The Correlation between Plasma Circulating Tumor DNA and Radiographic Tumor Burden.

Conventional blood-based biomarkers and radiographic imaging are excellent for use in monitoring different aspects of malignant disease, but given their specific shortcomings, their integration with other, complementary markers such as plasma circulating tumor DNA (ctDNA) will be beneficial toward a precision medicine-driven future. Plasma ctDNA analysis utilizes the measurement of cancer-specific molecular alterations in a variety of bodily fluids released by dying tumor cells to monitor and profile response to therapy, and is being employed in several clinical scenarios. Plasma concentrations of ctDNA have been reported to correlate with tumor burden. However, the strength of this association is generally poor and highly variable, confounding the interpretation of longitudinal plasma ctDNA measurements in conjunction with routine radiographic assessments. Herein is discussed what is currently understood with respect to the fundamental characteristics of tumor growth that dictate plasma ctDNA concentrations, with a perspective on its interpretation in conjunction with radiographically determined tumor burden assessments.

Corresponding ctDNA and tumor burden dynamics in metastatic melanoma patients on systemic treatment.

Radiographic imaging is the current standard for monitoring progression of tumor-burden and therapeutic resistance in patients with metastatic melanoma. Plasma circulating tumor DNA (ctDNA) has shown promise as a survelience tool, but longitudinal data on the dynamics between plasma ctDNA concentrations and radiographic imaging is lacking. We evaluated the relationship between longitudinal radiographic measures of tumor burden and ctDNA concentrations in plasma on 30 patients with metastatic melanoma on systemic treatment. In 9 patients with no radiographic evidence of disease over a total of 15 time points, ctDNA concentrations were undetectable. In 21 patients with radiographic tumor burden, ctDNA was detected in 81 % of 58 time points. Plasma ctDNA concentrations demonstrated a modest positive correlation with total tumor burden (TTB) measurements (R2= 0.49, p < 0.001), with the greatest degree of correlation observed under conditions of progressive disease (PD) (R2 = 0.91, p = 0.032). Plasma ctDNA concentrations were significantly greater at times of RECIST v1.1 progression (PD; 22.1 % ± 5.7 %) when compared to samples collected during stable disease (SD; 4.99 % ± 3.0 %) (p = 0.012); this difference was independent of total tumor burden (p = 0.997). Changes in plasma ctDNA showed a strong correlation with changes in TTB (R2= 0.88, p<0.001). These data suggest that measurements of plasma ctDNA during therapy are a better surrogate for responding versus non-responding disease compared to absolute tumor burden.

Results from an IFCC global survey on laboratory practices for the analysis of circulating tumor DNA.

BACKGROUND: The clinical validity of ctDNA analysis as a diagnostic, prognostic and predictive biomarker has been demonstrated in many studies. The rapid spread of tests for the analysis of ctDNA raises questions regarding their standardization and quality assurance. The aim of this study was to provide a global overview of the test methods, laboratory procedures and quality assessment practices using ctDNA diagnostics. METHODS: The Molecular Diagnostics Committee of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC C-MD) conducted a survey among international laboratories performing ctDNA analysis. Questions on analytical techniques, test parameters, quality assurance and the reporting of findings were included. RESULTS: A total of 58 laboratories participated in the survey. The majority of the participating laboratories (87.7 %) performed testing for patient care. Most laboratories conducted their assays for lung cancer (71.9 %), followed by colorectal (52.6 %) and breast (40.4 %) cancer, and 55.4 % of the labs used ctDNA analysis for follow-up/monitoring of treatment-resistant alterations. The most frequent gene analysed was EGFR (75.8 %), followed by KRAS (65.5 %) and BRAF (56.9 %). Participation in external quality assessment programs was reported by only 45.6 % of laboratories. CONCLUSIONS: The survey indicates that molecular diagnostic methods for the analysis of ctDNA are not standardized across countries and laboratories. Furthermore, it reveals a number of differences regarding sample preparation, processing and reporting test results. Our findings indicate that ctDNA testing is being conducted without sufficient attention to analytical performance between laboratories and highlights the need for standarisation of ctDNA analysis and reporting in patient care.

Enhancing the compatibility of BioCaRGOS silica sol-gel technology with ctDNA extraction and droplet digital PCR (ddPCR) analysis.

