PTEN and oligodendroglioma: Several studies have shown that PTEN variants are associated in 5% of cases with the development of CNS tumors (Liaw et al., 1997; Lynch et al., 1997; Staal et al., 2002; Sturm et al., 2014; Yakubov et al., 2016; Gröbner et al., 2018; Waszak et al., 2018; Kim et al., 2020), in particular glioblastoma, meningioma, dysplastic gangliocytoma, pineal tumor, and oligodendroglioma.