P18 tumor suppressor gene and progression of oligodendrogliomas to anaplasia

P18(INK4C) is a good candidate to be the tumor suppressor gene involved in oligodendrogliomas on 1p32. Loss of heterozygosity on Ip, mutation(s), homo zygous deletion(s), and expression of p18 in 30 oligodendroglial tumors wer e investigated. Loss of heterozygosity on Ip was found in 15 tumors. A p18 mutation was found at an recurrence of an anaplastic oligodendroglioma, but not in the primary, low-grade tumor. No homozygous deletions were found an d p18 was expressed in all cases. These results show that p18 alteration is involved in tumor progression in a subset of oligodendrogliomas.