In our previous works, we have demonstrated that application of hERG1/Kv11.1 potassium channel activator NS1643 to breast cancer cells caused an increase in Ca2+ entry [6] and increased p21waf/cip protein level that resulted in a senescence-like phenotype while no effect was observed in non-transformed cells [6, 7]. Here, KCNH2 is linked to breast carcinoma.