SCN5A and breast carcinoma: Both Nav1.5 and nNav1.5 are already recognised as a potent metastatic gene in potentiating breast cancer metastatic parameters i.e. motility, migration and invasion when specific VGSC blocker, TTX and other VGSC blockers e.g. phenytoin, ranolazine have all precisely suppressed breast cancer metastasis in vitro and in vivo even at dose concentration that does not interfere with proliferation [5, 13, 63–66].