EpiGe: A machine-learning strategy for rapid classification of medulloblastoma using PCR-based methyl-genotyping.

Molecular classification of medulloblastoma is critical for the treatment of this brain tumor. Array-based DNA methylation profiling has emerged as a powerful approach for brain tumor classification. However, this technology is currently not widely available. We present a machine-learning decision support system (DSS) that enables the classification of the principal molecular groups-WNT, SHH, and non-WNT/non-SHH-directly from quantitative PCR (qPCR) data. We propose a framework where the developed DSS appears as a user-friendly web-application-EpiGe-App-that enables automated interpretation of qPCR methylation data and subsequent molecular group prediction. The basis of our classification strategy is a previously validated six-cytosine signature with subgroup-specific methylation profiles. This reduced set of markers enabled us to develop a methyl-genotyping assay capable of determining the methylation status of cytosines using qPCR instruments. This study provides a comprehensive approach for rapid classification of clinically relevant medulloblastoma groups, using readily accessible equipment and an easy-to-use web-application.t.

Histiocitosis de células de Langerhans. Avances en la patogenia y práctica clínica / Langerhans cell histiocytosis. Advances in pathogenesis and clinical practice

La histiocitosis de células de Langerhans (HCL) es un tipo de neoplasia hematológica de origen mieloide, que puede afectar a diferentes órganos o tejidos, con gran variabilidad en la presentación clínica y comportamiento biológico, por lo que puede simular diferentes enfermedades. Se recomienda realizar diversas pruebas clínicas, analíticas y de imagen, para determinar la extensión de la afectación, que puede ser única o multisistémica, y la presencia o no de disfunción en órganos de riesgo como sistema hematopoyético, hígado y bazo. El diagnóstico se debe confirmar mediante biopsia y estudio histológico. Los estudios moleculares han permitido identificar mutaciones en la vía MAPK, lo que han ampliado las opciones terapéuticas. El diagnóstico es complejo y existe controversia en el manejo de ciertos casos. Las recomendaciones terapéuticas dependen de la localización de las lesiones y de la extensión de la afectación. Los estudios colaborativos internacionales han demostrado la efectividad de terapias prolongadas combinadas como vinblastina y prednisona en formas graves o multisistémicas y destaca el papel beneficioso de fármacos antiinflamatorios como indometacina y de otras combinaciones de citostáticos. La HCL representa un buen ejemplo de la importancia de la medicina de precisión y del beneficio de la identificación de dianas moleculares, comunes a diferentes neoplasias, para desarrollar nuevas terapias dirigidas. Los inhibidores de la vía MAPK representan una alternativa terapéutica en casos refractarios y en las formas neurodegenerativas de la HCL. Los estudios moleculares pueden contribuir en el pronóstico, el tratamiento y el seguimiento, especialmente en las formas graves. (AU)

Langerhans cell histiocytosis (LCH) is a type of myeloid neoplasia that can affect different organs or tissues and exhibits substantial variability in its clinical presentation and biological behaviour, so it may mimic different diseases. Performance of different clinical assessments and laboratory and imaging tests is recommended to determine the extent of involvement, which may be of a single location or multisystemic, and the presence or absence of dysfunction in risk organs, such as the haematopoietic system, liver and spleen. The diagnosis must be confirmed by histological examination of a biopsy sample. Molecular tests have identified mutations in the mitogen-activated protein kinase (MAPK) pathway, which has expanded treatment options. The diagnosis is complex and there is controversy regarding the management of certain cases. Treatment recommendations depend on the location of the lesions and the extent of involvement. International collaborative studies have demonstrated the effectiveness of prolonged combination therapies such as vinblastine and prednisone in severe or multisystemic forms, and anti-inflammatory drugs such as indomethacin and other cytostatic combinations have proven beneficial. LCH is a good example of the importance of precision medicine and the benefit of identifying molecular targets, common to different neoplasms, to develop new therapies. MAPK pathway inhibitors offer an alternative treatment option in refractory cases and neurodegenerative forms of LCH. Molecular testing can contribute to the prognosis, treatment and follow-up of LCH, especially in severe forms of disease. (AU)

Langerhans cell histiocytosis. Advances in pathogenesis and clinical practice.

