Opportunities and challenges associated with clinical diagnostic genome sequencing: a report of the Association for Molecular Pathology

Methods to improve the accuracy of next-generation sequencing

Next-generation sequencing (NGS) is present in all fields of life science, which has greatly promoted the development of basic research while being gradually applied in clinical diagnosis. However, the cost and throughput advantages of next-generation sequencing are offset by large tradeoffs with respect to read length and accuracy. Specifically, its high error rate makes it extremely difficult to detect SNPs or low-abundance mutations, limiting its clinical applications, such as pharmacogenomics studies primarily based on SNP and early clinical diagnosis primarily based on low abundance mutations. Currently, Sanger sequencing is still considered to be the gold standard due to its high accuracy, so the results of next-generation sequencing require verification by Sanger sequencing in clinical practice. In order to maintain high quality next-generation sequencing data, a variety of improvements at the levels of template preparation, sequencing strategy and data processing have been developed. This study summarized the general procedures of next-generation sequencing platforms, highlighting the improvements involved in eliminating errors at each step. Furthermore, the challenges and future development of next-generation sequencing in clinical application was discussed.

Analysis of mutational genotyping using correctable decoding sequencing with superior specificity

The ability to accurately identify SNPs or low-abundance mutations is important for early clinical diagnosis of diseases, but the existing high-throughput sequencing platforms are limited in terms of their accuracy. Here, we propose a correctable decoding sequencing strategy that may be used for high-throughput sequencing platforms. This strategy is based on adding a mixture of two types of mononucleotides, natural nucleotide and cyclic reversible termination (CRT), for cyclic sequencing. Using the synthetic characteristic of CRTs, about 75% of the calls are unambiguous for a single sequencing run, and the remaining ambiguous sequence can be accurately deduced by two parallel sequencing runs. We demonstrate the feasibility of this strategy, and its cycle efficiency can reach approximately 99.3%. This strategy is proved to be effective for correcting errors and identifying whether the sequencing information is correct or not. And its conservative theoretical error rate was determined to be 0.0009%, which is lower than that of Sanger sequencing. In addition, we establish that the information of only a single sequencing run can be used to detect samples with known mutation sites. We apply this strategy to accurately identify a mutation site in mitochondrial DNA from human cells.

Advanced Molecular and Immunological Diagnostic Methods to Detect SARS-CoV-2 Infection

COVID-19 emerged in late 2019 in China and quickly spread across the globe, causing over 521 million cases of infection and 6.26 million deaths to date. After 2 years, numerous advances have been made. First of all, the preventive vaccine, which has been implemented in record time, is effective in more than 95% of cases. Additionally, in the diagnostic field, there are numerous molecular and antigenic diagnostic kits that are equipped with high sensitivity and specificity. Real Time-PCR-based assays for the detection of viral RNA are currently considered the gold-standard method for SARS-CoV-2 diagnosis and can be used efficiently on pooled nasopharyngeal, or oropharyngeal samples for widespread screening. Moreover, additional, and more advanced molecular methods such as droplet-digital PCR (ddPCR), clustered regularly interspaced short palindromic repeats (CRISPR) and next-generation sequencing (NGS), are currently under development to detect the SARS-CoV-2 RNA. However, as the number of subjects infected with SARS-CoV-2 continuously increases globally, health care systems are being placed under increased stress. Thus, the clinical laboratory plays an important role, helping to select especially asymptomatic individuals who are actively carrying the live replicating virus, with fast and non-invasive molecular technologies. Recent diagnostic strategies, other than molecular methods, have been adopted to either detect viral antigens, i.e., antigen-based immunoassays, or human anti-SARS-CoV-2 antibodies, i.e., antibody-based immunoassays, in nasal or oropharyngeal swabs, as well as in blood or saliva samples. However, the role of mucosal sIgAs, which are essential in the control of viruses entering the body through mucosal surfaces, remains to be elucidated, and in particular the role of the immune response in counteracting SARS-CoV-2 infection, primarily at the site(s) of virus entry that appears to be promising.

Identification of Molecular Alterations Challenging Initial Pathologic Classification in Cases of Clinician-Initiated Next-Generation Sequencing Testing

OBJECTIVES

Large gene panel next-generation sequencing (NGS) is a powerful tool capable of generating predictive data on cancer prognosis and response to specific therapeutic interventions. The utility of large panel NGS data on tumor classification, however, may be underappreciated because of a workflow that often circumvents the surgical pathologist. We sought to describe cases in which NGS data lead to an unanticipated change in tumor classification and to discuss current workflow practices of NGS testing that limit its use as a diagnostic adjunct.

METHODS

We performed a retrospective review to identify cases in which NGS testing uncovered data that led to a revision of the initial pathologic diagnosis that an outside or in-house pathologist had made.

RESULTS

Nine cases are presented in which NGS data provided insights that led to a revision of the original pathologic diagnosis. Distinctive molecular signatures, mutational signatures, fusions, or identification of viral sequencing provided the critical evidence on which these tumors were reclassified.

CONCLUSIONS

The current workflow of NGS testing should always include the surgical pathologist as an active partner to ensure that the molecular results are fully reflected in the final diagnosis. In some instances, active participation by the surgical pathologist may require amendment of previously issued pathology reports.

Diagnostic yield and treatment impact of whole-genome sequencing in paediatric neurological disorders

AIM

To investigate the diagnostic yield and treatment impact of whole-genome sequencing (WGS) in patients with paediatric neurological disorders.

METHOD

From January 2016 to December 2019, paediatric patients who had suspected genetic neurological disorders were assessed using WGS. The phenotypes of eligible patients were divided into four groups: patients with neurodevelopmental disorders; patients with epilepsy; patients with neuromuscular disorders; and patients with movement disorders.

RESULTS

A total of 214 consecutive patients (128 males, 86 females) underwent WGS. The mean (SD) age of disease onset was 13.8 (27.6) months (range 1d-15y 5mo). The mean (SD) age at which WGS was performed was 71.7 (58.9) months (range 8d-18y). A molecular diagnosis was reported in 43.9% of patients. The highest diagnostic rate was achieved in 62.5% of patients with neuromuscular disorders, 47.5% of patients with epilepsy, 41.1% of patients with neurodevelopment disorders, and 15.4% of patients with movement disorders. All 94 patients with a WGS diagnosis were given access to genetic counselling and 23.4% of patients had immediate changes in treatment strategies after undergoing WGS.

