Gene Abnormality Found to Predict Childhood Leukem...(red and identify patients in whom differ...),Health

In the study, researchers analyzed genetic data on leukemia cells obtained at diagnosis from 221 children with high-risk leukemia (i.e. a high chance of relapse) who had been treated in an existing COG study. They conducted their analysis using microarrays and DNA sequencing -- technologies which allow researchers to quickly and efficiently identify and analyze multiple genes simultaneously in the same cell. Using these technologies to identify genetic abnormalities in leukemia cells, the investigators examined the DNA of the leukemia cells at the time of diagnosis and then determined if any of the identified genetic changes predicted relapse. To confirm that specific genetic changes were associated with relapse, the scientists also examined a second group of 258 children with ALL who were treated at St. Jude.

"We looked across the genome in an unbiased fashion in an attempt to pull out any genes that were significantly associated with outcome," said Charles Mullighan, M.D., Ph.D., assistant member in the St. Jude Department of Pathology and the paper's first author. "From these findings, we identified a group of genetic abnormalities that together predicted poor outcome."

The most significant association was with the deletions or changes in the IKAROS gene. Mutations of IKAROS were shown to identify a subgroup of patients who were treated in the COG study that had a very poor prognosis. The prognostic significance of these genetic alterations was validated in the independent St. Jude patient group, a finding of particular importance since different types of therapies were used in these two groups of patients.

Previous research has shown that the IKAROS gene serves as the blueprint for the production of the IKAROS protein, which regulates the activity of many other genes. The IKAROS protei
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