Comparison of Tissue Molecular Biomarker Testing Turnaround Times and Concordance Between Standard of Care and the Biocartis Idylla Platform in Patients With Colorectal Cancer

Liquid biopsy as a tool for KRAS/NRAS/BRAF baseline testing in metastatic colorectal cancer

BACKGROUND

The absence of KRAS and NRAS gene mutations (RAS wild type) in metastatic colorectal cancer (mCRC), is associated with a good response to targeted therapy with anti-EGFR receptor antibodies. The current gold standard for RAS mutational status identification is genetic testing on tissue biopsy samples.

OBJECTIVE

This study aimed to assess the relevance of liquid biopsy as a less invasive alternative to tissue biopsy for detecting KRAS/NRAS and BRAF mutations in patients with metastatic colorectal cancer (mCRC). The study also aimed to determine the concordance between liquid biopsy and tissue biopsy.

METHODS

This is a phase IV, observational, uncontrolled, non-comparative, non-randomized, open label study. RAS/BRAF status will be tested at baseline using tissue and liquid biopsy using the Idylla/Biocartis PCR-based device. The primary endpoint is the comparison of the RAS status based on liquid biopsy with the RAS status based on tissue biopsy.

RESULTS

100 patients with mCRC were included in the study. 75 % of patients showed concordant results between liquid biopsy and tissue biopsy, while 25 % had discordant results. Liquid biopsy demonstrated a sensitivity of 62 % and a specificity of 93 %. The accuracy of liquid biopsy was 75 %, with a moderate agreement between the two tests. The most frequent mutations in concordant cases were in KRAS (41 %), followed by NRAS (4 %) and BRAF (3 %). Mutations were not detected in 42 % of tissue biopsy samples and 60 % of liquid biopsy samples. The presence of hepatic metastases did not significantly affect the concordance between the biopsy methods.

CONCLUSION

Liquid biopsy using the Idylla™ system showed a relatively low sensitivity but high specificity for detecting KRAS/NRAS and BRAF mutations in mCRC patients. Despite some discordant cases, liquid biopsy remains a promising alternative to tissue biopsy due to its non-invasiveness, ability to provide multiple samples, and better representation of tumor heterogeneity.

Comparison and Validation of Rapid Molecular Testing Methods for Theranostic Epidermal Growth Factor Receptor Alterations in Lung Cancer: Idylla versus Digital Droplet PCR

Targeting EGFR alterations, particularly the L858R (Exon 21) mutation and Exon 19 deletion (del19), has significantly improved the survival of lung cancer patients. From now on, the issue is to shorten the time to treatment. Here, we challenge two well-known rapid strategies for EGFR testing: the cartridge-based platform Idylla™ (Biocartis) and a digital droplet PCR (ddPCR) approach (ID_Solution). To thoroughly investigate each testing performance, we selected a highly comprehensive cohort of 39 unique del19 (in comparison, the cbioportal contains 40 unique del19), and 9 samples bearing unique polymorphisms in exon 19. Additional L858R (N = 24), L861Q (N = 1), del19 (N = 63), and WT samples (N = 34) were used to determine clear technical and biological cutoffs. A total of 122 DNA samples extracted from formaldehyde-fixed samples was used as input. No false positive results were reported for either of the technologies, as long as careful droplet selection (ddPCR) was ensured for two polymorphisms. ddPCR demonstrated higher sensitivity in detecting unique del19 (92.3%, 36/39) compared to Idylla (67.7%, 21/31). However, considering the prevalence of del19 and L858R in the lung cancer population, the adjusted theranostic values were similar (96.51% and 95.26%, respectively). ddPCR performs better for small specimens and low tumoral content, but in other situations, Idylla is an alternative (especially if a molecular platform is absent).

Performance of Ultra-Rapid Idylla™ EGFR Mutation Test in Non-Small-Cell Lung Cancer and Its Potential at Clinical Molecular Screening

BACKGROUND

The Idylla™ EGFR Mutation Test is an ultra-rapid single-gene test that detects epidermal growth factor receptor (EGFR) mutations using formalin-fixed paraffin-embedded specimens. Here, we compared the performance of the Idylla EGFR Mutation Test with the Cobas^® EGFR Mutation Test v2.

