ERBB2 and breast cancer: The second cluster includes 12 other tumor types for which activationof these pathways is either a positive prognostic biomarker (HER2+, luminal Aand luminal B breast cancer, uterine corpus cancer; a total of 17–25% ofcluster 2 cancer types) or has no prognostic value (basal breast cancer,hepatocellular carcinoma, melanoma, etc.; a total of ~75% of cluster 2 cancertypes).