To license NK cells to kill membrane Hsp70+ (mHsp70+) tumor cells they can be activated by an incubation with full length Hsp70 protein, Hsp70-expressing exosomes (Multhoff et al., 1999; Gastpar et al., 2005) or a 14-mer Hsp70-peptide TKD (TKDNNLLGRFELSG) derived from the C-terminal substrate binding domain in combination with interleukin 2 (IL-2) (Multhoff et al., 1997; Multhoff et al., 2001). This evidence concerns the gene IL2 and neoplasm.