Mice were tail vein-injected with 1x106 MKN45 cells infected with shRNA-LV or the control vector. Each group contained 10 mice. The mice were sacrificed four weeks later, and the number of visible tumors in the liver was counted without magnification. The liver tissues were sectioned serially and then stained with H&E. *, p < 0.01. Liver metastases were marked by arrowheads.