BACKGROUND & AIMS: Circulating DNA can be isolated from the plasma of healthy subjects and from patients with cancer. The aim of this study was to detect K-ras mutations in DNA extracted from the plasma of patients with colorectal cancer. METHODS: Tumor and plasma DNA were extracted from 14 patients with colorectal cancer (stages A-D), and K-ras alterations were detected using a polymerase chain reaction assay that uses sequence-specific primers to amplify mutant DNA. These results were confirmed with another polymerase chain reaction assay that creates an enzyme restriction site in the absence of a K-ras mutation followed by direct sequencing and additional cloning techniques. RESULTS: Seven patients (50%) had a codon 12 K-ras mutation within their primary tumor, and identical mutations were found in the plasma DNA of 6 patients (86%). Mutant DNA was not detected in the plasma specimens of 7 patients whose tumors tested negative for K-ras alterations or in healthy control subjects. Similar results were obtained using all three molecular biological techniques. CONCLUSIONS: K-ras abnormalities can be detected in circulating DNA extracted from the plasma specimens of patients with colorectal cancer. If these results are confirmed in larger studies, genetic analysis of plasma DNA may have clinical applications in the future.
BACKGROUND & AIMS: Circulating DNA can be isolated from the plasma of healthy subjects and from patients with cancer. The aim of this study was to detect K-ras mutations in DNA extracted from the plasma of patients with colorectal cancer. METHODS:Tumor and plasma DNA were extracted from 14 patients with colorectal cancer (stages A-D), and K-ras alterations were detected using a polymerase chain reaction assay that uses sequence-specific primers to amplify mutant DNA. These results were confirmed with another polymerase chain reaction assay that creates an enzyme restriction site in the absence of a K-ras mutation followed by direct sequencing and additional cloning techniques. RESULTS: Seven patients (50%) had a codon 12 K-ras mutation within their primary tumor, and identical mutations were found in the plasma DNA of 6 patients (86%). Mutant DNA was not detected in the plasma specimens of 7 patients whose tumors tested negative for K-ras alterations or in healthy control subjects. Similar results were obtained using all three molecular biological techniques. CONCLUSIONS:K-ras abnormalities can be detected in circulating DNA extracted from the plasma specimens of patients with colorectal cancer. If these results are confirmed in larger studies, genetic analysis of plasma DNA may have clinical applications in the future.
Authors: Chunming Ding; Rossa W K Chiu; Tze K Lau; Tse N Leung; Li C Chan; Amy Y Y Chan; Pimlak Charoenkwan; Ivy S L Ng; Hai-Yang Law; Edmond S K Ma; Xiangmin Xu; Chanane Wanapirak; Torpong Sanguansermsri; Can Liao; Mary Anne Tan Jin Ai; David H K Chui; Charles R Cantor; Y M Dennis Lo Journal: Proc Natl Acad Sci U S A Date: 2004-07-09 Impact factor: 11.205
Authors: Elaine A Hart; William C Patton; John D Jacobson; Alan King; Johannah Corselli; Philip J Chan Journal: J Assist Reprod Genet Date: 2005-05 Impact factor: 3.412
Authors: J M Silva; R Rodriguez; J M Garcia; C Muñoz; J Silva; G Dominguez; M Provencio; P España; F Bonilla Journal: Gut Date: 2002-04 Impact factor: 23.059
Authors: José Miguel García; Vanesa García; Cristina Peña; Gemma Domínguez; Javier Silva; Raquel Diaz; Pablo Espinosa; Maria Jesús Citores; Manuel Collado; Félix Bonilla Journal: RNA Date: 2008-05-02 Impact factor: 4.942