An international team of scientists has successfully used a human vaccine to cure prostate cancer in mice, and without side effects. Results of the revolutionary study, which appear in the journal Nature Medicine, herald the potential for a way to eliminate prostate cancer in men, should future studies prove the vaccine also works in humans.
Researchers at Mayo Clinic, Rochester, Minnesota, in collaboration with colleagues from several institutions in the United Kingdom, report that the vaccine works in mice by notifying the immune system to recognize and destroy the prostate cancer tumor while leaving healthy prostate tissue undamaged. The study results show that nine intravenous (IV) injections of the vaccine cured more than 80 percent of the prostate tumors in the mice.
This new approach was developed by geneticists who took pieces of genetic code from healthy human prostate tissue and assembled it into a complementary DNA (cDNA) library. The pieces of cDNA were then placed into a group of viruses, which were cultured and reintroduced into the study mice as a vaccine via IV injections.
All infections, including cancerous tumors, possess a unique fingerprint called an antigen, a protein capable of triggering a response from the immune system. In this study, the human vaccine prostate cancer antigens were introduced into the mice via the viruses. The animals’ immune systems recognized the antigens in the viruses and launched an immune response to attack the prostate tumors.
A human vaccine for prostate cancer will not be ready overnight. Clinical trials in humans will likely begin within two years. Development of an effective, safe vaccine for prostate cancer can’t come too soon for the hundreds of thousands of men who face the challenge of the disease every day.
According to the American Cancer Society’s (ACS) Cancer Facts and Figures 2011 report, an estimated 240,890 men will get a diagnosis of prostate cancer in 2011, and 33,720 men will die of the disease. Prostate cancer is second only to skin cancer as the most common cancer among American men. About 62 percent of all prostate cancer cases are diagnosed in men 65 years of age and older, and 97 percent occur in men age 50 and older. The highest incidence rates occur in African American and Jamaican men of African descent. The ACS report also notes that diets high in dairy foods and processed meat may be a risk factor, and that obesity appears to raise the risk of aggressive prostate cancer.
The researchers note that if the vaccine proves effective in humans, it will allow men with prostate cancer to eliminate their tumors without experiencing the side effects associated with chemotherapy and radiation, which may include erectile dysfunction, urinary incontinence, hair loss, bowel symptoms, and loss of libido, among others.
Read more in our Prostate Cancer Health Center.
American Cancer Society, Cancer Facts & Figures 2011
Kottke T et al. Broad antigenic coverage induced by vaccination with virus-based cDNA libraries cures established tumors. Nature Medicine published online 2011 June 19; 17(7):854-59.