EDNRB and breast cancer: To determine if these trends were specific to breast cancer, we also analyzed EDNRB isoform expression by qPCR in HEPG2 liver cancer cell line-derived cDNA; overall EDNRB expression was substantially lower in these cell lines compared to the breast cancer cell lines, and the major isoform appeared to be EDNRB-532 (Supplementary Fig S1).