How Does Cancer Develop?


A new study reported in Cell  concluded that a variety of conditions are needed by cells to start forming cancer and this process helps to explain why some organs are more susceptible than others to developing disease. The research showed that cancers are more likely to start in stem cells or special cells that copy themselves so the body can grow new cells, repair damaged tissues, and replace old cells. But while stem cells more readily develop into cancer  cells they need to have accumulated DNA mistakes and be replicating to repair damage or wear and tear for cancer to start. The DNA mistakes can happen randomly as stem cells replicate and tend to buildup with age making cancer more common among the aged. Environmental factors such as tobacco smoke and UV radiation can also cause DNA mistakes.

Using a fluorescent dye to track the behavior of a particular group of cells in mice the researchers hoped to find out how cancer starts in different organs. DNA mistakes linked to different types of cancer were then introduced into the group of cells. They found that DNA mistakes by themselves were not enough to cause cancer. In organs where DNA mistakes were introduced into dormant stem cells,there was no signs of cancer. However, in other organs that were exposed to lots of wear and tear such as the bowel, introducing DNA mistakes into the replicating stem cells caused cancer to start. They continued “We can now say that cancer most likely starts in stem cells but is not just down to “bad luck.” The development of cancer involves a ‘Perfect storm’ of stem cells containing DNA mistakes that are replicating in response to damage or wear and tear.”  “Although stem cells can sometimes go wrong by chance, our research shows that things in our environment that lead to more DNA mistakes or that damage organs, causing these stem cells to divide, increases the chances of the “perfect storm” brewing. That’s why behaviors like smoking or UV exposure raises the risk of developing cancer.” “Our work also shows why some tyes of cancer are more common than others with tumors more likely to develop in organs with lots of replicating stem cells, for example the bowels.”

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