Expression of IL-17A, E, and F and their receptors in human prostatic cancer: Comparison with benign prostatic hyperplasia.

Background: Benign prostatic hyperplasia (BPH) and prostate cancer (PCa) are the most common urological diseases in elderly men. Although studies suggest the cytokine family might be associated with BPH and PCa, there has been no systematic comparisons of expression of IL-17A, E, F and their receptors, infiltration of inflammatory cells, and changes in structural cells in PCa and BPH.

Methods: Immunohistochemistry was employed to evaluate immunoreactivity for IL-17A, E, F and their receptors IL-17RA, IL-17BR, and IL-17CR, infiltration of inflammatory cells, and changes in structural cells including endothelial cells, fibroblasts, and smooth muscle cells in prostate tissues from subjects with PCa or BPH as well as controls.

Results: Immunostaining showed that expression of immunoreactivity for IL-17A, IL-17RA, IL-17E, and IL-17F was significantly elevated in prostatic tissue from BPH and PCa compared with that in controls, which was accompanied by increased numbers of infiltrating inflammatory cells and CD31(+) blood vessels. Compared with BPH, PCa was characterized by reduced immunoreactivity for IL-17BR and reduced numbers of CD68(+) macrophages, fibroblasts, and smooth muscle cells, although there was a trend for these changes to correlate with disease severity in both PCa and BPH.

Conclusion: Our data are compatible with hypothesis that IL-17A acting through IL-17RA, but not IL-17CR contribute to the pathogenesis of BPH and PCa. In contrast, IL-17E interacting with the IL-17BR might have an anti-tumor effect.