Quality metrics for enhanced performance of an NGS panel using single-vial amplification technology.

AIMS: Targeted next-generation sequencing (NGS) panels, which identify genomic alterations, are the stronghold of molecular oncology laboratories. In spite of technological advances, the quantity and quality of DNA from formalin-fixed paraffin-embedded tissue and paucicellular specimens are barriers to successful sequencing. Here, we describe an NGS assay employing single tube stem-loop inhibition mediated amplification technology that delivers highly accurate results with low input DNA. Rigorous quality metrics, regular monitoring and in-depth validation make the test attractive for clinical laboratories. METHODS: The study used a customised NGS panel, targeting 48 genes across several solid tumour types. Validation, in accordance with guidelines from New York State, sequenced patient samples harbouring 136 known variants, including single-nucleotide variants (SNVs) and indels. Specimen types included formalin-fixed paraffin embedded blocks, core biopsies and cytology material. Neoplastic cellularity of the tumours ranged from 10% to 80%. RESULTS: The assay was highly specific and sensitive with excellent accuracy, reproducibility and repeatability/precision. Concordant results for identification of SNVs and indels were obtained from specimens with DNA input of 2-3 ng, tissue with 10% neoplastic cellularity and variant allelic frequencies of 2.5%-3%. Over 99% of the target areas are shown to achieve at least 500X coverage when parsed through two bioinformatics pipelines. With over 2000 clinical specimens analysed, the success of the panel for reporting of results is 95.3% CONCLUSIONS: The advanced technology enables accurate identification of clinically relevant variants with uniformity of coverage and an impressive turn-around-time. The overall workflow and cost-effectiveness provide added value.

A treatment-refractory aggressive MDS-MLD with multiple highly complex chromosome 5 intrachromosomal rearrangements: a case report.

BACKGROUND: A patient with a myelodysplastic neoplasm exhibited a karyotype with multiple complex chromosome 5 rearrangements. This patient appeared to have a catastrophic cytogenetic event that manifested as a treatment-refractory aggressive form of disease, which lead to patient demise within one year. Both the clinical presentation and disease course were unusual based on the medical history and morphologic findings. Such cases of myelodysplastic syndrome with multilineage dysplasia (MDS-MLD) with complex abnormalities are not reported in the literature. CASE PRESENTATION: The patient was a 62-year-old female who presented with pancytopenia and dyspnea. The morphologic appearance of the peripheral blood smear and bone marrow biopsy, along with flow cytometric findings, favored the diagnosis of MDS-MLD unclassifiable. Myelodysplastic syndrome (MDS) with multilineage dysplasia (MDS-MLD), is an MDS characterized by one or more cytopenias and dysplastic changes in two or more of the myeloid lineages (i.e., erythroid, granulocytic, and megakaryocytic). The bone marrow, in particular, showed prominent dysplasia, including the presence of atypical megakaryocytes with small hypolobated morphology reminiscent of those typically seen in MDS with isolated 5q deletion. Cytogenetic analysis, including interphase and metaphase FISH, karyotype and SNP chromosomal microarray were performed, as well as DNA sequencing studies. Cytogenetic analysis showed a very complex karyotype featuring multiple 5q intrachromosomal rearrangements including a pericentric inversion with multiple interspersed deletions and monosomy 7. FISH studies showed a partial deletion of the PDGFRß gene, and SNP chromosomal microarray and targeted panel-based sequencing identified biallelic loss of function of the TP53 gene. Based on the pathologic findings, the patient was treated for MDS but did not respond to either lenalidomide or azacitidine. CONCLUSION: The genetic changes described, in particular, the complex intrachromosomal rearrangements of chromosome 5, suggest the occurrence of a sudden catastrophic event that led to an aggressive course in the patient's disease. Conventional karyotyping, metaphase and interphase FISH, SNP chromosomal microarray and NGS helped to identify the complex genetic changes seen in this case. This highlights the importance of utilizing a multimodality approach to fully characterize complex chromosomal events that may significantly impact disease progression, treatment and survival.

Expanding the phenotype of ATP6AP1 deficiency.

Vacuolar ATPases (V-ATPases) are large multisubunit proton pumps conserved among all eukaryotic cells that are involved in diverse functions including acidification of membrane-bound intracellular compartments. The ATP6AP1 gene encodes an accessory subunit of the vacuolar (V)-ATPase protein pump. Pathogenic variants in ATP6AP1 have been described in association with a congenital disorder of glycosylation (CDG), which are highly variable, but often characterized by immunodeficiency, hepatopathy, and neurologic manifestations. Although the most striking and common clinical feature is hepatopathy, the phenotypic and genotypic spectrum of ATP6AP1-CDG continues to expand. Here, we report identical twins who presented with acute liver failure and jaundice. Prenatal features included cystic hygroma, atrial septal defect, and ventriculomegaly. Postnatal features included pectus carinatum, connective tissue abnormalities, and hypospadias. Whole-exome sequencing (WES) revealed a novel de novo in-frame deletion in the ATP6AP1 gene (c.230_232delACT;p.Tyr77del). Although both twins have the commonly reported clinical feature of hepatopathy seen in other individuals with ATP6AP1-CDG-related disorder, they do not have neurological sequelae. This report expands the phenotypic spectrum of ATP6AP1-CDG-related disorder with both probands exhibiting unique prenatal and postnatal features, including fetal ventriculomegaly, umbilical hernia, pectus carinatum, micropenis, and hypospadias. Furthermore, this case affirms that neurological features described in the initial case series on ATP6AP1-CDG do not appear to be central, whereas the prenatal and connective tissue manifestations may be more common than previously thought. This emphasizes the importance of long-term clinical follow-up and variant interpretation using current updated recommendations.

