Genetic Abnormalities in Adult Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a heterogeneous disease characterized by a myriad of genetic defect. The genetic abnormalities of AML influence disease aggressiveness and response to therapy. Hematopoietic transcription factors which are crucial for myeloid differentiation can be disrupted by chromosomal translocations or mutations. Recently, two-hit model of leukemogenesis has been proposed: Class I mutations, exemplified by activating mutations in the hematopoietic tyrosine kinases that drive proliferation; and Class II mutations involving chromosomal translocations or non-translocation-generated mutations of hematopoietic transcription factors, that block differentiation. In the present project, we will conduct a systematic analysis of molecular abnormalities involving both classes of mutations. Our aims are (1) to determine the mutations of hematopoietic transcription factors in adult patients with de novo AML, (2) to define the type of cooperating mutations in the hematopoietic tyrosine kinases that collaborate with core binding factor or MLL rearrangements or AML with mutations of hematopoietic transcription factors and to test the hypothesis of two-hit model of leukemogenesis with clinical samples, (3) to determine the biologic relevance of mutants which have previously not been described or functionally not defined, (4) to determine the role of genetic abnormalities, especially focus on the multiple genetic mutations in the progression of AML, (5) to match the molecular events with the clinicohematologic data for determining their diagnostic and prognostic relevance. During the past 12 years, bone marrow samples from a large cohort of adult patients with de novo AML at diagnosis and/or relapse, myelodysplastic syndrome at diagnosis and at AML transformation have been freshly frozen, which allow us to examine their genetic abnormalities in a systematic and expeditious way. DNA/cDNA polymerase chain reaction followed by direct sequencing to detect the mutations of AML-1, PU.1, c-KIT, c-FMS, N-Ras and K-Ras. Transcriptional assay will be performed to determine the biologic consequence of AML-1 mutations outside the Runt domain, and immune complex kinase assay and clonal growth of transfected cells will be carried out to determine the function of c-KIT and c-FMS mutants. The networks of molecular genetic abnormalities in AML will provide us with important insights into the pathogenesis of the disease and hold promise to improve AML classification system and to direct patients to different targeted therapies in the future. The results of this study are expected to have immediate clinical implications and to provide a valuable resource for additional far-reaching biological investigations in leukemogenesis.

Project ID:PG9604-0163
External Project ID:NHRI-EX96-9434SI