The primary objective of this project is to validate and apply a genotoxicity assay for measuring in vivo. Somatic cell mutations in humans. The assay, which was developed during the last six years, will detect loss of gene expression (""""""""null"""""""" mutations) and also conversion of gene expression (mitotic recombination) at the locus coding for the erythrocyte cell surface sialoglycoprotein glycophorin A (GPA). It can be performed on small samples of peripheral blood and results in a measurement of the frequency of hemizygous or homozygous variant red blood cells, which are hypothesized to be the progeny of mutant erythroid precursor cells and reflect the exposure of the bone marrow to mutagenic events. Thus it appears to be a biodosimeter of exposure that should be useful in the conduct of epidemiologic studies. The assay also gives distinctive results for individuals that are heritably susceptible to high cancer incidence (Bloom's Syndrome and Ataxia Telangiectasia). Therefore, it appears to be a maker for susceptibility to mutagenic damage that might well be related to cancer risk, another important maker for epidemiologic studies. The experimental design is to perform this immunolabeling flow cytometric analysis on three different cohorts of individuals exposed to chemical mutagens; 1). cancer patients being treated with chemotherapy that includes known stem cell mutagens, 2) cigarette smokers, and 3) identical twins that have lived under different environmental conditions. Results from these exposed populations will be compared to results on matched control cohorts and/or to assays obtained on the same individuals prior to exposure. Thus, a validation of the relation between exposure to particular mutagenic chemicals and response of this new genotoxicity assay should be established and allow its more general use in epidemiologic studies.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project--Cooperative Agreements (U01)
Project #
5U01CA048518-02
Application #
3549226
Study Section
(SRC)
Project Start
1988-07-01
Project End
1991-06-30
Budget Start
1989-07-01
Budget End
1990-06-30
Support Year
2
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Lawrence Livermore National Laboratory
Department
Type
Organized Research Units
DUNS #
827171463
City
Livermore
State
CA
Country
United States
Zip Code
94550
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Grant, S G; Bigbee, W L (1993) In vivo somatic mutation and segregation at the human glycophorin A (GPA) locus: phenotypic variation encompassing both gene-specific and chromosomal mechanisms. Mutat Res 288:163-72
Compton-Quintana, P J; Jensen, R H; Bigbee, W L et al. (1993) Use of the glycophorin A human mutation assay to study workers exposed to styrene. Environ Health Perspect 99:297-301
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Jensen, R H; Bigbee, W L; Langlois, R G (1990) Multiple endpoints for somatic mutations in humans provide complementary views for biodosimetry, genotoxicity and health risks. Prog Clin Biol Res 340C:81-92
Langlois, R G; Nisbet, B A; Bigbee, W L et al. (1990) An improved flow cytometric assay for somatic mutations at the glycophorin A locus in humans. Cytometry 11:513-21
Langlois, R G; Bigbee, W L; Jensen, R H (1990) The glycophorin A assay for somatic cell mutations in humans. Prog Clin Biol Res 340C:47-56