Immunohistochemical expression of hyaluronic acid in the normal prostate, benign prostate hyperplasia and prostate carcinoma

Hyaluronic acid (HA), a component of the extracellular matrix, is present in various tissues and tissue fluids. HA regulates cell adhesion and migration and it has been implicated in the progression of prostate cancer (PCa) as a molecule associated with the biological potential of PCa. The concentration of HA is elevated in several cancers, including bladder, colon, breast and Wilms’ tumor. In this study, we compared the immunohistochemical expression of HA in the normal prostate, benign prostate hyperplasia (BPH) and prostate carcinoma. HA was immunohistochemically detected in 22 prostate tissues (6 histologically normal, 10 with BPH and 6 with PCa). Formalin fixed, paraffin-embedded sections were stained using an ABC method with biotinylated HA binding protein (B-HABP). Negative controls included sections incubated without B-HABP as well as sections incubated with Streptomyces hyaluronidase . In normal and BPH prostate glands staining was localized predominantly in the gland surrounding stroma, as well as in the fibrovascular core of the papillary projections of the glands. In prostate carcinoma samples the amount of HA in the stroma was markedly increased and staining was not localized around glandular structures but was diffuse throughout the stroma. There was a sharp diminution at the interface between tumor stroma and non-tumoral connective tissue. HA appears to be a supplementary tumor-associated marker. Insight gained in the mechanisms of increased production and hyaluronidase digestion of HA may eventually lead to new targets for pharmacological intervention in the treatment of PCa.