GJA1 and astrocytoma (excluding glioblastoma): GJIC facilitates the exchange of small molecules and microRNA.13, 14 Cx43 can exert both tumor suppressor and oncogenic functions.15 Astrocytes and astrocytomas express high levels of Cx43.16 During epithelial-to-mesenchymal transition and the period of overt tumor infiltration, there is a loss of GJIC between the malignant cells.17 However, the role of Cx43 in the migration of GBM cells is mixed.