CDKN2A and oligoastrocytoma: The authors analysed 270 gliomas and identified CDKN2A deletions via FISH in 57/108 grade 2 astrocytomas, 31/61 grade 3 astrocytomas, 23/96 oligodendrogliomas, and 19/49 oligoastrocytomas, inclusive of both homozygous and heterozygous CDKN2A deletions.