Concurrent ependymal and ganglionic differentiation in a subset of supratentorial neuroepithelial tumors with EWSR1-PLAGL1 rearrangement.

Neuroepithelial tumors with fusion of PLAGL1 or amplification of PLAGL1/PLAGL2 have recently been described often with ependymoma-like or embryonal histology respectively. To further evaluate emerging entities with PLAG-family genetic alterations, the histologic, molecular, clinical, and imaging features are described for 8 clinical cases encountered at St. Jude (EWSR1-PLAGL1 fusion n = 6; PLAGL1 amplification n = 1; PLAGL2 amplification n = 1). A histologic feature observed on initial resection in a subset (4/6) of supratentorial neuroepithelial tumors with EWSR1-PLAGL1 rearrangement was the presence of concurrent ependymal and ganglionic differentiation. This ranged from prominent clusters of ganglion cells within ependymoma/subependymoma-like areas, to interspersed ganglion cells of low to moderate frequency among otherwise ependymal-like histology, or focal areas with a ganglion cell component. When present, the combination of ependymal-like and ganglionic features within a supratentorial neuroepithelial tumor may raise consideration for an EWSR1-PLAGL1 fusion, and prompt initiation of appropriate molecular testing such as RNA sequencing and methylation profiling. One of the EWSR1-PLAGL1 fusion cases showed subclonal INI1 loss in a region containing small clusters of rhabdoid/embryonal cells, and developed a prominent ganglion cell component on recurrence. As such, EWSR1-PLAGL1 neuroepithelial tumors are a tumor type in which acquired inactivation of SMARCB1 and development of AT/RT features may occur and lead to clinical progression. In contrast, the PLAGL2 and PLAGL1 amplified cases showed either embryonal histology or contained an embryonal component with a significant degree of desmin staining, which could also serve to raise consideration for a PLAG entity when present. Continued compilation of associated clinical data and histopathologic findings will be critical for understanding emerging entities with PLAG-family genetic alterations.

Polygenic Pharmacogenomic Markers as Predictors of Toxicity Phenotypes in the Treatment of Acute Lymphoblastic Leukemia: A Single-Center Study.

PURPOSE: Acute lymphoblastic leukemia (ALL) is the most prevalent cause of childhood cancer and requires a long course of therapy consisting of three primary phases with interval intensification blocks. Although these phases are necessary to achieve remission, the primary chemotherapeutic agents have potentially serious toxicities, which may lead to delays or discontinuations of therapy. The purpose of this study was to perform a comprehensive pharmacogenomic evaluation of common antileukemic agents and develop a polygenic toxicity risk score predictive of the most common toxicities observed during ALL treatment. METHODS: This cross-sectional study included 75 patients with pediatric ALL treated between 2012 and 2020 at the University of Florida. Toxicity data were collected within 100 days of initiation of therapy using CTCAE v4.0 for toxicity grading. For pharmacogenomic evaluation, single-nucleotide polymorphisms (SNPs) and genes were selected from previous reports or PharmGKB database. 116 unique SNPs were evaluated for incidence of various toxicities. A multivariable multi-SNP modeling for up to 3-SNP combination was performed to develop a polygenic toxicity risk score of prognostic value. RESULTS: We identified several SNPs predictive of toxicity phenotypes in univariate analysis. Further multivariable SNP-SNP combination analysis suggest that susceptibility to chemotherapy-induced toxicities is likely multigenic in nature. For 3-SNPscore models, patients with high scores experienced increased risk of GI (P = 2.07E-05, 3 SNPs: TYMS-rs151264360/FPGS-rs1544105/GSTM1-GSTM5-rs3754446), neurologic (P = .0005, 3 SNPs: DCTD-rs6829021/SLC28A3-rs17343066/CTPS1-rs12067645), endocrine (P = 4.77E-08, 3 SNPs: AKR1C3-rs1937840/TYMS-rs2853539/CTH-rs648743), and heme toxicities (P = .053, 3 SNPs: CYP3A5-rs776746/ABCB1-rs4148737/CTPS1-rs12067645). CONCLUSION: Our results imply that instead of a single-SNP approach, SNP-SNP combinations in multiple genes in drug pathways increases the robustness of prediction of toxicity. These results further provide promising SNP models that can help establish clinically relevant biomarkers allowing for greater individualization of cancer therapy to maximize efficacy and minimize toxicity for each patient.

Romiplostim as a Therapeutic Intervention for Tacrolimus-induced Immune Thrombocytopenia in a Pediatric Cardiac Transplant Patient.

Tacrolimus-induced immune thrombocytopenia (ITP) is a rare entity that can occur years after initiation of tacrolimus therapy following solid organ transplantation, and platelet recovery can be substantially delayed following discontinuation of tacrolimus. Romiplostim, a thrombopoietin receptor agonist approved by the FDA in 2018 for the treatment of chronic ITP in children, may be a useful therapy to hasten platelet recovery in the acute ITP setting in place of immunomodulating agents. We present a case of tacrolimus-induced ITP successfully treated with romiplostim in a child following cardiac transplantation.

Parvovirus B19 infection masquerading as relapsed acute lymphoblastic leukaemia following haematopoietic stem cell transplantation.

A 7-year-old boy presented with a constellation of bone pain, a skeletal lesion, and pancytopenia after undergoing allogeneic haematopoietic stem cell transplantation for recurrent acute B-cell lymphoblastic leukaemia. Investigations to rule out leukaemia recurrence were unremarkable. Due to presence of maturation arrest in erythropoiesis with giant pronormoblasts and aberrant intranuclear inclusions on a bone marrow aspirate, parvovirus B19 (PVB-19) staining was completed and confirmed the diagnosis of disseminated PVB-19. Though PVB-19 infection after solid organ transplantation was reported in the literature as early as 1986, acquired PVB-19 viremia presenting with a solitary bone lesion is a novel presentation in paediatrics.

Chordoma of the Clivus and Acute Myeloid Leukemia: Is There a Connection?

Chordoma is a rare cancer in children and understanding the genesis of this tumor may contribute to treatment approaches. Evidence has proposed VDC/IE (vincristine, doxorubicin, cyclophosphamide/ifosfamide, etoposide) as a treatment option for young patients with chordoma to avoid the long-term effects of radiation therapy. We present a case of acute myeloid leukemia developing during treatment of localized chordoma of the clivus in a 20-month-old male. We propose a genomic relationship that may have contributed to the development of clival chordoma and acute myeloid leukemia without a latency period and advocate for genomic sequencing in children with chordoma before the initiation of systemic therapies.