Researchers that stirred controversy in 2015 by claiming that cancer was mostly due to mutation are back. This time, however, they did their homework. They backed up their point with a much broader sample and rephrased their findings to avoid misunderstandings.
The newest study was based on health records from 69 countries. Drawing from it, “they conclude that 66 percent of cancer-causing genetic mutations arise from the ‘bad luck’ of a healthy, dividing cell making a random mistake when it copies its DNA,” reports Scientific American.
An easy, first impression would be misleading: that preventive measures are pointless. But the findings don’t mean that you should smoke at leisure, for example. To be more precise, the study says that “the difference in cancer rates in different tissues can still be the result of different underlying rates of cell division”.
In other words, the more often a cell in any given organ divides, the higher the risk of a cancerous mutation. “Cells of the large intestine divide frequently, and 5 percent of people develop cancer in that tissue,” the Scientific American article says. “Cells of the small intestine divide rarely, and only 0.2 percent of people develop cancer there.”
Here are two reasons for caution. The first one is that we may assume the study not to be conclusive. Cancer is a widespread disease. Different researchers draw different conclusions from the same body of facts. Indeed, Dr. Yusuf Hannun, a critic of the study said he was “not very impressed with the overall conclusion.” Dr. Hannun, director of the Stony Brook Cancer Center led a 2015 study showing that the vast majority of cancers are due to extrinsic factors, not random mistakes in DNA copying.
The second reason to approach the study with care are implications for healthcare. In the United States, lawmakers introduced a bill Preserving Employee Wellness Programs Act. As Louise Aronson wrote in an OpEd for The New York Times, the legislation “would enable companies to coerce employees into participating in wellness programs that could require them to undergo genetic testing and provide genetic information about themselves and their families.”
From there to turning people down for hiring or promotion is just one step. A company would never tell you that the decision was based on your genetic makeup —i.e., that you are more likely to develop cancer. That would be illegal. They would simply tell you any other reason.