In all cancer cell lines tested, showing similar levels of SCN4B expression (Supplementary Fig. 5d), transfection of siSCN4B significantly increased the invasiveness, from 23.7±8.3% (n=3) increase for PC3 cells up to 60.9±9.5% (n=12) increase in A549 cells (Fig. 4d), confirming that SCN4B/β4 loss potentiates invasiveness independently of the pore-forming NaV subunit. This evidence concerns the gene SCN4B and cancer.