SMAD3 and neoplasm: Meanwhile, the percentage of Treg cells was increased from 4.7 to 5.7% compared with control by Smad3 wild-type NK cell therapy, and to 7.2% by Smad3 knockout NK therapy, while blocking GM-CSF production by these NK cells largely mitigated the pathogenic effect, resulting in a reduction in Treg proportion to 5.5% of total tumor-infiltrated leukocytes (Suppl.