Six genes (including genes encoding ER, PR, HER2 and their transcription factors MYC, FOXA1, MYBL2) were removed from PAM50 (the new panel is named PAM50–6) to exclude their confounding effect on the classifier, as the ground truth was based on tumor classification stratified by ER, PR and HER2. The gene discussed is ERBB2; the disease is neoplasm.