title: K-ras mutation detection by hybridization to a polypyrrole DNA chip.
abstract: BACKGROUND
  Detection of mutations in cancer-related genes is of major importance for both basic knowledge and clinical practice. Several strategies have been developed to diagnose these alterations. We describe a method based on polypyrrole DNA chip technology to detect K-ras gene mutations in tumors.
  
  
  METHODS
  An oligodeoxynucleotide array was constructed on a silicon device by copolymerization of 5'-pyrrole-labeled oligodeoxynucleotides and pyrrole. The samples to be analyzed were then amplified by PCR, and the single-stranded biotin-labeled amplified DNA was specifically hybridized to the addressed probes. Perfectly matched duplexes were detected by fluorescence microscopy using R-phycoerythrin as the detection label. The developed methodology was applied to genotype assignment of K-ras in human samples. The genotypes of 75 DNA genomic samples from colorectal cancer patients were analyzed side by side using direct DNA sequencing and a polypyrrole DNA chip.
  
  
  RESULTS
  The chip method unequivocally defined all of the genotypes. Mutations present at <10% of the wild-type DNA concentration could be distinguished.
  
  
  CONCLUSIONS
  This probe array assay is a rapid and reliable procedure that may be used to detect mutations.
authors.affiliation: CRLC Val d'Aurelle Paul-Lamarque, Centre de Recherche en Cancérologie, Parc Euromédecine, 34298 Montpellier Cedex 5, France. ecrapez@valdorel.fnclcc.fr
authors.forename: E
authors.initials: E
authors.lastname: Lopez-Crapez
authors.forename: T
authors.initials: T
authors.lastname: Livache
authors.forename: J
authors.initials: J
authors.lastname: Marchand
authors.forename: J
authors.initials: J
authors.lastname: Grenier
mesh_terms: D015179:Colorectal Neoplasms / Q000235:genetics*; D004273:DNA, Neoplasm / Q000235:genetics*; D011905:Genes, ras; D005838:Genotype; D006801:Humans; D008856:Microscopy, Fluorescence; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D015689:Oncogene Protein p21(ras) / Q000235:genetics*; D011108:Polymers; D011758:Pyrroles; D012680:Sensitivity and Specificity; D014407:Tumor Cells, Cultured
chemical_list: D004273:DNA, Neoplasm; D011108:Polymers; D011758:Pyrroles; C067635:polypyrrole; D015689:Oncogene Protein p21(ras)