Mice prone to developing a blood cell cancer gained partial protection from a human gene that influences blood cell development, suggesting that developmental genes may affect vulnerability to cancer, researchers say. Such genes may make a difference in how long normal cells remain susceptible to turning malignant, they said. The work is reported in Thursday's issue of the British journal Nature by Philip Leder, Michel Nussenzweig and Emmett Schmidt of Harvard Medical School with colleagues there and at the Childrens Hospital of Los Angeles. They worked with mice that carried a human c-myc gene, which puts them at high risk for developing a blood cell cancer called pre-B cell lymphoma. Pre-B cells are those that will develop as B cells, an important part of the body's disease-fighting immune system. Those mice were bred with others that carried a different human gene, one that makes B cells skip an early stage in their development. Some progeny from these matings inherited both human genes, and their lymphoma rates were compared to those that carried only the cancer-causing gene. Results showed that the gene that speeds development caused both a delay and a reduction in the tumors, researchers said. By 117 days of age, half the mice that carried only the cancer-causing gene had developed lymphoma, but none of the mice with both genes had developed it. After a year, more than 90 percent of the first group had developed tumors, compared to only 40 percent of the mice with both human genes. The developmental gene apparently hampered development of cancer by speeding up the maturation of pre-B cells, leaving fewer at stages most susceptible to the cancer-causing gene, researchers suggested. In general, a diverse group of genes that produce either an acceleration or pause in cell development may influence the rates and time of onset for cancer, researchers said.
