[THE BENEFIT OF MOLECULAR ANALYSIS USING NEXT GENERATION SEQUENCING METHODS IN PEDIATRIC "HARD TO TREAT" TUMORS - EXPERIENCE IN A TERTIARY MEDICAL CENTER].

INTRODUCTION: While survival rates among children with cancer are high, a significant proportion of the solid tumors are considered as hard to treat (HTT). Next generation sequencing (NGS) offers the ability to detect molecular changes in tumors. Its implementation may allow usage of targeted therapy for tumors that fail to respond to acceptable oncological treatment. Furthermore, these therapies are characterized by milder side effects than chemotherapy. NGS may also aid in establishing pathological diagnoses and occasionally, identifying cancer-predisposition syndromes. However, the benefit of NGS in the pediatric population is not clear. AIMS: Evaluating the benefit of NGS in children with 'HTT' Tumors. METHODS: A retrospective study of the usage of NGS in pediatric 'HTT' in the Department of Pediatric Hemato-Oncology at the Hadassah Medical Center. Patients' demographic and clinical characteristics, molecular changes in tumor, their influence on medical decisions and disease course - were all documented. RESULTS: Forty-seven NGS tests from 'HTT' tumors were completed between January 2018 to August 2020. The results of these tests dictated medical decisions in 18 cases (38.3%) while it proved utility in 10 cases (21.3%). Clinical response to targeted therapy, clarification of diagnosis and identification of germline changes were documented in 3 (6.4%), 4 (8.5%) and 3 (6.4%) cases, respectively. CONCLUSIONS: The usage of NGS may benefit children with 'HTT' and tumors with difficult diagnoses and in some cases may be life-saving. DISCUSSION: Cost-benefit considerations presumably prevent the assimilation of NGS tests in the standard care of pediatric oncology. It is possible that the current results will strengthen the more accurate usage of theses genomic techniques in children with 'HTT'.

Delayed diagnosis and treatment of children with cancer during the COVID-19 pandemic.

BACKGROUND: COVID-19, the novel coronavirus has caused a global pandemic affecting millions of people around the world. Although children, including children with cancer, have been found to be affected less commonly and less severely than adults, indirect effects of the pandemic on the diagnosis and treatment of children with cancer have been less described. METHODS: A survey was performed in the four largest tertiary pediatric hematology-oncology medical centers in Israel. Clinical and laboratory data were collected from the medical files of patients diagnosed or treated with cancer during April-October 2020. RESULTS: Seventeen patients are described, who had a significant delay in diagnosis or treatment of cancer. These represent approximately 10% of all pediatric cancer diagnosed during the study period in these centers. A main cause of delay was fear of exposure to COVID-19 (fears felt by the patient, parent, physician, or decision-makers at the institution; or the implementation of national guidelines). Delays also resulted from co-infection with COVID-19 and the attribution of the oncologic symptoms to the infection. In addition, treatment was delayed of patients already diagnosed with cancer, due to COVID-19 infection detected in the patient, a family member, or a bone marrow donor. CONCLUSION: Fear from the COVID-19 pandemic may result in delayed diagnosis and treatment of children with cancer, which may carry a risk to dismal prognosis. It is crucial that pediatricians and patients alike remember that other diseases still prevail and must be thought of and treated in a timely fashion.

Neuroinflammatory Disease as an Isolated Manifestation of Hemophagocytic Lymphohistiocytosis.

