All of the following statements are true regarding chronic myelogenous leukemia (CML) EXCEPT:
ExplanationChronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disorder. The disease is driven by the BCR-ABL1 chimeric gene product, a constitutively active tyrosine kinase, resulting from a reciprocal balanced translocation between the long arms of chromosomes 9 and 22, t(9;22) (q34;q11.2), cytogenetically detected as the Philadelphia chromosome. Untreated, the course of CML may be biphasic or triphasic, with an early indolent or chronic phase, followed often by an accelerated phase and a terminal blastic phase. Before the era of selective BCR-ABL1 tyrosine kinase inhibitors (TKIs), the median survival in CML was 3–7 years, and the 10-year survival rate was 30% or less. Introduced into CML therapy in 2000, TKIs, such as imatinib, nilotinib, and dasatinib, have revolutionized the treatment, natural history, and prognosis of CML. Today, the estimated 10-year survival rate with imatinib mesylate, the frst BCR-ABL1 TKI approved, is 85%. Allogeneic stem cell transplantation, a curative but risky treatment approach, is now ofered as second- or third-line therapy after failure of TKIs. The median age at diagnosis is 55–65 years. CML is uncommon in children; only 3% of patients with CML are younger than 20 years. Mutations of the HFE gene are associated with primary hemochromatosis.
