In NSCLC, NK cells infiltrate rather peritumoral than tumor tissue, in contrast to T lymphocytes (Esendagli et al., 2008; Schneider et al., 2011), and these NK cells which do infiltrate the tumor are predominantly CD56bright, negative for NK cell receptors (including KIRs), and exhibit low cytotoxic activity ex vivo (Carrega et al., 2008; Esendagli et al., 2008). This evidence concerns the gene KLRD1 and neoplasm.