Researchers at the Massachusetts Institute of Technology have for the first time inserted a human cancer gene into a mouse to produce a specific type of human cancer called chronic myelogenous leukemia (CML). Their research, reported last week in Science, demonstrates that the gene does, in fact, cause the disease in humans and opens the way for testing of new therapies.
CML affects 10,000 Americans each year. Patients usually respond well to chemotherapy for three to five years, then experience a sudden increase in abnormal cells, signaling the onset of acute disease. The only therapy for the acute stage is bone marrow transplants.
CML was the first cancer associated with a specific abnormality in chromosomes, the repository of genetic information. Researchers at the University of Pennsylvania reported in the 1960s that, in all victims of the disease, a small portion of chromosome 9 had become fused to a piece of chromosome 22, forming a characteristic chromosome called the Philadelphia chromosome.
Researchers subsequently found that a new gene is formed from sections of two normal genes when the Philadelphia chromosome is formed during development. Molecular biologist David Baltimore and his colleagues at MIT inserted ths gene into mice to produce CML in the animals.