KCNMA1 and glioblastoma: Based on the notion that 2D migration assays, as used in the previous studies, do not exactly mimic the type of migration taking place when GBM cells infiltrate through the brain parenchyma in vivo, Sontheimer and coworkers reexamined the effects of BK channel inhibitors and activators on GBM cell migration using the transwell migration assay with 8 μm pores, a size small enough for typical GBM cells to pass through only upon significant shrinking (Weaver et al., 2006).