Posts Tagged ‘prostate’

Prostate Cancer: Biology, Genetics, Prevalence

May 11, 2010

Prostate cancer can only occur in men because the prostate is a gland which exists in the male reproductive system. Prostate cancer detection begins with screening for prostate specific antigen (PSA). Detection occurs less often when symptoms develop or by physical examination. Prostate cancer diagnosis is confirmed by biopsy. Risk factors include age, ethnicity, family history and diet.

Prostate cancer is the most common cancer in American men. It can be painful, make urinating difficult and cause erectile dysfunction. Men who are at average risk of prostate cancer have a 14% chance of developing prostate cancer by the time they are 80 years of age. Prostate cancer is the second leading cause of cancer death in men. Many men develop prostate cancer, do not have any symptoms and die of other causes related to old age.

Biology of Cancer

Cancer occurs when genes mutate and do not produce the correct regulatory proteins which normally control cell functions. Cells then multiply out of control. Cancer can spread to other parts of the body, such as bones and lymph nodes. Genes can mutate before a person is born. This is considered to be hereditary. This type of cancer can be inherited by offspring in future generations. Genes can also mutate during a person’s lifetime. The cells derived from this line would then be immortal.

Prostate Cancer Genetics

Most prostate cancer is sporadic, so 75% of individuals with prostate cancer mutated genes after birth. Only 5% of men inherit prostate cancer. The remaining 20% develop familial prostate cancer, which means that a combination of environmental and shared genes resulted in cancer.

Genetics has been implicated in the development of prostate cancer. Every cell contains two copies of each gene; one copy originates from the mother and one from the father. When prostate cancer is inherited, it follows an autosomal dominant inheritance. This means that the mutation only has to occur in one copy of the gene for the individual to be at higher risk of developing cancer. Each child has 50% chance of inheriting the mutation causing prostate cancer from a parent who has the mutation.

The only way a person can know if they are at high risk of having a genetic mutation is genetic testing. Since there is no genetic test for prostate cancer, one must rely on family history. If a man has a strong family history of prostate cancer, he can participate in prostate cancer research to determine what the genes are that are correlated with it.

Prostate cancer risk factors include mutations in several genes. A gene on chromosome 17 is associated with increased risk of prostate cancer.  Research must be continued to verify these findings to determine if they can be used for genetic testing in the future. Several other mutated genes have been identified as being responsible for increased likelihood of developing prostate cancer.

Prevalence of Prostate Cancer

Rates of prostate cancer vary widely throughout the world. It is least prominent in South and East Asia, more common in Europe and most common in the United States. In 2008, about 186,000 men in the US will be diagnosed with prostate cancer. It normally develops in men over 50 years old. An estimated 28,000 deaths will occur from prostate cancer. Although the incidence of prostate cancer is decreasing overall, black men are twice as likely to develop this cancer as white men.

Progress toward a Cure

Prostate cancer prevention may be in the near future. Men can determine their risk factor through their family history and attempt to control certain environmental and lifestyle factors. These factors include a balanced diet, healthy weight, exercising, limiting alcoholic beverages and avoiding tobacco products. Eventually research will determine which genetic mutations are correlated with prostate cancer.