Here we review one of these companion tests, the Roche cobas® EGFR mutation test v2, from a methodological point of view, also exploring its. “The cobas® EGFR Mutation Test v2 is a companion diagnostic test that supports IRESSA® as an additional therapeutic option for patients and. The U.S. Food and Drug Administration (FDA) recently approved the cobas EGFR Mutation Test v2 as a companion diagnostic test with gefitinib.

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Quantitative results from the cobas assay were positively correlated with allele frequencies derived from digital droplet PCR measurements and showed good reproducibility among laboratories.

Analytical performance of the cobas EGFR mutation assay for Japanese non-small-cell lung cancer.

In our validation experiment using the Oncomine Lung cfDNA Assay, all mutations were detected in level 4 material when the coverage depth was more than ,X. None of the four target mutations were detected in level 4 material.

Amplification egfrr detection were performed using the cobas z analyzer Roche Molecular Systems, Inc. Tumor-derived ctDNA often represents a small percentage of the total cfDNA and can be present at allele fractions as low as 0.

TM mutation in relapsed tumors because of tumor heterogeneity [ 6 ]. The analytical sensitivities of the cobas assay were not identical for the different target mutations, similar to previous reports [ 14mutatikn ].

Therefore, caution is warranted in the setting of tumor relapse, and additional efforts should be made to optimize the experimental conditions to increase the sensitivity of p. Table of Contents Alerts. TM testing included pyrosequencing, digital PCR, and several allele-specific Muration platforms, using four levels of spiked materials [ 25 ]. Dots in the tesf represent negative measurement ND or the SQI value of the positive measurement for a p.

Therefore, SQI could be useful for patient monitoring. Individual laboratories should optimize NGS performance to maximize clinical utility.


When a mutation was detected, semiquantitative index SQI values for each mutation are reported automatically by the software using the observed threshold cycle for the target mutation. This is an open access article distributed under the Creative Commons Attribution Licensewhich dgfr unrestricted use, distribution, and reproduction in any medium, provided the original work mutstion properly cited.

This difference in assay performance according to target mutation might be due to the assay design and characteristics of the target regions [ 1415 ].

There was sufficient coverage at all target mutations to detect variants with allele frequencies of 0.

The cobas® EGFR Mutation Test

Therefore, highly sensitive methodologies have been developed to detect low abundance epidermal growth factor cobae EGFR mutations, including p. From November to Juneseven clinical diagnostic laboratories participated in the EQA program. External quality assessment EQA is a way to standardize interlaboratory results and to monitor and improve testing processes across laboratories [ 10 ]. The cobas assay showed reliable and robust test performance in all laboratories. In our pilot EQA, the cobas assay showed a higher detection rate and lower imprecision for exon 19 deletion and p.

Published by Elsevier Inc. The number of reactions per test method among participating laboratories was Results from two laboratories were consistent with the expected mutant allele frequencies calculated from absolute allele frequencies measured using digital droplet PCR. For all other variants, sensitivities varied between All results obtained using the cobas assay were concordant except for detection of EGFR exon 19 deletion and p.

The fraction of tumor-derived cell-free DNA cfDNA in blood plasma varies according to tumor stage, tumor burden, vascularization of the tumor, biological cobss of the tumor such as apoptotic rate, and the metastatic potential of the cancer cells [ 2 ].

Larger trial including more genotyping platforms including mutaton PCR with our sample preparation protocol is worthy of further investigation.


A limitation of this study is the small number of laboratories that participated, especially laboratories performing NGS. Subscribe to Table of Contents Alerts. Submitted qualitative results were evaluated as acceptable positive for expected mutations or negative for unexpected mutations or unacceptable negative for expected mutations or positive for unexpected mutationsaccording to the manufactured and validated target mutations in this study Table 1 and Supplementary Table S2.

TM and 70,X for p. TM and exon 20 insertion mutations were not detected in LOD level 4 material by any of the laboratories.

Analytical performance of the cobas EGFR mutation assay for Japanese non-small-cell lung cancer.

Details are provided in Supplementary Table S2. Introduction Circulating tumor DNA ctDNA carries the same molecular alterations as the tumor itself and can be used to select treatment, assess the emergence of drug resistance, and monitor lung cancer patients in routine clinical practice [ 1 ].

As a result, rigorous quality controls to avoid inappropriate patient treatment will become increasingly important in clinical diagnostic laboratories. Comparison of mutant allelic frequency from two laboratories using different next-generation sequencing platforms. It was unclear whether unacceptable responses were due to the performance of specific NGS methods or the laboratory. Molecular testing of EGFR is required to predict the response likelihood to targeted therapy in non-small cell lung cancer.

We performed a pilot external quality assurance EQA scheme to harmonize circulating tumor DNA testing among laboratories. Unacceptable response rate in pilot external quality assurance scheme. LeuArg variants for the lowest target copies.

LR than for p. These test samples had expected mutant allele frequencies of 3. A sensitive method is needed to detect the p.

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