As shown in Fig. 1, there were 59 luminal subtype and 4 undetermined subtype breast cancer in group A, 65 luminal subtype and 2 undetermined subtype breast cancer in group B, 45 luminal subtype and 5 undetermined subtype breast cancer in group C, 14 luminal subtype and 1 undetermined subtype breast cancer in group D. Within 195 HER2 FISH-equivocal patients, there were183 (93.8%) luminal subtype and 12 (6.2%) undetermined subtype breast cancer according to 2013 ASCO/CAP guideline. This evidence concerns the gene ERBB2 and breast cancer.