KCNN4 and neoplasm: It is involved in critical steps of the metastatic cascade, such as proliferation, migration, invasion, and extravasation.2, 3 Inhibition of the KCa3.1 channel leads in many different tumor entities to reduced proliferation, migration, and metastasis.4, 5, 6 Overexpression of this channel directly correlates with tumor grade and metastatic status and is often related to poor prognosis for tumor patients and high lethality rates.7 Moreover, expression of KCa3.1 channels is dysregulated in many tumor entities.