A new study led by St. Jude Children's Research Hospital could lead to a new treatment of certain types of childhood leukemia. The study, published in the journal Nature Genetics, has found a genetic basis for two leukemia subtypes seen in children.
While normal human cells have 46 chromosomes, the high-risk leukemia called hypodiploid acute lymphoblastic leukemia (ALL) has fewer than 44 chromosomes. Researchers found that more than one-third of patients with hypodiploid ALL also have Li-Fraumeni syndrome, an inherited mutation in a tumor suppressor gene. Also, two subtypes of the disease, low hypodiploid ALL and near haploid ALL, were found to be sensitive to compounds that block the proliferation of cancer cells.
"This study is a good example of the important insights that can be gained by studying the largest possible number of patients in as much detail as possible," said Dr. Charles Mullighan, lead author of the study and an associate member of the St. Jude Pathology Department. "This approach led us to key insights about these leukemia subtypes that we would otherwise have missed."
Though the subtypes are only 1 to 2% of the yearly diagnosed ALL cases in the U.S., they account for a larger portion of treatment failures for the disease. Patients with the high-risk subtypes have only a 40% chance of becoming a long-term survivor.
"The cure rate for hypodiploid ALL is only about half that obtained overall for children with ALL," said Dr. Stephen Hunger, co-author of the study and chair of the Children's Oncology Group ALL committee. "The findings of this study are very important and have the potential to impact how this high-risk subset of childhood ALL is treated."