Here, we demonstrate that the pharmacological activation of potassium channel Kv11.1, which is uniquely expressed in MDA-MB-231 triple negative breast cancer cells (TNBCs) but not in normal MCF-10A cells, induces the dephosphorylation of Cav-1 Tyr-14 by promoting the Ca2+-dependent stimulation of protein tyrosine phosphatase 1B (PTP1B). This evidence concerns the gene KCNA3 and triple-negative breast carcinoma.