Healthy cells ensure they function properly by patterning their DNA with molecules called methyl groups. These work like volume controls, silencing genes that are not needed and turning up others that are. In cancer cells, this patterning is hijacked so that only genes that help the cancer grow are switched on. While the DNA inside normal cells has methyl groups dotted all over it, the DNA inside cancer cells is largely bare, with methyl groups found only in small clusters at specific locations. Writing in the journal Nature Communications, the Queensland team described a series of tests that confirmed the telltale pattern of methyl groups in breast, prostate and colorectal cancer as well as lymphoma. They then showed that the patterns had a dramatic impact on the DNA's chemistry, making normal and cancer DNA behave very differently in water. The suspect DNA is added to water containing tiny gold nanoparticles, which 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 color," The Guardian reports. "But if DNA from healthy cells is added, the DNA binds to the particles differently, and turns the water blue."
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