Analysis of multidrug-resistance (MDR-1) glycoprotein and CD56 expression to separate monoclonal gammopathy from multiple myeloma |
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| Authors: | P. Sonneveld B. G. M. Durie H. M. Lokhorst Y. Frutiger M. Schoester E. E. Vela |
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| Affiliation: | Erasmus University and University Hospital Rotterdam Dijkzigt, Department of Haematology, Rotterdam, The Netherlands;Westminster and Charing Cross Medical School, Department of Haematology, University of London, U.K.;State University Hospital Utrecht, Department of Haematology, Utrecht, The Netherlands;University of Arizona Cancer Center, Tucson, U.S.A. |
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| Abstract: | Summary Monoclonal gammopathy of undetermined significance (MGUS) is different from multiple myeloma (MM) by a low proliferation and by its indolent clinical course. In this study, two biological parameters were investigated which mark the transition from MGUS to MM, i.e. expression of the P-170 glycoprotein associated with the multidrug resistance phenotype (MDR-1) and expression of the natural killer cell antigen, CD56. Strong MDR-1 expression was found in plasma cells of 32/38 untreated MGUS as compared with 33/105 untreated MM stage I–III (84% v 32%, P <0.001) and in 0/10 normal plasma cell samples. CD56 expression in high density was present in 43/57 analysed untreated MM but in none of 23 MGUS (78% v 0% P <0.0001). Plasma cells did characteristically show a low Ki-67 proliferation index in 14/15 MGUS patients (mean 0.05%, range 0–0.2%) and a higher index in 25 analysed MM patients (mean 2.31%, range 1–7%, P <0.03).
These data indicate that MDR-1 expression together with absence of CD56 expression and a low proliferation index can be used to separate MGUS from MM. |
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