Focus on current and emerging treatment options for glioma: A comprehensive review

Table 1 World Health Organization classification of gliomas

Grade	Name	Description and characteristics
I	Pilocytic astrocytoma	Well-differentiated, often cystic, slow-growing, generally benign
II	Diffuse astrocytoma	Infiltrative, moderately cellular, tends to recur, can progress to higher grades
II	Oligodendroglioma	Composed of oligodendrocyte-like cells, often associated with 1p/19q co-deletion
II	Mixed oligoastrocytoma	Combination of features of oligodendroglioma and diffuse astrocytoma
III	Anaplastic astrocytoma	Higher grade astrocytoma with increased cellularity and mitotic activity
III	Anaplastic oligodendroglioma	Higher grade oligodendroglioma with increased cellularity and atypia
III	Anaplastic oligoastrocytoma	Higher grade mixed tumor with features of both anaplastic astrocytoma and anaplastic oligodendroglioma
IV	Glioblastoma	Highly aggressive, necrosis, endothelial proliferation, molecular heterogeneity