Langerhans cell histiocytosis (LCH) is a type of myeloid neoplasia that can affect different organs or tissues and exhibits substantial variability in its clinical presentation and biological behaviour, so it may mimic different diseases. Performance of different clinical assessments and laboratory and imaging tests is recommended to determine the extent of involvement, which may be of a single location or multisystemic, and the presence or absence of dysfunction in risk organs, such as the haematopoietic system, liver and spleen. The diagnosis must be confirmed by histological examination of a biopsy sample. Molecular tests have identified mutations in the mitogen-activated protein kinase (MAPK) pathway, which has expanded treatment options. The diagnosis is complex and there is controversy regarding the management of certain cases. Treatment recommendations depend on the location of the lesions and the extent of involvement. International collaborative studies have demonstrated the effectiveness of prolonged combination therapies such as vinblastine and prednisone in severe or multisystemic forms, and anti-inflammatory drugs such as indomethacin and other cytostatic combinations have proven beneficial. Langerhans cell histiocytosis is a good example of the importance of precision medicine and the benefit of identifying molecular targets, common to different neoplasms, to develop new therapies. MAPK pathway inhibitors offer an alternative treatment option in refractory cases and neurodegenerative forms of LCH. Molecular testing can contribute to the prognosis, treatment and follow-up of LCH, especially in severe forms of disease.

Naxitamab combined with granulocyte-macrophage colony-stimulating factor as consolidation for high-risk neuroblastoma patients in complete remission.

BACKGROUND: Naxitamab is a humanized anti-disialoganglioside (GD2) monoclonal antibody approved for treatment of bone/bone marrow refractory high-risk neuroblastoma (HR-NB). Compassionate use (CU) expanded access program at Hospital Sant Joan de Deu permitted treatment of patients in complete remission (CR). We here report the survival, toxicity, and relapse pattern of patients in first or second CR treated with naxitamab and sargramostim (GM-CSF). PROCEDURE: Seventy-three consecutive patients with HR-NB (stage M at age >18 months or MYCN-amplified stages L1/L2 at any age) were treated in first or second CR. Treatment comprised five cycles of subcutaneous (SC) GM-CSF for 5 days at 250 µg/m2 /day (days -4 to 0), followed by naxitamab + SC GM-CSF for 5 days at 500 µg/m2 /day (days 1-5). Naxitamab was infused over 30 minutes at 3 mg/kg/day, days 1, 3, and 5, outpatient. RESULTS: Fifty-five patients were in first CR and 18 in second CR. Seventeen patients had MYCN-amplified NB and 11 detectable minimal residual disease in the bone marrow. Fifty-eight (79.5%) patients completed therapy. Four (5%) experienced grade 4 toxicities and 10 (14%) early relapse. Three-year event-free survival (EFS) 58.4%, 95% CI = (43.5%, 78.4%) and overall survival (OS) 82.4%, 95% CI = (66.8%, 100%). First CR patients 3-year EFS 74.3%, 95% CI = (62.7%, 88.1%), and OS 91.6%, 95% CI = (82.4%, 100%). EFS is significantly different between first and second CR (p = .0029). The pattern of relapse is predominantly (75%) of an isolated organ, mainly bone (54%). Univariate Cox models show prior history of relapse as the only statistically significant predictor of EFS but not OS. CONCLUSIONS: Consolidation with naxitamab and GM-CSF resulted in excellent survival rates for HR-NB patients in CR.

Clinical and Pathological Evidence of Anti-GD2 Immunotherapy Induced Differentiation in Relapsed/Refractory High-Risk Neuroblastoma.

BACKGROUND: Neuroblastic tumors (NBTs) originate from a block in the process of differentiation. Histologically, NBTs are classified in neuroblastoma (NB), ganglioneuroblastoma (GNB), and ganglioneuroma (GN). Current therapy for high-risk (HR) NB includes chemotherapy, surgery, radiotherapy, and anti-GD2 monoclonal antibodies (mAbs). Anti-GD2 mAbs induce immunological cytoxicity but also direct cell death. METHODS: We report on patients treated with naxitamab for chemorefractory NB showing lesions with long periods of stable disease. Target lesions with persisting 123I-Metaiodobenzylguanidine (MIBG) uptake after 4 cycles of immunotherapy were further evaluated by functional Magnetic Resonance Imaging (MRI) and/or Fluorodeoxyglucose (FDG)-positron emission tomography (PET). MIBG avid lesions that became non-restrictive on MRI (apparent diffusion coefficient (ADC) > 1) and/or FDG-PET negative (SUV < 2) were biopsied. RESULTS: Twenty-seven relapse/refractory (R/R) HR-NB patients were enrolled on protocol Ymabs 201. Two (7.5%) of the 27 showed persistent bone lesions on MIBG, ADC high, and/or FDG-PET negative. Forty-four R/R HR-NB patients received chemo-immunotherapy. Twelve (27%) of the 44 developed persistent MIBG+ but FDG-PET- and/or high ADC lesions. Twelve (86%) of the 14 cases identified were successfully biopsied producing 16 evaluable samples. Histology showed ganglioneuroma maturing subtype in 6 (37.5%); ganglioneuroma mature subtype with no neuroblastic component in 4 (25%); differentiating NB with no Schwannian stroma in 5 (31%); and undifferentiated NB without Schwannian stroma in one (6%). Overall, 10 (62.5%) of the 16 specimens were histopathologically fully mature NBTs. CONCLUSIONS: Our results disclose an undescribed mechanism of action for naxitamab and highlight the limitations of conventional imaging in the evaluation of anti-GD2 immunotherapy clinical efficacy for HR-NB.

