Genetic aberrations in sporadic and neurofibromatosis 2 (NF2)-associated schwannomas studied by comparative genomic hybridization (CGH)

Background. Schwannomas occur sporadically or in association with neurofibr omatosis 2 (NF2), an autosomal dominant disorder, which predisposes to mult iple schwannomas, meningiomas and spinal ependymomas, with bilateral vestib ular schwannomas as the classic hallmark. As NF2 and sporadic sc hwannomas differ in some respect in their clinical and biological behavior we evaluat ed whether there are any differences in the distribution of genetic aberrat ions between NF2 and sporadic schwannomas. Our interest was also to verify whether secondary genetic alterations besides the loss of 22q could be dete cted in schwannomas. Methods. We investigated DNA copy number changes in 25 schwannomas (12 NF2 and 13 sporadic schwannomas) using the comparative genomic hybridization (C GH) technique. Some chromosomal regions were further studied by LOH or FISH analysis. Findings. CGH detested genomic abnormalities in 15 of 25 schwannomas (60%). The most common alteration was loss on 22q, found in 32% (8/25) of schwann omas. No consistent changes were detected in other chromosomal regions. The overall number of genetic aberrations was similar in NF2 and in sporadic s chwannomas. Interpretation. Our results support the present view that loss of chromosom e 22q harboring the NF2 gene plays a universal role in the pathogenesis of schwannomas without consistent involvement of other chromosomal regions.