One cardiac side effect requiring longer time periods is evoking late Na+ currents, which has been reported after dofetilide treatment as well as many tyrosine kinase inhibitors used as cancer treatment.80–82 We explored overnight incubation with dofetilide to evoke late Na+ currents and compared the result to treatment with moxifloxacin, a hERG K+ channel blocker without known influence on late Na+ currents and control conditions. The gene discussed is KCNH2; the disease is cancer.