The present invention relates to the field of biomarkers and, more specifically, to biomarkers useful in diagnosing aggressive prostate cancer. In specific embodiments, a method for diagnosing aggressive prostate cancer in a patient comprises (a) measuring the levels of one or more biomarkers in a sample collected from the patient; and (b) comparing the levels of the one or more biomarkers with predefined levels of the same biomarkers that correlate to a patient having aggressive prostate cancer and predefined levels of the same biomarkers that correlate to a patient not having aggressive prostate cancer, wherein a correlation to one of the predefined levels provides the diagnosis. In a specific embodiment, the one or more biomarkers may comprise cathepsin-L (CTSL), periostin, microfibrillar-associated protein 4 (MFAP4), collagen XII, neprilysin, clusterin, neutrophil gelatinase associated lipocalin (NGAL), epithelial cell activating molecule (EpCAM), prostate specific antigen (PSA), membrane metallo-endopeptidase (MME) and asporin (ASPN).