ERBB2 and lung adenocarcinoma: According to Greulich H. et al. in the United States, somatic alterations of 5 lung adenocarcinoma oncogenes, KRAS, EGFR, ALK, ERBB2(HER2), and BRAF, are interestingly mutually exclusive and are represented in over 50% of lung adenocarcinomas (10) (Figure 1).