About this Journal Submit a Manuscript Table of Contents
Journal of Oncology
Volume 2013 (2013), Article ID 183602, 6 pages
http://dx.doi.org/10.1155/2013/183602
Review Article

Multiple Myeloma Macrophages: Pivotal Players in the Tumor Microenvironment

Department of Biomedical Sciences and Human Oncology, Clinica Medica “G. Baccelli,” University of Bari Aldo Moro Medical School, Piazza Giulio Cesare 11, 1-70124 Bari, Italy

Received 4 October 2012; Accepted 3 January 2013

Academic Editor: Rathindranath Baral

Copyright © 2013 Simona Berardi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Tumor microenvironment is essential for multiple myeloma (MM) growth, progression, and drug resistance through provision of survival signals and secretion of growth and proangiogenic factors. This paper examines the importance of macrophages within MM bone marrow (BM) microenvironment, referred to as MM-associated macrophages, as a potential niche component that supports tumor plasma cells. These macrophages are derived from peripheral blood monocytes recruited into the tumor. Upon activation by MM plasma cells and mesenchymal stromal cells, macrophages can release growth factors, proteolytic enzymes, cytokines, and inflammatory mediators that promote plasma cell growth and survival. Macrophages promote tumor progression through several mechanisms including angiogenesis, growth, and drug resistance. Indeed, these macrophages are essential for the induction of an angiogenic response through vasculogenic mimicry, and this ability proceeds in step with progression of the plasma cell tumors. Data suggest that macrophages play an important role in the biology and survival of patients with MM, and they may be a target for the MM antivascular management.