Prostate Cancer Can Be Inherited
Since 1992, the presence of a familial prostate cancer gene (or genes) had been suspected because of a clear link between a family history of prostate cancer and a man’s risk of developing the disease. Prostate cancer that is believed to have a genetic basis is called hereditary prostate cancer (HPC).
Researchers have identified a variety of different genes that may play a role a role in prostate cancer, including the BRCA genes that influence a woman’s risk of breast cancer. No one gene or set of genes can explain all cases of HPC. Different genes may be important in different racial, ethnic and geographic populations.
Most scientists believe that cancer happens because of a combination of mutations to a variety of genes. These mutations may be inherited or they may be acquired because of environmental factors, such as diet or smoking, or because of random mistakes in the replication or repair of DNA. Think of a genetic slot machine, in which to develop cancer, you need to get three, four or five oranges in a row. Each mutated gene is worth at least one orange.
Researchers hope that identifying the chromosomal location associated with some cases of HPC will lead to the identification of one or more specific genes involved in the development of prostate cancer. This would enable doctors to identify families that carry the mutated forms of these genes, and thus to identify men who are at high risk for developing the disease. Ultimately, the goal is either to develop therapies to prevent prostate cancer from occurring or to develop tests that enable doctors to detect prostate cancer in time to cure it. Men with HPC tend to develop the disease far sooner than other men, even as young as their late thirties or early forties. By the time these men start routine screening for prostate cancer, it may already be too late to cure it.
Until more is learned about HPC, men with a family history of the disease should talk with their doctor about a yearly digital rectal examination and PSA test, beginning at age 40.
The Dietary-Prostate Connection
Most risk factors for prostate cancer can’t be controlled. For example, the disease is more common among men who are older, have a family history of the disease or are African-American. How much diet influences prostate cancer risk remains unclear. Researchers have noted the following observations.
- Saturated fat. Population studies show that Asian men living in Asia have a 2 percent lifetime risk of prostate cancer; when they move to the United States, the risk in the next generation jumps to 10 percent. One possible reason: the fatty Western diet. Some studies suggest that men who eat more animal fat may have a higher rate of prostate cancer.
- Selenium. Earlier studies suggested that diets rich in selenium might lower prostate cancer risk. More recent studies have not confirmed this. Clearly, selenium supplements do not decrease your chance of developing prostate cancer.
- Vitamin D. Recent studies show that men who have higher intakes of vitamin D have a lower risk of advanced prostate cancer.
- Lycopene. Higher intake of a substance called lycopene — an antioxidant found in produce such as tomatoes, watermelon, pink grapefruit and guava — may be associated with a reduced risk of prostate cancer. However, it might not be the lycopene. Some studies have linked prostate cancer to a low intake of fresh fruits and vegetables in general.
- Calcium. A few studies have linked prostate cancer to a higher intake of calcium, which is found mainly in dairy products.