Higher colony numbers of C4‐2sc and CWRsc cells than those of C4‐2siIL‐6/CWRsiIL‐6 cells were detected after coculture with NK92 cells, suggesting higher resistance of IL‐6‐expressing cancer cells to the cytotoxic action of NK cells than that of IL‐6‐knockdown cells (Fig. 1C, data with primary NK cells). This evidence concerns the gene IL6 and cancer.