Expression of HPSE in subpopulations of the BM environment of patients with MM. (A) Expression of HPSE was determined in the WBM of 5 patients with MM as well as in MMCs, CD3⁺ cells, CD14⁺ cells, and CD15⁺ cells purified from the bone marrow of the same patients, using Affymetrix plus 2.0 microarrays. The 5 BMSC and 7 osteoclast samples were obtained by culture in vitro. (B) HPSE expression was measured by real-time RT-PCR. HPSE expression was normalized to that of GAPDH. One WBM sample was used as a reference and was assigned the arbitrary value of 100.