NFIL3 and neoplasm: Western blottings showed that deletion of Smad3 increased the expression of E4BP4 (or Nfil3), an important transcription factor for NK lineage commitment22, 23, 24, in both bone marrow-derived and splenic NK cells from the Smad3−/− mice on Day 10 after tumour inoculation (Fig. 4a).