Prognostic value of patient-derived xenograft engraftment in pediatric sarcomas.

The goals of this work were to identify factors favoring patient-derived xenograft (PDX) engraftment and study the association between PDX engraftment and prognosis in pediatric patients with Ewing sarcoma, osteosarcoma, and rhabdomyosarcoma. We used immunodeficient mice to establish 30 subcutaneous PDX from patient tumor biopsies, with a successful engraftment rate of 44%. Age greater than 12 years and relapsed disease were patient factors associated with higher engraftment rate. Tumor type and biopsy location did not associate with engraftment. PDX models retained histology markers and most chromosomal aberrations of patient samples during successive passages in mice. Model treatment with irinotecan resulted in significant activity in 20 of the PDXs and replicated the response of rhabdomyosarcoma patients. Successive generations of PDXs responded similarly to irinotecan, demonstrating functional stability of these models. Importantly, out of 68 tumor samples from 51 patients with a median follow-up of 21.2 months, PDX engraftment from newly diagnosed patients was a prognostic factor significantly associated with poor outcome (p = 0.040). This association was not significant for relapsed patients. In the subgroup of patients with newly diagnosed Ewing sarcoma classified as standard risk, we found higher risk of relapse or refractory disease associated with those samples that produced stable PDX models (p = 0.0357). Overall, our study shows that PDX engraftment predicts worse outcome in newly diagnosed pediatric sarcoma patients.

Synchronous choroid plexus papilloma and Wilms tumor in a girl, disclosing a Li-Fraumeni syndrome.

BACKGROUND: Li-Fraumeni Syndrome (LFS) is a cancer predisposition syndrome characterized by the early-onset of multiple primary cancers which can occur at different moments (metachronous onset) or, more rarely, coincidentally (synchronous onset). Here we describe a previously unreported patient with presentation of synchronous Wilms tumor and Choroid plexus papilloma, leading to the diagnosis of a Li-Fraumeni Syndrome (LFS). CASE PRESENTATION: A 6-year-old girl without previous complains presented with abdominal pain. Abdominal US and MRI showed a left renal tumor with subcapsular hematoma. Due to mild headaches, the diagnostic workup included a brain MRI that unexpectedly identified a large left parietal lobe tumor. Histopathological analysis determined the diagnosis of classic Wilms tumor and choroid-plexus papilloma (CPP), respectively. Both neoplasms showed intense nuclear p53 immunostaining associated with the pathogenic TP53 mutation c.844C > T (p.Arg282Trp). Our patient and her father shared the same heterozygous germline TP53 mutation, confirming the diagnosis of familiar Li-Fraumeni syndrome in the girl. The treatment was tailored to simultaneous tumor presentations. CONCLUSIONS: LFS has been associated with Choroid plexus carcinoma (CPC), but rarely with CPP as in our patient. That suggests that it may be advisable to consider the possibility of analyzing TP53 mutation, not only in all patients with CPC, but also in some patients with CPP, especially when histological or clinical evidences point out to perform this study. The dissimilar presentation of LFS among our patient's father, not having so far any neoplasia diagnosed, while her daughter presented precociously with two simultaneous different tumors, could be related to possible effects of modifier genes on the underlying mutant p53 genotype.

The Role of Autologous Stem-Cell Transplantation in High-Risk Neuroblastoma Consolidated by anti-GD2 Immunotherapy. Results of Two Consecutive Studies.

