To investigate subtype-specific prognostic genes, we calculated IPP scores for a total of 16 breast cancer datasets by reference to three distinct molecular subtypes: luminal (ER-positive/PR-positive; Supplementary Fig. 9A), HER2-enriched (ER-negative/PR-negative/HER2-positive; Supplementary Fig. 9C), and triple-negative (ER-negative/PR-negative/HER2-negative; Supplementary Fig. 9B) based on ER, PR, and HER2/ERBB2 immunohistochemistry information. This evidence concerns the gene ERBB2 and breast cancer.