Gene Expression Profiling Identifies Leukemia Subtype

Gene expression profiling can help doctors identify subtypes of acute lymphoblastic leukemia (ALL) in children, which will help doctors customize a treatment based on the patient's likelihood of responding to therapy, according to an article in the October 15, 2003, issue of Blood.

ALL patients currently have a 70-80% chance of surviving the disease, but the odds of survival decrease following a relapse. Patients are currently classified into risk groups based on factors such as age and gender, white blood cell count, the presence of leukemia in cerebral spinal fluid, and genetic characteristics of the leukemic cells. Researchers used DNA microarray technology to study the pattern of genes expressed in a leukemic cell. Computer-aided data analysis showed that the pediatric ALL cases clustered into seven major subtypes, including the six known prognostic subtypes. The researchers were able to use the expression profiles provided by the microarrays to diagnose and subclassify pediatric ALL, and they found that changes in a cell's expression profile vary markedly, depending on the genetic lesions that underlie the initiation of the leukemic process.

"DNA expression profiling allows us to make extremely accurate diagnoses,” noted senior author James R. Downing, M.D., of St. Jude Children's Research Hospital (Memphis, TN, USA; www.stjude.org). "If microarray technology can be implemented in a cost-effective manner, we may see a day when all leukemia patients undergo expression profiling and then have a unique treatment plan customized for them based on which genes are turned off in their leukemia cells.”




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