Non-invasive ‘liquid biopsies’ can find metastatic or recurrent prostate cancer, in a low cost assay suitable for most healthcare systems, finds new research. Genomic signatures of prostate cancer, isolated from plasma DNA, display abnormal copy numbers of specific areas of chromosomes. It is even possible to separate out patients who develop resistance against hormone deprivation therapy, which is the most common form of treatment in men with metastatic prostate cancer.