Clinical significance of macrophage heterogeneity in human malignant tumors

Authors

  • Yoshihiro Komohara,

    Corresponding author
    1. Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
    • Correspondence

      Yoshihiro Komohara, Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, Honjo 1-1-1, Kumamoto 860-8556, Japan.

      Tel: +81-96-373-5095; Fax: +81-96-373-5096;

      E-mail: ycomo@kumamoto-u.ac.jp

    Search for more papers by this author
  • Masahisa Jinushi,

    1. Research Center for Infection-associated Cancer, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
    Search for more papers by this author
  • Motohiro Takeya

    1. Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
    Search for more papers by this author

Abstract

The fact that various immune cells, including macrophages, can be found in tumor tissue has long been known. With the recent introduction of the novel concept of macrophage differentiation into a classically activated phenotype (M1) and an alternatively activated phenotype (M2), the role of tumor-associated macrophages (TAMs) is gradually beginning to be elucidated. Specifically, in human malignant tumors, TAMs that have differentiated into M2 macrophages act as “protumoral macrophages” and contribute to the progression of disease. Based on recent basic and preclinical research, TAMs that have differentiated into protumoral or M2 macrophages are believed to be intimately involved in the angiogenesis, immunosuppression, and activation of tumor cells. In this paper, we specifically discuss both the role of TAMs in human malignant tumors and the cell–cell interactions between TAMs and tumor cells.

Ancillary