Isolated neuroinflammatory disease has been described in case reports of familial hemophagocytic lymphohistiocytosis (FHL), but the clinical spectrum of disease manifestations, response to therapy and prognosis remain poorly defined. We combined an international survey with a literature search to identify FHL patients with (i) initial presentation with isolated neurological symptoms; (ii) absence of cytopenia and splenomegaly at presentation; and (iii) systemic HLH features no earlier than 3 months after neurological presentation. Thirty-eight (20 unreported) patients were identified with initial diagnoses including acute demyelinating encephalopathy, leukoencephalopathy, CNS vasculitis, multiple sclerosis, and encephalitis. Median age at presentation was 6.5 years, most commonly with ataxia/gait disturbance (75%) and seizures (53%). Diffuse multifocal white matter changes (79%) and cerebellar involvement (61%) were common MRI findings. CSF cell count and protein were increased in 22/29 and 15/29 patients, respectively. Fourteen patients progressed to systemic inflammatory disease fulfilling HLH-2004 criteria at a mean of 36.9 months after initial neurological presentation. Mutations were detected in PRF1 in 23 patients (61%), RAB27A in 10 (26%), UNC13D in 3 (8%), LYST in 1 (3%), and STXBP2 in 1 (3%) with a mean interval to diagnosis of 28.3 months. Among 19 patients who underwent HSCT, 11 neurologically improved, 4 were stable, one relapsed, and 3 died. Among 14 non-transplanted patients, only 3 improved or had stable disease, one relapsed, and 10 died. Isolated CNS-HLH is a rare and often overlooked cause of inflammatory brain disease. HLH-directed therapy followed by HSCT seems to improve survival and outcome.

Essential thrombocythemia A retrospective case series.

BACKGROUND: Essential thrombocythemia (ET) is rare in children, and pediatric guidelines are lacking. Therefore, we aimed to evaluate ET diagnosis and treatment in a pediatric cohort. PROCEDURE: Data of patients with ET from three hospitals were reviewed. Molecular diagnosis included JAK2V617F, CALR, and MPL mutations. Patients were evaluated for acquired von Willebrand syndrome (AVWS). Follow-up included clinical symptoms, adverse events, and treatment. RESULTS: Twelve children (median age: 8 years, range 1-14.5) were included. Mean lag period between the first documentation of thrombocytosis until ET diagnosis was 36 months. Six patients were positive for JAK2V617F and two for CALR mutations. In six of nine patients, AVWS was diagnosed. At diagnosis, only 33% of patients started therapy with aspirin (n = 4) and hydroxyurea (n = 2). In three of eight untreated patients, therapy was added during follow-up. The cohort was followed for a median of 32.5 months (range: 4-108 months). Clinical follow-up disclosed vascular complications in 4 of 12 patients (deep vein thrombosis, n = 1; transient ischemic attack, n = 3). Two females experienced excessive bleeding; both were diagnosed with AVWS. Neither leukemia nor myelofibrosis evolved in our cohort. CONCLUSION: Increased awareness to pediatric ET is warranted, as delayed diagnosis is common. Compared to adults, AVWS may be more prevalent among children with ET.

Sustained Response to Imatinib in a Pediatric Patient with Concurrent Myeloproliferative Disease and Lymphoblastic Lymphoma Associated with a CCDC88C-PDGFRB Fusion Gene.

BACKGROUND: The WHO defined myeloid and lymphoid neoplasms (MLN) with eosinophilia associated with PDGFRB, PDGFRA, FGFR1 rearrangements as a new entity in 2016. PDGFRB-rearranged MLN sensitive to imatinib were described in adult patients. We report the first pediatric patient with PDGFRB-rearranged myeloproliferative disorder associated with T-lymphoblastic lymphoma bearing the t(5; 14)(q33;q32) translocation who was successfully treated with imatinib only. Methods/Aims: Analysis of bone marrow and peripheral blood cells by fluorescent in situ hybridization identified the PDGFRB partner as CCDC88C. Whole genome sequencing of the patient's DNA identified the exact junction site, confirmed by PCR amplification and Sanger sequencing. A real-time quantitative PCR assay was designed to quantify the fused CCDC88C-PDGFRB product. RESULTS: A 2.5-year-old boy was diagnosed with myeloproliferative disorder and eosinophilia associated with lymphoblastic lymphoma both bearing the CCDC88C-PDGFRB fusion. Imatinib therapy resulted in rapid clinical, hematological, and cytogenetic response. Molecular response to treatment was monitored by a real-time PCR assay specific for the CCDC88C- PDGFRB fusion. CONCLUSION: This is the first description of MLN with eosinophilia in the pediatric age group. Response to treatment with imatinib only was monitored by specific quantitative PCR assay with sustained remission lasting 5.5 years from diagnosis.

Comparison of two cytoreductive regimens for αß-T-cell-depleted haploidentical HSCT in pediatric malignancies: Improved engraftment and outcome with TBI-based regimen.

