Moreover, the levels of USP22 mRNA and protein expression were significantly higher in the six GC cell lines (BGC-823, MGC-803, SGC-7901, MKN-45, AGS, and HGC-27) compared with the normal gastric mucosal epithelial cell line, GES-1 (Figure 1C, 1D). Here, USP22 is linked to gastric cancer.