Previously, our group had demonstrated long term stabilization of protein biomarkers using BioCaRGOS, a silica sol-gel technology. Herein, we describe workflow modifications to allow for extraction of cell free DNA (cfDNA) from primary samples containing working concentrations of BioCaRGOS, as well as the compatibility of BioCaRGOS with droplet digital PCR (ddPCR) analysis for pancreatic cancer biomarkers i.e., KRAS circulating tumor DNA (ctDNA). Preliminary attempts to extract ctDNA from BioCaRGOS containing samples demonstrated interference in the extraction of primary samples and the interference with ddPCR analysis when BioCaRGOS was directly introduced to stabilize sample extracts. In our modified technique, we have minimized the interference caused by methanol with ddPCR by complete removal of methanol from the activated BioCaRGOS formulation prior to addition to the biospecimen or ctDNA extract. Interference of the silica matrix present in BioCaRGOS with ctDNA extraction was eliminated through the introduction of invert filtration of the sample prior to extraction. These modifications to the workflow of BioCaRGOS containing samples allow for use of BioCaRGOS for stabilization of trace quantities of nucleic acid biomarkers such as plasma ctDNA, while retaining the capability to extract the biomarker and quantify based on ddPCR.

Molecular diagnostics of SARS-CoV-2: Findings of an international survey.

BACKGROUND: In the current COVID-19 pandemic, early and rapid diagnosis of potentially infected and contagious individuals enables containment of the disease through quarantine and contact tracing. The rapid global expansion of these diagnostic testing services raises questions concerning the current state of the art with regard to standardization of testing and quality assessment practices. The aim of this study was to provide a global overview of the test methods, laboratory procedures and quality assessment practices used for SARS-CoV-2 diagnostics. METHODS: The Molecular Diagnostics Committee of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC C-MD) initiated a survey among international laboratories performing molecular genetic detection of SARS-CoV-2. Questions on quality assurance, variant testing, sequencing and the transmission of findings were included in the survey. RESULTS: A total of 273 laboratories from 49 countries participated in the survey. The majority of the participating laboratories (92.2%) use reverse transcriptase polymerase chain reaction (RT-PCR). The majority of participating laboratories do not conduct testing to identify SARS CoV-2 variants. Participation in external quality assessment programs was reported by the majority of laboratories, however, 33.2% of the laboratories reported not participating in external quality assurance programmes. CONCLUSIONS: Based on the survey, molecular diagnostic methods for SARS-CoV-2 detection are clearly not standardized across different countries and laboratories. The survey found an array of responses in regard to sample preparation, collection, processing and reporting of results. This work suggests quality assurance is insufficiently performed by diagnostic laboratories conducting SARS-CoV-2 testing.

Current and future challenges in quality assurance in molecular diagnostics.

The development and performance of molecular genetic assays has required increasingly complex quality assurance in recent years and continues to pose new challenges. Quality management officers, as well as academic and technical personnel are confronted with new molecular genetic parameters, methods, changing regulatory environments, questions regarding appropriate validation, and quality control for these innovative assays that are increasingly applying quantification and/or multiplex formats. Yet, quality assurance and quality control guidelines are still not widely available or in some circumstances have become outdated. For these reasons, the need for solutions to provide test confidence continues to grow. In order to integrate new test procedures into existing quality assurance measures, the ISO 15189 guideline can serve as an orientation. The ISO 15189 guideline describes requirements for medical laboratories and thus includes those performing molecular diagnostics. This article gives an overview of the possibilities and challenges in quality assurance of molecular parameters and shows possible solutions.

A Shared Diagnostic Stewardship Approach toward Improving Autoimmune Encephalopathy Send-out Testing Utilization.

BACKGROUND: For many laboratories, autoimmune encephalopathy (AE) panels are send-out tests. These tests are expensive, and ordering patterns vary greatly. There is also a lack of consensus on which panel to order and poor understanding of the clinical utility of these panels. These challenges were presented to our newly formed, multidisciplinary, diagnostic stewardship committee (DSC). Through this collaboration, we developed an algorithm for ordering AE panels; combining diagnostic criteria with practice guidelines. METHODS: We analyzed test-ordering patterns in 2018 and calculated a true-positive rate based on clinical presentation and panel interpretation. An evidence-based approach was combined with input from the Department of Neurology to synthesize our algorithm. Efficacy of the algorithm (number of panels ordered, cost, and true positives) was assessed before and after implementation. RESULTS: In 2018, 77 AE-related panels were ordered, costing $137 510. The true-positive rate was 10%, although ordering multiple, similar panels for the same patient was common. Before implementing the algorithm (January 1-July 31, 2019), 55 panels were ordered, costing $105 120. The total true-positive rate was 3.6%. After implementation, 23 tests were ordered in a 5-month period, totaling $50 220. The true-positive rate was 13%. CONCLUSION: With the DSC-directed mandate, we developed an algorithm for ordering AE panels. Comparison of pre- and postimplementation data showed a higher true-positive rate, indicating that our algorithm was able to successfully identify the at-risk population for AE disorders. This was met with a 43% decrease in the number of tests ordered, with total cost savings of $25 000 over 5 months.

