Multifunctional role of the tumor associated monocytes/macrophages in the metastatic potential of inflammatory breast cancer

Inflammatory breast cancer (IBC) is the most aggressive and lethal phenotype form of breast cancer, which afflicts young women at high incidence in North Africa compared to other continents of the world. IBC is characterized by highly metastatic behavior and possesses specific pathobiological properties different from non-IBC. IBC disease displays unusual common properties at typical presentation, including positive metastatic lymph-nodes, high infiltration of tumor associated monocytes/macrophages, rapid progression to distant metastasis, and possibly the production of a unique repertoire of growth factors, cytokines and chemokines, as well as a striking association with different polarized macrophages compared to non-IBC. Indeed, tumor associated monocytes/macrophages (TAM/M) play a crucial role in breast cancer development. Previously, we showed that cross talk between IBC cells and patient derived TAMs occurs via secretion of inflammatory mediators from TAMs that act on specific extracellular domain receptors activating down-stream signaling pathways that promote the epithelial-to-mesenchymal transition, cancer cell invasion, IBC stem cell properties, drug resistance, local and metastatic recurrence of residual tumor cells and other key markers of malignancy, including in vitro colony formation capacity. In this mini review, we will discuss the role of TAMs in IBC cancer metastatic potential and molecules involved. The review also discusses the recent discoveries in the field of IBC research.