From the identification of actionable molecular targets to the generation of faithful neuroblastoma patient-derived preclinical models.

BACKGROUND: Neuroblastoma (NB) represents the most frequent and aggressive form of extracranial solid tumor of infants. Although the overall survival of patients with NB has improved in the last years, more than 50% of high-risk patients still undergo a relapse. Thus, in the era of precision/personalized medicine, the need for high-risk NB patient-specific therapies is urgent. METHODS: Within the PeRsonalizEd Medicine (PREME) program, patient-derived NB tumors and bone marrow (BM)-infiltrating NB cells, derived from either iliac crests or tumor bone lesions, underwent to histological and to flow cytometry immunophenotyping, respectively. BM samples containing a NB cells infiltration from 1 to 50 percent, underwent to a subsequent NB cells enrichment using immune-magnetic manipulation. Then, NB samples were used for the identification of actionable targets and for the generation of 3D/tumor-spheres and Patient-Derived Xenografts (PDX) and Cell PDX (CPDX) preclinical models. RESULTS: Eighty-four percent of NB-patients showed potentially therapeutically targetable somatic alterations (including point mutations, copy number variations and mRNA over-expression). Sixty-six percent of samples showed alterations, graded as "very high priority", that are validated to be directly targetable by an approved drug or an investigational agent. A molecular targeted therapy was applied for four patients, while a genetic counseling was suggested to two patients having one pathogenic germline variant in known cancer predisposition genes. Out of eleven samples implanted in mice, five gave rise to (C)PDX, all preserved in a local PDX Bio-bank. Interestingly, comparing all molecular alterations and histological and immunophenotypic features among the original patient's tumors and PDX/CPDX up to second generation, a high grade of similarity was observed. Notably, also 3D models conserved immunophenotypic features and molecular alterations of the original tumors. CONCLUSIONS: PREME confirms the possibility of identifying targetable genomic alterations in NB, indeed, a molecular targeted therapy was applied to four NB patients. PREME paves the way to the creation of clinically relevant repositories of faithful patient-derived (C)PDX and 3D models, on which testing precision, NB standard-of-care and experimental medicines.

Inside the Biology of the ß3-Adrenoceptor.

Since the first discovery in 1989, the ß3-adrenoceptor (ß3-AR) has gained great attention because it showed the ability to regulate many physiologic and metabolic activities, such as thermogenesis and lipolysis in brown and white adipose tissue, respectively (BAT, WAT), negative inotropic effects in cardiomyocytes, and relaxation of the blood vessels and the urinary bladder. The ß3-AR has been suggested as a potential target for cancer treatment, both in adult and pediatric tumors, since under hypoxia its upregulation in the tumor microenvironment (TME) regulates stromal cell differentiation, tumor growth and metastases, signifying that its agonism/antagonism could be useful for clinical benefits. Promising results in cancer research have proposed the ß3-AR being targeted for the treatment of many conditions, with some drugs, at present, undergoing phase II and III clinical trials. In this review, we report the scientific journey followed by the research from the ß3-Ars' discovery, with focus on the ß3-Ars' role in cancer initiation and progression that elects it an intriguing target for novel antineoplastic approaches. The overview highlights the great potential of the ß3-AR, both in physiologic and pathologic conditions, with the intention to display the possible benefits of ß3-AR modulation in cancer reality.

Outcome of primary hemophagocytic lymphohistiocytosis: a report on 143 patients from the Italian Registry.

Primary hemophagocytic lymphohistiocytosis (pHLH) is a severe, life-threatening hyperinflammatory syndrome caused by defects in genes of the granule-dependent cytotoxic pathway. Here we investigated the clinical presentation and outcome in a large cohort of 143 patients with pHLH diagnosed in the last 15 years and enrolled in the Italian registry. The median age at diagnosis was 12 months (IQR 2-81), and ninety-two patients (64%) fulfilled the HLH-2004 criteria. Out of 111 patients who received first-line combined therapy (HLH-94, HLH-2004, Euro-HIT protocols), 65 (59%) achieved complete response (CR) and 21 (19%) partial response (PR). Thereafter, 33 patients (30%) reactivated, and 92 (64%) received HSCT, 78 of whom (85%) survived and were alive at a median follow-up from diagnosis of 67 months. Thirty-six patients (25%) died before HSCT and 14 (10%) after. Overall, 93 patients (65%) were alive after a median follow-up of 30 months. Unadjusted predictors of non-response were age.

