LOSS OF HETEROZYGOSITY OF THE CHROMOSOMAL REGION 11Q22-Q23 IN PRIMARY TUMOURS OF THE CENTRAL NERVOUS SYSTEM

Loss of heterozygosity (LOH) of the chromosomal region 11q22-q24 is common in several types of human solid neoplasms, including carcinomas of the breast, lung, colon, nasopharynx, cervix, ovary, uterus and malignant melanoma, suggesting the presence of one or several tumour suppressor genes in this region. To determine if LOH occurs in this chromosomal region in tumours of the central nervous system, we screened for LOH in matched normal and tumour DNA samples from 32 patients with primary tumours of the CNS, of which 20 were benign and 12 were malignant. Nine polymorphic microsatellite loci from the 11q22-q23 region, between D11S940 and D11S934 were analyzed by the polymerase chain reaction (PCR). Six of the 32 cases (18.8%) demonstrated LOH at one or more of the nine loci studied and no significant increase in the frequency of LOH was observed at any particular locus. Of these six cases with LOH, two were benign and four were malignant tumours. Since LOH was detected in both benign and malignant cases, we conclude that LOH at the chromosomal region 11q22-q23 in tumors of the CNS is a random event and may not play an important role in the pathogenesis of these tumours.