INTERPRETATION

WGS allows paediatric neurologists to integrate genomic data into their diagnosis and adjust management strategies for a range of clinical and genetically heterogeneous disease entities to improve the clinical outcomes of patients. In our cohort, the diagnosis of a significant proportion of patients was reached through WGS (43.9%). Clinicians could use these results to directly guide the management of their patients and improve their clinical outcomes (23.4%). What this paper adds For selected children in our cohort, the diagnostic yield of whole-genome sequencing (WGS) was 43.9%. WGS can be used to expand our knowledge of phenotype-genotype variations.

A Curriculum for Genomic Education of Molecular Genetic Pathology Fellows: A Report of the Association for Molecular Pathology Training and Education Committee

Molecular genetic pathology (MGP) is a subspecialty of pathology and medical genetics and genomics. Genomic testing, which we define as that which generates large data sets and interrogates large segments of the genome in a single assay, is increasingly recognized as essential for optimal patient care through precision medicine. The most common genomic testing technologies in clinical laboratories are next-generation sequencing and microarray. It is essential to train in these methods and to consider the data generated in the context of the diagnosis, medical history, and other clinical findings of individual patients. Accordingly, updating the MGP fellowship curriculum to include genomics is timely, important, and challenging. At the completion of training, an MGP fellow should be capable of independently interpreting and signing out results of a wide range of genomic assays and, given the appropriate context and institutional support, of developing and validating new assays in compliance with applicable regulations. The Genomics Task Force of the MGP Program Directors, a working group of the Association for Molecular Pathology Training and Education Committee, has developed a genomics curriculum framework and recommendations specific to the MGP fellowship. These recommendations are presented for consideration and implementation by MGP fellowship programs with the understanding that MGP programs exist in a diversity of clinical practice environments with a spectrum of available resources.

The Application of Control Materials for Ongoing Quality Management of Next-Generation Sequencing in a Clinical Genetic Laboratory

Next-generation sequencing (NGS) has played an important role in detecting genetic variants with pathologic and therapeutic potential. The advantages of NGS, such as high-throughput sequencing capacity and massively parallel sequencing, have a significant impact on realization of genetic profiling in clinical genetic laboratories. These changes have enabled clinicians to execute precision medicine in diagnosis, prognosis, and treatment for patients. However, to adapt targeted gene panels in diagnostic use, analytical validation and ongoing quality control should be implemented and applied with both practical guidelines and appropriate control materials. Several guidelines for NGS quality control recommend usage of control materials such as HapMap cell lines, synthetic DNA fragments, and genetically characterized cell lines; however, specifications or applications of such usage are insufficient to guideline method development. This review focuses on what factors should be considered before control material selection for NGS assay and practical methods of how they could be developed in clinical genetic laboratories. This review also provides the detailed sources of critical information related to control materials.

Implementing Pharmacogenomics Testing: Single Center Experience at Arkansas Children's Hospital

Pharmacogenomics (PGx) is a growing field within precision medicine. Testing can help predict adverse events and sub-therapeutic response risks of certain medications. To date, the US FDA lists over 280 drugs which provide biomarker-based dosing guidance for adults and children. At Arkansas Children’s Hospital (ACH), a clinical PGx laboratory-based test was developed and implemented to provide guidance on 66 pediatric medications for genotype-guided dosing. This PGx test consists of 174 single nucleotide polymorphisms (SNPs) targeting 23 clinically actionable PGx genes or gene variants. Individual genotypes are processed to provide per-gene discrete results in star-allele and phenotype format. These results are then integrated into EPIC- EHR. Genomic indicators built into EPIC-EHR provide the source for clinical decision support (CDS) for clinicians, providing genotype-guided dosing.

The International Collaboration for Cancer Classification and Research

Gaps in the translation of research findings to clinical management have been recognized for decades. They exist for the diagnosis as well as the management of cancer. The international standards for cancer diagnosis are contained within the World Health Organization (WHO) Classification of Tumours, published by the International Agency for Research on Cancer (IARC) and known worldwide as the WHO Blue Books. In addition to their relevance to individual patients, these volumes provide a valuable contribution to cancer research and surveillance, fulfilling an important role in scientific evidence synthesis and international standard setting. However, the multidimensional nature of cancer classification, the way in which the WHO Classification of Tumours is constructed, and the scientific information overload in the field pose important challenges for the translation of research findings to tumour classification and hence cancer diagnosis. To help address these challenges, we have established the International Collaboration for Cancer Classification and Research (IC3 R) to provide a forum for the coordination of efforts in evidence generation, standard setting and best practice recommendations in the field of tumour classification. The first IC3 R meeting, held in Lyon, France, in February 2019, gathered representatives of major institutions involved in tumour classification and related fields to identify and discuss translational challenges in data comparability, standard setting, quality management, evidence evaluation and copyright, as well as to develop a collaborative plan for addressing these challenges.

Patients with coronary heart disease, dilated cardiomyopathy and idiopathic ventricular tachycardia share overlapping patterns of pathogenic variation in cardiac risk genes

Background

Ventricular tachycardia (VT) is a major cause of sudden cardiac death (SCD). Clinical investigations can sometimes fail to identify the underlying cause of VT and the event is classified as idiopathic (iVT). VT contributes significantly to the morbidity and mortality in patients with coronary artery disease (CAD) and dilated cardiomyopathy (DCM). Since mutations in arrhythmia-associated genes frequently determine arrhythmia susceptibility screening for disease-predisposing variants could improve VT diagnostics and prevent SCD in patients.

Methods

Ninety-two patients diagnosed with coronary heart disease (CHD), DCM, or iVT were included in our study. We evaluated genetic profiles and variants in known cardiac risk genes by targeted next generation sequencing (NGS) using a newly designed custom panel of 96 genes. We hypothesized that shared morphological and phenotypical features among these subgroups may have an overlapping molecular base. To our knowledge, this was the first study of the deep sequencing of 96 targeted cardiac genes in Kazakhstan. The clinical significance of the sequence variants was interpreted according to the guidelines developed by the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) in 2015. The ClinVar and Varsome databases were used to determine the variant classifications.

Results

Targeted sequencing and stepwise filtering of the annotated variants identified a total of 307 unique variants in 74 genes, totally 456 variants in the overall study group. We found 168 mutations listed in the Human Genome Mutation Database (HGMD) and another 256 rare/unique variants with elevated pathogenic potential. There was a predominance of high- to intermediate pathogenicity variants in LAMA2, MYBPC3, MYH6, KCNQ1, GAA, and DSG2 in CHD VT patients. Similar frequencies were observed in DCM VT, and iVT patients, pointing to a common molecular disease association. TTN, GAA, LAMA2, and MYBPC3 contained the most variants in the three subgroups which confirm the impact of these genes in the complex pathogenesis of cardiomyopathies and VT. The classification of 307 variants according to ACMG guidelines showed that nine (2.9%) variants could be classified as pathogenic, nine (2.9%) were likely pathogenic, 98 (31.9%) were of uncertain significance, 73 (23.8%) were likely benign, and 118 (38.4%) were benign. CHD VT patients carry rare genetic variants with increased pathogenic potential at a comparable frequency to DCM VT and iVT patients in genes related to sarcomere function, nuclear function, ion flux, and metabolism.

