Among all brain cancers arising from transformed glial cells, grade IV glioblastoma (GBM), as defined by the World Health Organization, is the most prevalent and aggressive . The diffusely invasive nature of these tumors precludes their complete surgical resection, which inevitably leads to tumor recurrence and patient death . Glioblastoma cells migrate onto normal brain microvessels for invasion and tumor growth . They communicate directly with surrounding normal cells such as astrocytes, glia and endothelial cells, through the formation of gap junctions. These cell-to-cell interactions modify astrocyte phenotype [4–6] and promote tumor angiogenesis and tumor growth . Therefore, gap junctions and their signaling are proposed as potential therapeutic targets in these patients.