The authentic gene responsible for the development of both retinoblastoma (Rb) and osteosarcoma has recently been cloned within our program. Using cDNA probes of the Rb gene, structural changes (deletions and rearrangements) were observed in 16 of 40 retinoblastomas examined as well as in an osteosarcoma. Whether or not structural aberrations were found, the retinoblastomas and osteosarcomas has either an absence of the Rb transcript or an abnormal transcript. Having cloned the Rb gene and shown that it is the loss or inactivation of both alleles of the Rb gene that is responsible for retinoblastoma and osteosarcoma, our plans include determining in which other cancers the Rb gene has a role in the etiology of the tumor. Prime candidates include: 1. other tumors arising in patients with hereditary retinoblastoma, especially soft tissue sarcomas, 2. alveolar rhabdomyosarcomas, 3. hereditary breast cancer, 4. small cell carcinoma of the lung and 5. melanomas. We shall examine the Rb gene in the tumors mentioned above as well as other tumor types to determine if changes at the structural or RNA level can be identified in a similar manner as retinoblastoma and osteosarcoma. Our group fortunately has access to a unique population of tumor specimens including the largest number of cases with second malignancies in the world who have previously had retinoblastoma. These studies could have extremely important implications in understanding the basis of human cancer and in identifying several other malignancies in which the Rb gene has a key role. We shall also examine whether the Rb gene has an etiological role in additional families who have dominantly inherited predisposition to develop cancer. Finally, we shall examine all known oncogenes for their expression in retinoblastomas, osteosarcomas, and other tumor in which the Rb gene is a causative factor. Methodologies to be used include standard molecular biological and cytogenetic techniques presently available in our laboratory.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
7R01EY002715-11
Application #
3257094
Study Section
Mammalian Genetics Study Section (MGN)
Project Start
1988-07-01
Project End
1991-03-31
Budget Start
1988-07-01
Budget End
1989-03-31
Support Year
11
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Baylor College of Medicine
Department
Type
Schools of Medicine
DUNS #
074615394
City
Houston
State
TX
Country
United States
Zip Code
77030
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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