The sugar made it hard for antibodies to stick, so it helped the virus avoid immune destruction. (scientificamerican.com)
In fact, some researchers are even suggesting that lung cancers use the PD - 1 pathway to escape immune destruction in the first place. (cancerresearch.org)
The selective pressure of the competent immune system «edits» the tumor by selecting for cells that can avoid immune destruction. (massgenomics.org)