'Bad Luck' Blamed for Some Types of Cancer
Some types of cancers are known to be linked with genes or risky behaviors. But for many other types, a new study shows, the cause is basically bad luck. They are the result of mistakes, or mutations, that occur when stem cells divide to replace old cells. In the new study, researchers looked at previous research on how often stem cells in a particular type of tissue divide. Then they looked at the lifetime risk of cancer in those parts of the body. Cancers were most common in tissues that divided most often. These included bone marrow, source of cancers such as leukemia and lymphoma. In all, 22 of the 31 cancers studied were linked most closely with these random mutations as cells divided. Other examples included cancers of the ovary and pancreas. The other 9 cancers were linked with random mutations, too.