[A MOLECULAR APPROACH TO DIAGNOSIS AND TREATMENT OF PEDIATRIC SOFT TISSUE SARCOMA FROM "E PLURIBUS UNUM" TO "EX UNO PLURES" AND BACK].

INTRODUCTION: Soft tissue sarcoma is a heterogeneous group of mesenchymal (fat, muscle, cartilage and blood vessel) tumors. It collectively comprises 1% of adult malignancies, and 7% of pediatric malignancies and according to the last WHO classification, contains over 50 histologic diagnoses. Due to its relatively infrequent occurrence, diversity of sub-types and high rates of inter-observer disagreement regarding the histological sub-type, the approach to both basic and clinical research, and, accordingly, treatment has traditionally been "one size fits all". All soft tissue sarcoma sub-types were merged in clinical studies, and assigned standard treatment. Although this approach made large scale clinical studies possible, it hindered our understanding of the treatment effect in specific sub-types of soft tissue sarcoma (since small sub-groups were diluted in the general study population), and did not promote our understanding of sub-type specific oncogenesis. In recent decades, as molecular understanding of oncogenesis advances, it is used increasingly as an adjunct to histology and immunohistochemistry for diagnostic as well as therapeutic purposes. As the diagnosis of the soft tissue sarcoma sub-type becomes more accurate and unambiguous, we can efficiently focus research (both basic and clinical) on sub-type specific oncogenesis, and (consequently) allow sub-type specific treatment.

Ocular venous occlusion in pediatrics: Should thrombophilia investigation and anticoagulant treatment be initiated?

Retinal vein occlusion (RVO) and superior ophthalmic vein thrombosis (SOVT) are rare diseases in the pediatric population; however, the ophthalmic and neurologic morbidity are significant. As published data are scarce for these conditions, we present our experience with pediatric ocular venous thrombosis in four patients, and discuss recommended management for evaluation and treatment. We suggest performing thrombophilia workup for all pediatric patients with RVO or SOVT. In patients with thrombophilia risk factors or patients with additional thrombi, we highly recommend initiating anticoagulation therapy. There is a need for more research in order to determine the optimal management strategy.

Genetic testing and surveillance in infantile myofibromatosis: a report from the SIOPE Host Genome Working Group.

Infantile myofibromatosis (IM), which is typically diagnosed in young children, comprises a wide clinical spectrum ranging from inconspicuous solitary soft tissue nodules to multiple disseminated tumors resulting in life-threatening complications. Familial IM follows an autosomal dominant mode of inheritance and is linked to PDGFRB germline variants. Somatic PDGFRB variants were also detected in solitary and multifocal IM lesions. PDGFRB variants associated with IM constitutively activate PDGFRB kinase activity in the absence of its ligand. Germline variants have lower activating capabilities than somatic variants and, thus, require a second cis-acting hit for full receptor activation. Typically, these mutant receptors remain sensitive to tyrosine kinase inhibitors such as imatinib. The SIOPE Host Genome Working Group, consisting of pediatric oncologists, clinical geneticists and scientists, met in January 2020 to discuss recommendations for genetic testing and surveillance for patients who are diagnosed with IM or have a family history of IM/PDGFRB germline variants. This report provides a brief review of the clinical manifestations and genetics of IM and summarizes our interdisciplinary recommendations.

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for disseminated intra-abdominal malignancies in children-a single-institution experience.

PURPOSE: Our purpose was to present our institutional experience with performing complete cytoreduction surgery and heated intraoperative chemotherapy (CRS-HIPEC) for children with disseminated intraabdominal malignancies, guided by a leading international center performing CRS-HIPEC in children. METHODS: Retrospective chart review of all cases of CRS-HIPEC in children in our institution, examining diagnosis, preoperative management, operative management, postoperative treatment, short term outcome including length of stay and complications, and long term outcome including survival and recurrence of disease. RESULTS: 9 children underwent CRS-HIPEC over 48months. The mean age of the patients was 8years. Tumors were: rhabdomyosarcoma (RMS), mesothelioma, Sertoli-Leydig, desmoplastic small round cell tumor, colon carcinoma and Wilms' tumor. Most patients received intraperitoneal cisplatin. Short term outcome was very good with median length of hospital stay of 13days and low rate of complications. Seven patients were alive at last follow up. Five patients developed a recurrent disease. Recurrence was intraabdominal in two of these patients. CONCLUSIONS: CRS-HIPEC for children with disseminated intraabdominal malignancies performed in a dedicated institution and with guidance by a leading international center can be performed safely. TYPE OF STUDY: Treatment study. LEVEL OF EVIDENCE: IV.

