CHROMOSOMAL LOSSES AND GAINS IN MENINGIOMAS - COMPARATIVE GENOMIC HYBRIDIZATION (CCH) STUDY OF THE WHOLE GENOME

We investigated chromosomal aberrations in meningiomas using newly dev eloped comparative genomic hybridization (CGH) technique and compared the results with the proliferating potential of the tumors. This techn ique permits the entire genome to be surveyed in one session of experi ments. Our results revealed chromosomal aberrations in 5 out of 10 (50 %) of the tumor samples studied. Losses of the distal parts of chromos ome 1p (5 out of 10) and 22q (3 out of 10) were the two most frequent chromosomal aberrations. Losses and/or gains in other regions were onl y sporadic. The MIB-1 staining indices (MIB-SI, %) were 1.9 +/- 0.9% ( mean +/- SD) in benign (n = 8), 4.5% in atypical (n = 1), and 11.7% in anaplastic in = 1) meningiomas. The comparison of MIB-SI between the tumors with (2.3 +/- 0.6%) and without 17.6 +/- 0.3%) chromosomal aber rations demonstrated a trend towards an increased MIB-SI in meningioma s with chromosomal aberrations (p < 0.07) by unpaired Student's t-test . This study suggests that alterations in chromosomes 1p and 22q could be a primary focus of further detailed assessment of tumorigenesis an d in understanding the biological behavior of meningiomas.