It is important to find out what makes some cancer cells spread and others stay where they are. For the investigators to do this they need to collect fresh samples of cancer tissue from the prostate and from different areas of a tumour within the prostate. This is because biopsies used to diagnose or exclude cancer by the hospital laboratory are not good enough to give investigators detailed genetic information. These biopsies have been put into a chemical called formalin which reduces the quality of the genetic information.