Antiproliferative effects of HER-2 and VEGF peptide mimics used as single treatments. BT474, SK-BR-3, MDA-468, and TS/A cells were incubated with HER-2 peptide, VEGF peptides, trastuzumab, and irrelevant peptide. Bioconversion of MTT was used to estimate the number of active tumor cells remaining after 3 days. Peptides were added at four different concentrations using the above-mentioned cell lines. The proliferation inhibition rate was calculated using the formula (ODnormal untreated − OD peptides or Ab)/ODnormal untreated × 100.