Recurrent Immune Thrombocytopenia After Influenza Vaccination: A Case Report.

Immune thrombocytopenia (ITP) is an isolated autoimmune condition, often preceded by a viral infection. Vaccines, mainly the measles-mumps-rubella vaccine, have also been associated with an increased risk of developing the disease. Although some case reports of ITP after influenza immunization in adults have been published, epidemiologic studies examining the role of the influenza vaccine as a trigger of ITP have not conclusively proven causality. We report a child with 3 occurrences of ITP, each within 1 week of receiving the influenza trivalent inactivated vaccine. He recovered fully in-between the episodes, and no further episodes have occurred since discontinuation of seasonal influenza vaccination. To the best of our knowledge, this report is the first showing, with high probability, the influenza vaccine as a cause for ITP in a pediatric patient.

The Risk of Serious Bacterial Infection in Neutropenic Immunocompetent Febrile Children.

Only few reports have looked into the risk of invasive bacterial infection in children with neutropenia that is not malignancy related. The objective of the current study was to determine the clinical significance of neutropenia as a predictor of serious bacterial infection (SBI) in immunocompetent children. We conducted a retrospective case-control study including children 3 months to 18 years of age with fever ≥ 38°C hospitalized or presenting to the emergency department. Patients who had neutropenia ≤ 1000 ANC/µL and had a blood culture taken were matched for age with the consecutive febrile patients for whom a blood culture was taken. The main outcome was the rate of SBI. SBIs were more prevalent among the control group than in the group of children with neutropenia, 19/71 and 6/71, respectively (P = 0.0005). More children were treated with antibiotics among the control group than in the group of children with neutropenia, 39/71 and 20/71, respectively (P < 0.0001). Acute-phase reactants including CRP and platelets were higher in the control group. We concluded that immunocompetent patients with fever and moderate neutropenia do not carry a higher risk for SBIs compared with patients with fever who do not have neutropenia.

Characterization of two unique α-globin gene cluster deletions causing α-thalassemia in Israeli Arabs.

The molecular basis of α-thalassemia (α-thal) is complex. The use of multiplex ligation-dependent probe amplification (MLPA) has offered the possibility of identifying more gene deletions causing α-thal. Our objective was to determine the molecular basis of two patients with Hb H (ß4) disease. By using MLPA in combination with comparative genomic hybridization (CGH) we identified two novel α-globin gene cluster deletions: a 30 kb deletion (patient 1) we refer to as - -(JAL) and a large 216 kb deletion (patient 2) we refer to as - -(LOD). Patient 1 was a compound heterozygote for - -(JAL) and -α(3.7) (rightward deletion). Twelve family members of patient 1 carrying the - -(JAL) deletion were available for evaluation: five with - -(JAL)/-α(3.7), four with - -(JAL)/α(Hph I)α and three with - -(JAL)/αα. Their clinical picture of compound heterozygosity was compatible with moderate Hb H disease. In patient 2 (- -(LOD)/-α(3.7)), no additional symptoms were present despite the heterozygous deletion of seven known genes, three non coding RNAs (ncRNAs), four unknown genes and two pseudo genes. Further analysis of more patients with α-thal deletions will have implications for genetic counseling and appropriate therapy.

Delta 9-tetrahydrocannabinol inhibits cell cycle progression by downregulation of E2F1 in human glioblastoma multiforme cells.

BACKGROUND: The active components of Cannabis sativa L., Cannabinoids, traditionally used in the field of cancer for alleviation of pain, nausea, wasting and improvement of well-being have received renewed interest in recent years due to their diverse pharmacologic activities such as cell growth inhibition, anti-inflammatory activity and induction of tumor regression. Here we used several experimental approaches, which identified delta-9-tetrahydrocannabinol (Delta(9)-THC) as an essential mediator of cannabinoid antitumoral action. METHODS AND RESULTS: Administration of Delta(9)-THC to glioblastoma multiforme (GBM) cell lines results in a significant decrease in cell viability. Cell cycle analysis showed G(0/1) arrest and did not reveal occurrence of apoptosis in the absence of any sub-G(1) populations. Western blot analyses revealed a THC altered cellular content of proteins that regulate cell progression through the cell cycle. The cell content of E2F1 and Cyclin A, two proteins that promote cell cycle progression, were suppressed in both U251-MG and U87-MG human glioblastoma cell lines, whereas the level of p16(INK4A), a cell cycle inhibitor was upregulated. Transcription of thymidylate synthase (TS) mRNA, which is promoted by E2F1, also declined as evident by QRT-PCR. The decrease in E2F1 levels resulted from proteasome mediated degradation and was prevented by proteasome inhibitors. CONCLUSIONS: Delta(9)-THC is shown to significantly affect viability of GBM cells via a mechanism that appears to elicit G(1) arrest due to downregulation of E2F1 and Cyclin A. Hence, it is suggested that Delta(9)-THC and other cannabinoids be implemented in future clinical evaluation as a therapeutic modality for brain tumors.

