Does everyone with CML have the Philadelphia chromosome?
Not everyone with CML has the Philadelphia chromosome, but the vast majority do. About 95 percent of people with CML have this specific genetic change.
The Philadelphia chromosome forms when pieces of chromosomes 9 and 22 break off and switch places, creating an Show Full Answer
Does everyone with CML have the Philadelphia chromosome?
Not everyone with CML has the Philadelphia chromosome, but the vast majority do. About 95 percent of people with CML have this specific genetic change.
The Philadelphia chromosome forms when pieces of chromosomes 9 and 22 break off and switch places, creating an abnormal gene called BCR-ABL. This gene produces a protein that signals cells to grow and divide uncontrollably, which is what defines CML.
People with CML who don't have the Philadelphia chromosome actually face different challenges. They tend to have a worse outlook because the most effective CML treatments—tyrosine kinase inhibitors (TKIs) like imatinib—work by blocking the BCR-ABL protein. When this protein isn't present, TKIs may not be as effective.
For those without the Philadelphia chromosome, other factors that can affect outcomes include:
- Older age
- Anemia
- High levels of white blood cells
Your doctor can determine whether you have the Philadelphia chromosome through genetic testing of your blood or bone marrow samples.
April 17
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