CD8A and cancer: Accumulation of senescent CD8+CD28null T cells has been found in patients with chronic viral infections and with certain types of cancers, but the mechanisms responsible for the induction of these senescent T cells have been unclear (Chen et al, 2009; Effros et al, 2005; Meloni et al, 2006; Tsukishiro et al, 2003; Weng et al, 2009; Wolfram et al, 2000).