MicroRNA-mediated control of macrophages and its implications for cancer.

Deregulation of microRNAs (miRNAs) can drive oncogenesis, tumor progression, and metastasis by acting cell-autonomously in cancer cells. However, solid tumors are also infiltrated by large amounts of non-neoplastic stromal cells, including macrophages, which express several active miRNAs. Tumor-associated macrophages (TAMs) enhance angiogenic, immunosuppressive, invasive, and metastatic programming of neoplastic tissue and reduce host survival. Here, we review the role of miRNAs (including miR-155, miR-146, and miR-511) in the control of macrophage production and activation, and examine whether reprogramming miRNA activity in TAMs and/or their precursors might be effective for controlling tumor progression.