Conclusions

In this study we showed that in patients with VT secondary to coronary artery disease, DCM, or idiopathic etiology multiple rare mutations and clinically significant sequence variants in classic cardiac risk genes associated with cardiac channelopathies and cardiomyopathies were found in a similar pattern and at a comparable frequency.

全基因體定序對兒童神經疾病的診斷率和治療影響

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"…This Has to Do With My Identity. And I Don't Want to Make it Totally Transparent." Identity Relevance in the Attitudes of Affected People and Laypersons to the Handling of High-Throughput Genomic Data

With the establishment of genome sequencing, the influence of genomic information on self-understanding and identity construction has become increasingly important. New sequencing methods far exceed previous genetic tests in terms of scope and quantity. Despite theoretical approaches, however, there are few empirical findings on the identity-relevant influence of genomic information. The present study examines genomic information's identity-relevant influences and considers whether developments in the field of genome sequencing may generate problems that are not yet addressed by existing identity concepts based on traditional genetic tests. The study is based on 10 partially standardized interviews with personally affected persons and four focus groups with medical laypersons as representatives of the public, which were evaluated on the basis of qualitative content analysis. As a result, this paper presents five thematic areas with identity-relevant references within subjective attitudes toward the handling of genomic information, and also derives two basic identity concepts. The results indicate that the lay discourse is still strongly based on older debates about genetic testing and that the view on the complexity of genomic information established in the scientific context has thus far no influence on the perspectives either of those affected or laypersons.

Comprehensive genomic diagnosis of inherited retinal and optical nerve disorders reveals hidden syndromes and personalized therapeutic options

PURPOSE

In the era of precision medicine, genomic characterization of blind patients is critical. Here, we evaluate the effects of comprehensive genetic analysis on the etiologic diagnosis of potentially hereditary vision loss and its impact on clinical management.

METHODS

We studied 100 non-syndromic and syndromic Spanish patients with a clinical diagnosis of blindness caused by alterations on the retina, choroid, vitreous and/or optic nerve. We used a next-generation sequencing (NGS) panel (OFTALMOgenics™), developed and validated within this study, including up to 362 genes previously associated with these conditions.

RESULTS

We identified the genetic cause of blindness in 45% of patients (45/100). A total of 28.9% of genetically diagnosed cases (13/45) were syndromic and, of those, in 30.8% (4/13) extraophthalmic features had been overlooked and/or not related to visual impairment before genetic testing, including cases with Mainzer-Saldino, Bardet-Biedl, mucolipidosis and MLCRD syndromes. In two additional cases-syndromic blindness had been proposed before, but not specifically diagnosed, and one patient with Heimler syndrome had been misdiagnosed as an Usher case before testing. 33.3% of the genetically diagnosed patients (15/45) had causative variants in genes targeted by clinical trials exploring the curative potential of gene therapy approaches.

CONCLUSION

Comprehensive genomic testing provided clinically relevant insights in a large proportion of blind patients, identifying potential therapeutic opportunities or previously undiagnosed syndromes in 42.2% of the genetically diagnosed cases (19/45).

Pitfalls in variant annotation for hereditary cancer diagnostics: The example of Illumina® VariantStudio®

Next Generation Sequencing (NGS), and specifically targeted panel sequencing is the state-of-the-art in clinical genetic diagnosis of Mendelian diseases. However, the bioinformatics analysis and interpretation of the generated data can be challenging. A spotlight on the default transcript selection of a user-friendly, commercially available software that is widely used by genetics professionals, i.e. Illumina® VariantStudio®, is presented. For the sake of comparison, we employed Ensembl VEP, an open-source command-line tool, as it provides flexibility regarding transcript selection. The analysis of NGS data deriving from sequencing of 857 germline DNA samples of cancer patients indicated a concordance of 82.82% between the two software programs. Significantly, using the default transcript configuration of VariantStudio®, we failed to annotate correctly 11.45% of the identified loss-of-function variants. Our results underline the importance of cautious software and transcript selection and the need for reliable, white-box data analysis, along with bioinformatics expertise in clinical diagnostics.

An ethical framework for genetic counseling in the genomic era

The field of genetic counseling has grown and diversified since the profession emerged in the early 1970s. In the same period, genomic testing has become more complex, profitable, and widespread. With these developments, the scope of ethical considerations relevant to genetic counseling has expanded. In light of this, we find it helpful to revisit how ethical and relational variables are used to inform genetic counseling practice. Our specific focus is on whether, and to what extent, it is ethically acceptable for genetic counselors to make normative recommendations to patients. This article builds on prior literature that has critiqued nondirectiveness, a concept that has influenced and constrained the modern profession of genetic counseling since its origin. In it, we review scholarly efforts to move beyond nondirectiveness, which we believe privilege patient autonomy at the expense of other important values. We then argue that genetic counselors should favor a more explicit commitment to the principles of beneficence and non-maleficence, as well as a broader understanding of autonomy and the relational variables that impact genetic counseling. Finally, to translate our arguments into practice, we present a framework of six considerations that genetic counselors should take into account when deciding whether it is ethically acceptable, or even desirable, to make recommendations to patients in certain areas of their work.

Patient reactions to receiving negative genomic screening results by mail

PURPOSE

As genomic screening is incorporated into a wider array of clinical settings, it is critical that we understand how patients may respond to a various screening results. Although multiple studies have examined how patients understand positive genomic screening results, few data exist regarding patient engagement with negative screening results.

METHODS

An 82-item survey was administered to 1712 individuals who received negative genomic screening results by mail following evaluation of 109 medically actionable genes. Genetic counselors were available to assist with the interpretation of screening results.

RESULTS

One thousand four hundred forty-two participants completed the survey (84.2%). The vast majority of respondents valued the information they received, with 98% of respondents reporting that negative genomic screening results were valuable and 72% indicating they would recommend genomic screening to others. Nonetheless, many respondents had questions about their genomic screening results (28%) and would have preferred to receive their screening results in person (18%).

CONCLUSION

These data suggest most patients value receiving negative genomic screening results and are comfortable receiving their results by mail. Nevertheless, a significant proportion of patients also reported difficulty understanding some aspects of their results. This finding challenges the idea that communicating genomic screening results by mail alone is sufficient to meet patients' needs.