Key considerations for comprehensive validation of an RNA fusion NGS panel.

OBJECTIVES: Validation of RNA-based NGS assays for the detection of therapeutically targetable gene fusions is challenging. Here, we report systematic validation and quality control monitoring of our targeted fusion panel for the detection of 17 clinically relevant fusion transcripts across several tumor types. We implemented this RNA Fusion Panel as a reflex test for tumors lacking DNA driver mutations. DESIGN: Forty-four formalin-fixed, paraffin-embedded (FFPE) or fresh-frozen lung, brain, soft tissue and skin tumors were used to determine the accuracy of the assay. Additional fusion-positive specimens and a calibrated reference standard were used to establish the precision, reproducibility and sensitivity of the assay. All aspects of the validation, including quality control metrics, were performed according to New York State guidelines. RESULTS: For the RNA fusion panel, accuracy, reproducibility and precision studies were above 99%. Reproducibility and sensitivity studies with the reference standard were helpful in identifying inconsistencies. The limit of detection for most RNA fusion transcripts was 50 copies. Application of the RNA fusion assay as a reflex test to 450 tumor samples lacking DNA driver mutations resulted in a 10% increase in diagnostic yield with minimal additional processing time. CONCLUSIONS: The validated RNA fusion panel provides clinical utility in therapy selection for patients with solid tumors. By using a sequential testing approach, the RNA fusion assay complements the DNA hotspot assay in identifying clinically relevant variants across many tumor types with minimal additional increase in processing time.

Targeting SLMAP-ALK-a novel gene fusion in lung adenocarcinoma.

Assessment of ALK gene rearrangements is strongly recommended by the Molecular Testing Guideline for Selection of Lung Cancer Patients proposed by IASLC, AMP, and CAP at the time of diagnosis for patients with advanced stage disease. Non-small-cell lung cancer (NSCLC) with ALK gene rearrangements or the resulting fusion proteins have been, for the most part, successfully targeted with ALK tyrosine kinase inhibitors (TKIs). The most frequent rearrangement, the EML4-ALK oncogenic fusion, has more than 10 distinct variants, each with a discrete breakpoint in EML4 Recent studies have suggested that EML4-ALK variants may have differential responses to TKIs. Additionally, non-EML4-ALK fusions that result from ALK rearrangements with diverse 5' partners could possibly have varied biologic and clinical implications in their therapeutic responses and outcomes of patients with NSCLC. Existing literature documents at least 20 non-EML4 fusion partners for ALK, and the clinical responsiveness to crizotinib ranges from increased sensitivity to resistance. This underscores the importance of identifying the precise 5' fusion partner to ALK before initiation of therapy. Herein we report the identification of a novel SLMAP-ALK fusion in a patient with NSCLC.

Lifestyle, pregnancy and epigenetic effects.

Rapidly growing evidences link maternal lifestyle and prenatal factors with serious health consequences and diseases later in life. Extensive epidemiological studies have identified a number of factors such as diet, stress, gestational diabetes, exposure to tobacco and alcohol during gestation as influencing normal fetal development. In light of recent discoveries, epigenetic mechanisms such as alteration of DNA methylation, chromatin modifications and modulation of gene expression during gestation are believed to possibly account for various types of plasticity such as neural tube defects, autism spectrum disorder, congenital heart defects, oral clefts, allergies and cancer. The purpose of this article is to review a number of published studies to fill the gap in our understanding of how maternal lifestyle and intrauterine environment influence molecular modifications in the offspring, with an emphasis on epigenetic alterations. To support these associations, we highlighted laboratory studies of rodents and epidemiological studies of human based on sampling population cohorts.

Folic acid supplementation in pregnancy and implications in health and disease.

Maternal exposure to dietary factors during pregnancy can influence embryonic development and may modulate the phenotype of offspring through epigenetic programming. Folate is critical for nucleotide synthesis, and preconceptional intake of dietary folic acid (FA) is credited with reduced incidences of neural tube defects in infants. While fortification of grains with FA resulted in a positive public-health outcome, concern has been raised for the need for further investigation of unintended consequences and potential health hazards arising from excessive FA intakes, especially following reports that FA may exert epigenetic effects. The objective of this article is to discuss the role of FA in human health and to review the benefits, concerns and epigenetic effects of maternal FA on the basis of recent findings that are important to design future studies.