Document Detail


Detection of KRAS mutations in colorectal carcinoma patients with an integrated PCR/sequencing and real-time PCR approach.
MedLine Citation:
PMID:  20712532     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
AIMS: Patients with metastatic colorectal carcinoma (mCRC) carrying activating mutations of the KRAS gene do not benefit from treatment with anti-EGF receptor monoclonal antibodies. Therefore, KRAS mutation testing of mCRC patients is mandatory in the clinical setting to aid in the choice of appropriate therapy.
MATERIALS & METHODS: We developed a cost-effective approach for the determination of KRAS mutations in codons 12 and 13 in clinical practice based on a sensitive PCR/sequencing technique and the commercially available real-time PCR-based Therascreen kit (DxS Ltd).
RESULTS & CONCLUSION: The PCR/sequencing test was able to detect 10% mutant DNA in a background of wild-type DNA. By using this assay, we determined the mutational status of KRAS in 527 out of 540 (97.6%) formalin-fixed paraffin-embedded tissues from mCRC patients. PCR/sequencing was not conclusive in 13 cases, in which low-intensity peaks suggestive of potential mutations were identified. The DxS assay, which showed a sensitivity of 1%, identified mutations in 11 out of 13 inconclusive cases. Interestingly, five of these 11 cases showed high levels of DNA fragmentation. No significant difference was found in the ability of PCR/sequencing and DxS to identify KRAS mutations within 160 cases with more than 30% tumor cells. However, in 24 samples with less than 30% tumor cells, DxS showed an higher sensitivity. In conclusion, our findings suggest that PCR/sequencing can be used for mutational analysis of the majority of tumor samples that have more than 30% tumor cell content, whereas more sensitive and expensive tests should be reserved for inconclusive cases and for samples with a low amount of tumor cells.
Authors:
Pietro Carotenuto; Cristin Roma; Anna Maria Rachiglio; Fabiana Tatangelo; Carmine Pinto; Fortunato Ciardiello; Oscar Nappi; R Vincenzo Iaffaioli; Gerardo Botti; Nicola Normanno
Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Pharmacogenomics     Volume:  11     ISSN:  1744-8042     ISO Abbreviation:  Pharmacogenomics     Publication Date:  2010 Aug 
Date Detail:
Created Date:  2010-08-17     Completed Date:  2010-12-28     Revised Date:  2011-05-12    
Medline Journal Info:
Nlm Unique ID:  100897350     Medline TA:  Pharmacogenomics     Country:  England    
Other Details:
Languages:  eng     Pagination:  1169-79     Citation Subset:  IM    
Affiliation:
Pharmacogenomic Laboratory, Centro Ricerche Oncologiche di Mercogliano, Avellino, Italy.
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MeSH Terms
Descriptor/Qualifier:
Adenocarcinoma / genetics*,  pathology
Cohort Studies
Colorectal Neoplasms / genetics*,  pathology
Humans
Mutation*
Neoplasm Metastasis
Oligonucleotide Array Sequence Analysis*
Proto-Oncogene Proteins / genetics*
Reproducibility of Results
Reverse Transcriptase Polymerase Chain Reaction*
Sensitivity and Specificity
ras Proteins / genetics*
Chemical
Reg. No./Substance:
0/KRAS protein, human; 0/Proto-Oncogene Proteins; EC 3.6.5.2/ras Proteins
Comments/Corrections
Comment In:
Pharmacogenomics. 2011 Mar;12(3):307-8; author reply 309-10   [PMID:  21449668 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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