All about KRAS for clinical oncology practice: Gene profile, clinical implications and laboratory recommendations for somatic mutational testing in colorectal cancer

Linardou, Helena; Briasoulis, Evangelos; Dahabreh, Issa J; Mountzios, Giannis; Papadimitriou, Christos; Papadopoulos, Savvas; Bafaloukos, Dimitrios; Kosmidis, P.; Murray, Samuel

doi:10.1016/j.ctrv.2010.07.008

Cited by 49 publications

(42 citation statements)

References 111 publications

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“…pmKRAS analysis may help overcome some of the obvious limitations of tissue analysis for KRAS mutations, which are underlined in a recent review addressing KRAS for clinical oncological practice (22). Tissue availability and selection of specimens with a sufficient number of tumor cells together with tumor heterogeneity are the major challenges affecting the quality and liability of DNA extracted.…”

Section: Discussionmentioning

confidence: 99%

Quantitative Cell-Free DNA, KRAS, and BRAF Mutations in Plasma from Patients with Metastatic Colorectal Cancer during Treatment with Cetuximab and Irinotecan

Spindler

Pallisgaard

Vogelius

et al. 2012

Clinical Cancer Research

242

212

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Purpose: The present study investigated the levels of circulating cell-free DNA (cfDNA) in plasma from patients with metastatic colorectal cancer (mCRC) in relation to third-line treatment with cetuximab and irinotecan and the quantitative relationship of cfDNA with tumor-specific mutations in plasma.Experimental Design: Inclusion criteria were histopathologically verified chemotherapy-resistant mCRC, adequate Eastern Cooperative Oncology Group performance status, and organ function. Treatment consisted of irinotecan being administered at 350 mg/m 2 for 3 weeks and weekly administration of 250 mg/m 2 cetuximab until progression or unacceptable toxicity. A quantitative PCR method was developed to assess the number of cfDNA alleles and KRAS and BRAF mutation alleles in plasma at baseline. Results: The study included 108 patients. Only three patients were positive for BRAF mutations. The majority of KRAS mutations detected in tumors were also found in the plasma [32 of 41 (78%)]. Plasma cfDNA and plasma mutant KRAS levels (pmKRAS) were strongly correlated (r ¼ 0.85, P < 10 À4). The disease control rate was 77% in patients with low cfDNA (<25% quartile) and 30% in patients with high cfDNA [>75% quartile (P ¼ 0.009)]. Patients with pmKRAS levels higher than 75% had a disease control rate of 0% compared with 42% in patients with lower pmKRAS (P ¼ 0.048). Cox analysis confirmed the prognostic importance of both cfDNA and pmKRAS. High levels were clear indicators of a poor outcome.Conclusions: KRAS analysis in plasma is a viable alternative to tissue analysis. Quantitative levels of cfDNA and pmKRAS are strongly correlated and hold promise of clinical application.

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Section: Discussionmentioning

confidence: 99%

Quantitative Cell-Free DNA, KRAS, and BRAF Mutations in Plasma from Patients with Metastatic Colorectal Cancer during Treatment with Cetuximab and Irinotecan

Spindler

Pallisgaard

Vogelius

et al. 2012

Clinical Cancer Research

242

212

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“…Our results show a consistently high analytical sensitivity, with no crossreactivity among the specific probes we used to detect distinct alleles. No clear standardized procedures for KRAS mutational testing have been established or proposed (20,21 ). The incremental clinical value offered by highly sensitive techniques needs to be established.…”

Section: Discussionmentioning

confidence: 99%

“…Such frequently used techniques as pyrosequencing and allele-specific PCR have analytical sensitivities ranging from 1% to 10% for the detection of mutant DNA diluted into a background of wild-type DNA (18 -20 ). The TheraScreen K-RAS Mutation Kit (DxS Limited), a test based on an amplification-refractory mutation system (ARMS) 9 technology and possibly the most widely used CEmarked kit for diagnostic use, has a reported analytical sensitivity of approximately 1% of mutant allele (21 ). More-sensitive methods are available for KRAS analysis, such as mutant-enriched PCR (9 ) and COLD-PCR, which has a reported analytical sensitivity of about 0.1% (22)(23)(24) or better (25 ).…”

Section: Mutations In the Krasmentioning

confidence: 99%

Nanofluidic Digital PCR for KRAS Mutation Detection and Quantification in Gastrointestinal Cancer

et al. 2012

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“…No clearly standardized procedures for KRAS/NRAS mutational testing have been proposed and established (12,13) and an increasing number of techniques have been developed with different levels of sensitivity and specificity (12,(14)(15)(16)(17)(18)(19)(20)(21). Several highly sensitive techniques are currently being evaluated.…”

Section: Introductionmentioning

confidence: 99%

Nanofluidic Digital PCR and Extended Genotyping of RAS and BRAF for Improved Selection of Metastatic Colorectal Cancer Patients for Anti-EGFR Therapies

Azuara

Santos

López-Dóriga

et al. 2016

Molecular Cancer Therapeutics

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The clinical significance of low-frequent RAS pathwaymutated alleles and the optimal sensitivity cutoff value in the prediction of response to anti-EGFR therapy in metastatic colorectal cancer (mCRC) patients remains controversial. We aimed to evaluate the added value of genotyping an extended RAS panel using a robust nanofluidic digital PCR (dPCR) approach. A panel of 34 hotspots, including RAS (KRAS and NRAS exons 2/3/4) and BRAF (V600E), was analyzed in tumor FFPE samples from 102 mCRC patients treated with anti-EGFR therapy. dPCR was compared with conventional quantitative PCR (qPCR). Response rates, progression-free survival (PFS), and overall survival (OS) were correlated to the mutational status and the mutated allele fraction. Tumor response evaluations were not available in 9 patients and were excluded for response rate analysis. Twenty-two percent of patients were positive for one mutation with qPCR (mutated alleles ranged from 2.1% to 66.6%). Analysis by dPCR increased the number of positive patients to 47%. Mutated alleles for patients only detected by dPCR ranged from 0.04% to 10.8%. An inverse correlation between the fraction of mutated alleles and radiologic response was observed. ROC analysis showed that a fraction of 1% or higher of any mutated alleles offered the best predictive value for all combinations of RAS and BRAF analysis. In addition, this threshold also optimized prediction both PFS and OS. We conclude that mutation testing using an extended gene panel, including RAS and BRAF with a threshold of 1% improved prediction of response to anti-EGFR therapy.

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All about KRAS for clinical oncology practice: Gene profile, clinical implications and laboratory recommendations for somatic mutational testing in colorectal cancer

Cited by 49 publications

References 111 publications

Quantitative Cell-Free DNA, KRAS, and BRAF Mutations in Plasma from Patients with Metastatic Colorectal Cancer during Treatment with Cetuximab and Irinotecan

Quantitative Cell-Free DNA, KRAS, and BRAF Mutations in Plasma from Patients with Metastatic Colorectal Cancer during Treatment with Cetuximab and Irinotecan

Nanofluidic Digital PCR for KRAS Mutation Detection and Quantification in Gastrointestinal Cancer

Nanofluidic Digital PCR and Extended Genotyping of RAS and BRAF for Improved Selection of Metastatic Colorectal Cancer Patients for Anti-EGFR Therapies

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