TP53 DNA binding domain mutational status and rituximab-based treatment are independent prognostic factors for pediatric Burkitt lymphoma patients stratification.

Not available.

Blockade of IL-10 Signaling Ensures Mifamurtide Efficacy in Metastatic Osteosarcoma.

Osteosarcoma (OS) is the most common primary malignancy of the bone, highly aggressive and metastasizing, and it mainly affects children and adolescents. The current standard of care for OS is a combination of surgery and chemotherapy. However, these treatment options are not always successful, especially in cases of metastatic or recurrent osteosarcomas. For this reason, research into new therapeutic strategies is currently underway, and immunotherapies have received considerable attention. Mifamurtide stands out among the most studied immunostimulant drugs; nevertheless, there are very conflicting opinions on its therapeutic efficacy. Here, we aimed to investigate mifamurtide efficacy through in vitro and in vivo experiments. Our results led us to identify a new possible target useful to improve mifamurtide effectiveness on metastatic OS: the cytokine interleukin-10 (IL-10). We provide experimental evidence that the synergic use of an anti-IL-10 antibody in combination with mifamurtide causes a significantly increased mortality rate in highest-grade OS cells and lower metastasis in an in vivo model compared with mifamurtide alone. Overall, our data suggest that mifamurtide in combination with an anti-IL-10 antibody could be proposed as a new treatment protocol to be studied to improve the outcomes of OS patients.

Approaching hemophagocytic lymphohistiocytosis.

Hemophagocytic Lymphohistiocytosis (HLH) is a rare clinical condition characterized by sustained but ineffective immune system activation, leading to severe and systemic hyperinflammation. It may occur as a genetic or sporadic condition, often triggered by an infection. The multifaceted pathogenesis results in a wide range of non-specific signs and symptoms, hampering early recognition. Despite a great improvement in terms of survival in the last decades, a considerable proportion of patients with HLH still die from progressive disease. Thus, prompt diagnosis and treatment are crucial for survival. Faced with the complexity and the heterogeneity of syndrome, expert consultation is recommended to correctly interpret clinical, functional and genetic findings and address therapeutic decisions. Cytofluorimetric and genetic analysis should be performed in reference laboratories. Genetic analysis is mandatory to confirm familial hemophagocytic lymphohistiocytosis (FHL) and Next Generation Sequencing is increasingly adopted to extend the spectrum of genetic predisposition to HLH, though its results should be critically discussed with specialists. In this review, we critically revise the reported laboratory tools for the diagnosis of HLH, in order to outline a comprehensive and widely available workup that allows to reduce the time between the clinical suspicion of HLH and its final diagnosis.

Targeted treatment of solid tumors in pediatric precision oncology.

The treatment of childhood solid cancer has markedly evolved in recent years following a refined molecular characterization and the introduction of novel targeted drugs. On one hand, larger sequencing studies have revealed a spectrum of mutations in pediatric tumors different from adults. On the other hand, specific mutations or immune dysregulated pathways have been targeted in preclinical and clinical studies, with heterogeneous results. Of note, the development of national platforms for tumor molecular profiling and, in less measure, for targeted treatment, has been essential in the process. However, many of the available molecules have been tested only in relapsed or refractory patients, and have proven poorly effective, at least in monotherapy. Our future approaches should certainly aim at improving the access to molecular characterization, to obtain a deeper picture of the distinctive phenotype of childhood cancer. In parallel, the implementation of access to novel drugs should not only be limited to basket or umbrella studies but also to larger, multi-drug international studies. In this paper we reviewed the molecular features and the main available therapeutic options in pediatric solid cancer, focusing on available targeted drugs and ongoing investigations, aiming at providing a useful tool to navigate the heterogeneity of this promising but complex field.

