Master Chronic Myelogenous Leukemia (CML) with Picmonic for Medicine

Chronic myelogenous leukemia (CML) is a myeloproliferative disorder characterized by the presence of a chimeric BCR-ABL gene derived from portions of the BCR gene on chromosome 22 and the ABL gene on chromosome 9 caused by (9;22) translocation. This is called a Philadelphia chromosome and this gene synthesizes a constitutively active BCR-ABL tyrosine kinase.

Chronic myelogenous leukemia (CML) is a myeloproliferative disorder characterized by the presence of a chimeric BCR-ABL gene derived from portions of the BCR gene on chromosome 22 and the ABL gene on chromosome 9 caused by a 9;22 translocation. This is called a Philadelphia chromosome and this gene synthesizes a constitutively active BCR-ABL tyrosine kinase.

Chronic myelogenous leukemia is characterized by the presence of a chimeric BCR-ABL gene derived from portions of the BCR gene on chromosome 22 and the ABL gene on chromosome 9 caused by translocation. This is called a Philadelphia chromosome and this gene synthesizes a constitutively active BCR-ABL tyrosine kinase.

CML is characterized by a constitutively active BCR-ABL tyrosine kinase. Activation of this kinase induces pro-growth and pro-survival pathway that are normally turned on by hematopoietic growth factors. For unknown reasons, the BCR-ABL tyrosine kinase preferentially stimulates the proliferation of granulocytic and megakaryocytic progenitors and causes the abnormal release of immature granulocytic forms from the bone marrow into the blood.

CML is characterized by low alkaline phosphatase levels due to elevated immature granulocytes as opposed to a leukemoid reaction, in which the alkaline phosphatase is normal or elevated.

The spleen is often greatly enlarged as a result of extramedullary hematopoiesis. Sometimes the first symptom of disease is a dragging sensation in the abdominal region caused by massive splenomegaly.

After an average period of 3 years, about half of CML patients enter an accelerated phase of disease, marked by increasing anemia and thrombocytopenia. When lab work reveals a blast (immature blood cell) count of greater than 30%, the patient is said to be in a blast crisis. On average, this occurs 6-12 months after the accelerated phase. It’s important to note that while this phase resembles acute leukemia, they are in fact two separate conditions with unique outcomes and treatments.In 70 percent of blast crises, the blasts are of myeloid origin whereas the remainders are of pre-B cell origin.

CML is primarily a disease of adults between the ages 30 and 90, with the median age of diagnosis being 60 years of age.

Understanding the molecular pathogenesis of CML has led to the use of the drug imatinib, which is a specific BCR-ABL inhibitor. Imatinib results in sustained hematologic remission in about 90% of patients with markedly decreased number of BCR-ABL positive cells in the marrow.