Mechanisms operative in the antitumor activity of temozolomide in glioblastoma multiforme.

PURPOSE: Glioblastoma multiforme (GBM) is the most frequent and incurable brain tumor in adults. Although temozolomide (TMZ) does not cure GBM, it has demonstrated anti-GBM activity and has improved survival (8-14 months) and quality of life. We studied the mechanisms by which TMZ affects 2 human GBM cell lines; U251-MG and U87-MG, aiming to unravel the drug-activated cascades to enable the development of combination therapies that will improve the efficacy of TMZ. MATERIALS AND METHODS: The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium assay was used to assess cell viability. Modulation of gene expression by TMZ therapy was assayed by gene profiling and verified by quantitative real-time polymerase chain reaction. Protein levels influenced by the treatment were studied by Western blots and immunocytochemistry. RESULTS: Increasing concentrations of TMZ decreased cell viability in a concentration-dependent manner. The expression of 1,886 genes was altered >2-fold after TMZ treatment. We focused on the 81 genes similarly altered by TMZ treatment in both cell lines to neutralize tissue-specific characteristics. Fourteen target genes of hypoxia-inducible factor (HIF-1), were found to be up-regulated after TMZ treatment including vascular endothelial growth factor (VEGF). HIF-1alpha expression was constant at the mRNA level; however, its post-treatment protein levels increased compared with those of untreated control cells. DISCUSSION: The genetic analyses suggest that treatment with TMZ activates stress mechanisms in GBM cells that include the angiogenesis-inducing proteins HIF-1alpha and VEGF. We propose that treatment with TMZ be supplemented with either an antibody to VEGF or down-regulators of HIF-1alpha to improve clinical results of TMZ in the treatment of GBM.

CD133-positive hematopoietic stem cell "stemness" genes contain many genes mutated or abnormally expressed in leukemia.

Affymetrix human Hu133A oligonucleotide arrays were used to study the expression profile of CD133+ cord blood (CB) and peripheral blood (PB) using CD133 cell-surface marker. An unsupervised hierarchical clustering of 14,025 valid probe sets showed a clear distinction between the CD133+ cells representing the hematopoietic stem cell (HSC) population and CD133-differentiated cells. Two hundred forty-four genes were found to be upregulated by at least twofold in the CD133-positive cells of both CB and PB compared with the CD133-negative cells. These genes represent the hematopoietic "stemness," whereas the 218 and 304 upregulated genes exclusively in PB and CB, respectively, represent tissue specificity. Some of the stemness genes were also common to HSC genes found to be upregulated in several recently published studies. Among these common stemness genes, we identified several groups of genes that have an important role in hematopoiesis: growth factor receptors, transcription factors, genes that have an important role in development, and genes involved in cell growth. Sixteen selected stemness genes are known to be mutated or abnormally regulated in acute leukemias. It can be suggested that key hematopoietic stemness machinery genes may lead to abnormal proliferation and leukemia upon mutation or change of their expression.

Scopolamine treatment for severe extra-pyramidal signs following organophosphate (chlorpyrifos) ingestion.

BACKGROUND: The use of competitive inhibitors of acetylcholine other than atropine, for patients with organophosphate poisoning is controversial. Because scopolamine ability to cross the blood-brain barrier is better than that of atropine, it has been suggested that it should be used in patients with organophosphate poisoning who have central nervous system manifestations. CASE DESCRIPTION: A 17-year-old girl was admitted to the pediatric ward after ingesting chlorpyrifos as a suicidal attempt. She reported vomiting three times. She had no other symptoms for 12 hours and then over the course of 36 hours gradually developed extrapyramidal signs and became comatose. She was treated with intravenous scopolamine. Within 3 minutes the patient started to respond to verbal commands and answered simple questions rigidity subsided, and she was able to sit in bed. She was discharged after 4 days with no neurological sequelae. CONCLUSIONS: We suggest, that in patients with organophosphate poisoning who have mainly central nervous system toxicity scopolamine administration might be considered.