ß3-adrenergic receptor on tumor-infiltrating lymphocytes sustains IFN-γ-dependent PD-L1 expression and impairs anti-tumor immunity in neuroblastoma.

Neuroblastoma (NB) is a heterogeneous extracranial tumor occurring in childhood. A distinctive feature of NB tumors is their neuroendocrine ability to secrete catecholamines, which in turn, via ß-adrenergic receptors ligation, may affect different signaling pathways in tumor microenvironment (TME). It was previously demonstrated that specific antagonism of ß3-adrenergic receptor (ß3-AR) on NB tumor cells affected tumor growth and progression. Here, in a murine syngeneic model of NB, we aimed to investigate whether the ß3-AR modulation influenced the host immune system response against tumor. Results demonstrated that ß3-AR antagonism lead to an immune response reactivation, partially dependent on the PD-1/PD-L1 signaling axis involvement. Indeed, ß3-AR blockade on tumor-infiltrating lymphocytes (TILs) dampened their ability to secrete IFN-γ, which in turn reduced the PD-L1 expression, caused by TILs infiltration, on NB tumor cells. Further investigations, through a genomic analysis on NB patients, showed that high ADRB3 gene expression correlates with worse clinical outcome compared to the low expression group, and that ADRB3 gene expression affects different immune-related pathways. Overall, results indicate that ß3-AR in NB TME is able to modulate the interaction between tumor and host immune system, and that its antagonism hits multiple pro-tumoral signaling pathways.

Therapeutic Targeting of ALK in Neuroblastoma: Experience of Italian Precision Medicine in Pediatric Oncology.

Neuroblastoma (NB) is the most common extracranial solid tumor in childhood. Patients with relapsed/refractory disease have a poor prognosis, and additional therapeutic options are needed. Mutations and amplifications in the ALK (Anaplastic Lymphoma Kinase) gene constitute a key target for treatment. Our goal, within the Italian project of PeRsonalizEdMEdicine (PREME), was to evaluate the genomic status of patients with relapsed/refractory NB and to implement targeted therapies in those with targetable mutations. From November 2018 to November 2021, we performed Whole Exome Sequencing or Targeted Gene Panel Sequencing in relapsed/refractory NB patients in order to identify druggable variants. Activating mutations of ALK were identified in 8(28.57%) of 28 relapsed/refractory NB patients. The mutation p.F1174L was found in six patients, whereas p.R1275Q was found in one and the unknown mutation p.S104R in another. Three patients died before treatment could be started, while five patients received crizotinib: two in monotherapy (one with p.F1174L and the other with p.S104R) and three (with p.F1174L variant) in combination with chemotherapy. All treated patients showed a clinical improvement, and one had complete remission after two cycles of combined treatment. The most common treatment-related toxicities were hematological. ALK inhibitors may play an important role in the treatment of ALK-mutated NB patients.

Italian Precision Medicine in Pediatric Oncology: Moving beyond Actionable Alterations.

Neuroblastoma (NB) is the most common extracranial solid tumor encountered in childhood. Although there has been significant improvement in the outcomes of patients with high-risk disease, the prognosis for patients with metastatic relapse or refractory disease is poor. Hence, the clinical integration of genome sequencing into standard clinical practice is necessary in order to develop personalized therapy for children with relapsed or refractory disease. The PeRsonalizEdMEdicine (PREME) project focuses on the design of innovative therapeutic strategies for patients suffering from relapsed NB. We performed whole exome sequencing (WES) of patient-matched tumor-normal samples to identify genetic variants amenable to precision medicine. Specifically, two patients were studied (First case: a three-year-old male with early relapsed NB; Second case: a 20-year-old male who relapsed 10 years after the first diagnosis of NB). Results were reviewed by a multi-disciplinary molecular tumor board (MTB) and clinical reports were issued to the ordering physician. WES revealed the mutation c.G320C in the CUL4A gene in case 1 and the mutation c.A484G in the PSMC2 gene in case 2. Both patients were treated according to these actionable alterations, with promising results. The effective treatment of NB is one of the main challenges in pediatric oncology. In the era of precision medicine, the need to design new therapeutic strategies for NB is fundamental. Our results demonstrate the feasibility of incorporating clinical WES into pediatric oncology practice.

