STAT3 and gastric cancer: Compared with positive control compound S3I-201, 11a (SDL-1) showed better anti-gastric cancer effects with the IC50 values of 31.52 , 26.49 , 11.78 , and 44.90 μΜ in HGC27, MGC803, AZ521, and MKN1 cells, respectively, consistent with the conclusion that in contrast to small molecule inhibitors (SMIs) that require occupation of the STAT3 binding site, PROTACs catalyze the degradation of multiple POI molecules through an event-driven pharmacological mechanism of action, exhibiting significantly lower concentrations than SMIs to trigger the required (Khan et al., 2020).