Cancer in one twin indicates much higher risk for sibling – Huewire News

Posted by on Jan 6th, 2016 and filed under Medical News. You can follow any responses to this entry through the RSS 2.0. You can leave a response or trackback to this entry

Cancer in one twin indicates much higher risk for sibling – Huewire News

Having a twin sibling diagnosed with cancer increases the risk for also developing the disease, according to a new study published Tuesday in JAMA. The study found out that twins with any form of cancer usually developed other forms of cancer later on showing that there is a probability of prevalence of the disease among families.

Mucci and her fellow researchers analyzed data from the Nordic Twin Study of Cancer conducted between 1943 and 2010.

A total of 27,156 incident cancers were diagnosed in 23,980 individuals, translating to a cumulative incidence of 32 percent.

Therefore, the risk of cancer in an identical twin whose twin was diagnosed was calculated to be 46 percent. And, accordingly, this was the first study to look at twin pairs where both twins had developed cancer-but different types-to suggest that while cancer risk may be genetic, it does not always yield the same result.

Previous studies have shown how cancer risk may be due to a number of environmental factors and personal lifestyle choices.

Teasing out the differences between identical and fraternal twins is a time-honored way of differentiating between inherited, genetic influences and other factors, such as a shared environment.

It was noted that the overall heritability of cancer was 33 percent, with significant heritability found for skin melanoma (958 percent), prostate cancer (57 percent), non-melanoma skin cancer (43 percent), ovarian cancer (39 percent), and kidney cancer (38 percent).

Mucci added even though genes and family history play an important role it is important to focus on the factors people can modify to reduce cancer risk and increase prevention like diet, smoking and exercise.

“Familial risk and heritability of cancer among twins in Nordic countries”, Lorelei A. Mucci, Jacob B. Hjelmborg, Jennifer R. Harris, Kamila Czene, David J. Havelick, Thomas Scheike, Rebecca E. Graff, Klaus Holst, Sören Möller, Robert H. Unger, Christina McIntosh, Elizabeth Nuttall, Ingunn Brandt, Kathryn L. Penney, Mikael Hartman, Peter Kraft, Giovanni Parmigiani, Kaare Christensen, Markku Koskenvuo, Niels V. Holm, Kauko Heikkilä, Eero Pukkala, Axel Skytthe, Hans-Olov Adami, Jaakko Kaprio, on behalf of the Nordic Twin Study of Cancer (NorTwinCan) collaboration.

“It was surprising that the estimate of heritability of melanoma was the largest of all of the studied cancers”, Mucci said. One of the strongest familial risks was observed for testicular cancer. The types of cancer each developed were not always the same, however. Unfortunately, it seems like developing cancer may be one of the qualities both identical and fraternal twins share. Cancer was diagnosed in both twins for 3,316 of the pairs, in whom the same cancer was diagnosed among 38% of the identical twins and 26% of the fraternal twins.

Although this study was based on twins, Mucci said the findings are relevant to siblings more generally.

Finally, researchers identified a set of cancers in which genetics play a very small role. For example, if a man has a brother who was diagnosed with testicular cancer, the man’s lifetime risk of testicular cancer is substantially elevated, and he may benefit more than the average person from frequent screening exams, she explained.

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