CD34 and neoplasm: NSG mice aged 3 to 4 weeks were implanted with 3×104 initial human CD34+ HSC (Stem Cell Technologies, Vancouver, British Columbia, Canada) via tail vein injection.9 PC3 vector (group A to E) or N-cad-KO (group F) prostate cancer cells (2×106) were implanted into the bilateral flank by subcutaneous injection 8 weeks after HSC engraftment.10 Group A was implanted with tumor cells only and served as the blank control.