ESR2 and breast carcinoma: For instance, in HER2-overexpressing breast carcinoma SK-BR-3 cells, the IC50s of hERB-hRNase and ERB-HPR, fusion proteins consisting of human pancreatic RNase and scFv antibodies for specific targeting to HER2, were 12.5 nM and 50 nM, respectively [55], [50].