While the high extracellular PS contributed by apoptotic cells from caspase activation and caspase-activated scramblases such as Xkr8 can be conceptually rationalized, the high extracellular PS contributed by dysregulated viable cells in the tumor microenvironment is likely equally important for driving inhibitory pathways and immune suppression, but much less well understood at the molecular and cellular level. This evidence concerns the gene XKR8 and neoplasm.