ras Gene Mutations in Human Prostate Cancer

Point mutations at codons 12, 13, or 61 of the Ha-, Ki-, and N-ros genes are able to convert these normal cellular genes into activated oncogenes. Previous studies have shown that ras gene mutations occur in a variety of human solid tumors and may be important in the pathogenesis of some of these tumors. In order to test the hypothesis that ras gene mutations may be associated with prostate cancer, we have used an oligodeoxynucleotide hybridization assay to detect wild-type and mutant alleles in genomic DNA from prostate tumors and prostate tumor cell lines amplified using the polymerase chain reaction. Twenty-four primary prostate tumors (23 acinar tumors and one ductal tumor) and five prostate tumor cell lines were examined for mutations at codons 12,13, and 61 of the Ki-ros, Ha-rof, and N-ras genes. Two mutations were detected: an A → G transition causing a glutamine to arginine amino acid substitution at codon 61 of the Ha-ras gene in a primary prostatic duct adenocarcinoma and a G → T transversion causing a glycine to valine amino acid substitution at codon 12 of the Ha-ras gene in a prostate tumor cell line (TSU-PR1) derived from a lymph node metastasis. While the overall frequency of ras gene mutations in prostate tumors is low, when these mutations do occur they may have a role in the progression of disease or the development of the unusual ductal variant of prostatic adenocarcinoma.