NEW YORK (Reuters Health) - An experimental vaccine can provide long-term protection against prostate cancer in mice genetically predisposed to the disease, new research indicates.
"By early vaccination, we have basically given these mice life-long protection against a disease they were destined to have," senior investigator Dr. W. Martin Kast, from the University of Southern California in Los Angeles, said in a statement.
"This has never been done before and, with further research, could represent a paradigm shift in the management of human prostate cancer."
The vaccine stimulates an immune response against PSCA, which stands for prostate stem cell antigen. PSCA is a good vaccine target because it is overly expressed in prostate cancer, but displays limited expression in other tissues, the investigators note.
In the new study reported in the journal Cancer Research, the investigators administered a PSCA-based vaccine to mice made prone to prostate cancer. The animals were 8 weeks old and already had pre-cancerous prostate lesions.
Vaccination was associated with a robust immune response. At 12 months, 90 percent of the vaccinated mice were still alive, while all of the control animals had either died or had large tumors.
Human studies are needed to confirm the safety and efficacy of this vaccine strategy. "We feel this is a very promising approach. With just two shots, the vaccine will prime immune cells to be on the lookout for any cell that over-expresses PSCA."
SOURCE: Cancer Research, February 1, 2008.