METHODS

Surgically resected NSCLC specimens obtained at two Japanese institutions (N = 170) were examined. The Idylla EGFR Mutation Test and the Cobas EGFR Mutation Test v2 were performed independently and the results were compared. For discordant cases, the Ion AmpliSeq Colon and Lung Cancer Research Panel V2 was performed.

RESULTS

After the exclusion of five inadequate/invalid samples, 165 cases were evaluated. EGFR mutation analysis revealed 52 were positive and 107 were negative for EGFR mutation in both assays (overall concordance rate: 96.4%). Analyses of the six discordant cases revealed that the Idylla EGFR Mutation Test was correct in four and the Cobas EGFR Mutation Test v2 was correct in two. In a trial calculation, the combination of the Idylla EGFR Mutation Test followed by a multi-gene panel test will reduce molecular screening expenses if applied to a cohort with EGFR mutation frequency >17.9%.

CONCLUSIONS

We demonstrated the accuracy and potential clinical utility of the Idylla EGFR Mutation Test as a molecular screening platform in terms of turnaround time and molecular testing cost if applied to a cohort with a high EGFR mutation incidence (>17.9%).

Comparison between Three Different Techniques for the Detection of EGFR Mutations in Liquid Biopsies of Patients with Advanced Stage Lung Adenocarcinoma

Oncogenic mutations in the EGFR gene are targets of tyrosine kinase inhibitors (TKIs) in lung adenocarcinoma (LC) patients, and their search is mandatory to make decisions on treatment strategies. Liquid biopsy of circulating tumour DNA (ctDNA) is increasingly used to detect EGFR mutations, including main activating alterations (exon 19 deletions and exon 21 L858R mutation) and T790M mutation, which is the most common mechanism of acquired resistance to first- and second-generation TKIs. In this study, we prospectively compared three different techniques for EGFR mutation detection in liquid biopsies of such patients. Fifty-four ctDNA samples from 48 consecutive advanced LC patients treated with TKIs were tested for relevant EGFR mutations with Therascreen® EGFR Plasma RGQ-PCR Kit (Qiagen). Samples were subsequently tested with two different technologies, with the aim to compare the EGFR detection rates: real-time PCR based Idylla™ ctEGFR mutation assay (Biocartis) and next-generation sequencing (NGS) system with Ion AmpliSeq Cancer Hotspot panel (ThermoFisher). A high concordance rate for main druggable EGFR alterations was observed with the two real-time PCR-based assays, ranging from 100% for T790M mutation to 94% for L858R variant and 85% for exon 19 deletions. Conversely, lower concordance rates were found between real-time PCR approaches and the NGS method (L858R: 88%; exon19-dels: 74%; T790M: 37.5%). Our results evidenced an equivalent detection ability between PCR-based techniques for circulating EGFR mutations. The NGS assay allowed detection of a wider range of EGFR mutations but showed a poor ability to detect T790M.

Utility of Select Gene Mutation Detection in Tumors by the Idylla Rapid Multiplex PCR Platform in Comparison to Next-Generation Sequencing

Testing of tumors by next generation sequencing (NGS) is impacted by relatively long turnaround times and a need for highly trained personnel. Recently, Idylla oncology assays were introduced to test for BRAF, EGFR, KRAS, and NRAS common hotspot mutations that do not require specialized trained personnel. Moreover, the interpretation of results is fully automated, with rapid turnaround time. Though Idylla testing and NGS have been shown to have high concordance in identifying EGFR, BRAF, KRAS, and NRAS hotspot mutations, there is limited experience on optimal ways the Idylla system can be used in routine practice. We retrospectively evaluated all cases with EGFR, BRAF, KRAS, or NRAS mutations identified in clinical specimens sequenced on two different NGS panels at the University of Rochester Medical Center (URMC) molecular diagnostics laboratory between July 2020 and July 2021 and assessed if these mutations would be detected by the Idylla cartridges if used. We found that the Idylla system could accurately identify Tier 1 or 2 actionable genomic alterations in select associated disease pathologies if used. Yet, in a minority of cases, we would have been unable to detect NGS-identified pathogenic mutations due to their absence on the Idylla panels. We derived algorithmic practice guidelines for the use of the Idylla cartridges. Overall, Idylla molecular testing could be implemented either as a first-line standalone diagnostic tool in select indications or for orthogonal confirmation of uncertain results.

