STAT1 and cancer: In addition, we also treated these cells with IR, STAT1 inhibitor Fludarabine or combination of IR and Fludarabine and found that IR or Fludarabine along had little effect on inhibiting the cell proliferation; however, combined treatment of IR with a small dose of Fludarabine significantly suppressed cancer cell survival and growth (Fig. 5f–i and Supplementary Fig. S7a, b).