NRG1 and familial pancreatic carcinoma: We determined the growth response of human pancreatic cancer cell lines to treatment with EGFR ligands (EGF, TGFα, AR, Epigen), HER-3 and HER-4 ligand NRG-1, EGFR and HER-4 ligands ( HB-EGF, Epiregulin and BTC) , IGF-IR ligands (IGF-I and IGF-II) and insulin at a concentration of 40 nM for 72 h using the SRB assay (Figure 2).