ERBB2 and breast cancer: FGFR2 overexpression occurred in both the TNBC/basal and luminal subtypes and was rarely observed in HER2 cancers (Fig. 5a, Additional file 4: Fig. S8a), while 19 breast cancer patients (1.9%) exhibited mutation or fusion of FGFR2 in the TCGA dataset (Additional file 4: Fig. S8a).