ABNORMALITIES OF CHROMOSOME 22 IN MENINGIOMAS AND CONFIRMATION OF THE ORIGIN OF A DICENTRIC 22 BY INSITU HYBRIDIZATION

We report three cases of meningioma. Case 1 had a dicentric chromosome number 22 resulting in partial monosomy for a portion of the q-arm, i.e., 46,XX,idic[22][pter --> q11.2 = q11.2 --> pter] and 46,XX,psu dic[22][pter --> q11.2 = q11.2 --> pter], which was the sole clonal abnormality. The origin of the dicentric chromosome from 22 was confirmed by in situ hybridization studies, using biotin-labeled alpha centromeric DNA probes for the acrocentric chromosomes. Case 2 had two distinct clonal abnormalities: deletion of 22q and monosomy of 22. Case 3 also had a deleted 22q.