BACKGROUND: Graft manipulation using selective depletion of αß-T cells provides a source of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) enriched in effector cells. We report our experience implementing this haplo-HSCT for high-risk malignancies in pediatric patients focusing on the conditioning regimen. PROCEDURE: We performed a retrospective study of patients who underwent T-cell receptor αß-depleted haplo-HSCT for high-risk pediatric malignancies. RESULTS: Eighteen patients underwent haplo-HSCT using this method. The initial reduced-toxicity chemotherapy-based conditioning regimen was given to eight patients, and resulted in a high rate of graft rejections (six of eight patients). Thus, total body irradiation (TBI) based regimen was introduced in the following 10 patients and resulted in engraftment in all patients. Neutrophil and platelet engraftment were rapid (median time to engraft, 10 days and 12 days, respectively). Significant treatment-related complications for both cohorts were all due to graft failure in patients receiving chemotherapy-based conditioning, with a treatment-related mortality rate of 17%. None of the patients developed hepatic sinusoidal-obstruction syndrome, and no grade III-IV acute graft versus host disease (GVHD) was observed. The majority of patients were free of immunosuppression in the first 100 days post-HSCT, and only two patients developed chronic GVHD. The cumulative incidence of relapse was 39%. Compared to patients conditioned with chemotherapy, patients conditioned with TBI had superior actuarial overall survival (66% vs. 37%, P = 0.05) and event-free survival (61% vs. 33%, P = 0.04). CONCLUSIONS: A TBI-based conditioning for haplo-HSCT using αß-T-cell depletion for malignant diseases ensured engraftment and resulted in acceptable outcomes.

Cutaneous Chronic Graft Versus Host Disease Following Allogeneic Haematopoietic Stem Cell Transplantation in Children: A Retrospective Study.

Chronic graft versus host disease (cGVHD) is a complication of allogeneic haematopoietic stem cell transplantation (HSCT). The aim of this study was to clinically characterize childhood cutaneous cGVHD. A retrospective study of children treated with HSCT at 2 tertiary medical centres in Israel between 2011 and 2014 was performed. A total of 112 children were included. Cutaneous cGVHD developed in 18% of subjects. Risk factors were older age, HSCT from peripheral blood and acute lymphoblastic leukaemia. The eruption was lichenoid in 90% of subjects, of whom one-third progressed to sclerosis. Topical treatments were usually sufficient in localized disease. Widespread eruption necessitated phototherapy, extracorporeal photopheresis and/or systemic immunosuppressants. Patients presenting with palmoplantar keratoderma, developed sclerosis. To the best of our knowledge, this is the first study describing childhood cutaneous cGVHD. Lichenoid eruption is the most common cutaneous pattern of cGVHD in children. Sclerotic changes may be associated with prior keratoderma. cGVHD poses a therapeutic challenge and better treatments should be sought.

The metabolic syndrome and its components in pediatric survivors of allogeneic hematopoietic stem cell transplantation.

Metabolic syndrome (MetS) is a known complication after hematopoietic stem cell transplantations (HSCT) that contributes to long-term morbidity. We assessed the prevalence of components of the MetS in pediatric survivors of allogeneic HSCT and identified associated risk factors. Thirty-eight patients, median age at HSCT, 8.5 years, were evaluated at a median of 3.9 years post-HSCT. Overweight or obesity was seen in 23.7% of the patients, 15.8% had hypertension, 15.8% had hypertriglyceridemia, and 13% had low high-density lipoprotein cholesterol levels according to age and gender. Four (10.5%) met the criteria of MetS; all were transplanted for malignant disease. Twelve patients (31.6%) had at least one component of the MetS. The 5-year probability of developing components of the MetS revealed that patients with BMI-Z score ≥0 at HSCT were significantly at higher risk than those with lower BMI-Z. Patients who developed components of the MetS had higher levels of insulin, homeostasis model assessment, uric acid, leptin, and lower adiponectin levels. Multivariable regression analysis revealed that BMI-Z-score >1.036 at time of evaluation was associated with 4.3-fold increased risk (P=.050) and adiponectin levels ≤6 µg/mL were associated with 6.7-fold increased risk of develop components of the MetS (P=.007). Overweight and obesity and adiponectin levels may be useful as markers in HSCT survivors.

