Genetic abnormalities and challenges in the treatment of acute myeloid leukemia

Acute myeloid leukemia (AML) is a hematopoietic disorder in which there are too many immature blood-forming cells accumulating in the bone marrow and interfering with the production of normal blood cells. It has long been recognized that AML is a clinically heterogeneous disease characterized by a multitude of chromosomal abnormalities and gene mutations, which translate to marked differences in responses and survival following chemotherapy. The cytogenetic and molecular genetic aberrations associated with AML are not mutually exclusive and often coexist in the leukemic cells. AML is a disease of the elderly, with a mean age of diagnosis of 70 years. Adverse cytogenetic abnormalities increase with age, and within each cytogenetic group, prognosis with standard treatment worsens with age. In the past 20 years, there has been little improvement in chemotherapeutic regimens and hence the overall survival for patients with AML. A huge unmet need exists for efficacious targeted therapies for elderly patients that are less toxic than available chemotherapy regimens. The multitude of chromosomal and genetic abnormalities makes the treatment of AML a challenging prospect. A detailed understanding of the molecular changes associated with the chromosomal and genetic abnormalities in AML is likely to provide a rationale for therapy design and biomarker development. This review summarizes the variety of cytogenetic and genetic changes observed in AML and gives an overview of the clinical status of new drugs in development.