For example, the Nav1.5 subtype is upregulated in breast cancer cells where it plays a critical role in promoting cellular migration, invasion, and metastasis (Besson et al., 2015; Brackenbury, 2012; Brackenbury, Chioni, Diss, & Djamgoz, 2007; Fraser et al., 2005; Martin, Ufodiama, Watt, Bland, & Brackenbury, 2015; Nelson, Yang, Dowle, Thomas, & Brackenbury, 2015; Nelson, Yang, Millican‐Slater, & Brackenbury, 2015; Roger, Besson, & Le Guennec, 2003). The gene discussed is SCN5A; the disease is breast cancer.