Neutral, Negative, or Negligible? Changes in Patient Perceptions of Disease Risk Following Receipt of a Negative Genomic Screening Result

Most individuals who undergo genomic screening will receive negative results or results not sufficient to warrant a clinical response. Even though a majority of individuals receive negative results, little is known about how negative results may impact individuals' perception of disease risk. Changes in risk perception (specifically reductions in perceived risk) may affect both probands and their family members if inaccurate information is communicated to family members. We surveyed patients who received negative results as part of their participation in a genomic screening study and assessed their perceptions of disease risk following receipt of results. Participants had either hyperlipidemia or colon polyps (or both) and received their negative genomic screening results by mail. Of 1712 total individuals recruited, 1442 completed the survey (84.2% completion rate). Approximately one quarter of individuals believed their risk for heart disease to be lower and approximately one third of individuals believed their risk for colon cancer to be lower after receiving and evaluating their negative genomic screening result. 78% of those who believed their risk for one or both diseases had declined had already shared or intended to share their result with family members. Our study suggests patients may interpret a negative genomic screening result as implying a reduction in their overall disease risk.

How Can Law and Policy Advance Quality in Genomic Analysis and Interpretation for Clinical Care?

Delivering high quality genomics-informed care to patients requires accurate test results whose clinical implications are understood. While other actors, including state agencies, professional organizations, and clinicians, are involved, this article focuses on the extent to which the federal agencies that play the most prominent roles - the Centers for Medicare and Medicaid Services enforcing CLIA and the FDA - effectively ensure that these elements are met and concludes by suggesting possible ways to improve their oversight of genomic testing.

Clinical application of genomic high-throughput data: Infrastructural, ethical, legal and psychosocial aspects

Genomic high-throughput technologies (GHTT) such as next-generation sequencing represent a fast and cost-effective tool toward a more comprehensive understanding of the molecular background of complex diseases. However, technological advances contrast with insufficient application in clinical practice. Thus, patients, physicians, and other professionals are faced with tough challenges that forestall the efficient and effective implementation. With the increasing application of genetic testing, it is of paramount importance that physicians and other professionals in healthcare recognize the restrictions and potential of GHTT, in order to understand and interpret the complex data in the context of health and disease. At the same time, the growing volume and complexity of data is forever increasing the need for sustainable infrastructure and state-of-the-art tools for efficient data management, including their analysis and integration. The large pool of sensitive information remains difficult to interpret and fundamental questions spanning from billing to legal, social, and ethical issues have still not been resolved. Here we summarize and discuss these obstacles in an interdisciplinary context and suggest ways to overcome them. Continuous discussion with clinicians, data managers, biostatisticians, systems medicine experts, ethicists, legal scholars, and patients illuminates the strengths, weakness, and current practices in the pipeline from biomaterial to sequencing and data management. This discussion also highlights the new, cross-disciplinary working collaborations to realize the wide-ranging challenges in clinical genomics including the exceptional demands placed on the staff preparing and presenting the data, as well as the question as to how to report the data and results to patients.

Molecular profiling of gynecologic cancers for treatment and management of disease - demonstrating clinical significance using the AMP/ASCO/CAP guidelines for interpretation and reporting of somatic variants

Molecular features of gynecologic cancers have been investigated in comprehensive studies, but correlation of these molecular signatures with clinical significance for precision medicine is yet to be established. Towards this end, we evaluated 95 gynecologic cancer cases submitted for testing using The JAX ActionSeq™ NGS panel. Molecular profiles were studied and compared to TCGA datasets to identify similarities and distinguishing features among subtypes. We identified 146 unique clinically significant variants (Tier I and II) across 45 of the 212 genes (21%), in 87% (83/95) of cases. TP53, PTEN, ARID1A, PIK3CA and ATM were the most commonly mutated genes; CCNE1 and ERBB2 amplifications were the most frequently detected copy-number alterations. PARP inhibitors were among the most commonly reported drug class with clinical trials, consistent with the frequency of DNA damage-response pathway mutations in our cohort. Overall, our study provides additional insight into the molecular profiles of gynecologic cancers, highlighting regulatory pathways involved, raising the potential implications for targeted therapeutic options currently available.

Considerations for whole exome sequencing unique to prenatal care

Whole exome sequencing (WES) is increasingly being used in the prenatal setting. The emerging data support the clinical utility of prenatal WES based on its diagnostic yield, which can be as high as 80% for certain ultrasound findings. However, detailed practice and laboratory guidelines, addressing the indications for prenatal WES and the surrounding technical, interpretation, ethical, and counseling issues, are still lacking. Herein, we review the literature and summarize the most recent findings and applications of prenatal WES. This review offers specialists and clinical genetic laboratorians a body of evidence and expert opinions that can serve as a resource to assist in their practice. Finally, we highlight the emerging technologies that promise a future of prenatal WES without the risks associated with invasive testing.

The Journal of Molecular Diagnostics: 20 Years Defining Professional Practice

This editorial highlights 20 years of JMD defining professional practice.

The current state of molecular testing in the treatment of patients with solid tumors, 2019

The world of molecular profiling has undergone revolutionary changes over the last few years as knowledge, technology, and even standard clinical practice have evolved. Broad molecular profiling is now nearly essential for all patients with metastatic solid tumors. New agents have been approved based on molecular testing instead of tumor site of origin. Molecular profiling methodologies have likewise changed such that tests that were performed on patients a few years ago are no longer complete and possibly inaccurate today. As with all rapid change, medical providers can quickly fall behind or struggle to find up-to-date sources to ensure he or she provides optimum care. In this review, the authors provide the current state of the art for molecular profiling/precision medicine, practice standards, and a view into the future ahead.

Exploring DNA quantity and quality from raw materials to botanical extracts

OBJECTIVES

The aim of this study was to explore the variability in DNA quality and quantity along a gradient of industrial processing of botanical ingredients from raw materials to extracts.

METHODS

A data matrix was assembled for 1242 botanical ingredient samples along a gradient of industrial processing commonly used in the Natural Health Product (NHP) industry. Multivariate statistics was used to explore dependant variables for quality and quantity. The success of attaining a positive DNA test result along a gradient of industrial processing was compared among four biotechnologies: DNA barcoding, NGS, Sanger sequencing and qPCR.

RESULTS

There was considerable variance in DNA quality and quantity among the samples, which could be interpreted along a gradient from raw materials with greater quantities (50-120 ng/μL) of DNA and longer DNA (400-500bp) sequences to extracts, which were characterized by lower quantities (0.1-10.0 ng/μL) and short fragments (50-150bp).

