Implications of altered O-glycosylation in tumour immune evasion.

Aberrant glycosylation on tumour cells has been implicated in tumour immune modulation. A recent article published in The Journal of Biochemistry (Sutoh Yoneyama et al., A mechanism for evasion of CTL immunity by altered O-glycosylation of HLA class I, J. Biochem. 2017;161:479-492) showed that bladder cancer cells evaded cytotoxic T lymphocyte-mediated antitumour immunity by a novel mechanism involving the loss of Core 2 structures on human leukocyte antigen Class I O-glycans and subsequent impairment of galectin-glycan lattice formation. The immunosuppressive action of O-glycans on natural killer cell-mediated tumour immunity is also considered an immune evasion system. Furthermore, sialylated O-glycans have been proposed to play a central role in tumour immune escape by modulating the production of immunoregulatory cytokines and growth factors through interactions with sialic acid-binding immunoglobulin-like lectins. Therefore, a better understanding of how alterations in O-glycosylation influence tumour immune evasion will enable the development of novel and more effective therapeutic options for cancer treatment.