AGS-Akata cells (1×107) were injected into each flank of NSG mice. There are 4 mice per group, i.e. a Compound treated group, a Vehicle control group, and a Gemcitabine treated group. After 35 days, mice were injected with 60 mg/kg of Gemcitabine (once), 25 mg/kg of 21 or 22 (once a day for 3 days), and vehicle (5% DMSO and 5% Solutol) (once a day for 3 days). Tumor masses were homogenized and immunoblots were performed to detect the lytic EBV, BZLF1(Z; immediate early protein) and the loading control β-actin.