Cancer in twins Increased disease risk in the family detected

Study investigates cancer likelihood in families
There are several theories about how cancer can develop. Many physicians suspect that the disease is usually triggered by an unhealthy lifestyle and negative environmental influences. Now new study results prove that our genes have more massive effects on various cancers than previously thought.

What causes cancer in humans? Environmental influences and an unhealthy lifestyle have long been regarded as the main trigger. A recent study on twins, conducted by the Harvard T.H. Chan School of Public Health, found that our genes could have a greater impact on cancer than previously thought. The results of their study, scientists now published in the journal "JAMA".

The cancer risk in twins is extremely closely related. (Image: Vitalinka / fotolia.com)

New study also examines rare cancers for the first time
Collaborating between the Harvard T.H. School of Public Health, the University of Helsinki and the University of Southern Denmark, researchers have now shown that our human genes have a major impact on the development of cancer. The study was conducted by the physicians on twins. If one of the twins developed cancer, the risk of the other twin for any cancer increased significantly. This was also the case for more rare cancers, such as gastric and ovarian cancers, the researchers said. In particular, the physicians examined two factors in their study. They looked at the heritability and evaluated how closely the cancer risk is related to our genes. In addition, the scientists analyzed the familial and individual risk of developing cancer.

Cancer risk increased by up to 46 percent
For the purpose of the study, the researchers examined more than 150,000 dizygotic and identical twins from Nordic regions such as Denmark and Finland. These had participated in a cancer study from 1943 to 2010, explained the doctors. The study found that at least 3,000 pairs of twins both developed cancer. As soon as one of the twins became ill with cancer, the second twin was more likely to develop cancer as well. The risk of cancer increased by 27 percent in the dizygotic twins. In the identical twins, the value even increased by 46 percent. In addition, it could be observed that if one of the twins already had cancer, the other twin was more likely to develop the same type of cancer as well. Identical twins fell ill with 38 percent of the same cancer, with dizygotic twins the value was 26 percent.

Testicular and prostate cancer particularly risky for twins
The highest familial risk, according to the researchers in a testicular cancer disease. The likelihood of developing this type of cancer after a twin has cancer has increased twelvefold in dizygotic twins. For identical twins, the risk is even 30 times greater, explain the researchers in their study. In terms of hereditary connections, skin melanoma is a leader. The likelihood of second-twin disease in previous disease of the first was 58 percent. Behind it followed the prostate cancer disease. The new study was important because previous research focused on the genetic risk among common types of cancer, the researchers said. The new study was the first study to include rare cancers. The results suggest that there is some type of familial cancer risk and that this risk increases significantly in twins.