Long term storage of miRNA at room and elevated temperatures in a silica sol-gel matrix.

Storage of biospecimens in their near native environment at room temperature can have a transformative global impact, however, this remains an arduous challenge to date due to the rapid degradation of biospecimens over time. Currently, most isolated biospecimens are refrigerated for short-term storage and frozen (-20 °C, -80 °C, liquid nitrogen) for long-term storage. Recent advances in room temperature storage of purified biomolecules utilize anhydrobiosis. However, a near aqueous storage solution that can preserve the biospecimen nearly "as is" has not yet been achieved by any current technology. Here, we demonstrate an aqueous silica sol-gel matrix for optimized storage of biospecimens. Our technique is facile, reproducible, and has previously demonstrated stabilization of DNA and proteins, within a few minutes using a standard benchtop microwave. Herein, we demonstrate complete integrity of miRNA 21, a highly sensitive molecule at 4, 25, and 40 °C over a period of ∼3 months. In contrast, the control samples completely degrade in less than 1 week. We attribute excellent stability to entrapment of miRNA within silica-gel matrices.

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

OBJECTIVES: Management of colorectal cancer warrants mutational analysis of KRAS/NRAS when considering anti-epidermal growth factor receptor therapy and BRAF testing for prognostic stratification. In this multicenter study, we compared a fully integrated, cartridge-based system to standard-of-care assays used by participating laboratories. METHODS: Twenty laboratories enrolled 874 colorectal cancer cases between November 2017 and December 2018. Testing was performed on the Idylla automated system (Biocartis) using the KRAS and NRAS-BRAF cartridges (research use only) and results compared with in-house standard-of-care testing methods. RESULTS: There were sufficient data on 780 cases to measure turnaround time compared with standard assays. In-house polymerase chain reaction (PCR) had an average testing turnaround time of 5.6 days, send-out PCR of 22.5 days, in-house Sanger sequencing of 14.7 days, send-out Sanger of 17.8 days, in-house next-generation sequencing (NGS) of 12.5 days, and send-out NGS of 20.0 days. Standard testing had an average turnaround time of 11 days. Idylla average time to results was 4.9 days with a range of 0.4 to 13.5 days. CONCLUSIONS: The described cartridge-based system offers rapid and reliable testing of clinically actionable mutation in colorectal cancer specimens directly from formalin-fixed, paraffin-embedded tissue sections. Its simplicity and ease of use compared with other molecular techniques make it suitable for routine clinical laboratory testing.

External quality assessment (EQA) and alternative assessment procedures (AAPs) in molecular diagnostics: findings of an international survey.

Objectives: Quality management for clinical laboratories requires the establishment of internal procedures including standard operating procedures (SOPs), internal quality control (QC), validation of test results and quality assessment. External quality assessment (EQA) and alternativeassessment procedures (AAPs) are part of the quality hierarchy required for diagnostic testing. The International Organization for Standardization (ISO) document with requirements for conformance ISO 15189 and the Clinical and Laboratory Standards Institute document (CLSI) QMS24 require participation in EQA schemes and AAPs where applicable. The purpose of this study was to perform a global survey of EQA and AAPs for key procedures in molecular diagnostic laboratories. Methods: The Committee for Molecular Diagnostics of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC C-MD) conducted a survey of international molecular laboratories that covered specific topics of molecular diagnostic services as well as methods for EQA and AAPs. The survey addressed the following aspects: (1) usage of laboratory-developed test (LDT), (2) participation in EQA schemes and (3) performance of AAPs. Results: A total of 93 responses from laboratories located in Asia, Europe, the Middle East, North America and South America were received. The majority of the participating laboratories (65.9%) use LDTs and 81.3% stated that it is mandatory for them to participate in EQA programs, while 22% of the laboratories reported not performing AAPs. Thirty-one percent of the laboratories use EQAs for fewer than 50.0% of their reported parameters/analytes. Conclusions: While the majority of laboratories perform EQA and AAPs to improve their quality in molecular diagnostics, the amount of AAPs as quality procedures differs within the laboratories. Further surveys are necessary to clarify the existing needs in additional EQAs and standardized AAPs. The survey will also guide future efforts of the IFCC C-MD for identifying quality practices in need to improve harmonization and standardization within molecular diagnostics.