CONCLUSIONS

Targeted molecular diagnostic tests for species identity can be used in the NHP industry for raw and processed samples. Non-targeted tests or the use of NGS for any identity test needs considerable research and development and must be validated before it can be used in commercial operations as these methods are subject to considerable risk of false negative and positive results. Proper use of these tools can be used to ensure ingredient authenticity, and to avert adulteration, and contamination with plants that are a health concern. Lastly these tools can be used to prevent the exploitation of rare herbal species and the harvesting of native biodiversity for commercial purposes.

Development of Reference Materials for Noninvasive Prenatal Aneuploidy Testing by Massively Parallel Sequencing: A Proof-of-Concept Study

BACKGROUND

Noninvasive prenatal aneuploidy testing (NIPT) represents the first large-scale clinical application of massively parallel sequencing technology. However, no NIPT reference material (RM) has yet been widely adopted, impeding the development of quality management systems and standardization. Developing an NIPT RM from a biological sample is complicated by the low concentration of cell-free DNA (cfDNA), which implies pooling specimens and frequent resampling.

METHODS

We tested the feasibility of using DNA from immortalized cell lines of a woman and her aneuploid offspring to spike an artificial plasma matrix. Enzymatic fragmentation of extracted DNA was optimized to achieve fragment size profiles with a mode of 150 to 200 bp, similar to biological cfDNA. This synthetic material was compared with routine biological samples from pregnant women by a targeted NIPT assay in a multiplex sequencing run on a Proton platform.

RESULTS

Sequencing statistics were similar between artificially prepared material and routine biological samples, as well as relative chromosomal representation, and no matrix effects could be detected. Estimate of fetal fraction (FF) was within the range of expected value, and aneuploidy detection statistic (z-score) was also comparable between both types of samples.

CONCLUSIONS

Artificial plasma spiked with DNA from cell lines of mother and offspring is a promising strategy for developing NIPT RM. This type of material would offer the advantage of a constant and stable composition, allowing for greater standardization of NIPT assays. Moreover, it preserves the parental relatedness used by targeted assay to estimate FF by identification of paternal alleles in single-nucleotide polymorphisms or other variable regions.

A Review of the Genomic Analysis of Children Presenting with Developmental Delay/Intellectual Disability and Associated Dysmorphic Features

This review describes the clinical criteria of developmental delay (DD)/intellectual disability (ID) as well as the various techniques that are currently implemented to diagnose neurodevelopmental disorders that typically present with associated dysmorphic features such as Angelman syndrome, Prader-Willi syndrome, and DiGeorge syndrome. These analyses include various forms of chromosomal microarray (CMA), which have proven to be superior to previously implemented techniques such as G-banded karyotyping and fluorescent in situ hybridization (FISH) analysis, as well as whole exome sequencing (WES), which is implemented as a secondary examination when CMA analysis is unrevealing. The clinical significance of identified variants and how it relates to facilitating the management of specific genetic disorders such as the above mentioned is also discussed. In addition, the importance of genomic databases and bioinformatics technologies as they relate to variant classification is also considered. Essentially, the discovery of pathogenic variants allows for enhanced management of a patient’s clinical phenotype, whereas the identification of variants of uncertain significance (VUS) has proven to have an increase in the number of associated conflicts as they typically generate more ambiguity in regard to the clinical manifestations present within the child. As a result, additional procedures need to be implemented to mitigate the issues that surround their identification. The concluding remarks are in regard to both the ethical and legal considerations of genetic testing as they relate to informed consent, testing of minors, how to handle secondary findings, as well as the anticipated future direction of genomic analysis.

Designing and Implementing NGS Tests for Inherited Disorders: A Practical Framework with Step-by-Step Guidance for Clinical Laboratories

Comprehensive next-generation sequencing (NGS) tests are increasingly used as first-line tests in the evaluation of patients with suspected heritable disease. Despite major technical simplifications, these assays still pose significant challenges for molecular testing laboratories. Existing professional guidelines and recommendations provide a framework for laboratories implementing such tests, but in-depth, concrete guidance is generally not provided. Consequently, there is variability in how laboratories interpret and subsequently implement these regulatory frameworks. To address the need for more detailed guidance, the College of American Pathologists with representation from the Association for Molecular Pathologists assembled a working group to create a practical resource for clinical laboratories. This initial work is focused on variant detection in the setting of inherited disease and provides structured worksheets that guide the user through the entire life cycle of an NGS test, including design, optimization, validation, and quality management with additional guidance for clinical bioinformatics. This resource is designed to be a living document that is publicly available and will be updated with user and expert feedback as the wet bench and bioinformatic landscapes continue to evolve. It is intended to facilitate the standardization of NGS testing across laboratories and therefore to improve patient care.

From the Past to the Present: Insurer Coverage Frameworks for Next-Generation Tumor Sequencing

Next-generation sequencing promises major advancements in precision medicine but faces considerable challenges with insurance coverage. These challenges are especially important to address in oncology in which next-generation tumor sequencing (NGTS) holds a particular promise, guiding the use of life-saving or life-prolonging therapies. Payers' coverage decision making on NGTS is challenging because this revolutionary technology pushes the very boundaries of the underlying framework used in coverage decisions. Some experts have called for the adaptation of the coverage framework to make it better equipped for assessing NGTS. Medicare's recent decision to cover NGTS makes this topic particularly urgent to examine. In this article, we discussed the previously proposed approaches for adaptation of the NGTS coverage framework, highlighted their innovations, and outlined remaining gaps in their ability to assess the features of NGTS. We then compared the three approaches with Medicare's national coverage determination for NGTS and discussed its implications for US private payers as well as for other technologies and clinical areas. We focused on US payers because analyses of coverage approaches and policies in the large and complex US health care system may inform similar efforts in other countries. We concluded that further adaptation of the coverage framework will facilitate a better suited assessment of NGTS and future genomics innovations.

