Frequent loss of 1p32 region but no mutation if the p18 tumor suppressor gene in meningiomas

After chromosome 22 and NF2 inactivation, the loss of chromosome 1p is one of the most frequent abnormalities encountered in meningiomas. However the putative tumor suppressor gene located on 1p inactivated in meningiomas has still to be identified. We screened 68 meningiomas for LOH on chromosome 2 2 and 1. We found 34 LOH on the NF2 region on chromosome 22 (50%) and 19 LO H on 1p (28%), 16 being associated with loss of chromosome 22. Partial dele tions delimited a candidate region located between D1S234 and D1S2797. The p18 tumor suppressor gene, a member of the genes family coding for inhibito rs of cyclin-dependent kinases, is located in this region. To determine whe ther p18 is involved in development of meningiomas, we performed a mutation analysis of the p18 gene and a search for homozygous deletion in the 19 me ningiomas with 1p loss. Sequencing analysis of the p18 gene revealed one po lymorphism, but no somatic mutations and no homozygous deletions were found . These results confirm that the loss of chromosome 1p32 is a frequent feat ure in meningiomas, however the p18 tumor suppressor gene which is located in this region, does not seem to be involved.