Polypharmacy: a healthcare conundrum with a pharmacogenetic solution.

The use of multiple medications is growing at an alarming rate with some reports documenting an average of 12-22 prescriptions being used by individuals ≥50 years of age. The indirect consequences of polypharmacy include exacerbation of drug-drug interactions, adverse drug reactions, increased likelihood of prescribing cascades, chronic dependence, and hospitalizations - all of which have significant health and economic burden. While many practical solutions for reducing polypharmacy have been proposed, they have been met with limited efficacy. This highlights the need for a new systematic approach for fine-tuning dispensing of medications. Pharmacogenetic testing provides an empirical and scientifically rigorous approach for guiding appropriate selection of medicines, with the potential to reduce unnecessary polypharmacy while improving clinical outcomes. The goal of this review article is to provide healthcare providers with an understanding of polypharmacy, its adverse effects on the healthcare system and highlight how pharmacogenetic information can be used to avoid polypharmacy in patients.

Cell-free DNA diagnostics: current and emerging applications in oncology.

Liquid biopsy is a noninvasive dynamic approach for monitoring disease over time. It offers advantages including limited risks of blood sampling, opportunity for more frequent sampling, lower costs and theoretically non-biased sampling compared with tissue biopsy. There is a high degree of concordance between circulating tumor DNA mutations versus primary tumor mutations. Remote sampling of circulating tumor DNA can serve as viable option in clinical diagnostics. Here, we discuss the progress toward broad adoption of liquid biopsy as a diagnostic tool and discuss knowledge gaps that remain to be addressed.

Avoidable drug-gene conflicts and polypharmacy interactions in patients participating in a personalized medicine program.

AIM: Determine the ability of a pharmacogenetic service, PRIMER, to identify drug-gene (DGI) and drug-drug interactions (DDI) in patients across multiple conditions. PRIMER consists of patient selection criteria, a gene panel and actionable guidance for DGIs and DDIs. RESULTS: The average patient was prescribed 12 medications. PRIMER identified significant DGIs in 73% of patients tested, with 43% having more than one DGI. DDIs were found in 87% of patients. The most common actionable DGIs were for opioid, psychotropic and cardiovascular medications. CONCLUSION: The pairing of patient selection criteria, a multigene panel with evidence-based interpretation and review of DDIs maximizes the patients tested who have actionable benefit and alerts physicians to potentially critical adjustments needed for the patient's medication regimen.

Clinical Utility and Economic Impact of CYP2D6 Genotyping.

Pharmacogenetics examines an individual's genetic makeup to help predict the safety and efficacy of medications. Practical application optimizes treatment selection to decrease the failure rate of medications and improve clinical outcomes. Lack of efficacy is costly due to adverse drug reactions and increased hospital stays. Cytochrome P450 2D6 (CYP2D6) metabolizes roughly 25% of all drugs. Detecting variants that cause altered CYP2D6 enzymatic activity identifies patients at risk of adverse drug reactions or therapeutic failure with standard dosages of medications metabolized by CYP2D6. This article discusses the clinical application of pharmacogenetics to improve care and decrease costs.

Extracellular Vesicles Move Toward Use in Clinical Laboratories.

Extracellular vesicles (EVs) are membranous particles found in a variety of biofluids that encapsulate molecular information from the cell, which they originate from. This rich source of information that is easily obtained can then be mined to find diagnostic biomarkers. This article explores the current biological understanding of EVs and specific methods to isolate and analyze them. A case study of a company leading the charge in using EVs in diagnostic assays is provided.

Liquid Biopsies in Oncology and the Current Regulatory Landscape.

There is a profound need in oncology to detect cancer earlier, guide individualized therapies, and better monitor progress during treatment. Currently, some of this information can be achieved through solid tissue biopsy and imaging. However, these techniques are limited because of the invasiveness of the procedure and the size of the tumor. A liquid biopsy can overcome these barriers as its non-invasive nature allows samples to be collected over time. Liquid biopsies may also allow earlier detection than traditional imaging. Liquid biopsies include the analysis of circulating tumor cells (CTCs), cell-free nucleic acid (cfNA), or extracellular vesicles obtained from a variety of biofluids, such as peripheral blood. In this review, we discuss different liquid biopsy types and how they fit into the current regulatory landscape.

Circulating tumor cells: a review of present methods and the need to identify heterogeneous phenotypes.

