The name chronic myeloid leukemia (CML) is sometimes used for other types of myeloid leukemia that have a chronic course. The difference between people with CML and people with related chronic leukemias is that patients with the related disorders don't have the BCR-ABL oncogene, the mutated gene that causes CML. Patients who have these related disorders undergo different treatments than those patients with CML because they don't respond to the successful targeted therapies used to treat CML.
These less common diseases are called myeloproliferative neoplasms and are subtypes of myeloid leukemia. They progress more slowly than acute myeloid leukemia. Chronic leukemias related to CML are:
- Chronic myelomonocytic leukemia (CMML)
- Juvenile myelomonocytic leukemia (JMML)
- Chronic neutrophilic leukemia (CNL)
Another small group of people without the BCR-ABL gene can't be included in the disease groups above. In these rare cases, doctors suspect that another mutated gene mimics the effects of BCR-ABL. These patients, who still have symptoms similar to those of CML, are classified as having:
- Atypical CML, which can't be adequately described by the criteria for CMML or CML
- Ph-negative CML, which has the clinical signs of CML but not the BCR-ABL gene