The role of immunoglobulin prophylaxis for prevention of cytomegalovirus infection in pediatric hematopoietic stem cell transplantation recipients.

BACKGROUND: Following cessation of intravenous immunoglobulin (IVIg) administration for allogeneic hematopoietic stem cell transplantation (HSCT) recipients at our unit, we observed a sharp decline in the incidence of cytomegalovirus (CMV) infection. PROCEDURE: We conducted a retrospective study of the role of IVIg in the prevention of CMV infection in children and young adults who underwent HSCT from matched related donor. RESULTS: We included 109 patients (IVIg+/IVIg- ratio 82/27). Median age was 8.5 years. Patients were transplanted for malignant (59.7%) and nonmalignant diseases (40.3%) with myeloablative, reduced-intensity, and nonmyeloablative conditioning in 76, 22, and 2% of the transplants, respectively. Graft sources were peripheral blood stem cells, bone marrow, and cord blood in 58.7, 39.4, and 2%, respectively. The cumulative incidence of CMV infection at 1 year after HSCT was significantly higher in the cohort that did not receive IVIg compared with the one that did (44.4% vs. 13.4%, respectively, P = 0.001). Significant risk factor for CMV infection in the cohort not receiving IVIg was conditioning with total body irradiation (TBI) (87.5% in TBI+ vs. 26.3% in TBI-, P = 0.003). CONCLUSIONS: We conclude that children and young adults who undergo HSCT with TBI may need a preemptive regimen of anti-CMV treatment, if they do not get IVIg prophylaxis.

Abnormal body mass index at diagnosis in patients with Ewing sarcoma is associated with inferior tumor necrosis.

BACKGROUND: Abnormal body mass index (BMI) in cancer patients at diagnosis has been associated with lower survival rates. The degree of tumor necrosis after induction chemotherapy in Ewing sarcoma (EWS) is highly associated with treatment failure. We analyzed the effect of BMI on tumor necrosis in children and young adults undergoing induction treatment for EWS. PROCEDURE: Retrospective review of BMI and tumor necrosis in children and young adults with EWS. Patients were grouped into normal and abnormal BMI groups. Multivariate logistic regression and multivariate Cox regression were used to evaluate the impact of BMI on tumor necrosis, recurrence of disease, and survival. RESULTS: Fifty patients who underwent resection of the tumor were eligible. Of them, 32 (64%) and 18 (36%) had normal and abnormal BMI, respectively. Poor histologic response (PR), defined as tumor necrosis of less than 90%, was achieved in 35 (70%) patients. When comparing abnormal to normal BMI, there were more cases of PR [9 (50%) vs. 6 (19%) (P = 0.025)], more relapses [8 (44%) vs. 8 (25%) (P = 0.164)], and more deaths [10 (57%) vs. 7 (22%) (P = 0.040)], respectively. Abnormal BMI was independently associated with PR (OR 4.33, 95% CI 1.12-19.14 P = 0.034) and worse overall survival (HR 2.76, 95% CI 1.19-9.99 P = 0.022), while it had no impact on event free survival. CONCLUSIONS: The association between abnormal BMI and lower survival in EWS is presumed to be due to PR to chemotherapy. These findings stress the significance of BMI on treatment response in malignant diseases.

Patient and central venous catheter related risk factors for blood stream infections in children receiving chemotherapy.

BACKGROUND: The use of central venous catheters (CVCs) has greatly improved the quality of care in children receiving chemotherapy, yet these catheters may cause serious infectious complications. The aim of this prospective registry study was to assess the host and CVC-related risk factors for blood stream infections (BSIs). PROCEDURE: Patients undergoing CVC insertion for chemotherapy were followed prospectively for CVC complications. At the time of enrollment demographic-, clinical- and CVC-related data were collected. Survival and Cox-regression analysis were performed. RESULTS: A total of 423 CVCs were inserted into 262 patients for a total of 76,540 catheter-days. The incidence of BSIs was 1.95 per 1,000 patient-days (95% CI 1.66-2.29). Myeloid leukemia and younger age were associated with higher risk for BSI. At least one BSI occurred in 187 CVCs with an incidence of 2.84 per 1,000 catheter-days (95% CI 2.47-3.24). Externalized CVCs, that is, tunneled externalized catheters and peripheral inserted central catheters, were associated with higher risk for BSI in the group of diseases with relatively lower rate of infection. However, in diseases with high rate of infection no such association was found. The type of BSI was associated with the diagnosis and the CVC type. CVC occlusion was associated with higher risk for recurrent BSI and for coagulase negative staph BSI. CONCLUSIONS: Both patient and CVC-related factors are associated with higher risk of BSI in children receiving chemotherapy. The results of this study could be used in developing studies aiming to reduce the rate of BSIs in children with cancer.

