chromosome 22 is called a 'Philadelphia chromosome' after the city where researchers discovered it.

Your genes carry special instructions for making proteins that help your cells do their work. But the abnormal BCR-ABL1 gene has instructions for an abnormal protein. The protein causes certain bone marrow cells to make large numbers of abnormal white blood cells.

These abnormal white blood cells are leukemia cells. They don't protect you from infections like healthy white blood cells do. They can build up in the blood and bone marrow and crowd out healthy blood cells.

There are different types of BCR-ABL1 genetic tests. They check your blood or bone marrow for: The abnormal BCR-ABL1 gene; Changes in chromosome 22 that show it has become a Philadelphia chromosome; An abnormal BCR-ABL1 gene is an acquired genetic change. That means you don't inherit it from your parents, and you can't pass it on to your children.

Acquired changes happen after birth if cells make a mistake when dividing to make new cells or if your DNA is damaged from exposure to substances that cause cancer. The changes show up only in certain types of cells. Changes in your genes are also called mutations or variants.

Why this test is done

If your health care provider thinks you may have a type of leukemia that involves the BCR-ABL1 gene, you may need a BCR-ABL1 genetic test to make a diagnosis. Signs and symptoms of these blood cancers include:

• High levels of white blood cells on a complete blood count (CBC) test
• Fatigue
• Fever
• Weight loss
• Night sweats (heavy sweating during sleep)
• Joint or bone pain
• Pain or fullness below your ribs on the left side
• Painless lumps in your armpits, groin, neck, or belly

If you have already been diagnosed with a type of leukemia that involves a BCR-ABL1 gene, you may need this test to:

• Help guide treatment decisions
• See how well your treatment is working (if treatment is helping, the number of cells with BCR-ABL1 genes will decrease.)
• Monitor your health after treatment to see if blood cancer is coming back

How to prepare

You usually don't need any special preparations for a blood test. If you're having a bone marrow test, your provider will tell you whether you need to fast (not eat or drink) for a few hours before the procedure.

Sample type

Blood Tissue/Biopsy

Other names for this test

BCR-ABL, BCR-ABL fusion, Philadelphia chromosome, B-cell acute lymphoblastic leukemia (B-ALL), chronic myelogenous leukemia (CML), t(9;22), BCR-ABL1 Transcript Detection by RT-PCR, Quantitative BCR-ABL1 Translocation Detection by RT-PCR