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K Tory

Publications and source records attributed to K Tory.

53 records · Page 3Linked to original sources

Molecular analysis of genetic changes in the origin and development of renal cell carcinoma.

Renal cell carcinoma has been characterized by an abnormality on the short arm of chromosome 3 which suggests the presence of a tumor suppressor gene at this location. In order to more precisely define the location of the renal cell carcinoma gene and to differentiate molecular changes occurring in early stages of renal neoplasia versus those occurring later in malignant progression, DNA from normal and tumor tissue from 60 patients with various stages of renal cell carcinoma was analyzed for loss of alleles at different chromosomal loci. In tumor tissue from 51 of 58 evaluable patients (88%) there was loss of heterozygosity at one or more of 10 loci tested on chromosome 3 independently of tumor stage. Analysis of the genotypes identified the distal portion of 3p bounded by D3S2 and D3S22 (3p21-26) as the region of the disease gene. In tumor tissue from patients with advanced renal cell carcinoma, we found loss of heterozygosity on chromosome 11p in 5 of 21 (24%), on chromosome 13 in 3 of 9 (33%), and on chromosome 17 in 2 of 19 (11%). We found no loss of heterozygosity at the loci on chromosomes 11, 13, or 17 in tumor tissue from patients with localized renal cell carcinoma (N = 5). These data suggest the existence of a tumor suppressor gene on chromosome 3p which may be essential to the genesis of sporadic renal cell carcinoma and that other tumor suppressor genes are associated with progression of this malignancy.

Adult↗

Molecular mapping of deletion sites in the short arm of chromosome 3 in human lung cancer.

We used 10 restriction fragment length polymorphism (RFLP) probes spanning the length of the short arm of chromosome 3 (3p) to map deletion sites in human lung cancer. Two approaches were used. 1) When a patient's tumor and normal tissue were available, loci with allelic heterozygosity in the normal tissue were tested for loss of alleles at 3p. 2) When the corresponding normal tissue was not available, the frequency of heterozygosity at each locus in a panel of tumors was compared to the corresponding published frequencies in nontumor tissue of healthy individuals or patients with lung cancer. In 14 small cell lung carcinomas (SCLC) with normal DNA for comparison, allele loss was found at all heterozygous loci, with one exception at a locus near the 3p centromere (D3S4). In the total of 53 SCLCs, which included tumors without paired normal tissue, frequency of heterozygosity was significantly reduced in all 10 3p loci. Three loci, DNF 15S2, RAF1, and D3S18, were homozygous in all tumors in the SCLC panel. These loci, which are in regions 3p21 and 3p25, may thus be involved in the origin or evolution of SCLC. We also investigated 24 non-SCLC tumors. In this panel, frequency of heterozygosity was significantly reduced at seven of the 10 loci tested. Comparison of the results shows that the pattern of allele loss on 3p is different in SCLC and non-SCLC, suggesting a difference in pathogenesis at the genetic level.

Alleles↗

Specific genetic change in tumors associated with von Hippel-Lindau disease.

Previous reports showed that the loss of DNA sequences on the short arm of chromosome 3 (3p) is consistently found in sporadic renal cell carcinomas. To evaluate the significance of this genetic change, we looked for the loss of 3p alleles in hereditary renal cell carcinomas and other tumors from patients with von Hippel-Lindau disease. Specific loss of alleles from chromosome 3p was detected with polymorphic DNA markers in 11 renal cell carcinomas, one pheochromocytoma, two spinal hemangioblastomas and one cerebellar hemangioblastoma from von Hippel-Lindau patients. Multiple renal cell carcinomas in individuals with von Hippel-Lindau disease showed loss of the same chromosome 3p alleles, which demonstrated that the same chromosome was deleted in each tumor. Analysis of haplotypes indicated that the loss of chromosome 3p alleles was from the chromosome bearing the balancing, wild-type allele of the VHL gene. These results are consistent with the concept that the VHL gene is a recessive oncogene. Renal cell carcinoma, pheochromocytoma, and spinal and cerebellar hemangioblastomas develop in predisposed family members when somatic mutational events lead to loss of chromosome 3p sequences bearing the wild-type allele of the VHL gene.

Alleles↗

Cytostatic activity of daunorubicin analogs containing daunosamine as furanoside.

This paper describes the synthesis of daunorubicin (daunomycin) analogs, differing from the natural antibiotics in the ring size of the sugar moiety (furanosides instead of pyranosides). Both, the 5-O-methyl derivative 7 as well as the daunosaminofuranoside 16 were less active cytostatics than doxorubicin (adriamycin), but 16 was also much less toxic, consequently its therapeutic index is more favourable.

Animals↗

Mechanism of tumorigenesis of renal carcinomas associated with the constitutional chromosome 3;8 translocation.

PURPOSE: Members of a family carrying a constitutional balanced translocation [t(3;8) (p14;q24)] have a high risk of developing multiple, bilateral clear-cell renal carcinomas. Two genetic mechanisms of carcinogenesis for this malignancy have been proposed: (1) disruption of a gene at the translocation breakpoint and (2) mutation of the von Hippel-Lindau tumor-suppressor gene at 3p25. This study further evaluates the role of the von Hippel-Lindau gene in the etiology and pathogenesis of t(3;8)-associated renal carcinomas. METHODS: Two new t(3;8)-associated renal carcinomas were tested for mutations in the von Hippel-Lindau gene by single-stranded conformational polymorphism analysis followed by direct DNA sequencing, for loss of alleles on chromosomes 3p and 8, and for methylation abnormalities in the first cloned exon of the von Hippel-Lindau gene. RESULTS: A missense mutation in the von Hippel-Lindau gene was found in one of the two t(3;8)-associated renal carcinomas. This mutation would produce a stop codon and a truncated protein. Both tumors showed a loss of alleles on the derivative 8 chromosome. When these results were combined with the results of our previous studies, two of the four t(3;8)-associated renal carcinomas, which were examined for molecular genetic changes, showed different von Hippel-Lindau somatic mutations. All renal tumors from the 3;8 translocation family showed loss of the translocated portion of chromosome 3. CONCLUSIONS: These results support a mechanism of tumorigenesis in the chromosome (3;8) translocation family that involves the loss of both copies of the von Hippel-Lindau gene.

Carcinoma, Renal Cell↗