In the same sense, in vitro proliferation of gastric cancer cell lines is markedly slower when they are incubated in the presence of TTX, EIPA (5-(N-ethyl-N-isopropyl) amiloride; a Na+/H+ exchanger 1 inhibitor), or when they are transfected with siRNAs against NaV1.7, consistent with a reduced xenograft tumor growth of stable NaV1.7 knockdown BGC-823 cells compared to scramble-transfected control cells (Xia et al., 2016), and smaller tumor size generated by MDA-MB-231 cells in phenytoin-treated animals (Nelson et al., 2015). The gene discussed is SCN9A; the disease is neoplasm.