Sweet escape: sialic acids in tumor immune evasion

Biochim Biophys Acta. 2014 Aug;1846(1):238-46. doi: 10.1016/j.bbcan.2014.07.005. Epub 2014 Jul 12.


Sialic acids represent a family of sugar molecules derived from neuraminic acid that frequently terminate glycan chains and contribute to many biological processes. Already five decades ago, aberrantly high expression of sialic acids has been proposed to protect cancer cells from recognition and eradication by the immune system. Today, increased understanding at the molecular level demonstrates the broad immunomodulatory capacity of tumor-derived sialic acids that is, at least in part, mediated through interactions with immunoinhibitory Siglec receptors. Here we will review current studies from a sialic acid sugar perspective showing that tumor-derived sialic acids disable major killing mechanisms of effector immune cells, trigger production of immune suppressive cytokines and dampen activation of antigen-presenting cells and subsequent induction of anti-tumor immune responses. Furthermore, strategies to modulate sialic acid expression in cancer cells to improve cancer immunotherapy will be discussed.

Keywords: Cancer; Immune evasion; Sialic acids; Sialoglycans; Siglecs; Tumor microenvironment.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Complement System Proteins / immunology
  • Complement System Proteins / metabolism
  • Dendritic Cells / immunology
  • Humans
  • Immune System / metabolism
  • Immunotherapy
  • Myeloid Cells / immunology
  • Neoplasms / immunology
  • Neoplasms / therapy
  • Sialic Acids / metabolism*
  • T-Lymphocytes, Cytotoxic / immunology
  • T-Lymphocytes, Cytotoxic / metabolism
  • Tumor Escape* / immunology


  • Sialic Acids
  • Complement System Proteins