To explore the impact of TfR expression on TfR-BiTE activity, we tested the potency of TfR-BiTE on human breast cancer cell line MX-1 which expresses TfR at very low levels, and multiple tumor cell lines (HT1080, HepG2.215, HepG2) with various levels of surface TfR expression (Figure 3C). The gene discussed is TFRC; the disease is breast carcinoma.