Carcinogen-specific mutation and amplification of Ha-ras during mouse skin carcinogenesis

M Quintanilla, K Brown, M Ramsden, A Balmain - Nature, 1986 - nature.com
M Quintanilla, K Brown, M Ramsden, A Balmain
Nature, 1986nature.com
Cellular proto-oncogenes can be activated by both point mutations and chromosomal
translocations, suggesting that there may be a direct link between exposure to agents which
damage DNA and genetic change leading to malignancy (see refs 1, 2 for reviews). Several
groups have therefore analysed mutations found in cellular oncogenes of tumours induced
by particular physical or chemical carcinogens3–9. Here, we have analysed the molecular
changes at different stages of carcinogenesis in mouse skin tumours induced by initiating …
Abstract
Cellular proto-oncogenes can be activated by both point mutations and chromosomal translocations, suggesting that there may be a direct link between exposure to agents which damage DNA and genetic change leading to malignancy (see refs 1, 2 for reviews). Several groups have therefore analysed mutations found in cellular oncogenes of tumours induced by particular physical or chemical carcinogens3–9. Here, we have analysed the molecular changes at different stages of carcinogenesis in mouse skin tumours induced by initiating and promoting agents. Over 90% of tumours, including premalignant papillomas, initiated with dimethylbenz-anthracene (DMBA) have a specific A→T transversion at the second nucleotide of codon 61 of the Harvey-ras (Ha-ras) gene. The frequency of this mutation was dependent on the initiating agent used, but not on the promoter, suggesting that the mutation occurs at the time of initiation. The mutation was heterozygous in most papillomas tested, but was homozygous or amplified in some carcinomas. The development of further chromosomal changes at the c-Ha-ras gene locus is therefore a common feature of tumour progression.
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