The impact of tumor associated macrophages on multiple myeloma prognosis

Bone marrow stromal cells support the growth, survival, migration and drug resistance of myeloma cells. Tumor associated macrophages (TAM) are also known to support the survival and proliferation of tumor cells, and neo-angiogenesis in the tumor tissuesIn this respect, we investigated whether TAM might have a role in pathogenesis and prognosis of MM. Sixty-eight patients who were diagnosed with MM at Gazi University Faculty of Medicine, Department of Hematology from January 2000 through January 2011 were included in this study. Median age of the patients was 60 (range, 40-84) years with 36 males and 32 females. Immunohistochemical staining using anti CD63 and anti CD163 monoclonal anticors were performed on parffin embedded tissue blocks were analysed retrospectively for the assessment of TAM. Median CD68+ cell number was found to be 1 (range, 0-8) and median CD163+ cell number was found to be 5 (range, 0-13). Seventeen (25%) of the patients had > 7 CD163+ cells and 51 (75%) had ? 7 CD163+ cells. Median survival of the patients was 9.5 (range, 1-75) months in patients with > 7 CD163+cells and 33 (range, 1.5-108) months in patients with ? 7 CD163+ cells (p=0.005). The probability of overall survival at 6 years was 22% in patients with > 7 CD163+ cells and 57% in patients with ? 7 CD163+ cells (p=0,011). In univariate and multivariate analysis, CD163+ cell number had an impact on 6 year survival (p=0,015 v.s. 0,039). CD163 expression could be used as a prognostic marker in newly diagnosed patients.