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ras Oncogene activation in mammary carcinomas induced by n-methyl-n-nitrosourea in copenhagen rats

✍ Scribed by Shi-Jiang Lu; Michael C. Archer

Publisher
John Wiley and Sons
Year
1992
Tongue
English
Weight
590 KB
Volume
6
Category
Article
ISSN
0899-1987

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✦ Synopsis

Abstract

The occurrence of Ha‐ras and Ki‐ras oncogenes was investigated in mammary tumors produced by treating genetically resistant Copenhagen (Cop) rats with N‐methyl‐N‐nitrosourea. G^35^A codon 12 mutations in both Ha‐ras and Ki‐ras genes were analyzed by a polymerase chain reaction/liquid hybridization and gel retardation assay. More than half of the adenocarcinomas analyzed contained an activated Ha‐ras gene. This was also the predominant mutation in similar tumors from susceptible Buf/N rats, suggesting a common mechanism of initiation. In contrast, only two of 15 mammary adenosquamous carcinomas from the Cop rats contained an activated Ha‐ras gene, suggesting a different initiation mechanism for most of these tumors. Ki‐ras activation was found in none of five and one of five adenocarcinomas from Buf/N and Cop rats, respectively, and in none of 13 adenosquamous carcinomas from Cop rats. These results suggest that Ki‐ras activation does not play a major role in the initiation of the mammary tumors. © 1992 Wiley‐Liss, Inc.

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