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Simple Summary: Clonality testing and somatic hypermutation analysis performed on B-cell receptor encoding genes are the most widely used molecular assays for lymphoma diagnostics. Currently, PCR-based methods standardized by the BIOMED2 consortium are regarded as the gold standard. In the last few years, new approaches based on next-generation sequencing (NGS) have been proposed and validated in phase I–II studies. Here, we present the first phase III diagnostic accuracy study, evaluating an NGS-based protocol (LymphoTrack® IGH assay, and LymphoTrack® IGH somatic hypermutation assay) compared to the gold standard. We formally documented a high diagnostic accuracy providing a clinical validation of the assays. Background: Multiplex PCR based on consensus primers followed by capillary electrophoresis and Sanger sequencing are considered as the gold standard method for the evaluation of clonality and somatic hypermutation in lymphoid malignancies. As an alternative, the next-generation sequencing (NGS) of immune receptor genes has recently been proposed as a solution, due to being highly effective and sensitive. Here, we designed a phase III diagnostic accuracy study intended to compare the current gold standard methods versus the first commercially available NGS approaches for testing immunoglobulin heavy chain gene rearrangements. Methods: We assessed IGH rearrangements in 68 samples by means of both the NGS approach (LymphoTrack® IGH assay, and LymphoTrack® IGH somatic hypermutation assay, run on Illumina MiSeq) and capillary electrophoresis/Sanger sequencing to assess clonality and somatic hypermutations (SHM). Results: In comparison to the routine capillary-based analysis, the NGS clonality assay had an overall diagnostic accuracy of 96% (63/66 cases). Other studied criteria included sensitivity (95%), specificity (100%), positive predictive value (100%) and negative predictive value (75%). In discrepant cases, the NGS results were confirmed by a different set of primers that provided coverage of the IGH leader sequence. Furthermore, there was excellent agreement of the SHM determination with both the LymphoTrack® FR1 and leader assays when compared to the Sanger sequencing analysis (84%), with NGS able to assess the SHM rate even in cases where the conventional approach failed. Conclusion: Overall, conventional Sanger sequencing and next-generation-sequencing-based clonality and somatic hypermutation analyses gave comparable results. For future use in a routine diagnostic workflow, NGS-based approaches should be evaluated prospectively and an analysis of cost-effectiveness should be performed. [ABSTRACT FROM AUTHOR]

In 2009, the four laboratories of the Fondazione Italiana Linfomi (FIL) minimal residual disease (MRD) Network started a collaborative effort to harmonize and standardize their methodologies at the national level, performing quality control (QC) rounds for follicular lymphoma (FL) and mantle cell lymphoma (MCL) MRD assessment. In 16 QC rounds between 2010 and 2017, the four laboratories received 208 bone marrow (BM) samples (126 FL; 82 MCL); 187 were analyzed, according to the EuroMRD Consortium guidelines, by both nested (NEST) polymerase chain reaction (PCR) and real-time quantitative (RQ) PCR for BCL2/IGH MBR or IGHV rearrangements. Here, we aimed at analyzing the samples that challenged the interlaboratory reproducibility and data interpretation. Overall, 156/187 BM samples (83%) were concordantly classified as NEST+/RQ+ or NEST-/RQ- by all the four laboratories. The remaining 31 samples (17%) resulted alternatively positive and negative in the interlaboratory evaluations, independently of the method and the type of rearrangement, and were defined "borderline" (brd) samples: 12 proved NEST brd/RQ brd, 7 NEST-/RQ brd, 10 NEST brd/RQ positive not quantifiable (PNQ), and 2 NEST brd/RQ-. Results did not change even increasing the number of replicates/sample. In 6/31 brd samples, droplet digital PCR (ddPCR) was tested and showed no interlaboratory discordance. Despite the high interlaboratory reproducibility in the MRD analysis obtained and maintained by the QC round strategy, samples with the lowest MRD levels can still represent a challenge: 17% (31/187) of our samples showed discordant results in interlaboratory assessments, with 6.4% (12/187) remained brd even applying the two methods. Thus, although representing a minority, brd samples are still problematic, especially when a clinically oriented interpretation of MRD results is required. Alternative, novel methods such as ddPCR and next-generation sequencing have the potential to overcome the current limitations. [ABSTRACT FROM AUTHOR]

Genomic DNA extraction is a primary component of genomic research and diagnostic routine analysis. Recently, the importance of this process has been highlighted by the necessity to standardize the diagnostic procedure. In this regard, the Minimal Residual Disease (MRD) Network of the Fondazione Italiana Linfomi (FIL MRD Network) has performed a comparative study of four different commercially available kits for DNA extraction, applying them on a panel of cellular pellets, with the aim of defining possible technical recommendations in order to harmonize and standardize diagnostic procedures in the clinical setting. Overall, all four kits usually allowed the recovery of a significant quantity of high-quality DNA (in most conditions), although specific indications could be addressed for cellular pellets of different sizes. [ABSTRACT FROM PUBLISHER]

In recent years, the development of new techniques for clonality detection has allowed to better characterize and classify hematological neoplasms as well as to follow them in their clinical evolution. In the past, clonality used to be studied by southern blot approach performed on immunoglobulin (IG) and T-cell receptor (TCR) gene rearrangement segments. To date, the most commonly used method for sensitive nucleic acid detection in the clinical molecular diagnostic laboratories is PCR. This technique is fast, accurate, specific, and sensitive, thus appointing this approach as the world standard for IG/TCR clonality testing. In the last years, there has been a rapid development of technologies able to manage high-throughput sequence analysis of DNA. These novel approaches have the potential to significantly improve sensitivity and reduce the costs for clonal detection and post-treatment minimal residual disease (MRD) monitoring in both B- and T-cell malignancies; however, additional experiments are required to prove utility, sensitivity, and benefits in order to apply these systems into clinical practice. In this review, the authors focus on the developments on more sensitive systems for clonality testing that could improve the diagnostic workup and the MRD assessment. [ABSTRACT FROM AUTHOR]