Dual roles of immune cells and their factors in cancer development and progression

Int J Biol Sci. 2011;7(5):651-8. doi: 10.7150/ijbs.7.651. Epub 2011 May 21.


Traditional wisdom holds that intact immune responses, such as immune surveillance or immunoediting, are required for preventing and inhibiting tumor development; but recent evidence has also indicated that unresolved immune responses, such as chronic inflammation, can promote the growth and progression of cancer. Within the immune system, cytotoxic CD8(+) and CD4(+) Th1 T cells, along with their characteristically produced cytokine IFN-γ, function as the major anti-tumor immune effector cells, whereas tumor associated macrophages (TAM) or myeloid-derived suppressive cells (MDSC) and their derived cytokines IL-6, TNF, IL-1β and IL-23 are generally recognized as dominant tumor-promoting forces. However, the roles played by Th17 cells, CD4(+) CD25(+) Foxp3(+) regulatory T lymphocytes and immunoregulatory cytokines such as TGF-β in tumor development and survival remain elusive. These immune cells and the cellular factors produced from them, including both immunosuppressive and inflammatory cytokines, play dual roles in promoting or discouraging cancer development, and their ultimate role in cancer progression may rely heavily on the tumor microenvironment and the events leading to initial propagation of carcinogenesis.

Keywords: Hepatocellular Carcinoma; TGF-β; Treg; Tumor Associated Macrophages.

Publication types

  • Research Support, N.I.H., Intramural
  • Review

MeSH terms

  • Animals
  • Carcinoma, Hepatocellular / immunology
  • Carcinoma, Hepatocellular / metabolism
  • Cytokines / metabolism
  • Humans
  • Liver Neoplasms / immunology
  • Liver Neoplasms / metabolism
  • Macrophages / immunology
  • Macrophages / metabolism
  • T-Lymphocytes, Regulatory / immunology*
  • T-Lymphocytes, Regulatory / metabolism*
  • Transforming Growth Factor beta / metabolism


  • Cytokines
  • Transforming Growth Factor beta