VRK1 and neoplasm: In addition, the caspase3 assay further verified the effect of VRK1 downregulation on mouse LUSC tumors, and the results showed that the tumor apoptosis level was significantly increased in the shVRK1 group compared with the shNA group (P < 0.01), while the tumor apoptosis level was further significantly decreased in the shVRK1 + DOX group compared with the shVRK1 group (P < 0.001) (Figures 8(d) and 8(f)).