LOH profiles of chromosome 22 and the NF2 gene in sporadic meningiomas (n = 15). Rows (n = 6206) correspond to individual SNPs along the entire chromosome 22 and columns identify different meningiomas. Blue indicates presence of LOH, allele retention is shown in yellow, while red indicates conflict between PB DNA and tumor DNA SNP calls (AA or BB in PB and AB or BB and AB or AA in the tumor sample, respectively), and absence of call for non-informative SNPs (AA or BB) are depicted in white and grey, respectively. Two tumors (M7 and M12) showed a pattern compatible with biclonal allele deletions with copy number value of 1 in the absence of LOH. The NF2 gene locus containing 16 SNPs in the array is amplified in the right side of the figure to better show the status of those SNPs heterozygously distributed in introns 1, 4, 6, 8, 10, 11, 14 and 15. LOH for three NF2-associated SNPs was found in one tumor (M6), for two SNPs in another case (M11) and for one SNP in another two meningiomas (M16 and M18).