Do immunocompromised children benefit from having surgical lung biopsy performed?

BACKGROUND: Surgical lung biopsy is considered a gold standard for the evaluation of pulmonary disease in immunocompromised children. However, in the literature, its accuracy and the rate of complications vary. OBJECTIVE: We aimed to evaluate the yield of surgical lung biopsies in the management of persistent pulmonary findings in immunocompromised children. METHODS: We performed a retrospective review of clinical records of immunocompromised children who underwent surgical lung biopsies, and evaluated the impact that preoperative factors had on outcomes. RESULTS: Twenty-five patients underwent 27 surgical lung biopsies. The underlying immunodeficiency included allogeneic stem cell transplantation (n = 12), chemotherapy for solid tumors (n = 6), hematologic malignancy (n = 4), primary immunodeficiency (n = 4) and chronic steroid use (n = 1). Biopsies provided a specific histopathologic or microbiologic diagnosis in 10 cases (37%). No preoperative factor predicted a diagnostic biopsy. Five of the 27 biopsies were beneficial for the patients (18%). A major complication related to the procedure was reported for 1 biopsy (4%). CONCLUSIONS: We conclude that surgical lung biopsy in pediatric immunocompromised patients appears to be safe, but has a relatively low diagnostic yield and an even lower yield with regards to the benefit it provides.

Distribution and predictors of F-18-FDG uptake values of non-malignant cervical lymph nodes in pediatric patients.

BACKGROUND: F-18-flurodeoxyglucose (FDG) PET/CT is routinely used for staging, evaluation of response to treatment and follow-up of most pediatric malignancies. Cervical lymph nodes can be involved in some pediatric malignancies, but increased uptake in non-malignant cervical lymph nodes is not exceptional in this population. The aim of the present study is to identify predictors of the maximum uptake in non-malignant cervical lymph nodes in the pediatric population. METHODS: 191 FDG PET/CT studies of pediatric patients without malignant involvement of cervical lymph nodes were retrospectively reviewed. The maximal Standard Uptake Value in the hottest cervical lymph node (SUVmaxCLN), as well as demographic, technical and imaging variables were recorded. The predictive effect of those variables on SUVmaxCLN was estimated using linear regression models. RESULTS: Increased FDG activity in cervical nodes was observed in 136/191 studies (71%). The mean SUVmaxCLN was 2.2 ± 1.3. Ipsilateral palatine tonsil SUVmax, mean liver uptake, and treatment status were all statistically significant predictors of SUVmaxCLN. However, in multivariate regression analysis, only ipsilateral palatine tonsil SUVmax was found to be significant. In addition, SUVmaxCLN was greater than the mean liver uptake in 50% of all studies. This proportion was higher in younger children, reaching 77% of studies of children younger than six years. CONCLUSION: SUVmax in ipsilateral palatine tonsil is a strong predictor of the maximal uptake value of non-malignant cervical lymph nodes in children. The intensity of uptake in non-malignant cervical lymph nodes is frequently higher than liver uptake in children, and this tendency increases for younger patients. TRIAL WAS REGISTERED: In the internal hospital registry under TRN 0209-22-HMO on date 23.04.2022.

Invasive Fungal Infections in Children with Acute Leukemia: Epidemiology, Risk Factors, and Outcome.

