Prostate cancer is the most common cancer in men and is the second leading cause of death by cancer amongst men in the United States and United Kingdom. Now, new research is suggesting that this cancer may result from infection with a sexually transmitted disease. However, more research will be required to confirm any sort of causative link in human tumour genesis or the degree to which human prostate cancer rate may be due to this infection.
Trichomoniasis, commonly referred to as trich, is the most common of the curable sexually transmitted diseases and is the result of infection with the Trichomonas vaginalis parasite. This parasite likes to live in the genital tracts, and given the greater surface content of the female tracts, women contract this disease at approximately double the rate men do. However, the parasite is also known to infect male prostate cells and can cause inflammation of that gland, called prostatitis.
A number of cancers are already known to be caused by infections. Cervical, liver and gut cancers can be caused by exposure to human papillamavirus, hepatitis B & C viruses and Helicobactor pylori. Previous work has already suggested that there may be an epidemiological link between this cancer and infection with trichomoniasis. However, evidence that prostate cancer might actually be caused by the sexually transmitted disease had been lacking until now.
In the current study, scientists examined how this infection interacted with human prostate cells in cultures. They found that a major protein secreted by the trichomoniasis parasites (TvMIF) was able to act on different benign and cancerous prostate cells to increase inflammation, cell proliferation and the invasiveness of these newly made cells. They then examined humans who were infected with the T. vaginalis parasite. It was found that these men contained the TvMIF protein, and exhibited a significant immune response to it. Finally, the research team found that blood serum from males showed a stronger reaction to the TvMIF than did the serum taken from women.
It is thought that some 275 million people worldwide are infected by the parasites, with the parasites more commonly found amongst women. In the United States, almost 2.5 million women – or 3.1 percent – are infected, with rates much higher amongst African American women, according to the Centers for Disease Control. Also, as up to 85 percent of women are asymptomatic, it is less likely that women will get tested and treated for the disease. Those who do show symptoms, however, can exhibit difficulty and pain with urination as well as vaginal discharge with an unpleasant odor. Men may experience similar symptoms, with pain during urination or ejaculation, discharge from the penis, and penile itching and irritation.
Trichomoniasis has also been involved with other health problems. For example, T. vaginalis infection can make contraction of the HIV virus easier. Women with this parasite are also more likely to give birth prematurely and have babies with low body weight.
The asymptomatic nature of this infection for most people makes it easier to transmit, as most carriers will be unaware that they have this parasite. However, transmission of this disease can be prevented by use of condoms. The good news is that this parasite can also be killed by a single dose of a specific oral antibiotic treatment. So, should a causal link between this sexually transmitted disease and prostate cancer be confirmed, rates of trichomaniasis infection may also be easily prevented with regular screening.
By Bryan A. Jones