What`s new in childhood leukemia research and treatment?

Researchers are now studying the causes, diagnosis, supportive care, and treatment of leukemia at many medical centers, university hospitals, and other institutions.

Genetics

As noted in the section "Do we know what causes childhood leukemia?" scientists are making progress in understanding how changes in DNA can cause bone marrow stem cells to develop into leukemia cells. Understanding the gene changes (such as translocations or extra chromosomes) that often occur in leukemia gives us insight into why these cells may grow out of control, and why they do not develop into normal, mature cells. Doctors are now looking to use these changes to help them determine a child's outlook and whether they should receive more or less intensive treatment.

This progress has already led to vastly improved and highly sensitive tests for detecting leukemia in blood or bone marrow samples. The polymerase chain reaction (PCR) test, for example, can identify very small numbers of leukemia cells based on their gene translocations or rearrangements. This test is useful in determining how completely the leukemia has been destroyed by treatment, and whether a relapse will occur if further treatment is not given.

Clinical trials

Most children are treated for leukemia at major medical centers, where treatment often involves taking part in clinical trials to provide the most up-to-date care. Several important questions are now being studied in clinical trials. Among them are:

• Why do some children with acute lymphocytic leukemia (ALL) relapse after treatment, and how can this be prevented?
• Are there other prognostic factors that will help identify which children need more or less intensive treatment?
• Can chemotherapy drug resistance in acute myelogenous leukemia (AML) be reversed?
• Are there better drugs or combinations of drugs for treating the different types of childhood leukemia?
• Can drugs, toxins, or radiation be specifically targeted to the leukemia cells by using manmade antibodies? Such antibodies can now be designed to specifically seek out leukemia cells, which are then destroyed by the drug, toxin, or radiation.
• Can natural immune proteins called biologic response modifiers help the body's immune system fight the leukemia cells?
• When exactly should a stem cell transplant be used to treat leukemia?
• How effective are stem cell transplants in children who don't have a brother or sister who is a good tissue type match?
• Can a second stem cell transplant help children who relapse after a first stem cell transplant?
• Can the outlook for children with acute lymphocytic leukemia (ALL) with the "Philadelphia chromosome" be improved? Children whose leukemia cells have this translocation tend to have a lower cure rate than others with ALL. Imatinib (Gleevec) and dasatinib (Sprycel), drugs that specifically kill cells with this translocation, have been very helpful in treating certain leukemias in adults. Studies are now under way to see if adding these drugs to chemotherapy can improve treatment outcomes. Early study results of this approach have been promising so far.
• What are the best treatment approaches for children with less common forms of leukemia, such as juvenile myelomonocytic leukemia (JMML) and chronic myeloid leukemia (CML)?