Two thirds of cancers are unavoidable even if you live a healthy life, according to a study published by doctors from John Hopkins. The research, published in the journal Science, indicates that the majority of cancer-causing mutations are due to DNA copying errors.
The recent discovery challenges the widespread belief that cancer mutations are generally inherited or triggered by environmental factors and helps explain why cancer often strikes people who seem to follow the rules of healthy living and have no family history of cancer.
The Hopkins team studied genetic mutations that drive abnormal cell growth in 32 different types of cancer. Using DNA sequencing and epidemiological data, they developed a mathematical system of assessing the role of genetic copying errors in cancer.
Overall they found that 66% of cancer mutations resulted from copying errors, 29% from lifestyle or environmental factors, and just 5% from inherited faulty genes.
In some cancer types, such as those affecting the prostate, brain and bone, more than 95% of the cancer causing mutations were due to random DNA copying errors. Copying mistakes were linked to 77% of pancreatic cancers but only 35% of lung cancers. Lung cancer was more likely to be triggered by smoking and other environmental factors.
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The study confirms what many cancer researchers have suspected; that people will develop cancers due to random DNA copying errors irrespective of environmental influence and lifestyle. Despite these findings however, we still need to continue to encourage people to avoid environmental agents and lifestyles that increase their risk of developing cancer mutations and other diseases. Better methods to detect all cancers earlier, when they are most curable are needed, as are improvements in the treatment of the specific genetic mutations causing the cancer. Development of precision cancer medicines to target specific genetic mutations is an area of rapid innovation and improvement in cancer treatment.
Reference: Cristian Tomasetti, Lu Li, Bert Vogelstein. Stem cell divisions, somatic mutations, cancer etiology, and cancer prevention. Science, 2017 DOI: 10.1126/science.aaf9011