What is a BCR-ABL genetic test?A BCR-ABL genetic test looks for a genetic mutation (change) on a specific chromosome.Chromosomes are the parts of your cells that contain your genes. Genes are parts of DNA passed down from your mother and father. They carry information that determines your unique traits, such as height and eye color.People normally have 46 chromosomes, divided into 23 pairs, in each cell. One of each pair of chromosomes comes from your mother, and the other pair comes from your father.BCR-ABL is a mutation that is formed by the combination of two genes, known as BCR and ABL. It's sometimes called a fusion gene.The BCR gene is normally on chromosome number 22.The ABL gene is normally on chromosome number 9.The BCR-ABL mutation happens when pieces of BCR and ABL genes break off and switch places.The mutation shows up on chromosome 22, where the piece of chromosome 9 has attached itself.The mutated chromosome 22 is called the Philadelphia chromosome because that's the city where researchers first discovered it.The BCR-ABL gene is not the type of mutation that is inherited from your parents. It is a type of somatic mutation, which means you are not born with it. You get it later in life.The BCR-ABL gene shows up in patients with certain types of leukemia, a cancer of the bone marrow and white blood cells. BCR-ABL is found in almost all patients with a type of leukemia called chronic myeloid leukemia (CML). Another name for CML is chronic myelogenous leukemia. Both names refer to the same disease.The BCR-ABL gene is also found in some patients with a form of acute lymphoblastic leukemia (ALL) and rarely in patients with acute myelogenous leukemia (AML).Certain cancer medicines are especially effective in treating leukemia patients with the BCR-ABL gene mutation. These medicines also have fewer side effects than other cancer treatments. The same medicines are not effective in treating different types of leukemia or other cancers.Other names: BCR-ABL1, BCR-ABL1 fusion, Philadelphia chromosome
