ERBB2 and breast cancer: The GMP frequency was increased among the aggressive basal-like and HER2 subgroups of breast cancer based on gene expression data on these cases (GMP frequency: basal-like 33%, HER2 44%, luminal-A 15%, luminal-B 23% P=0.040) (Perou et al, 2000; Sorlie et al, 2001).