Consistent with the observation that NTP-GM-D17 enhanced tumour-killing activity, the numbers of NK cells positive for intracellular IFN-γ increased from 0.8 to 16.1% after treatment with NTP-GM-D17 (Fig. 4f, *P < 0.01: the right panel depicts the integrated data from three experiments). Here, IFNG is linked to neoplasm.