Currently, physicians diagnose and treat a rare form of cancer that strikes infants as a particularly aggressive form of the more common acute lymphoblastic leukemia. The cancer may respond to chemotherapy at first, but it tends to recur fatally. That’s why the prognosis is so much worse than for most types of childhood leukemia, which today can usually be treated effectively. Using the relatively new technology of gene chips, scientists working at Dana-Farber Cancer Institute have discovered that this rare leukemia is genetically distinct from other types of leukemia. The discovery will help researchers single out the abnormal genes that make the leukemia so difficult to treat, as well as identifying new targets within the cancer cells for drugs that would be more selective than those used today. “This finding is very exciting to us because it forces us to think about this as a separate disease and to think about other therapies,” said Scott Armstrong, lead author of the research paper and instructor in pediatric oncology at Dana-Farber and Harvard Medical School. The research was funded by the National Institutes of Health, the American Society of Hematology, the Belfer Cancer Genomics Center, and Bristol-Myers Squibb, Millennium Pharmaceuticals and Affymetrix.