ESR1 and breast cancer: The HER2-enriched subtype is defined by the ERBB2, GRB7, PERLD1, and SYCP3 genes.14 Until early 2016, the Agendia Breast Cancer Suite also included a separate single-gene microarray for the estrogen receptor (ER), progesterone receptor (PR), and HER2 receptor, namely TargetPrint (TP).