Antitumour activity of TfR-lytic peptide in tumour xenograft model in vivo: (A) MDA-MB-231 breast cancer cells were implanted subcutaneously into athymic nude mice. Intravenous injection of either saline (control) or TfR-lytic peptide (3 mg/kg) was provided from day 5 as indicated by the arrows. Each group had six animals (n = 6), and experiments were repeated twice. Data are expressed as mean ± SD. (B) Histological examination after treatment with TfR-lytic peptide. Images (× 400 magnification) of liver, kidney and spleen from mice after treatment with saline (control) or TfR-lytic peptide (5 mg/kg) nine times were obtained by staining with hemaetoxylin and eosin (H&E).