KLK3 and prostate cancer: SKP2 overexpression has been found in 86.4 % (64 of 74 samples) of pre-malignant high grade-prostatic intraepithelial neoplasia (HG-PIN) and in 557 of 622 (89.5%) primary prostate cancer specimens, showing a strong positive association with pre-operative serum prostate specific antigen (PSA) levels, Gleason score, tumor grade, and biochemical failure in men treated by prostatectomy [7–11].