For these studies, we selected five human breast cancer cell lines that exhibit an array of characteristics, including invasive and metastatic breast cancer cell lines, which express high levels of Nodal (MDA-MB-231, BT-549), invasive, weakly metastatic cell lines that express low levels of Nodal (Hs578t), as well as non-invasive breast cancer cell lines that express low levels of Nodal (MCF-7, T47D) (Fig. 5C). The gene discussed is NODAL; the disease is breast cancer.