Invasive fungal infections (IFI) cause morbidity and mortality in children with acute leukemia (AL). We retrospectively collected data on febrile neutropenic episodes (FNE) in AL children (2016-2021) and assessed factors associated with proven/probable IFI. Ninety-three children developed 339 FNE. Seventeen (18.3%) children developed 19 proven/probable IFI (11 yeast; eight molds). The proven/probable yeast IFI rate was 6/52 (11.5%) in children who belong to the high risk for IFI category (HR-IFI-AL: high-risk acute lymphocytic leukemia (ALL), acute myeloid leukemia, relapse); and 5/41 (12.2%) in the non-HR-IFI-AL category (standard/intermediate risk ALL). The proven/probable mold IFI rate was 7/52 (13.5%) in HR-IFI-AL children and 1/41 (2.4%) in the non-HR-IFI-AL category. In the multivariable analysis, underlying genetic syndrome, oral mucositis, and older age were significantly associated with proven/probable IFI, while a longer time since AL diagnosis was protective. Two of 13 (15.4%) HR-IFI-AL children died because of IFI. The elevated risks of proven/probable mold IFI and the associated mortality in HR-IFI-AL children, and high risk of invasive candidiasis in the non-HR-IFI-AL group, emphasize the need for the close monitoring of local epidemiology and the adjustment of practices accordingly.

Analysis of risk factors of cord blood transplantation for children.

BACKGROUND: As cord blood (CB) is being used frequently as a source for heamtopoetic stem cell transplantation defining risk factors for transplantation outcome is an important issue. PROCEDURE: The data of all single unit CB transplantation preformed in Israel from 1992 to 2011 were collected. The risk factors for myeloid engraftment, event free survival (EFS) and overall survival (OS) were studied in 87 children. RESULTS: There were 49 children with hematological malignancies and 38 with non-malignant diseases. Cumulative rate of neutrophil recovery was 78.3%, while median time to myeloid recovery was 26 days. The incidence of platelet engraftment at 150 days was 53%, and the median time to platelet recovery was 36 days. ABO blood group matching between CB unit and recipient was associated with superior myeloid engraftment. Acute graft versus host disease of grades II-IV occurred in 33% of the patients. Chronic graft versus host disease occurred in 16% of patients. Probabilities of EFS and OS at 1 year were 45% and 57%, respectively. Factors associated with inferior OS were Rh major mismatch versus matched Rh and transplantation from unrelated donor versus related donor. CONCLUSIONS: These results indicate that matching of ABO blood groups is an important factor that affects engraftment, and also that Rh matching seem to have an impact on OS, which was not previously described in the setting of CB transplantation.

Impact of conditioning on outcome of hematopoietic stem cell transplantation for wiskott-Aldrich syndrome.

Hematopoietic stem cell transplantation (HSCT) is the treatment of choice for Wiskott-Aldrich syndrome (WAS). The aim of this retrospective study is to report the effect of the conditioning regimen and donor source on disease-free survival (DFS) in children undergoing HSCT for WAS. Fourteen children who underwent HSCT at 4 Israeli centers from 1996 to 2011 were included in this study. Five children were transplanted from matched related donors (4/5 siblings, 1/5 fully matched uncle) and other donors were used in 9 children. Six patients were conditioned with full dose busulfan/cyclophosphamide (Bu/Cy) whereas 8 patients were conditioned with other regimens. Thirteen of 14 patients (92.8%) are alive with a median follow-up of 3.4 years (range, 5 mo to 12.5 y). Nine patients (64.3%) survive with complete clinical, immunologic, and hematologic recovery. Children conditioned with full dose Bu/Cy had a 100% DFS, compared with children conditioned with other regimens, 25%±19% (P=0.022). Donor source was not associated with DFS. Graft failure was related to the use of conditioning regimens other than full dose Bu/Cy and not to the donor source. Further studies are required to determine the best conditioning regimen and optimal donor source for children with WAS.

Targeted therapy with low doses of 131I-MIBG is effective for disease palliation in highly refractory neuroblastoma.

