Which of the following cancers is associated with the Philadelphia chromosome?

The Philadelphia chromosome is a specific genetic abnormality that is most commonly associated with chronic myeloid leukemia (CML). This chromosome is created by a translocation between chromosome 9 and chromosome 22, which results in the fusion of the BCR gene on chromosome 22 with the ABL gene on chromosome 9, forming the BCR-ABL fusion gene. This fusion gene produces a tyrosine kinase that is constitutively active, promoting increased cell proliferation and survival, leading to the pathogenesis of CML.

While acute lymphoblastic leukemia can also express the Philadelphia chromosome, particularly in its pre-B-cell subtype, it is predominantly recognized in the context of chronic myeloid leukemia. CML is characterized by an increase in myeloid cells, splenomegaly, and a chronic phase that can transform into accelerated and blast phases if untreated. The distinct cytogenetic marker of the Philadelphia chromosome is crucial for diagnosis and can also inform treatment options, as targeted therapies (like tyrosine kinase inhibitors) have been developed to specifically counteract the effects of the BCR-ABL fusion protein.

In summary, the presence of the Philadelphia chromosome is a hallmark of chronic myeloid leukemia, making it the correct