We previously observed that the high levels of STAT3 phosphorylation in SGC7901/DDP cells were causally related with their chemo drug resistance.28 In consistent, we found that all three drug-resistant GC cell lines, SGC7901/DDP, BGC823 and HGC27, exhibited higher activation of STAT3, when compared with those of drug-sensitive GC cell lines (Figure 2a). Here, STAT3 is linked to gastric cancer.