Minimal Residual Disease (MRD) in Leukemia: Acute lymphoblastic leukemia (ALL) is the most common form of childhood cancer. About 20%of all children with ALL relapse, and the prognosis for those children is relatively poor. At our Children's Cancer Research Laboratory, Sharon Mayer and others are working at MRD in acute lymphoblastic leukemia (ALL) for more than two years. This research has successfully passed the first phase: perfecting the DNA-based (PCR) technique of finding even the smallest number of leukemia cells in the body. With our technique, we can detect even one leukemia cell among 500,000 normal cells in the bone marrow. Currently available microscopic examination can detect leukemia cells only when they are present in relatively large numbers-- one or more leukemia cells among 20 normal cells.

At present, our laboratory is one of few laboratories in the United States capable of performing this test. We are currently in the second phase of our research: collaborating with a few other children's hospitals to accrue large number of patients for our study. Our study aims to prove that, by following MRD, physicians can identify children at very high risk of relapse. We hope to convince the pediatric oncologists in the United States that all children with ALL on treatment should be monitored with MRD testing so that those who are not responding well to treatment can be offered more intensive therapy, with the hope of preventing relapse. Our work was presented at the annual meeting of the American Society of Pediatric Hematology-Oncology, San Francisco. We have also recently submitted a paper for publication regarding our technique of testing MRD.