ERBB2 and breast cancer: We investigated the gene expression levels of typical breast-cancer-related markers (ESR1, PGR, ERBB2, and MKI67) on the two subtypes (luminal-HER2 subtypes and pure-HER2 subtypes) compared with the luminal subtypes (Figure S1: luminal-HER2 subtypes, Figure S2: pure-HER2 subtypes, and Figure S3: luminal subtypes).