TUESDAY, Jan. 5, 2016 — A new study by PCF researcher Lorelei Mucci, ScD, reports new evidence for the “significant heritability” of prostate cancer. Her exciting results, published in the January 5 issue of The Journal of the American Medical Association, provide a new, compelling reason for men to get checked for prostate cancer if they have (or have had) at least one close relative diagnosed with the disease.
For years, scientists and physicians have associated family history of prostate cancer with an increased risk of developing the disease. However, the exact mechanism of this link has not been completely clear.
To understand the specific ways that genetic and environmental factors influence cancer development, Dr. Mucci and her team analyzed data from the Nordic Twin Study of Cancer conducted between 1943 and 2010. In total, the study included 80,309 identical and 123,382 same-sex fraternal twin individuals. Identical twins share 100 percent of their genetic material, while fraternal twins share 50 percent. Twins were followed for a median of 32 years, and any incidence of cancer was recorded.
Overall, Dr. Mucci and her team found that 1 in 3 people in the study developed some type of cancer during their lifetime. For instances where both twin-siblings developed cancer, 38 percent of identical and 26 percent of fraternal twin sets were diagnosed with the same type of cancer.
The team then compared rates of individual cancer incidence and mortality with environmental factors such as socioeconomic status, lifestyle, and occupation, as well as screening patterns in adult life. This is because even though family members may not share all of the same genetics, they are more likely to share certain behaviors, such as smoking.
Their analysis further indicated that some cancer types carry a higher than average “familial risk”–the risk of cancer in an individual given a close family member’s development of cancer. In the case of prostate cancer, 57% of cancers were estimated to have significant heritability.
In addition to this important discovery, these findings show how genetics and environment together play important roles in the development, progression, and prevention of cancer.
The full text of Dr. Mucci’s report, “Familial Risk and Heritability of Cancer Among Twins in Nordic Countries,” may be found here: http://jama.jamanetwork.com/article.aspx?articleid=2480486