CYTOGENETIC EVIDENCE THAT A TUMOR-SUPPRESSOR GENE IN THE LONG ARM OF CHROMOSOME-1 CONTRIBUTES TO GLIOMA GROWTH

In a patient with a rare subtype of glioma, pleomorphic xanthoastrocyt oma, cytogenetic studies revealed that both homologues of chromosome 1 were involved in translocations at the same band 1q42 but with differ ent partner chromosomes. In addition, 5 glioblastomas out of 25 glioma s karyotyped in our laboratory had lost at least one copy of band 1q42 through deletions, unbalanced rearrangements, or chromosome losses. T wenty-one gliomas that had lost at least one copy of chromosome band 1 q42 were identified in the literature; all were astrocytic tumors and the majority were glioblastomas. It indicates a covert tumor suppresso r gene in the region that is involved in astrocytic gliomas.