According to recent research, the majority of cancers are caused by random mutations in cell DNA during stem cell division, as opposed to lifestyle, inherited, or environmental risk factors. These findings were reported in the journal Science.
It’s understood that cancer is more likely to develop in certain tissues in the body than in others. Research hasn’t yet explained, however, why this occurs. In other words, it hasn’t been well understood why some people are at greater risk for cancer or to what extent factors such as genetics, lifestyle, and environment contribute to development of cancer.
A recent study now sheds light on the process by which cancer develops in certain tissues more profusely. According to this research, the more the normal stem cells of a tissue divide, the more likely that tissue is to develop cancer. This applies to many types of cancers. This cell division, a random mutation that occurs during DNA replication in normal stem cells, accounts for the majority of difference in cancer risk among tissues.
To gauge the link between cell division and cancer risk, the researchers compare the frequency of cell divisions in 31 tissue types over an average person’s lifetime with the lifetime incidence of cancer in those 31 tissues. They concluded that 65% of all cancers are the result of random genetic mutations that occur when cells divide. Only one-third of the difference in risk from one tissue to another is due to environmental or inherited (genetic) risk.
Though the researchers call this elevated cancer risk due to cell division “bad luck,” they say that these findings are still important—they can help expand understanding of cancer and contribute to advances in research. Importantly, the conclusion that most cancers are the result of a factor we can’t control (a random mutation) intensifies the need for more aggressive detection and treatment of cancer in its earliest stages. As well, healthy lifestyle and understanding of hereditary risk remain important preventive measures for the portion of cancers linked to these factors.
Reference: Tomasetti C, Vogelstein B. Variation in Cancer Risk Among Tissues Can Be Explained by the Number of Stem Cell Divisions. Science. 2015 January 2;347(6217):78-81. doi: 10.1126/science.1260825.