KLK3 and neoplasm: Notably, the median PSA staining score was higher in metastases with than without glandular differentiation (9 vs. 6, P = 0.016, n = 72) and in cases without pronounced atypia (9 vs. 6, P = 0.012, n = 72), suggesting that high cellular PSA is a marker for preserved epithelial and glandular differentiation in tumor cells.