Biomonitoring for traditional herbal medicinal products using DNA metabarcoding and single molecule, real-time sequencing

Global concerns have been paid to the potential hazard of traditional herbal medicinal products (THMPs). Substandard and counterfeit THMPs, including traditional Chinese patent medicine, health foods, dietary supplements, etc. are potential threats to public health. Recent marketplace studies using DNA barcoding have determined that the current quality control methods are not sufficient for ensuring the presence of authentic herbal ingredients and detection of contaminants/adulterants. An efficient biomonitoring method for THMPs is of great needed. Herein, metabarcoding and single-molecule, real-time (SMRT) sequencing were used to detect the multiple ingredients in Jiuwei Qianghuo Wan (JWQHW), a classical herbal prescription widely used in China for the last 800 years. Reference experimental mixtures and commercial JWQHW products from the marketplace were used to confirm the method. Successful SMRT sequencing results recovered 5416 and 4342 circular-consensus sequencing (CCS) reads belonging to the ITS2 and psbA-trnH regions. The results suggest that with the combination of metabarcoding and SMRT sequencing, it is repeatable, reliable, and sensitive enough to detect species in the THMPs, and the error in SMRT sequencing did not affect the ability to identify multiple prescribed species and several adulterants/contaminants. It has the potential for becoming a valuable tool for the biomonitoring of multi-ingredient THMPs.

Use of the Ion PGM and the GeneReader NGS Systems in Daily Routine Practice for Advanced Lung Adenocarcinoma Patients: A Practical Point of View Reporting a Comparative Study and Assessment of 90 Patients

Background: With the integration of various targeted therapies into the clinical management of patients with advanced lung adenocarcinoma, next-generation sequencing (NGS) has become the technology of choice and has led to an increase in simultaneously interrogated genes. However, the broader adoption of NGS for routine clinical practice is still hampered by sophisticated workflows, complex bioinformatics analysis and medical interpretation. Therefore, the performance of the novel QIAGEN GeneReader NGS system was compared to an in-house ISO-15189 certified Ion PGM NGS platform. Methods: Clinical samples from 90 patients (60 Retrospectively and 30 Prospectively) with lung adenocarcinoma were sequenced with both systems. Mutations were analyzed and EGFR, KRAS, BRAF, NRAS, ALK, PIK3CA and ERBB2 genes were compared and sampling time and suitability for clinical testing were assessed. Results: Both sequencing systems showed perfect concordance for the overlapping genes. Correlation of allele frequency was r² = 0.93 for the retrospective patients and r² = 0.81 for the prospective patients. Hands-on time and total run time were shorter using the PGM system, while the GeneReader platform provided good traceability and up-to-date interpretation of the results. Conclusion: We demonstrated the suitability of the GeneReader NGS system in routine practice in a clinical pathology laboratory setting.

The reliable assurance of detecting somatic mutations in cancer-related genes by next-generation sequencing: the results of external quality assessment in China

To evaluate the proficiencies of laboratories utilizing next-generation sequencing (NGS) to detect somatic mutations in cancer-related genes, an external quality assessment (EQA) was implemented by the National Center for Clinical Laboratories of China in 2015. We prepared a panel of samples that comprised eight samples made by mixing synthetic mutated DNA fragments with normal human genomic DNA and one reference sample containing only genomic DNA. We validated our sample panel, and then distributed it to laboratories across China. We received complete results from 64 laboratories. The performances of 51.6 % (33/64) respondent labs were acceptable and 26.6 % (17/64) of the labs returned perfect results. In total, 449 mistakes were reported, including 201 false-negatives (201/449, 44.8 %) and 222 false-positives (222/449, 49.4 %) and 26 slightly discordant results (26/449, 5.8 %). We believe these unsatisfactory results and varied performances are mainly due to the enrichment methods used, the diverse sequencing chemistries of the different NGS platforms, and other errors within the sequencing process. The results indicate that our sample panel is suitable for use in EQA studies, and that further laboratory training in targeted NGS testing is urgently required. To address this, we propose a targeted NGS workflow with details on quality assurance procedures according to the current guidelines.

Assessment of Capture and Amplicon-Based Approaches for the Development of a Targeted Next-Generation Sequencing Pipeline to Personalize Lymphoma Management

Targeted next-generation sequencing panels are increasingly used to assess the value of gene mutations for clinical diagnostic purposes. For assay development, amplicon-based methods have been preferentially used on the basis of short preparation time and small DNA input amounts. However, capture sequencing has emerged as an alternative approach because of high testing accuracy. We compared capture hybridization and amplicon sequencing approaches using fresh-frozen and formalin-fixed, paraffin-embedded tumor samples from eight lymphoma patients. Next, we developed a targeted sequencing pipeline using a 32-gene panel for accurate detection of actionable mutations in formalin-fixed, paraffin-embedded tumor samples of the most common lymphocytic malignancies: chronic lymphocytic leukemia, diffuse large B-cell lymphoma, and follicular lymphoma. We show that hybrid capture is superior to amplicon sequencing by providing deep more uniform coverage and yielding higher sensitivity for variant calling. Sanger sequencing of 588 variants identified specificity limits of thresholds for mutation calling, and orthogonal validation on 66 cases indicated 93% concordance with whole-genome sequencing. The developed pipeline and assay identified at least one actionable mutation in 91% of tumors from 219 lymphoma patients and revealed subtype-specific mutation patterns and frequencies consistent with the literature. This pipeline is an accurate and sensitive method for identifying actionable gene mutations in routinely acquired biopsy materials, suggesting further assessment of capture-based assays in the context of personalized lymphoma management.

Highly accurate fluorogenic DNA sequencing with information theory-based error correction

Eliminating errors in next-generation DNA sequencing has proved challenging. Here we present error-correction code (ECC) sequencing, a method to greatly improve sequencing accuracy by combining fluorogenic sequencing-by-synthesis (SBS) with an information theory-based error-correction algorithm. ECC embeds redundancy in sequencing reads by creating three orthogonal degenerate sequences, generated by alternate dual-base reactions. This is similar to encoding and decoding strategies that have proved effective in detecting and correcting errors in information communication and storage. We show that, when combined with a fluorogenic SBS chemistry with raw accuracy of 98.1%, ECC sequencing provides single-end, error-free sequences up to 200 bp. ECC approaches should enable accurate identification of extremely rare genomic variations in various applications in biology and medicine.

The emerging roles of NGS-based liquid biopsy in non-small cell lung cancer

The treatment paradigm of non-small cell lung cancer (NSCLC) has evolved into oncogene-directed precision medicine. Identifying actionable genomic alterations is the initial step towards precision medicine. An important scientific progress in molecular profiling of NSCLC over the past decade is the shift from the traditional piecemeal fashion to massively parallel sequencing with the use of next-generation sequencing (NGS). Another technical advance is the development of liquid biopsy with great potential in providing a dynamic and comprehensive genomic profiling of NSCLC in a minimally invasive manner. The integration of NGS with liquid biopsy has been demonstrated to play emerging roles in genomic profiling of NSCLC by increasing evidences. This review summarized the potential applications of NGS-based liquid biopsy in the diagnosis and treatment of NSCLC including identifying actionable genomic alterations, tracking spatiotemporal tumor evolution, dynamically monitoring response and resistance to targeted therapies, and diagnostic value in early-stage NSCLC, and discussed emerging challenges to overcome in order to facilitate clinical translation in future.

