“A major advantage of this technique is that it is very cheap and extremely simple to do, so it could be adopted in the clinic quite easily,” said Laura Carrascosa, a researcher at the University of Queensland. The test has a sensitivity of about 90% and requires more focused investigations because it shows whether patient has cancerous cells in the body but does not reveal where or how serious it is. The test was made possible by the Queensland team’s discovery that cancer DNA and normal DNA stick to metal surfaces in markedly different ways.
The suspect DNA is added to water containing tiny gold nanoparticles. Though made of gold, the particles turn the water pink. If DNA from cancer cells is then added, it sticks to the nanoparticles in such a way that the water retains its original colour. But if DNA from healthy cells is added, the DNA binds to the particles differently, and turns the water blue. The result is known in ten minutes. The scientists are now working towards clinical trials with patients that have a broader range of cancer types than they have tested so far. Ged Brady, of the Cancer Research UK Manchester Institute, said: “This approach represents an exciting step forward in detecting tumour DNA in blood samples and opens up the possibility of a generalised blood-based test to detect cancer.