Aurora-A over-expression in high-grade PIN lesions and prostate cancer

BACKGROUND. Over-expression of Aurora-A (Aurora 2 kinase, STK-15), a protein found in centrosomes thought to be associated with genetic instability, has been previously documented in prostate cancer [Pihan et al.: Cancer Res 61(5):2212-2219, 2001]. It is unknown if this protein is also over-expressed in high-grade prostatic intraepithelial neoplasia (PIN) lesions. METHODS. PIN lesions were examined for increased Aurora-A using immunohistochemical staining on archival paraffin embedded prostatectomy tissue. Aurora-A expression was scored using size, number, and staining intensity. Protein expression was examined and compared between stromal cells, normal glands, high-grade PIN lesions, and invasive cancer. RESULTS. Immunohistochemistry shows an increased expression of Aurora-A in 96% of high-grade PIN cases, and 98% in cancer lesions. Twenty-nine percent of cases of normal glands from cancerous prostates also showed increased Aurora-A expression. CONCLUSIONS. Over-expression of Aurora-A is present in some normal and the majority of high-grade PIN lesions indicating that this may be an early event that leads to the genetic instability seen in prostate carcinogenesis.