Clinical mutation assay of tumors: new developments

Mutation detection in tumors started with classical cytogenetics as the method of choice more than 50 years ago. Karyotyping proved to be sensitive enough to detect deletions or duplications of large chromosome segments, and translocations. Over time, new techniques were developed to detect mutations that are much smaller in scope. The availability of Sanger sequencing and the invention of the PCR improved the discriminatory power of mutation detection to just one base change in the genomic DNA sequence. Techniques derived from PCR (allele-specific PCR, qPCR) and improved or modified sequencing methods (capillary electrophoresis, pyrosequencing) considerably increased the efficiency and sample throughput of mutation detection assays. With the advent of massive parallel sequencing [also called next-generation sequencing (NGS)] in the past decade, a major shift to even higher sample throughput and a significant decrease in cost per sequenced base occurred. The application of the new technology provided a whole slew of novel biomarkers and potential therapy targets to improve diagnosis and treatment. It even led to changes in cancer classification as new information on the mutation profile of tumors became available that characterizes some disease entities better than morphology. NGS, which usually interrogates multiple genes at once and is a prime example of a multianalyte assay, started to replace older single analyte assays focused on analysis of one target, one gene. However, the transition to these extremely complex NGS-based assays is associated with multiple challenges. There are issues with adequate tissue source of nucleic acids, sequencing library preparation, bioinformatics, government regulations and oversight, reimbursement, and electronic medical records that need to be resolved to successfully implement the new technology in a clinical laboratory.

Analysis and Annotation of Whole-Genome or Whole-Exome Sequencing Derived Variants for Clinical Diagnosis

Over the last 10 years, next-generation sequencing (NGS) has transformed genomic research through substantial advances in technology and reduction in the cost of sequencing, and also in the systems required for analysis of these large volumes of data. This technology is now being used as a standard molecular diagnostic test in some clinical settings. The advances in sequencing have come so rapidly that the major bottleneck in identification of causal variants is no longer the sequencing or analysis (given access to appropriate tools), but rather clinical interpretation. Interpretation of genetic findings in a complex and ever changing clinical setting is scarcely a new challenge, but the task is increasingly complex in clinical genome-wide sequencing given the dramatic increase in dataset size and complexity. This increase requires application of appropriate interpretation tools, as well as development and application of appropriate methodologies and standard procedures. This unit provides an overview of these items. Specific challenges related to implementation of genome-wide sequencing in a clinical setting are discussed. © 2017 by John Wiley & Sons, Inc.

Discrimination of Germline EGFR T790M Mutations in Plasma Cell-Free DNA Allows Study of Prevalence Across 31,414 Cancer Patients

Purpose: Plasma cell-free DNA (cfDNA) analysis is increasingly used clinically for cancer genotyping, but may lead to incidental identification of germline-risk alleles. We studied EGFR T790M mutations in non-small cell lung cancer (NSCLC) toward the aim of discriminating germline and cancer-derived variants within cfDNA.Experimental Design: Patients with EGFR-mutant NSCLC, some with known germline EGFR T790M, underwent plasma genotyping. Separately, deidentified genomic data and buffy coat specimens from a clinical plasma next-generation sequencing (NGS) laboratory were reviewed and tested.Results: In patients with germline T790M mutations, the T790M allelic fraction (AF) in cfDNA approximates 50%, higher than that of EGFR driver mutations. Review of plasma NGS results reveals three groups of variants: a low-AF tumor group, a heterozygous group (∼50% AF), and a homozygous group (∼100% AF). As the EGFR driver mutation AF increases, the distribution of the heterozygous group changes, suggesting increased copy number variation from increased tumor content. Excluding cases with high copy number variation, mutations can be differentiated into somatic variants and incidentally identified germline variants. We then developed a bioinformatic algorithm to distinguish germline and somatic mutations; blinded validation in 21 cases confirmed a 100% positive predictive value for predicting germline T790M. Querying a database of 31,414 patients with plasma NGS, we identified 48 with germline T790M, 43 with nonsquamous NSCLC (P < 0.0001).Conclusions: With appropriate bioinformatics, plasma genotyping can accurately predict the presence of incidentally detected germline risk alleles. This finding in patients indicates a need for genetic counseling and confirmatory germline testing. Clin Cancer Res; 23(23); 7351-9. ©2017 AACR.

Machine learning applications for prediction of relapse in childhood acute lymphoblastic leukemia

The prediction of relapse in childhood acute lymphoblastic leukemia (ALL) is a critical factor for successful treatment and follow-up planning. Our goal was to construct an ALL relapse prediction model based on machine learning algorithms. Monte Carlo cross-validation nested by 10-fold cross-validation was used to rank clinical variables on the randomly split training sets of 336 newly diagnosed ALL children, and a forward feature selection algorithm was employed to find the shortest list of most discriminatory variables. To enable an unbiased estimation of the prediction model to new patients, besides the split test sets of 150 patients, we introduced another independent data set of 84 patients to evaluate the model. The Random Forest model with 14 features achieved a cross-validation accuracy of 0.827 ± 0.031 on one set and an accuracy of 0.798 on the other, with the area under the curve of 0.902 ± 0.027 and 0.904, respectively. The model performed well across different risk-level groups, with the best accuracy of 0.829 in the standard-risk group. To our knowledge, this is the first study to use machine learning models to predict childhood ALL relapse based on medical data from Electronic Medical Record, which will further facilitate stratification treatments.

Good Laboratory Standards for Clinical Next-Generation Sequencing Cancer Panel Tests

Next-generation sequencing (NGS) has recently emerged as an essential component of personalized cancer medicine due to its high throughput and low per-base cost. However, no sufficient guidelines for implementing NGS as a clinical molecular pathology test are established in Korea. To ensure clinical grade quality without inhibiting adoption of NGS, a taskforce team assembled by the Korean Society of Pathologists developed laboratory guidelines for NGS cancer panel testing procedures and requirements for clinical implementation of NGS. This consensus standard proposal consists of two parts: laboratory guidelines and requirements for clinical NGS laboratories. The laboratory guidelines part addressed several important issues across multistep NGS cancer panel tests including choice of gene panel and platform, sample handling, nucleic acid management, sample identity tracking, library preparation, sequencing, analysis and reporting. Requirements for clinical NGS tests were summarized in terms of documentation, validation, quality management, and other required written policies. Together with appropriate pathologist training and international laboratory standards, these laboratory standards would help molecular pathology laboratories to successfully implement NGS cancer panel tests in clinic. In this way, the oncology community would be able to help patients to benefit more from personalized cancer medicine.

