Korean J Med.
2011 Oct;81(4):517-525.
Myeloid Sarcoma in Patients with RUNX1/RUNX1T1 Positive AML and a c-kit Mutation
- Affiliations
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- 1Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea School of Medicine, Seoul, Korea. cumckim@catholic.ac.kr
Abstract
- t (8;21)(q22;q22) is the most frequently detected cytogenetic abnormality in patients with acute myeloid leukemia (AML) and accounts for 8-21% of de novo AML. The translocation involves two genes, RUNX1 (formerly AML1) on 21q22 and RUNX1T1 (ETO) on 8q22. RUNX1/RUNX1T1 translocation confers a favorable prognosis, but a subset of patients has a precipitous course with a high incidence of relapse. This patient subset is associated with the presence of a c-kit mutation. c-kit is a proto-oncogene, which encodes a type III transmembrane tyrosine kinase, which elicits a variety of cellular responses essential for the development of bone marrow stem cells. The expression of the c-kit mutation in AML is < 2%, whereas AML with RUNX1/RUNX1T1 shows higher rates of c-kit mutation and is associated with extramedullary leukemia and poor clinical outcome. We report cases of myeloid sarcoma in patients with RUNX1/RUNX1T1-positive AML and a c-kit mutation.