During the first five years of this grant we have defined the first polymorphic enzyme marker system for a solid human tumor. The esterase D (EsD) locus is closely linked to the locus for both the deletion and the dominantly inherited forms of retinoblastoma (Rb) allowing, in informative families, either prenatal or postnatal screening for the presence or absence of the retinoblastoma predisposing genotype. Our biochemical and cytogenetic investigation of Rb tumors has revealed that locus of chromosome 13 or deletion of region 13q14 is a non-random cytogenetic event in this tumor. This observation suggests that the Rb gene is recessive at the cellular level and that loss or inactivation of both wild type alleles at the Rb locus is associated with tumorigenesis. Using restriction fragment length polymorphisms (RFLPs), collaborators demonstrated that gross chromosomal changes leading to homozygosity or hemizygosity at 13q14 is, in fact, a common event in Rb tumors. Primary objectives of the renewal grant are: 1) to prove that the 13 chromosome carrying the wild type allele (Rb+) at the Rb locus is lost or deleted in the tumor as predicted to result in the homozygosity observed at this locus; 2) to determine if similar chromosomal mechanisms involving 13q14 are found in second primary tumors, the cause of death of more than 80% of the survivors of hereditary Rb; 3) to determine if tumor chromosomal karyotyping is useful, as preliminary data suggest, in identifying multifocal (i.e. hereditary) tumors among patients with unilateral disease, and finally 4) to determine the role of other non-random chromosomal changes found in Rb, namely iso 6 p and double minutes (evidence of gene amplification). We plan to meet our objectives by obtaining fresh tumor specimens from preselected patients in whom the 13 chromosome containing the Rb susceptibility allele can be identified. These tumors, obtained through a nationwide network of referring pediatric ophthalmologists, along with second primary tumors will be examined for loss of the wild type allele either cytogenetically or through the use of EsD or DNA RFLPs. The objectives of this renewal grant are directed toward continued improvement of genetic counseling for families with retinoblastoma, understanding the function of the Rb gene, and the ultimate cloning of this human cancer gene.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
2R01EY002715-07
Application #
3257087
Study Section
Mammalian Genetics Study Section (MGN)
Project Start
1979-01-01
Project End
1987-12-31
Budget Start
1985-01-14
Budget End
1985-12-31
Support Year
7
Fiscal Year
1985
Total Cost
Indirect Cost
Name
Children's Hospital of Los Angeles
Department
Type
DUNS #
094878337
City
Los Angeles
State
CA
Country
United States
Zip Code
90027
Xu, H J; Sumegi, J; Hu, S X et al. (1991) Intraocular tumor formation of RB reconstituted retinoblastoma cells. Cancer Res 51:4481-5
Ishikawa, J; Xu, H J; Hu, S X et al. (1991) Inactivation of the retinoblastoma gene in human bladder and renal cell carcinomas. Cancer Res 51:5736-43
Oka, K; Ishikawa, J; Bruner, J M et al. (1991) Detection of loss of heterozygosity in the p53 gene in renal cell carcinoma and bladder cancer using the polymerase chain reaction. Mol Carcinog 4:10-3
Takahashi, R; Hashimoto, T; Xu, H J et al. (1991) The retinoblastoma gene functions as a growth and tumor suppressor in human bladder carcinoma cells. Proc Natl Acad Sci U S A 88:5257-61
Xu, H J; Hu, S X; Benedict, W F (1991) Lack of nuclear RB protein staining in G0/middle G1 cells: correlation to changes in total RB protein level. Oncogene 6:1139-46
Xu, H J; Hu, S X; Cagle, P T et al. (1991) Absence of retinoblastoma protein expression in primary non-small cell lung carcinomas. Cancer Res 51:2735-9
Hashimoto, T; Takahashi, R; Yandell, D W et al. (1991) Characterization of intragenic deletions in two sporadic germinal mutation cases of retinoblastoma resulting in abnormal gene expression. Oncogene 6:463-9
Benedict, W F; Xu, H J; Hu, S X et al. (1990) Role of the retinoblastoma gene in the initiation and progression of human cancer. J Clin Invest 85:988-93
Benedict, W F; Xu, H J; Takahashi, R (1990) The retinoblastoma gene: its role in human malignancies. Cancer Invest 8:535-40
Leach, R J; Magewu, A N; Buckley, J D et al. (1990) Preferential retention of paternal alleles in human retinoblastoma: evidence for genomic imprinting. Cell Growth Differ 1:401-6

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