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.

Localization of the von Hippel-Lindau disease gene to a small region of chromosome 3

We studied 25 families with von Hippel-Lindau disease (VHL) to locate VHL more precisely on chromosome 3. We found that VHL was linked to RAF1, confirming previous observations, and to two polymorphic DNA markers, D3S18 and D3S191. Multipoint linkage analysis indicated that the most likely location for VHL was in the interval between RAF1 and D3S18. D3S18 was located at 3p26. Genetic heterogeneity was not detected in this panel of von Hippel-Lindau disease families. The polymorphic markers RAF1, D3S18, and D3S191 should be useful in identifying asymptomatic gene carriers in VHL families and in guiding efforts at gene isolation.

A new polymorphic probe on chromosome 3p: lambda LIB49-63 (D3S192E)

Images

A new polymorphic probe on chromosome 3p: lambda LIB28-77 (D3S169E)

Images

Styrene oxide as a stereochemical probe for the mechanism of aralkylation at different sites on guanosine

The stereochemistry at the alpha-carbon atom of the styrene moiety in styrene oxide-guanosine products was established, and the stereochemical consequences of reaction of optically active styrene oxide with guanosine were investigated. Inversion of stereochemistry in products at the alpha-carbon of styrene oxide decreased in the sequence 7- much greater than N2- greater than O6-substituted guanosines. These findings show that an extensively ionized substrate is needed for reaction at the exocyclic N2 and O6 sites on guanosine but that the reactive intermediate is not an ideal planar trigonal carbonium ion. This follows because inversion exceeds retention in both of the exocyclic substituted products.