TGFB1 and neoplasm: In summary, OVs pretreatment further stimulated NK cell proliferation, upregulated the expression of CD69 and CD107a, induced NK cells to secrete perforin, granzyme B, and TNF-α, inhibited TGF-β expression, and promoted apoptosis of HCT116 and LoVo cells, thereby promoting the anti-tumor effect of NK cells.