To assess the effect of USP22 on gastric tumorigenesis and cancer progression, we subcutaneously inoculated stable USP22-silenced USP22 MGC-803 cells (shUSP22 with GFP tag) and negative control (shCtrl with GFP tag) cells (5×106) into the flanks of BALB/c mice respectively (one flank for shCtrl cells and the other for shUSP22 cells). The gene discussed is USP22; the disease is cancer.