Prostate tissue staining for Ki-67/MIB-1 has been described previously (25 (link)). The monoclonal antibody, MIB-1 (clone MIB-1, DAKO) was used to determine the proportion of cancer epithelial, cancer-associated stromal and benign-associated stromal cells staining positive for Ki-67. Prostate cancer tissue microarray slides were scanned on Aperio ScanScope AT (Aperio Technologies, Vista, CA, USA). High-resolution 20× digital images were created for the cancer and benign cores of twenty randomly selected cases. Positive Ki-67-stained cells and the total number of cells in 20× fields were counted using ImageJ2 Cell Counter plug-in (ImageJ, U. S. National Institutes of Health, Bethesda, Maryland, USA). Any nuclear staining, regardless of intensity, was considered positive for Ki-67/MIB-1. For the stromal compartment, only spindle-like cells were included in the analysis, while round small nuclei cells were not considered for immunohistochemical evaluation, thus avoiding the inclusion of inflammatory cell in the analysis. The number of Ki-67 positive cells was expressed as a percentage of immunoreactive stromal (or epithelial) cells to the total counted stromal cells (or epithelial) in a 20× field.