Español
Questions About Cancer? 1-800-4-CANCER
  • Print
  • Facebook
  • Twitter
  • Google+
  • Pinterest

NCI Dictionary of Cancer Terms


BCR-ABL fusion gene  listen  (... FYOO-zhun jeen)

  A gene formed when pieces of chromosomes 9 and 22 break off and trade places. The ABL gene from chromosome 9 joins to the BCR gene on chromosome 22, to form the BCR-ABL fusion gene. The changed chromosome 22 with the fusion gene on it is called the Philadelphia chromosome. The BCR-ABL fusion gene is found in most patients with chronic myelogenous leukemia (CML), and in some patients with acute lymphoblastic leukemia (ALL) or acute myelogenous leukemia (AML).

Enlarge
Philadelphia chromosome; three-panel drawing shows a piece of chromosome 9 and a piece of chromosome 22 breaking off and trading places, creating a changed chromosome 22 called the Philadelphia chromosome. In the left panel, the drawing shows a normal chromosome 9 with the abl gene and a normal chromosome 22 with the bcr gene. In the center panel, the drawing shows chromosome 9 breaking apart in the abl gene and chromosome 22 breaking apart below the bcr gene. In the right panel, the drawing shows chromosome 9 with the piece from chromosome 22 attached and chromosome 22 with the piece from chromosome 9 containing part of the abl gene attached. The changed chromosome 22 with bcr-abl gene is called the Philadelphia chromosome.