Recent evidence indicates that the mutation of retinoblastoma suscep tibility (RB) gene is also involved in the development of osteosarcoma. We studied 30 cases of osteosarcoma for the structural anomalies of the RB gene by Southern hybridization analysis with cDNA probes of the RB gene. Thirteen cases (43%) showed structural anomalies of the RB gene. They included the total or partial deletion...

We have previously described in tuberous sclerosis (TSC) hamartomas the phenomenon of loss of heterozygosity (LOH) for DNA markers in the region of both the TSC2 gene on chromosome 16p13.3 and the TSC1 gene on 9q34. We now describe the spectrum of LOH in 51 TSC hamartomas from 34 cases of TSC. DNA was extracted from leucocytes or normal paraffin embedded tissue, and from frozen paraffin embedde...

Loss of tumor suppressor genes is involved in the mechanism of tumorigenesis of many solid tumors. We tested 9 hepatitis B virus (HBV)-positive and 10 HBV-negative hepatocellular carcinomas for loss of somatic heterozygosity using 14 polymorphic probes mapping to chromosomes 4, 11, 13, and 17. Losses were found on all chromosome arms tested. The highest frequency of loss was observed at the D13...

The striking correlation between advanced age and an increased incidence of cancer has led investigators to examine the influence of aging on genome maintenance. Because loss of heterozygosity (LOH) can lead to the inactivation of tumor suppressor genes, and thus carcinogenesis, understanding the affect of aging on this type of mutation event is particularly important. Several factors may affec...

PURPOSE Head and neck cancers account for about 6% of all human cancers. Molecular changes leading to the disease development and progression still remain not fully explained. Examination of loss of heterozygosity (allelic loss, LOH) using the specific microsatellite markers is a method of choice in assessing tumour suppressor genes (TSGs) localisation in human genome. MATERIAL AND METHODS Th...

Mice bearing retinoblastoma susceptibility gene (RB) germ-line muta tions almost invariably develop pituitary neoplasms. We therefore tested 17 patients with pituitary tumors for loss of heterozygosity (LOH) using an RB sequence polymorphism and 5 polymorphic microsatellite markers surrounding the RB gene on the long arm of chromosome 13. In all of the 13 malignant or highly invasive pituitary ...

Incidence of the loss of heterozygosity on chromosome 3p was evaluated using 7 polymorphic probes in 35 Japanese patients with sporadic renal cell carcinoma (RCC). Overall frequency of the loss of heterozygosity on 3p was 53%, representing 16 of 30 informative cases. Examination of the relationship between histopathological phenotypes of RCC and incidence of the 3p loss revealed that the loss o...

Hyperdiploidy with greater than or equal to 50 chromosomes is a frequent and distinct karyotypic pattern in the malignant cells of children with acute lymphoblastic leukemia. To understand better the mechanism of formation of the hyperdiploid karyotype, we studied 15 patients using 20 DNA probes that detect restriction fragment length polymorphisms. We first examined disomic chromosomes for los...

The detection of loss of heterozygosity, indicative of the presence of a tumor suppressor gene, has been reported to occur frequently on chromosome 22q in human ovarian cancer. In this study, 110 sporadic ovarian tumors were analyzed using 8 polymorphic loci to define a minimum region of loss. Fifty-eight (53%) tumors showed loss of heterozygosity, and of these 6 exhibited partial loss, enablin...