Since we observed negative regulation of MMP9 by PDEF and published results suggested that the activity of MMP9 is associated with the progression and metastasis of prostate cancer [27], we also evaluated MMP9 expression in the tissue microarray slides containing 40 cores of prostate cancer and 9 cores of normal prostate that were used for PDEF expression analysis. This evidence concerns the gene MMP9 and Familial prostate cancer.