TGFB1 and cancer: The above result indicate TGF-β/Smads pathway was activated with miR-4666-3p downregulation in colon cancer cells, and it has been reported that TGF-β1 is highly expressed in and secreted by cancer stem cells (15, 16), so it is rational to explore if there is a positive loop regulation mechanism exist here; herein, we evaluated TGF-β1 expression in PKHhi, PKHlow, and PKHneg cells by flow cytometry.