A functional analysis demonstrated that the expression of certain proteinases such as dipeptidyl peptidase 4 (DPP4), carboxypeptidase E (CPE) and prostate specific antigen (KLK3), were significantly altered in both primary aggressive PCa and metastatic tumors compared to primary NAG PCa and normal prostate tissues. The gene discussed is DPP4; the disease is metastatic neoplasm.