PIK3CA and central nervous system cancer: Moreover, heparan sulfate-glucosamine 3-sulfotransferase 1 (HS3ST1) and calponin 3 (CNN3) are overexpressed in astrocytoma, and mutations in phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), PDGFRA, and MYCN are generally associated with poorer prognosis in gliomas [25].