Next-Generation DNA Sequencing-Based Gene Panel for Diagnosis and Genetic Risk Stratification in Onco-Hematology.

A suitable diagnostic classification of myeloid neoplasms and acute leukemias requires testing for a large number of molecular biomarkers. Next-generation sequencing is a technology able to integrate identification of the vast majority of them in a single test. This manuscript includes the design, analytical validation and clinical feasibility evaluation of a molecular diagnostic kit for onco-hematological diseases. It is based on sequencing of the coding regions of 76 genes (seeking single-nucleotide variants, small insertions or deletions and CNVs), as well as the search for fusions in 27 target genes. The kit has also been designed to detect large CNVs throughout the genome by including specific probes and employing a custom bioinformatics approach. The analytical and clinical feasibility validation of the Haematology OncoKitDx panel has been carried out from the sequencing of 170 patient samples from 6 hospitals (in addition to the use of commercial reference samples). The analytical validation showed sensitivity and specificity close to 100% for all the parameters evaluated, with a detection limit of 2% for SNVs and SVs, and 20% for CNVs. Clinically relevant mutations were detected in 94% of all patients. An analysis of the correlation between the genetic risk classification of AML (according to ELN 2017) established by the hospitals and that obtained by the Haematology OncoKitDx panel showed an almost perfect correlation (K = 0.94). Among the AML samples with a molecular diagnosis, established by the centers according to the WHO, the Haematology OncoKitDx analysis showed the same result in 97% of them. The panel was able to adequately differentiate between MPN subtypes and also detected alterations that modified the diagnosis (FIP1L1-PDGFRA). Likewise, the cytogenetic risk derived from the CNV plot generated by the NGS panel correlated substantially with the results of the conventional karyotype (K = 0.71) among MDS samples. In addition, the panel detected the main biomarkers of prognostic value among patients with ALL. This validated solution enables a reliable analysis of a large number of molecular biomarkers from a DNA sample in a single assay.

Germline Predisposition to Pediatric Cancer, from Next Generation Sequencing to Medical Care.

Knowledge about genetic predisposition to pediatric cancer is constantly expanding. The categorization and clinical management of the best-known syndromes has been refined over the years. Meanwhile, new genes for pediatric cancer susceptibility are discovered every year. Our current work shares the results of genetically studying the germline of 170 pediatric patients diagnosed with cancer. Patients were prospectively recruited and studied using a custom panel, OncoNano V2. The well-categorized predisposing syndromes incidence was 9.4%. Likely pathogenic variants for predisposition to the patient's tumor were identified in an additional 5.9% of cases. Additionally, a high number of pathogenic variants associated with recessive diseases was detected, which required family genetic counseling as well. The clinical utility of the Jongmans MC tool was evaluated, showing a high sensitivity for detecting the best-known predisposing syndromes. Our study confirms that the Jongmans MC tool is appropriate for a rapid assessment of patients; however, the updated version of Ripperger T criteria would be more accurate. Meaningfully, based on our findings, up to 9.4% of patients would present genetic alterations predisposing to cancer. Notably, up to 20% of all patients carry germline pathogenic or likely pathogenic variants in genes related to cancer and, thereby, they also require expert genetic counseling. The most important consideration is that the detection rate of genetic causality outside Jongmans MC et al. criteria was very low.

Comprehensive NGS Panel Validation for the Identification of Actionable Alterations in Adult Solid Tumors.

The increasing identification of driver oncogenic alterations and progress of targeted therapies addresses the need of comprehensive alternatives to standard molecular methods. The translation into clinical practice of next-generation sequencing (NGS) panels is actually challenged by the compliance of high quality standards for clinical accreditation. Herein, we present the analytical and clinical feasibility study of a hybridization capture-based NGS panel (Action OncoKitDx) for the analysis of somatic mutations, copy number variants (CNVs), fusions, pharmacogenetic SNPs and Microsatellite Instability (MSI) determination in formalin-fixed paraffin-embedded (FFPE) tumor samples. A total of 64 samples were submitted to extensive analytical validation for the identification of previously known variants. An additional set of 166 tumor and patient-matched normal samples were sequenced to assess the clinical utility of the assay across different tumor types. The panel demonstrated good specificity, sensitivity, reproducibility, and repeatability for the identification of all biomarkers analyzed and the 5% limit of detection set was validated. Among the clinical cohorts, the assay revealed pathogenic genomic alterations in 97% of patient cases, and in 82.7%, at least one clinically relevant variant was detected. The validation of accuracy and robustness of this assay supports the Action OncoKitDx's utility in adult solid tumors.

Cingulate epileptogenesis in hypothalamic hamartoma.

Hypothalamic hamartoma (HH) is a relatively rare cause of epilepsy, mainly affecting children. Nearly all patients develop gelastic seizures, often followed by other focal seizure types. Our case illustrates the mechanisms of epileptogenesis in HH. The patient developed gelastic attacks as a baby, and secondarily generalized seizures and drop attacks at 9 years of age. Magnetic resonance imaging (MRI) confirmed the presence of a HH. Presurgical assessment with intracranial electroencephalography (EEG) monitoring recorded gelastic seizures with generalized epileptiform activity. Functional stimulation of the hamartoma provoked gelastic attacks. Single pulse electrical stimulation (SPES) was used to identify epileptogenic cortex. SPES of the left cingular cortex provoked generalized responses similar to the spontaneous generalized discharges. Our results suggest that long-standing history of epilepsy in patients with HH may be related to additional sources of epileptogenic activity. Electrical stimulation performed in this patient provided additional data to favor the hypothesis of secondarily epileptogenesis in the cingulate gyrus independently from the primary origin in the HH.