The cyclic, non-phosphorylated peptide (named G7-18NATE (cyclo-(CH2CO-WFEGYDNTFPC)-amide) was developed via phage display and was found to specifically decrease binding between Grb7 and tyrosine phosphorylated HER family members in breast cancer cell extracts, but have no effect on the interaction between Grb2 and HER3 (Pero et al., 2002). The gene discussed is GRB7; the disease is breast carcinoma.