GFAP and anaplastic astrocytoma: For instance, the transformed glial fibrillary acidic protein (GFAP)-positive astrocytes induced anaplastic astrocytomas (WHO grade III and IV), while the transformed glutamate/L-aspartate transporter (GLAST)-positive astrocytes formed low-grade astrocytomas (WHO grade I) (Irvin et al., 2017).