CD8A and neoplasm: Earlier in vivo investigations of the effects of components of the TME on gene expression have elicited a substantial downregulation of a large number of microRNAs that are associated with the regulation and function of the immune system in hypoxic tumor areas (e.g., accumulation of cytotoxic CD8+ T cells in highly vascularized, normoxic areas vs. exclusion of cytotoxic CD8+ T cells from viable hypoxic tumor areas in vivo) raising the possibility that hypoxic tumor regions represent an immune-privileged tumor niche (12).