The Significance of ras Oncogene Mutation for the Development of Human Breast Cancer

Abstract

Abstract: Activation of ras oncogenes has been described in various human tumors. Additionally there is strong evidence that ras oncogenes are involved in experimental mammary carcinogenesis. The role of these oncogenes in the development of human breast cancer has not yet been fully clarified. We investigated 45 cases of primary human breast cancer for point mutation in the hot spot regions codon 12 and 13 of exon 1 and codon 61 of exon 2 of H-, K-, and N-ras gene, applying polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) technique followed by direct sequencing. One case of an invasive ductal breast cancer showed an activation by point mutation in codon 61, exon 2 of the H-ras gene. We could demonstrate a transversion of adenine to thymine leading to an exchange between glutamine and leucine. Our findings suggest that in spite of experimental carcinogenesis the rate occurrence of ras-oncogene activation by point mutation does not play an important role in human breast cancer.