RGS1 expression is associated with poor prognosis in multiple myeloma

Aims Multiple myeloma (MM) is an invariably fatal disease with highly heterogeneous outcome. Because of this heterogeneity of MM, risk stratification is crucial for therapeutic decision-making. However, no immunohistochemical prognostic or predictive markers have been established yet. The expression of regulator of G-protein signalling (RGS) proteins, which desensitise G-protein-coupled receptor signalling, has been reported to be associated with the prognosis of various malignancies. Recently, our group demonstrated the importance of RGS1 in chemokine signalling in a human MM cell line and normal plasmablasts. In the present study, we explored the prognostic value of RGS1 expression in patients with MM using immunohistochemistry. Methods We evaluated RGS1 protein expression in 79 bone marrow biopsies obtained from patients with MM between 2008 and 2010 at Asan Medical Center. Correlations between RGS1 expression and clinicopathological factors were analysed. Results High RGS1 protein expression was significantly associated with poor overall survival (p=0.005). After an adjusted multivariable analysis, high RGS1 protein expression (p=0.010), high International Myeloma Working Group risk (p=0.003) and high serum lactate dehydrogenase levels (p=0.040) were significantly associated with poor outcomes. Conclusions RGS1 expression may be a prognostic marker for risk stratification and a promising target for the development of a new MM therapy.