ERBB2 and breast cancer: HER-2 is already known as a prognostic biomarker in various solid tumors (for more than a decade in breast cancer [18][19], more recently for gastric cancer [20], esophageal adenocarcinoma [21], pancreatic [22] and rectal cancer [23]) and even more importantly as a potential target in the specific tumor therapy in clinical routine for breast and metastatic gastric cancer.