Development and Characterization of Reference Materials for Genetic Testing: Focus on Public Partnerships

Characterized reference materials (RMs) are needed for clinical laboratory test development and validation, quality control procedures, and proficiency testing to assure their quality. In this article, we review the development and characterization of RMs for clinical molecular genetic tests. We describe various types of RMs and how to access and utilize them, especially focusing on the Genetic Testing Reference Materials Coordination Program (Get-RM) and the Genome in a Bottle (GIAB) Consortium. This review also reinforces the need for collaborative efforts in the clinical genetic testing community to develop additional RMs.

Integration of next-generation sequencing in clinical diagnostic molecular pathology laboratories for analysis of solid tumours; an expert opinion on behalf of IQN Path ASBL

The clinical demand for mutation detection within multiple genes from a single tumour sample requires molecular diagnostic laboratories to develop rapid, high-throughput, highly sensitive, accurate and parallel testing within tight budget constraints. To meet this demand, many laboratories employ next-generation sequencing (NGS) based on small amplicons. Building on existing publications and general guidance for the clinical use of NGS and learnings from germline testing, the following guidelines establish consensus standards for somatic diagnostic testing, specifically for identifying and reporting mutations in solid tumours. These guidelines cover the testing strategy, implementation of testing within clinical service, sample requirements, data analysis and reporting of results. In conjunction with appropriate staff training and international standards for laboratory testing, these consensus standards for the use of NGS in molecular pathology of solid tumours will assist laboratories in implementing NGS in clinical services.

Decision Making on Medical Innovations in a Changing Health Care Environment: Insights from Accountable Care Organizations and Payers on Personalized Medicine and Other Technologies

BACKGROUND

New payment and care organization approaches, such as those of accountable care organizations (ACOs), are reshaping accountability and shifting risk, as well as decision making, from payers to providers, within the Triple Aim context of health reform. The Triple Aim calls for improving experience of care, improving health of populations, and reducing health care costs.

OBJECTIVES

To understand how the transition to the ACO model impacts decision making on adoption and use of innovative technologies in the era of accelerating scientific advancement of personalized medicine and other innovations.

METHODS

We interviewed representatives from 10 private payers and 6 provider institutions involved in implementing the ACO model (i.e., ACOs) to understand changes, challenges, and facilitators of decision making on medical innovations, including personalized medicine. We used the framework approach of qualitative research for study design and thematic analysis.

RESULTS

We found that representatives from the participating payer companies and ACOs perceive similar challenges to ACOs' decision making in terms of achieving a balance between the components of the Triple Aim-improving care experience, improving population health, and reducing costs. The challenges include the prevalence of cost over care quality considerations in ACOs' decisions and ACOs' insufficient analytical and technology assessment capacity to evaluate complex innovations such as personalized medicine. Decision-making facilitators included increased competition across ACOs and patients' interest in personalized medicine.

CONCLUSIONS

As new payment models evolve, payers, ACOs, and other stakeholders should address challenges and leverage opportunities to arm ACOs with robust, consistent, rigorous, and transparent approaches to decision making on medical innovations.

Validation of biomarkers to predict response to immunotherapy in cancer: Volume I - pre-analytical and analytical validation

Immunotherapies have emerged as one of the most promising approaches to treat patients with cancer. Recently, there have been many clinical successes using checkpoint receptor blockade, including T cell inhibitory receptors such as cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed cell death-1 (PD-1). Despite demonstrated successes in a variety of malignancies, responses only typically occur in a minority of patients in any given histology. Additionally, treatment is associated with inflammatory toxicity and high cost. Therefore, determining which patients would derive clinical benefit from immunotherapy is a compelling clinical question.

Although numerous candidate biomarkers have been described, there are currently three FDA-approved assays based on PD-1 ligand expression (PD-L1) that have been clinically validated to identify patients who are more likely to benefit from a single-agent anti-PD-1/PD-L1 therapy. Because of the complexity of the immune response and tumor biology, it is unlikely that a single biomarker will be sufficient to predict clinical outcomes in response to immune-targeted therapy. Rather, the integration of multiple tumor and immune response parameters, such as protein expression, genomics, and transcriptomics, may be necessary for accurate prediction of clinical benefit. Before a candidate biomarker and/or new technology can be used in a clinical setting, several steps are necessary to demonstrate its clinical validity. Although regulatory guidelines provide general roadmaps for the validation process, their applicability to biomarkers in the cancer immunotherapy field is somewhat limited. Thus, Working Group 1 (WG1) of the Society for Immunotherapy of Cancer (SITC) Immune Biomarkers Task Force convened to address this need. In this two volume series, we discuss pre-analytical and analytical (Volume I) as well as clinical and regulatory (Volume II) aspects of the validation process as applied to predictive biomarkers for cancer immunotherapy. To illustrate the requirements for validation, we discuss examples of biomarker assays that have shown preliminary evidence of an association with clinical benefit from immunotherapeutic interventions. The scope includes only those assays and technologies that have established a certain level of validation for clinical use (fit-for-purpose). Recommendations to meet challenges and strategies to guide the choice of analytical and clinical validation design for specific assays are also provided.

The nuanced negative: Meanings of a negative diagnostic result in clinical exome sequencing

Genomic sequencing technology is moving rapidly from the research setting into clinical medicine but significant technological and interpretive challenges remain. Exome sequencing (ES) in its recent clinical application provides a genetic diagnosis in about 25 per cent of cases (Berg 2014). While this diagnostic yield is substantial, it also indicates that in a majority of cases, patients are receiving negative results (i.e. no explanatory genetic variant found) from this technology. There are a number of uncertainties regarding the meaning of a negative result in the current context of ES. A negative result may be due to current technological limitations that hinder detection of disease-causing variants or to gaps in the knowledge base that prohibit accurate interpretation of their pathogenicity; or it may indicate that there is not a genetic etiology for the disorder. In this paper we examine the uncertainties and nuances of the negative result from genome sequencing and how both clinicians and patients make meaning of it as revealed in ethnographic observations of the clinic session where results are returned, and in interviews with patients. We find that clinicians and patients construct the meaning of a negative result in ways that are uncertain, contingent, and multivalent; but invested with optimism, promise, and potentiality.

Genetic Testing Requires NGS and Sanger Methodologies

Investigators from the EuroEPINOMICS rare epilepsy syndromes Dravet working group performed whole-exome sequencing on 31 trios that had been reported negative for SCN1A mutations by Sanger sequencing.