The finding has raised hopes of a new vaccine to help combat the disease.
Researchers at Nottingham Trent University have identified characteristics in a protein that may stimulate the body's own defences to attack tumour cells.
Their study has focused on the protein called prostatic acid phosphatase (PAP), which occurs in 90% of prostate tumours.
From their research, scientists at the university's John van Geest Cancer Research Centre have developed a prostate cancer vaccination strategy.
Prostate cancer is the most common form in UK men, killing more than 10,000 every year.
Professor Robert Rees, research centre director, said he hoped the work would lead to a clinical trial.