In future, genetic variant results may make it possible to single out high-risk individuals using a simple saliva test.
They can then be monitored closely for the first signs of developing cancer or be offered preventative treatment.
Experts believe the cheap and easy tests could be conducted in family doctors' surgeries.
Samples would initially be sent off to laboratory specialists, but eventually GPs could be doing the analysis themselves.
The chip used in the analysis cost just £30, and although the study relied on blood samples the same tests can easily be carried out on saliva.
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Planning on going to the London Marathon tomorrow? Read our handy guide first!