In our previous work on patient-derived primary glioblastoma stem cell cultures, KCa3.1 expression varied considerably between individual tumors and was associated with mesenchymal subpopulations of stem cells [3,43], which are especially radiation-resistant [44] and may, hence, represent the subpopulation of glioblastoma cells to test further anti-KCa3.1 therapies in. This evidence concerns the gene KCNN4 and glioblastoma.