Detection of Ki-ras mutations in tissue and plasma samples of patients with pancreatic cancer using PNA-mediated PCR clamping and hybridisation probes.
In the present study, we combined the PCR-clamping approach with melting curve analysis using mutant specific hybridisation probes and wild-type specific peptide nucleic acids (PNAs) to determine the genotypes of the most frequent point mutation in codon 12 of the proto-oncogene Ki-ras in tissue and plasma samples of patients with pancreatic cancer. The sensitivity of our assay was 1-5 x 10(-5). The melting curve analysis of tissue samples of four patients revealed two valine mutations, one none-valine mutation and one wild-type sequence. Ki-ras alterations were found in 28% of DNAs (18 out of 64) of nonrelated plasma samples of 10 patients with ductal adenocarcinoma of the pancreas. The valine mutation was the predominantly detected gene alteration (83%). Out of ten patients investigated, four patients (40%) became positive during clinical observation with respect to Ki-ras mutation. All four patients exhibited progressive disease and high levels of tumour marker CA 19-9. In conclusion, the one-step procedure discribed may be a useful clinical tool for analysing Ki-ras point mutations in tissue and plasmas samples. In addition, this method can be adapted for simultanous detection of multiple mutations and quantitation.
Däbritz
J
J
Charité - Universitätsmedizin Berlin, Campus Virchow-Klinikum, Medizinische Klinik und Poliklinik m.S. Hämatologie und Onkologie, Augustenburger Platz 1, 13353 Berlin, Germany.
Hänfler
J
J
Preston
R
R
Stieler
J
J
Oettle
H
H
D021441:Carcinoma, Pancreatic Ductal / Q000097:blood / Q000235:genetics*; D005260:Female; D011905:Genes, ras; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D010190:Pancreatic Neoplasms / Q000097:blood / Q000235:genetics*; D020135:Peptide Nucleic Acids; D017354:Point Mutation; D016133:Polymerase Chain Reaction / Q000379:methods*; D000090063:Proto-Oncogene Mas; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
C000715470:MAS1 protein, human; D020135:Peptide Nucleic Acids; D000090063:Proto-Oncogene Mas