Background: Prostate Cancer (CaP) is the second most common cancer in men and a major public health problem. Clinical outcomes at diagnosis are heterogeneous and difficult to predict, so predictive and diagnostic markers are needed. Heat shock proteins (HSPs) such as HSP27 are highly regulated in several malignant tumors. Basal HSP27 levels in most human tissues are low compared to high levels in tumors. Methods: In this work, we evaluated, in subjects with CaP, the levels of expression of the HSP27 antigen in tumor tissues and its association with tumor aggressiveness. The Immunohistochemical (IHC) method was used to determine the expression of HSP27 in 58 prostate cancer tissues and 4 prostate hyperplasia (BPH). Results: Tissue levels of HSP27 were significantly higher in patients with CaP than in BPH (QSM = 153.43±0; P 7), we found a very significant increase in HSP27 protein (QSM = 169.73±84.26; P