Study Marker No. of BM specimens Comparison tissue (No. of specimens) Results Significance Gu et al., 2000 [37 ] PSCA 9 Normal (25) Primary PC (112, 3 matched) All normal tissues were negative. PSCA expression was positive in 105/112 (94%) primary and in 9/9 (100%) BM NR Knudsen et al., 2002 [38 ] Met receptor 45 Primary PC (90) LN (35) Other soft tissues (8) High Met expression in 52% of primary, 83% of BM, and 54% of LN metastases for BM versus LNLam et al., 2005 [39 ] PSCA 47 LN (6, 5 matched) Matched liver (3) PSCA staining intensity was higher in BM (87%) compared with LN (67%) and liver (67%) metastases for BM versus LN. No statistical analysis for liver metastases due to small sample sizeWiesner et al., 2008 [40 ] c-kit, SCF 20 Primary PC (21) BPH (22) Positive staining for c-kit in 5% of BPH, 14% of primary PC, and 40% of BM Positive SCF staining in 95% of BPH and primary PC and in 85% of BM specimens for BM versus BPHEaton et al., 2010 [41 ] CD133, CD44, α 2β 1 integrin, CXCR4, c-met, α 6 integrin 11 Matched primary PC (11) 50% of samples positive for CD133. >70% positive for CD44, α 2β 1, c-met, and α 6 integrin. No difference in expression between primary and BM samples for all markers except for CD44. Higher expression of CD44 in BM, with positive staining in bone stoma. Low staining for CXCR4 in both BM and primary samples NR van den Hoogen et al., 2010 [42 ] ALDH isoforms 10 Matched primary PC (10) No staining for ALDH1 in BM or primary PC ALDH7A1 in 7/10 primary PC and 8/10 BM with no staining in bone stroma NR Castellón et al., 2012 [43 ] CD133, CD44 5 Primary PC (34) LN (7) BM and LN showed lower expression of both CD133 and CD44 compared with primary tissues for BM and LN versus medium Gleason gradeSottnik et al., 2013 [44 ] α 2β 1184 BPH (43) Primary PC (76) LN (61) Liver (36) Higher expression in BM compared to primary PC and nonskeletal metastases for BM versus LN