Background: Treatment of HR-NB comprise induction, consolidation with autologous stem cell transplant (ASCT) followed by anti-GD2 immunotherapy and isotretinoin. Childrens Oncology Group and SIOPEN studies used dinutuximab and cytokines to treat patients in complete remission or refractory Bone/Bone marrow (B/BM) disease after ASCT. Methods: HR-NB patients referred to Hospital Sant Joan de Déu for anti-GD2 immunotherapy were eligible for two consecutive studies (dinutuximab for EudraCT 2013-004864-69 and naxitamab for 017-001829-40) and naxitamab/Sargramostim CU with or without prior ASCT. Patients enrolled in first complete remission or with primary refractory B/BM disease. We accrued a study population of two groups whose therapy, aside from ASCT, was similar. This is a retrospective analysis of their outcome calculated from study entry. Results: From December 2014-2019, 67 patients were treated with dinutuximab and cytokines (n = 21) in the Hospital Sant Joan de Déu-HRNB-Ch14.18 study or with naxitamab and Sargramostim either in the Ymabs study 201 (n = 12) or CU (n = 34). 23 patients were treated with primary refractory disease in the B/BM (11 with dinutuximab and 12 with naxitamab), and 44 in first CR (10 with dinutuximab and 34 with naxitamab). Study patients included 13 (19.4%) treated following single ASCT and 54 following conventional chemotherapy. Median follow-up for all patients is 16.2 months. Two-year rates for ASCT and non-ASCT patients were, respectively, EFS 64.1% vs. 54.2% (p = 0.28), and OS 66.7% vs. 84.1% (p = 0.81). For the 44 pts in first CR, 2-years rates for ASCT and non-ASCT patients were, respectively, EFS 65.5% vs. 58.7% (p = 0.48), and OS 71.4% vs. 85.4% (p = 0.63). Conclusions: In this retrospective, single center study, ASCT did not provide survival benefit when anti-GD2 immunotherapy was used after induction chemotherapy.

Treatment-driven selection of chemoresistant Ewing sarcoma tumors with limited drug distribution.

Ewing sarcoma is a bone and soft tissue tumor predominantly affecting adolescents and young adults. To characterize changes in anticancer drug activity and intratumor drug distribution during the evolution of Ewing sarcomas, we used immunodeficient mice to establish pairs of patient-derived xenografts (PDX) at early (initial diagnosis) and late (relapse or refractory progression) stages of the disease from three patients. Analysis of copy number alterations (CNA) in early passage PDX tissues showed that two tumor pairs established from patients which responded initially to therapy and relapsed more than one year later displayed similar CNAs at early and late stages. For these two patients, PDX established from late tumors were more resistant to chemotherapy (irinotecan) than early counterparts. In contrast, the tumor pair established at refractory progression showed highly dissimilar CNA profiles, and the pattern of response to chemotherapy was discordant with those of relapsed cases. In mice receiving irinotecan infusions, the level of SN-38 (active metabolite of irinotecan) in the intracellular tumor compartment was reduced in tumors at later stages compared to earlier tumors for those pairs bearing similar CNAs, suggesting that distribution of anticancer drug shifted toward the extracellular compartment during clonal tumor evolution. Overexpression of the drug transporter P-glycoprotein in late tumor was likely responsible for this shift in drug distribution in one of the cases.

Epigenetic loss of RNA-methyltransferase NSUN5 in glioma targets ribosomes to drive a stress adaptive translational program.

Tumors have aberrant proteomes that often do not match their corresponding transcriptome profiles. One possible cause of this discrepancy is the existence of aberrant RNA modification landscapes in the so-called epitranscriptome. Here, we report that human glioma cells undergo DNA methylation-associated epigenetic silencing of NSUN5, a candidate RNA methyltransferase for 5-methylcytosine. In this setting, NSUN5 exhibits tumor-suppressor characteristics in vivo glioma models. We also found that NSUN5 loss generates an unmethylated status at the C3782 position of 28S rRNA that drives an overall depletion of protein synthesis, and leads to the emergence of an adaptive translational program for survival under conditions of cellular stress. Interestingly, NSUN5 epigenetic inactivation also renders these gliomas sensitive to bioactivatable substrates of the stress-related enzyme NQO1. Most importantly, NSUN5 epigenetic inactivation is a hallmark of glioma patients with long-term survival for this otherwise devastating disease.

Second re-irradiation for DIPG progression, re-considering "old strategies" with new approaches.

Diffuse intrinsic pontine glioma (DIPG) is an aggressive infiltrative glioma for which no curative therapy is available. Radiation therapy (RT) is the only potentially effective intervention in delaying tumor progression, but only transiently. At progression, re-irradiation is gaining popularity as an effective palliative therapy. However, at second progression, exclusive symptomatic treatment is usually offered. Here we report two patients with DIPG at second progression who were treated with a second re-irradiation course with good response. Importantly, treatment was well tolerated with no irradiation associated acute toxicity identified.