ERBB2 and gastric cancer: Immunohistochemistry of nude mouse xenografts showed that all the liver metastasis-derived intestinal-type gastric cancer cell lines (GLM-1, GLM-2, GLM-4 and NCI-N87) overexpressed HER2 on their cell surface, and were judged as positive (2+ or 3+) based on the criteria of HercepTest (Figure 1A).