Strategies for Potentiating NK-Mediated Neuroblastoma Surveillance in Autologous or HLA-Haploidentical Hematopoietic Stem Cell Transplants.

High-risk neuroblastomas (HR-NB) still have an unacceptable 5-year overall survival despite the aggressive therapy. This includes standardized immunotherapy combining autologous hemopoietic stem cell transplantation (HSCT) and the anti-GD2 mAb. The treatment did not significantly change for more than one decade, apart from the abandonment of IL-2, which demonstrated unacceptable toxicity. Of note, immunotherapy is a promising therapeutic option in cancer and could be optimized by several strategies. These include the HLA-haploidentical αßT/B-depleted HSCT, and the antibody targeting of novel NB-associated antigens such as B7-H3, and PD1. Other approaches could limit the immunoregulatory role of tumor-derived exosomes and potentiate the low antibody-dependent cell cytotoxicity of CD16 dim/neg NK cells, abundant in the early phase post-transplant. The latter effect could be obtained using multi-specific tools engaging activating NK receptors and tumor antigens, and possibly holding immunostimulatory cytokines in their construct. Finally, treatments also consider the infusion of novel engineered cytokines with scarce side effects, and cell effectors engineered with chimeric antigen receptors (CARs). Our review aims to discuss several promising strategies that could be successfully exploited to potentiate the NK-mediated surveillance of neuroblastoma, particularly in the HSCT setting. Many of these approaches are safe, feasible, and effective at pre-clinical and clinical levels.

Quantification of Minimal Disease by Digital PCR in ALK-Positive Anaplastic Large Cell Lymphoma: A Step towards Risk Stratification in International Trials?

Minimal disseminated and residual disease (MDD/MRD) analyzed by qualitative PCR for NPM-ALK fusion transcripts are validated prognostic factors in pediatric ALK-positive anaplastic large cell lymphoma (ALCL). Although potentially promising, MDD quantification by quantitative real-time PCR in international trials is technically challenging. Quantification of early MRD might further improve risk stratification. We aimed to assess droplet digital PCR for quantification of minimal disease in an inter-laboratory setting in a large cohort of 208 uniformly treated ALCL patients. Inter-laboratory quality control showed high concordance. Using a previously described cut-off of 30 copies NPM-ALK/104 copies ABL1 (NCN) in bone marrow and peripheral blood, MDD quantification allowed identification of very high-risk patients (5-year PFS% 34 ± 5 for patients with ≥30 NCN compared to 74 ± 6 and 76 ± 5 for patients with negative or <30 NCN, respectively, p < 0.0001). While MRD positivity was confirmed as a prognostic marker for the detection of very high-risk patients in this large study, quantification of MRD fusion transcripts did not improve stratification. PFS% was 80 ± 5 and 73 ± 6 for MDD- and MRD-negative patients, respectively, versus 35 ± 10 and 16 ± 8 for MRD-positive patients with <30 and ≥30 NCN, p < 0.0001. Our results suggest that MDD quantification by dPCR enables improved patient stratification in international clinical studies and patient selection for early clinical trials already at diagnosis.

Cell surface Nucleolin represents a novel cellular target for neuroblastoma therapy.

