Loss of chromosomal regions on 1p and 19q is characteristic of oligodendrogliomas, but there is also evidence for another subset of oligodendrogliomas that have amplification of EGFR oncogene, loss of heterozygosity on chromosome 10 and homozygous deletion of the CDKN2A tumor suppressor gene. Here, CDKN2A is linked to oligodendroglioma.