A targeted osmotic lysis (TOL) of tumor cells that over-express voltage-gated sodium channels (VGSCs) has been developed that uses a combined therapy of a drug that blocks sodium, potassium-adenosine triphosphatase (Na+, K+-ATPase) that is then followed by an activation of VGSCs, for example, by electrical or pharmacological stimulation. Activation of VGSCs conducts sodium into the cancer cells in much greater amounts than non-cancer cells. Water follows this sodium gradient into the cancer cells, causing swelling and lysis. Because non-cancerous cells do not over-express VGSCs, less sodium and less water will enter the cells, and the non-cancerous cells will not lyse. This method is applicable to all cells that over-express VGSCs, including, but not limited to, highly invasive breast cancer, prostate cancer, small cell lung cancer, non-small cell lung carcinoma, lymphoma, mesothelioma, neuroblastoma, and cervical cancer.