BACKGROUND: Neuroblastoma (NB) represents the most frequent and aggressive form of extracranial solid tumor of infants. Nucleolin (NCL) is a protein overexpressed and partially localized on the cell surface of tumor cells of adult cancers. Little is known about NCL and pediatric tumors and nothing is reported about cell surface NCL and NB. METHODS: NB cell lines, Schwannian stroma-poor NB tumors and bone marrow (BM)-infiltrating NB cells were evaluated for the expression of cell surface NCL by Flow Cytometry, Imaging Flow Cytometry and Immunohistochemistry analyses. The cytotoxic activity of doxorubicin (DXR)-loaded nanocarriers decorated with the NCL-recognizing F3 peptide (T-DXR) was evaluated in terms of inhibition of NB cell proliferation and induction of cell death in vitro, whereas metastatic and orthotopic animal models of NB were used to examine their in vivo anti-tumor potential. RESULTS: NB cell lines, NB tumor cells (including patient-derived and Patient-Derived Xenografts-PDX) and 70% of BM-infiltrating NB cells show cell surface NCL expression. NCL staining was evident on both tumor and endothelial tumor cells in NB xenografts. F3 peptide-targeted nanoparticles, co-localizing with cell surface NCL, strongly associates with NB cells showing selective tumor cell internalization. T-DXR result significantly more effective, in terms of inhibition of cell proliferation and reduction of cell viability in vitro, and in terms of delay of tumor growth in all NB animal model tested, when compared to both control mice and those treated with the untargeted formulation. CONCLUSIONS: Our findings demonstrate that NCL could represent an innovative therapeutic cellular target for NB.

Antibiotic Resistant Bloodstream Infections in Pediatric Patients Receiving Chemotherapy or Hematopoietic Stem Cell Transplant: Factors Associated with Development of Resistance, Intensive Care Admission and Mortality.

Bloodstream infections (BSI) are a severe complication of antineoplastic chemotherapy or hematopoietic stem cell transplantation (HSCT), especially in the presence of antibiotic resistance (AR). A multinational, multicenter retrospective study in patients aged ≤ 18 years, treated with chemotherapy or HSCT from 2015 to 2017 was implemented to analyze AR among non-common skin commensals BSI. Risk factors associated with AR, intensive care unit (ICU) admission and mortality were analyzed by multilevel mixed effects or standard logistic regressions. A total of 1291 BSIs with 1379 strains were reported in 1031 patients. Among Gram-negatives more than 20% were resistant to ceftazidime, cefepime, piperacillin-tazobactam and ciprofloxacin while 9% was resistant to meropenem. Methicillin-resistance was observed in 17% of S. aureus and vancomycin resistance in 40% of E. faecium. Previous exposure to antibiotics, especially to carbapenems, was significantly associated with resistant Gram-negative BSI while previous colonization with methicillin-resistant S. aureus was associated with BSI due to this pathogen. Hematological malignancies, neutropenia and Gram-negatives resistant to >3 antibiotics were significantly associated with higher risk of ICU admission. Underlying disease in relapse/progression, previous exposure to antibiotics, and need of ICU admission were significantly associated with mortality. Center-level variation showed a greater impact on AR, while patient-level variation had more effect on ICU admission and mortality. Previous exposure to antibiotics or colonization by resistant pathogens can be the cause of AR BSI. Resistant Gram-negatives are significantly associated with ICU admission and mortality, with a significant role for the treating center too. The significant evidence of center-level variations on AR, ICU admission and mortality, stress the need for careful local antibiotic stewardship and infection control programs.

Multiparametric flow cytometry highlights B7-H3 as a novel diagnostic/therapeutic target in GD2neg/low neuroblastoma variants.

BACKGROUND: High-risk neuroblastomas (HR-NBs) are rare, aggressive pediatric cancers characterized by resistance to therapy and relapse in more than 30% of cases, despite using an aggressive therapeutic protocol including targeting of GD2. The mechanisms responsible for therapy resistance are unclear and might include the presence of GD2neg/low NB variants and/or the expression of immune checkpoint ligands such as B7-H3. METHOD: Here, we describe a multiparametric flow cytometry (MFC) combining the acquisition of 106 nucleated singlets, Syto16pos CD45neg CD56pos cells, and the analysis of GD2 and B7-H3 surface expression. 41 bone marrow (BM) aspirates from 25 patients with NB, at the onset or relapse, are analyzed, comparing results with cytomorphological analysis (CA) and/or immunohistochemistry (IHC). Spike in experiments assesses the sensitivity of MFC. Kaplan-Meier analysis on 498 primary NBs selects novel prognostic markers possibly integrating the MFC panel. RESULTS: No false positive are detected, and MFC shows high sensitivity (0.0005%). Optimized MFC identifies CD45negCD56pos NB cells in 11 out of 12 (91.6%) of BM indicated as infiltrated by CA, 7 of which coexpress high levels of GD2 and B7-H3. MFC detects CD45negCD56posGD2neg/low NB variants expressing high surface levels of B7-H3 in two patients with HR-NB (stage M) diagnosed at 53 and 139 months of age. One of them has a non-MYCN amplified tumor with unusual THpos PHOX2Bneg phenotype, which relapsed 141 months post-diagnosis with BM infiltration and a humerus lesion. All GD2neg/low NB variants are detected in patients at relapse. Kaplan-Meier analysis highlights an interesting dichotomous prognostic value of MML5, ULBPs, PVR, B7-H6, and CD47, ligands involved in NB recognition by the immune system. CONCLUSIONS: Our study validates a sensitive MFC analysis providing information on GD2 and B7-H3 surface expression and allowing fast, specific and sensitive evaluation of BM tumor burden. With other routinely used diagnostic and prognostic tools, MFC can improve diagnosis, prognosis, orienting novel personalized treatments in patients with GD2low/neg NB, who might benefit from innovative therapies combining B7-H3 targeting.

