However, the mutation rate differed among lung adenocarcinoma subtypes: the 22 cases of HER-2 mutation were observed in APA (36.4 %), PPA (36.4 %), MIA (13.6 %), SPA (9.2 %), and IMA (4.5 %), whereas no mutations were detected in LPA, MPA, EA, or AIS (Table 1 and Fig. 4). This evidence concerns the gene ERBB2 and lung adenocarcinoma.