Validation and clinical application of transactivation assays for RUNX1 variant classification

Familial platelet disorder with associated myeloid malignancies (RUNX1-FPD) is caused by heterozygous pathogenic germline variants of RUNX1. In the present study, we evaluate the applicability of transactivation assays to investigate RUNX1 variants in different regions of the protein. We studied 11 variants to independently validate transactivation assays supporting variant classification following the ClinGen Myeloid Malignancies variant curation expert panel guidelines. Variant classification is key for the translation of genetic findings. We showed that new assays need to be developed to assess C-terminal RUNX1 variants. Two variants of uncertain significance (VUS) were reclassified to likely pathogenic. Additionally, our analyses supported the (likely) pathogenic classification of two other variants. We demonstrated functionality of four VUS, but reclassification to (likely) benign was challenging and suggested the need to reevaluate current classification guidelines. Finally, clinical utility of our assays was illustrated in the context of seven families. Our data confirmed RUNX1-FPD suspicion in three families with RUNX1-FPD-specific family history. Whereas for three variants identified in non RUNX1-FPD-typical families, no functional defect was detected. Applying functional assays to support RUNX1 variant classification can be essential for adequate care of index patients and their relatives at risk. It facilitates translation of genetic data into personalized medicine.

Recent Progress in Lymphangioma

Lymphangioma is a common type of congenital vascular disease in children with a broad spectrum of clinical manifestations. The current classification of lymphangioma by International Society for the Study of Vascular Anomalies is largely based on the clinical manifestations and complications and is not sufficient for selection of therapeutic strategies and prognosis prediction. The clinical management and outcome of lymphangioma largely depend on the clinical classification and the location of the disease, ranging from spontaneous regression with no treatment to severe sequelae even with comprehensive treatment. Recently, rapid progression has been made toward elucidating the molecular pathology of lymphangioma and the development of treatments. Several signaling pathways have been revealed to be involved in the progression and development of lymphangioma, and specific inhibitors targeting these pathways have been investigated for clinical applications and clinical trials. Some drugs already currently in clinical use for other diseases were found to be effective for lymphangioma, although the mechanisms underlying the anti-tumor effects remain unclear. Molecular classification based on molecular pathology and investigation of the molecular mechanisms of current clinical drugs is the next step toward developing more effective individualized treatment of children with lymphangioma with reduced side effects.

Malignancy-Associated Membranous Nephropathy with Positive Anti-PLA2R Autoantibodies: Coincidence or Connection

Membranous nephropathy (MN) is currently classified as either primary – often associated with positive anti-phospholipase-A2 receptor (PLA2R) autoantibodies – or as secondary – associated with malignancy, infection, medications, or autoimmune disease. We present a case of biopsy-proven MN with very high serum titer of anti-PLA2R autoantibodies in a patient with a synchronous diagnosis of poorly differentiated esophageal adenocarcinoma and renal cell carcinoma who presented with nephrotic syndrome. Based on the current classification, MN in the presence of active malignancy is diagnosed as secondary and unlikely to have positive anti-PLA2R autoantibodies. This raises several questions: whether this patient has secondary MN associated with malignancy and coincidentally discovered anti-PLA2R autoantibodies, primary MN due to anti-PLA2R autoantibodies with coincidentally discovered malignancy, or whether malignancy can induce the formation of anti-PLA2R autoantibodies that result in MN. This case report highlights the importance of age-appropriate cancer screening, even in patients with presumed primary MN and positive anti-PLA2R autoantibodies.

NEW APPROACHES TO THE DEFINITION AND CLASSIFICATION OF BRONCHOPULMONARY DYSPLASIA IN PRETERM INFANTS

Bronchopulmonary dysplasia (BPD) remains a pressing problem of modern neonatology and pediatrics. Since this disease is chronic and often results in negative long-term consequences, the search for the optimal definition of BPD that would be accuratein predicting long- term respiratory and neurological outcomes is ongoing. It has been 20 years since the definition and classification of BPDs that are currently used had been approved. Over time, the patient population prone to BPD development has changed and new factors have emerged that make it difficult to apply this classification in contemporary clinical practice. In particular, it concerns greater survival of extremely premature infants, which form the majority of patients with BPD. Oxygen dependence during the first month in such infants may be determined by the immaturity of the respiratory system and may not be associated with the development of BPD. Also, new methods of respiratory support have been introduced into practice of intensive care units, which is not accounted for by the current classification. The population of infants with severe BPD, according to classical definition, is heterogeneous with different indicators of long-term chronic morbidity and development. All this justifies the need for new methodological approaches and criteria for the definition and classification of BPD in the modern population of premature infants.This review presents new data, proposals and clarifications for the definition and classification of BPD, which take into account modern features of clinical practice.

Annotation of pituitary neuroendocrine tumors with genome-wide expression analysis

Pituitary neuroendocrine tumors (PitNETs) are common, generally benign tumors with complex clinical characteristics related to hormone hypersecretion and/or growing sellar tumor mass. PitNETs can be classified based on the expression pattern of anterior pituitary hormones and three main transcriptions factors (TF), SF1, PIT1 and TPIT that regulate differentiation of adenohypophysial cells. Here, we have extended this classification based on the global transcriptomics landscape using tumor tissue from a well-defined cohort comprising 51 PitNETs of different clinical and histological types. The molecular profiles were compared with current classification schemes based on immunohistochemistry. Our results identified three main clusters of PitNETs that were aligned with the main pituitary TFs expression patterns. Our analyses enabled further identification of specific genes and expression patterns, including both known and unknown genes, that could distinguish the three different classes of PitNETs. We conclude that the current classification of PitNETs based on the expression of SF1, PIT1 and TPIT reflects three distinct subtypes of PitNETs with different underlying biology and partly independent from the expression of corresponding hormones. The transcriptomic analysis reveals several potentially targetable tumor-driving genes with previously unknown role in pituitary tumorigenesis.

Acoustic non-Hermitian skin effect from twisted winding topology

The recently discovered non-Hermitian skin effect (NHSE) manifests the breakdown of current classification of topological phases in energy-nonconservative systems, and necessitates the introduction of non-Hermitian band topology. So far, all NHSE observations are based on one type of non-Hermitian band topology, in which the complex energy spectrum winds along a closed loop. As recently characterized along a synthetic dimension on a photonic platform, non-Hermitian band topology can exhibit almost arbitrary windings in momentum space, but their actual phenomena in real physical systems remain unclear. Here, we report the experimental realization of NHSE in a one-dimensional (1D) non-reciprocal acoustic crystal. With direct acoustic measurement, we demonstrate that a twisted winding, whose topology consists of two oppositely oriented loops in contact rather than a single loop, will dramatically change the NHSE, following previous predictions of unique features such as the bipolar localization and the Bloch point for a Bloch-wave-like extended state. This work reveals previously unnoticed features of NHSE, and provides the observation of physical phenomena originating from complex non-Hermitian winding topology.