ONE catastrophic event could result in hundreds of mutations, and get cancers started much more quickly than usual. This unexpected discovery challenges the received wisdom that cancers occur only after several mutations have taken place independently over time.
at the Wellcome Trust Sanger Institute in Cambridge, UK, was studying genes from someone with leukaemia when he spotted that a chromosome had apparently been smashed into hundreds of fragments and stuck back together, Humpty Dumpty-like. The result was a random mosaic of genetic material containing a number of cancer-causing mutations.
鈥淭he first patient was a chance finding and we didn鈥檛 know what to make of it,鈥� says Campbell. His team then sequenced genomes from over 700 people with a range of cancers, and found the same pattern of damage in around 2 to 3 per cent of them (Cell, ).
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Rather than committing cell suicide, as would be expected after such serious damage, some cells appear to have stitched the chromosome fragments back together. In some cases there were up to three cancer-causing mutations, suggesting those cells have taken a 鈥渟ignificant leap on the road to cancer鈥�, says Campbell.
聯One single event has made these cells take a significant leap on the road to cancer聰
Although there are other known situations in which genetic mutations are linked, what鈥檚 different here is that the damage is localised, says at Harvard Medical School in Boston. 鈥淚t shows [mutations] can happen in a narrow window.鈥�
The team are unsure what causes these chromosomes to become 鈥渃ompletely pulverised鈥�, but speculate that radiation could be to blame. Campbell now plans to study the history of people with this damage to discover whether there is anything distinctive about their occupation or the number of X-rays they鈥檝e had.