Mismatch repair deficiency: The what, how and why it is important

The mismatch repair system is a major pathway that functions in the maintenance of genomic integrity. It is involved in mitotic and meiotic recombination, apoptosis, immunoglobulin gene rearrangement, somatic hypermutation, and other processes. Deficiencies in mismatch repair give rise to hypermutability and the phenomenon called microsatellite instability. Detection of deficient mismatch repair function or microsatellite instability is used diagnostically, predictively, and prognostically. Specifically, deficient mismatch repair function is used for screening of Lynch syndrome, determining patients who are likely to respond to immune checkpoint inhibition, and to contributes to an understanding of which cancer patients may pursue a more aggressive clinical course. Microsatellite instability can be evaluated directly by polymerase chain reaction (PCR) or indirectly by assessment of mismatch repair protein expression using immunohistochemistry (IHC), and mismatch repair function using next-generation sequencing assays which evaluates homopolymer indels. In this article, we provide a concise practical review on mismatch repair deficiency (MMR-d)/microsatellite instability (MSI), focusing on clinical testing, different testing methods, interpretation of findings, the predictive, and prognostic utility of MSI.

A graphical, interactive and GPU-enabled workflow to process long-read sequencing data

Background

Long-read sequencing has great promise in enabling portable, rapid molecular-assisted cancer diagnoses. A key challenge in democratizing long-read sequencing technology in the biomedical and clinical community is the lack of graphical bioinformatics software tools which can efficiently process the raw nanopore reads, support graphical output and interactive visualizations for interpretations of results. Another obstacle is that high performance software tools for long-read sequencing data analyses often leverage graphics processing units (GPU), which is challenging and time-consuming to configure, especially on the cloud.

Results

We present a graphical cloud-enabled workflow for fast, interactive analysis of nanopore sequencing data using GPUs. Users customize parameters, monitor execution and visualize results through an accessible graphical interface. The workflow and its components are completely containerized to ensure reproducibility and facilitate installation of the GPU-enabled software. We also provide an Amazon Machine Image (AMI) with all software and drivers pre-installed for GPU computing on the cloud. Most importantly, we demonstrate the potential of applying our software tools to reduce the turnaround time of cancer diagnostics by generating blood cancer (NB4, K562, ME1, 238 MV4;11) cell line Nanopore data using the Flongle adapter. We observe a 29x speedup and a 93x reduction in costs for the rate-limiting basecalling step in the analysis of blood cancer cell line data.

Conclusions

Our interactive and efficient software tools will make analyses of Nanopore data using GPU and cloud computing accessible to biomedical and clinical scientists, thus facilitating the adoption of cost effective, fast, portable and real-time long-read sequencing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07927-1.

Comparison of Biocartis IDYLLA ™ cartridge assay with Qiagen GeneReader NGS for detection of targetable mutations in EGFR, KRAS/NRAS, and BRAF genes

Lung and colorectal cancers (CRC) have two of the highest mortality rates among all cancer types, and their occurrence and the need for personalized diagnostics and subsequent therapy were not influenced by the COVID-19 pandemics. However, due to the disruption of established delivery chains, standard assays for in vitro diagnostics of those cancers were temporarily not available, forcing us to implement alternative testing methods that enabled at least basic therapy decision making. For this reason, we evaluated rapid testing on the Biocartis Idylla™ platform (Biocartis, Mechelen, Belgium) for four important genes commonly mutated in lung and colorectal cancers, namely EGFR, NRAS, KRAS, and BRAF. Clinical specimens from which the mutation status has previously been determined using Next Generation Sequencing (NGS), were retested to determine whether Idylla™ can offer accurate results. To compare the results, the sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) are calculated for each of the mutation types and then combined to determine the values of the Idylla™ system in total, while setting NGS as the gold-standard basis the assays were compared with. Idylla testing thereby displayed acceptable sensitivity and specificity and delivered reliable results for initial therapy decisions.