Risk doubled The research, published in the British Journal of Cancer, showed that the radiation produced genetic changes in the makeup of the cells and some of the damage was passed on to the next generation of mice. The risk of developing leukaemia was nearly doubled in the PPI mice. The damage in the bone marrow cells alone was not enough to cause the leukaemia, but it increased vulnerability to the disease. Leukaemia developed earlier and more frequently in the cells when they were exposed to a powerful cancer-causing chemical. Cause unknown Scientists are not sure what causes cancer.
Genes certainly play a part and certain chemicals, substances called carcinogens, are also involved.
Radiation an important factor The Director General of Britain's Cancer Research Campaign charity, Professor Gordon McVie, said some scientists believed that cancer required two factors to combine to develop. Radiation could be one of those factors. Second factors could include a virus or a genetic defect inherited from the mother. Scientists have been debating whether radiation causes childhood leukaemia for many years. A controversial study in 1990 claimed that a cluster of cases in northern England resulted from parents working at the Sellafield nuclear power plant in Cumbria.