The measurement and characterization of circulating tumor cells (CTCs) hold promise for advancing personalized therapeutics. CTCs are the precursor to metastatic cancer and thus have the potential to radically alter patient treatment and outcome. Currently, clinical information provided by the enumeration of CTCs is limited to predicting clinical outcome. Other areas of interest in advancing the practice of pathology include: using CTCs for early detection of potential metastasis, determining and monitoring the efficacy of individualized treatment regimens, and predicting site-specific metastasis. Important hurdles to overcome in obtaining this type of clinical information involve present limitations in defining, detecting, and isolating CTCs. Currently, CTCs are detected using epithelial markers. The definition of what distinguishes a CTC should be expanded to include CTCs with heterogeneous phenotypes, and markers should be identified to enable a more comprehensive capture. Additionally, most methods available for detecting CTCs do not capture functionally viable CTCs. Retaining functional viability would provide a significant advantage in characterizing CTC-subtypes that may predict the site of metastatic invasion and thus assist in selecting effective treatment regimens. In this review we describe areas of clinical interest followed by a summary of current circulating cell-separation technologies and present limitations. Lastly, we provide insight into what is required to overcome these limitations as they relate to applications in advancing the practice of pathology and laboratory medicine.

Development of predictive models for estimating warfarin maintenance dose based on genetic and clinical factors.

In this chapter, we use calculation of estimated warfarin maintenance dosage as an example to illustrate how to develop a multiple linear regression model to quantify the relationship between several independent variables (e.g., patients' genotype information) and a dependent variable (e.g., measureable clinical outcome).

Prospective pilot trial of PerMIT versus standard anticoagulation service management of patients initiating oral anticoagulation.

We performed a randomised pilot trial of PerMIT, a novel decision support tool for genotype-based warfarin initiation and maintenance dosing, to assess its efficacy for improving warfarin management. We prospectively studied 26 subjects to compare PerMIT-guided management with routine anticoagulation service management. CYP2C9 and VKORC1 genotype results for 13 subjects randomly assigned to the PerMIT arm were recorded within 24 hours of enrolment. To aid in INR interpretation, PerMIT calculates estimated loading and maintenance doses based on a patient's genetic and clinical characteristics and displays calculated S-warfarin plasma concentrations based on planned or administered dosages. In comparison to control subjects, patients in the PerMIT study arm demonstrated a 3.6-day decrease in the time to reach a stabilised INR within the target therapeutic range (4.7 vs. 8.3 days, p = 0.015); a 12.8% increase in time spent within the therapeutic interval over the first 25 days of therapy (64.3% vs. 55.3%, p = 0.180); and a 32.9% decrease in the frequency of warfarin dose adjustments per INR measurement (38.3% vs. 57.1%, p = 0.007). Serial measurements of plasma S-warfarin concentrations were also obtained to prospectively evaluate the accuracy of the pharmacokinetic model during induction therapy. The PerMIT S-warfarin plasma concentration model estimated 62.8% of concentrations within 0.15 mg/l. These pilot data suggest that the PerMIT method and its incorporation of genotype/phenotype information may help practitioners increase the safety, efficacy, and efficiency of warfarin therapeutic management.

A diagnostic informatics approach for stratifying risk outcome based on combined genotype effects.

BACKGROUND: Diagnostic informatics (DI) in the context of personalized medicine involves the integration of molecular information to provide "actionable" diagnostic and therapeutic strategies. In many cases, retrospective predictions of clinical outcomes affected by multiple genes are complicated by not having the relevant genes measured within the same study. Multiplicative effect modeling is a statistical method for estimating the net effect of ≥ 2 independent variables. The authors demonstrate a DI approach that uses multiplicative-effect modeling to combine genetic information from ≥ 2 independent studies to predict a net clinical outcome. METHODS: As a hypothetical working model, 2 independent studies were selected each reporting on a unique genetic factor proposed to influence the risk of stent thrombosis (ST) among subjects treated with clopidogrel. A multiplicative effect model was used for developing a hypothesis regarding their combined influence on clinical outcome. RESULTS: Application of multiplicative risk modeling yielded a revised estimated risk of outcomes based on combined genotype. In this scenario, combined genotype revised the categorical risk level (high versus low) estimated from single gene effects for 41.5% of the subjects. Further, the maximum relative risk based on single gene effects was increased from 4.54 to 7.84 based on combined genotype. The revised relative risk values in conjunction with combined genotype frequency estimates provides the data necessary to frame a trial hypothesis and conduct appropriate power analysis to estimate the number of subjects needed to test that hypothesis. CONCLUSIONS: This DI approach can be used to generate quantitative hypotheses on multiple gene effects derived from independent genotype studies. This approach is useful for estimating parameters needed in designing future studies to evaluate the net effect of ≥ 2 genetic variants on a common clinical endpoint.