We showed how TMZ could cause GJIC for the passage of small molecules (<2 kDa) such as miRNA.29 In the CNS, astrocytes abundantly express gap junctions for cellular maintenance and regulation.30 Cx43 is the main contributor of GJIC formation in astrocytes.16 Astrocytomas commonly overexpress the same gap junction proteins as shown here for GBM, which is World Health Organization grade IV astrocytomas.31 The identification of Cx43 as key in the resistance of GBM to TMZ is in line with the argument that this could be important for the migration of GBM.18 This evidence concerns the gene GJA1 and astrocytoma (excluding glioblastoma).