Friday Dec 18, 2015
Most cases of cancer are a result of avoidable factors such as toxic chemicals and radiation, according to a new study.
Published in the journal Nature, the findings refute research out earlier this year which claimed cancers were mainly the result of bad luck and would therefore be relatively resistant to prevention efforts.
It showed differences in cellular processes were the chief reason some tissue could become cancerous more often than others.
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Researchers found the more stem-cell divisions that occurred in tissue over a lifetime, the more likely it was to become cancerous.
While they said some cancers were clearly linked to external factors - such as lung cancer as a result of smoking - there were others for which the variation was explained mainly by defects in stem-cell division. In those cases, they argued, early detection and treatment would be more effective than prevention.
But a cancer researcher at Stony Brook University in New York, argues a different case.
Yusuf Hannun and his team studied environmental factors contributing to cancer risk, reviewing data which showed people who migrated from areas of lower cancer risk to those with higher risk came to develop disease at rates consistent with their new environment.
They also examined patterns in mutations associated with certain cancers.
For example, ultraviolet light can create a telltale signature of mutations in DNA, plus various mathematical models.
They found that mutations during cell division rarely build up to the point of producing cancer, even in tissues with relatively high rates of cell division. In almost all cases, the team found that some exposure to environmental factors would be needed to set off the disease.