A facial cancer that plagues Tasmanian Devils is yielding new insights into how the disease evades the immune system, researchers said last night.
Researchers say the same immune-avoidance strategy is found in some human cancers as in the animal disease.
The Tasmanian Devil disease is passed between animals and is fatal, partly because of their tendency to bite each other’s faces during courtship or fighting.
Australian researchers have been studying the PRC2 protein complex which can prevent cells from presenting the MHC class I protein. This is essential for the disease to be recognised by the immune system.
Researcher Dr Marian Burr, of the University of Melbourne, Australia, said: “We think this could contribute to some cancers in people becoming resistant to immunotherapies and why cancer cells are not destroyed when transmitted between Tasmanian devils.”
Fellow researcher Professor Mark Dawson said that EZH2 inhibitors, which are already in clinical trials for lymphoma, could be an effective treatment for this kind of cancer. In laboratory tests, the drugs led to MHC Class I molecules returning to cell surfaces.
He said: "We want to investigate whether they can be combined with immunotherapy treatments, and if they could help patients who don’t respond to immunotherapies alone. This approach may be particularly beneficial for cancers such as small cell lung cancer that have low expression of MHC class I.”
Burr et al. An evolutionarily conserved function of polycomb silences the MHC class I antigen presentation pathway and enables immune evasion in cancer. Cancer Cell 26 September 2019; doi: 10.1016/j.ccell.2019.08.008
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