The PSA staining score inversely correlated to tumor cell proliferation in bone metastases (Rs = −0.32, P = 0.007, n = 71; Fig. 3C), and a combinatory score identified four groups of metastases with the following frequencies: high PSA, low Ki67 (41%); low PSA, low Ki67 (32%); low PSA, high Ki67 (18%); high PSA, high Ki67 (8.5%) (Fig. 3D). The gene discussed is KLK3; the disease is neoplasm.