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Zhang PL , Calaf G , Russo J
Allele Loss and Point Mutation in Codon-12 and Codon-61 of the C-Ha-Ras Oncogene in Carcinogen-Transformed Human Breast Epithelial-Cells
Molecular Carcinogenesis. 1994 Jan;9(1) :46-56
PMID: ISI:A1994MU88600007   
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There is significant evidence that the ras oncogene plays a role in experimental mammary carcinogenesis; the evidence in human breast cancer, however, is more limited. We induced the expression of transformation phenotypes in the human breast epithelial cell line MCF-10F with the chemical carcinogens 7,12-dimethylbenz[a]anthracene, N-methyl-N-nitrosourea, N- methyl-N-nitro-N'-nitrosoguanidine, and benzo[a]pyrene. This work was designed to clarify whether chemically induced neoplastic transformation correlates with alterations in the ras gene. MCF-10F cells have two c-Ha-ras alleles, identified by 1.0-kb and 1.2-kb restriction fragments. Treatment with carcinogens resulted in the loss of one of the alleles (1.0 kb). Polymerase chain reaction-amplified DNA from all carcinogen-treated cells was analyzed for point mutations in c- Ha-ras at codons 12 and 61. All of the carcinogens induced a mutation of the remaining allele at the first position of codon 12 (GGC-->ACC). Another frequent mutation occurred at the first position of codon 61 (CAG-->GAG). The changes in c-Ha-ras were associated with the emergence of colony formation in agar- methocel, but no specific changes in this gene correlated with the emergence of invasiveness or tumorigenesis, indicating that other genes may be involved in the process. (C) 1994 Wiley- Liss, Inc.
English Article MU886 MOL CARCINOGEN