In human tissue, single-nucleotide polymorphisms in the MIF gene alter infiltration of CD8+ T lymphocyte, as well as that of other leukocytes, into the TME.85 In an in vitro murine model of neuroblastoma, a peripheral nervous system tumor, MIF overexpression resulted in overall (ie, CD3+) T lymphocyte overactivation and subsequent activation-induced apoptosis.86 This mechanism remains to be investigated in primary CNS tumors; however, it is possible that locally elevated levels of MIF in the TME may directly induce CD8+ T lymphocyte apoptosis. The gene discussed is CD8A; the disease is neuroblastoma.