Many human meningiomas show loss of heterozygosity at distal loci but retain constitutional heterozygosity at one or more proximal loci of 22q. Molecular analysis indicted deletions involving at least the region 22q12.3-qter. In this region, distal to myoglobin, the putative meningioma locus ought to be expected. Long-range mapping was performed around two loci from 22q12.3-q13.1 (D22S16 and PDGFB, the most proximal locus to be lost in meningioma). D22S16, originally assigned to 22q13-qter by isotopic in situ hybridization, was placed in the vicinity of PDGFB by utilizing a set of somatic cell hybrids, an assignment confirmed by fluorescence in situ hybridization (FISH) of a cosmid clone containing the D22S16 locus. Moreover, pulsed field gel electrophoresis suggests a close linkage of both markers within 630 kb.