ERBB2 and gastric adenocarcinoma: To establish the gastric cancer PDX model GCX-004, a surgical specimen was received, with limited ex vivo time (<25 min), after total gastrectomy of a primary well-differentiated intestinal type HER2-negative gastric adenocarcinoma (ypT1aN0) from a 64 year-old man treated with preoperative chemotherapy (EOX: epirubicin + cisplatin + 5-fluoro-uracil).