BACKGROUND: Palliative treatment ore remains a significant clinical problem. OBJECTIVES: To retrospectively determine the clinical response to 131I-MIBG therapy at low doses in patients with refractory neuroblastoma. METHODS: We performed a retrospective chart review of 10 patients with neuroblastoma treated with 1311-MIBG at Rambam Health Care Campus from 1994 to 2012. Clinical data, number of 131I-MIBG courses delivered, toxicities, and clinical responses were reviewed. MIBG scan was performed after each course. RESULTS: Twenty-one courses of 131I-MIBG were delivered to 10 patients (3 girls, 7 boys). Their mean age was 3.8 years (range 1.5-6 years). All patients received several protocols of chemotherapy including the high dose form. Three patients received three courses of 131I-MIBG with a minimum of 6 weeks between each course, five patients received two courses, and two patients received only one course. An objective response to the first course was obtained in nine patients and to the second course in six of eight, and in three children who underwent the third course the pain decreased. One patient has no evidence of disease, four are alive with disease, and five died of the disease. No unanticipated toxicities were observed. CONCLUSIONS: Low dose 131I-MIBG is an effective and relatively non-toxic treatment in neuroblastoma disease palliation. Rapid and reproducible pain relief with 131I-MIBG was obtained in most of the children. Treatment with systemic radiotherapy in the form of low dose 131I-MIBG was easy to perform and effective in cases of disseminated neuroblastoma, demonstrating that this primary therapy can be used for palliative purposes.

Case report: Robust response of metastatic clear cell sarcoma treated with cabozantinib and immunotherapy.

Clear Cell Sarcoma (CCS), also referred to as malignant melanoma of soft parts, is a rare and aggressive malignant tumor. It comprises 1% of all soft tissue sarcomas and is known to be radio- and chemotherapy resistant. CCS shares morphological and immunohistochemical features with malignant melanoma, including melanin biosynthesis and melanocytic markers. However, it is distinct for the presence of EWSR1-ATF1 translocation which activates MITF transcription factor. We report here of an aggressive case of CCS in a 9-year-old patient, which demonstrates the critical role of molecular analysis in the diagnosis and treatment of uncommon cancer variants in the era of personalized medicine. The EWSR1-ATF1 translocation induces pathological c-Met activation, and so, following unsuccessful CTLA4 and PD-1 blockade immunotherapy, the child received cabozantinib, a small molecule tyrosine kinase inhibitor, with the intent to block c-Met oncogenic effect. In parallel, active immunization, using hapten di-nitrophenyl modified autologous tumor cells was administered with monotherapy PD-1 inhibitor nivolumab. Under this "triplet" therapy, the patient attained an initial partial response and was progression-free for 2 years, in good performance status and resumed schooling. Based on our observation, cabozantinib can be used as an effective and potentially life-prolonging treatment in CCS. We suggest that priming the child's immune system using her autologous tumor and combating T cell exhaustion with PD-1 blockade may have synergized with the targeted therapy. Combining targeted and immunotherapy is a rapidly growing practice in solid tumors and provides a glimpse of hope in situations that previously lacked any treatment option.

Evaluating differential expression of fibrosis-related genes and their correlation with blood vessel density in chronic cutaneous graft-versus-host disease.

BACKGROUND: Sclerodermoid graft-versus-host disease (GVHD) is the most severe form of chronic GVHD (cGVHD) and represents a considerable therapeutic challenge. Due to the scarcity of human studies on sclerodermoid cGVHD, the pathogenesis of this entity is not fully understood. OBJECTIVE: To identify the differential expression of fibrosis-related genes in skin lesions of human lichenoid and sclerodermoid cGVHD and to assess the expression of their corresponding proteins. METHODS: PCR array analysis was performed on RNA extracted from three skin biopsies of sclerodermoid cGVHD patients and three normal skin samples, for fibrosis-related gene expression profiles followed by evaluation of their corresponding protein expressions. The expressions of Tissue inhibitor of metalloproteinase 3 (TIMP3), matrix metalloproteinase 1 (MMP1), TIMP1, and TIMP2 were further studied by immunohistochemistry. Demographic, clinical and immunohistochemical parameters of the two cGVHD groups and the control group were compared. The Pearson correlation coefficient was used to assess the correlation between data among the study groups. RESULTS: We identified 44 upregulated and 14 downregulated genes in the skin samples of sclerodermoid cGVHD compared to the control group. TIMP3 was positive in 13/21 biopsies of cGVHD and in one biopsy of the control group. The average staining intensity was significantly higher in the cGVHD group compared to the control group. TIMP3 was expressed mainly in dermal blood vessels. cGVHD specimens with positive TIMP3 staining had a statistically significantly higher total microvascular area than the negative specimens. CONCLUSION: TIMP3 levels are increased in both subtypes of cGVHD and are associated with increased dermal vascularity.