Using a well-established multidrug resistant (MDR) breast cancer MCF-7/MDR line (Kiss et al, 1994) as a model resistant cancer line, we report for the first time that TF expression is observed on tumour VECs in chemoresistant human breast tumour xenograft in mice and then report the efficacy and safety of fVII-targeted SnCe6 PDT (Hu et al, 2010a) for effective treatment of chemoresistant breast cancer in vitro and in vivo. The gene discussed is TF; the disease is breast cancer.