In order to examine the role of TGF-β1 in gastric cancer, SGC-7901 cells were exposed to various concentrations of exogenous TGF-β1 ranging from 5 to 30 ng/mL for 36 h, and Lgr5 expression was shown to be concentration-dependent (Figures 6A,B). Here, LGR5 is linked to gastric cancer.