Metastatic progression in infants diagnosed with stage 4S neuroblastoma. A study of the Italian Neuroblastoma Registry.

PURPOSE: Stage 4S neuroblastoma, a tumor affecting infants, is characterized by the capacity to regress spontaneously and high cure rate. About a third of these infants undergo tumor progression requiring antitumor treatment and 10-15% eventually die. In case of metastatic progression, it may occur either at 4S sites (mainly liver) or sites characterizing stage 4 (mainly bone). Aim of this study was to estimate incidence, presenting features and outcome of infants who progressed to stage 4S or stage 4 sites. PATIENTS: Of 280 Italian infants diagnosed with stage 4S neuroblastoma between 1979 and 2013 and registered in the Italian Neuroblastoma Registry, 268 were evaluable for this study, of whom 57 developed metastatic progression. RESULTS: Progression to stage 4S sites occurred in 29/268 infants (10.8%) (Group A) and to stage 4 in 28/268 (10.4%) (Group B). No significant difference was observed between the two groups at the time of diagnosis. At the time of progression, Group A infants were younger (7.3 vs 14.4 months, P = .001) and had a shorter interval from diagnosis to progression (3.8 vs 9.6 months, P = .001). Survival after progression was worse for Group B infants (45% vs 69%, P = .058) and was associated with age at diagnosis lower than 2 months (P = .005) and adrenal primary tumor site (P = .008). Survival rates increased for both groups along the study period. CONCLUSIONS: Infants who progressed to stage 4 did worse, possibly in relation to older age at progression and longer interval between diagnosis and progression. Large prospective studies of these patients may lead to more effective treatments.

Germline IKAROS dimerization haploinsufficiency causes hematologic cytopenias and malignancies.

IKAROS is a transcription factor forming homo- and heterodimers and regulating lymphocyte development and function. Germline mutations affecting the IKAROS N-terminal DNA binding domain, acting in a haploinsufficient or dominant-negative manner, cause immunodeficiency. Herein, we describe 4 germline heterozygous IKAROS variants affecting its C-terminal dimerization domain, via haploinsufficiency, in 4 unrelated families. Index patients presented with hematologic disease consisting of cytopenias (thrombocytopenia, anemia, neutropenia)/Evans syndrome and malignancies (T-cell acute lymphoblastic leukemia, Burkitt lymphoma). These dimerization defective mutants disrupt homo- and heterodimerization in a complete or partial manner, but they do not affect the wild-type allele function. Moreover, they alter key mechanisms of IKAROS gene regulation, including sumoylation, protein stability, and the recruitment of the nucleosome remodeling and deacetylase complex; none affected in N-terminal DNA binding defects. These C-terminal dimerization mutations are largely associated with hematologic disorders, display dimerization haploinsufficiency and incomplete clinical penetrance, and differ from previously reported allelic variants in their mechanism of action. Dimerization mutants contribute to the growing spectrum of IKAROS-associated diseases displaying a genotype-phenotype correlation.