The underlying mechanism behind gemcitabine inhibitory effect on TGF-β could be driven by its modulatory effect on STAT3 phosphorylation [45] Alternative explanation to the observed stronger synergism against squamous carcinoma may be attributed to MYC inhibitor in SN extracts (eg: fisetin [46]) may downregulate MYC to enhance the cytotoxicity effect of gemcitabine. This evidence concerns the gene STAT3 and squamous cell carcinoma.