In 1321N1 astrocytoma cells, P2X7 receptor was shown to activate ERK1/2 phosphorylation via activation of proline-rich tyrosine kinase 2 (Pyk2), c-Src, phosphatidylinositol 3′-kinase (PI3K), and protein kinase C (PKC) [75]. Here, PTK2B is linked to astrocytoma (excluding glioblastoma).