Down-Regulation of S100A8 is an Independent Predictor of PSA Recurrence in Prostate Cancer Treated by Radical Prostatectomy

Dysregulation of S100A8 is described in many different human tumor types, but its role in prostate cancer is unknown. To evaluate the clinical relevance of S100A8 expression in prostate cancer, a tissue microarray containing 13,665 tumors was analyzed by immunohistochemistry. Cytoplasmic S100A8 staining was compared to prostate cancer phenotype, patient prognosis and molecular features including TMPRSS2:ERG fusion status and deletions of PTEN, 3p, 5q and 6q. S100A8 immunostaining was typically seen in normal prostate tissue but lost in 60% of 9786 interpretable prostate cancers. In the remaining tumors, S100A8 was considered weak in 17.9%, moderate in 17.8% and strong in 5.4% of cases. Loss of S100A8 expression was linked to advanced tumor stage, high Gleason grade, positive nodal status, positive surgical margin and high preoperative PSA (P