ERBB2 and breast cancer: Perou and colleagues laid the foundation for what would be known as the PAM50 assay, a genomic test that classifies BC into one of four intrinsic molecular subtypes: luminal A, luminal B, HER2-enriched, and basal-like, with 93% accuracy, and in 2009, Dr. Joel Parker officially introduced and validated the PAM50 assay.