The frequency of IFN‐γ+ cells within live NK cells in HSCT recipients was significantly higher as compared with that in no‐treatment mice, regardless of the YAC‐1 restimulation (27.1% for non‐HSCT vs. 93.0% for HSCT; P = 0.000033) (Fig. 2E and Fig. S2), indicating that NK cells in HSCT tumor are endowed with cytotoxic and cytokine productive capacities. The gene discussed is IFNG; the disease is neoplasm.