Gene can 'switch off' cancer in mice

Scientists have engineered an on-off cancer "switch" in mice that may help to develop human treatment. The switch is a gene forming a vital link in the step-by-step process leading to leukaemia in humans.

Scientists have engineered an on-off cancer "switch" in mice that may help to develop human treatment. The switch is a gene forming a vital link in the step-by-step process leading to leukaemia in humans.

In the genetically engineered mice, the BCR-ABL1 gene can be turned on or off at will. Exposure to tetracycline, an antibiotic, keeps the gene in the off position.

Dr Daniel Tenen and colleagues at the Harvard Institute of Medicine in Boston, Massachusetts, found that gene-switch mice given the antibiotic in drinking water stayed healthy. When tetracycline was withdrawn - switching on the gene - the animals quickly developed leukaemia and died. But returning the antibiotic to the water stopped the disease in its tracks.

The experiments, reported in the journal Nature Genetics , show that the protein produced by BCR-ABL1 is necessary to induce and maintain the cancer.

Full reversibility may depend on how long cells must be exposed to the gene's protein to develop the cancer. Longer exposure might raise the chance of other cancer-causing genetic abnormalities occurring that were independent of BCR-ABL1. The scientists said: "Our findings suggest that complete and lasting remissions may be achieved if the genetic abnormality is abolished or silenced before secondary mutations are acquired."