Studies of identical and fraternal twins have found that prostate cancer has a stronger hereditary component than many other cancers, including breast and colon cancer. Having one first-degree relative (a brother or father) with prostate cancer doubles the risk of developing the disease; having a second-degree relative (an uncle or grandfather) with the disease confers only a small increase in risk.
A number of genetic alterations that affect how the body handles inflammation and infections, fat metabolism, repair of genetic damage, and other processes have been linked to prostate cancer development and progression. For example, researchers have discovered that gene fusions—a process in which genes separate from their normal location and fuse to another gene—are an early event in prostate cancer development.
Researchers found that men who inherit a rare mutation on a gene known as HOXB13 are up to 20 times more likely than noncarriers to develop prostate cancer. However, the mutation is responsible for only 2 to 5 percent of prostate cancer cases. In most cases, rather than inheriting a defect in a single gene that results in prostate cancer, it is more likely that minor variations in a number of genes (any one of which alone may have no adverse effects) when combined act like the “perfect storm” to increase a man’s risk.
The lifestyle choices a man makes most likely act in concert with these genetic variants to cause the development and progression of prostate cancer. Although genes can influence a man’s risk of developing prostate cancer, other factors also are at work. The likelihood that identical twins (who share all genetic information) will both develop prostate cancer is 27 percent. This suggests that lifestyle choices can modify the effects of the genetic cards that a person is dealt at birth.