title: Progressive myeloma after thalidomide therapy in a patient with immature phenotype of myeloma (plasma) cells.
abstract: In our experience with thalidomide treatment for refractory multiple myeloma (MM), most patients with progressive disease (PD) did not show an increase in M-protein despite the tumor burden of myeloma cells. This finding led us to suspect that proliferation of immature myeloma cells showing MPC-1(-)/CD49e(-) phenotype may be a sign of PD. We report the results of consecutive analysis of the phenotype of myeloma (plasma) cells in an MM patient with PD during treatment with thalidomide. The myeloma cells decreased by thalidomide therapy were mature (MPC-1(+)/CD49e(+)) and intermediate (MPC-1(+)/CD49e(-)) types. When the patient was in the PD state, extramedullary plasmacytoma was recognized without proliferation of myeloma cells in the bone marrow (BM). The phenotype of myeloma (plasma) cells in both of these locations was that of immature myeloma cells (MPC-1(-)/CD49e(-)), and they showed decreased intensity of CD38 expression. The level of immunoglobulin G (IgG) in serum was decreased, and myeloma (plasma) cells in BM did not increase in PD. Although these clinical features may not be specific to MM patients in PD undergoing treatment with thalidomide, we suggest that immature myeloma cells may be resistant to thalidomide.
authors.affiliation: Department of Hematology and Oncology, Division of Clinical Research, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Okikawa
authors.forename: Akira
authors.initials: A
authors.lastname: Sakai
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Takimoto
authors.forename: Masaaki
authors.initials: M
authors.lastname: Noda
authors.forename: Jun
authors.initials: J
authors.lastname: Imagawa
authors.forename: Yuta
authors.initials: Y
authors.lastname: Katayama
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kuroda
authors.forename: Hajime
authors.initials: H
authors.lastname: Okita
authors.forename: Kingo
authors.initials: K
authors.lastname: Fujimura
authors.forename: Akiro
authors.initials: A
authors.lastname: Kimura
mesh_terms: D000368:Aged; D002455:Cell Division; D018450:Disease Progression; D004351:Drug Resistance; D006801:Humans; D039482:Integrin alpha5 / Q000032:analysis; D008297:Male; D009101:Multiple Myeloma / Q000188:drug therapy* / Q000473:pathology*; D009363:Neoplasm Proteins / Q000032:analysis; D010641:Phenotype; D010950:Plasma Cells / Q000473:pathology*; D013792:Thalidomide / Q000627:therapeutic use*; D017211:Treatment Failure
chemical_list: D039482:Integrin alpha5; C084913:MPC-1 antigen; D009363:Neoplasm Proteins; D013792:Thalidomide