Long-term endocrine sequelae after hematopoietic stem cell transplantation in children and adolescents

PURPOSE

As the survival rate from pediatric cancers has increased significantly with advances in treatment modalities, long-term endocrine complications have also risen. This study investigated the frequencies and risks of endocrine sequelae in childhood cancer survivors who received hematopoietic stem cell transplantation (HSCT).

METHODS

This study included 200 pediatric patients who underwent HSCT. Clinical and endocrinological findings were collected retrospectively. The median follow-up duration after HSCT was 14 years.

RESULTS

Endocrine complications occurred in 135 patients (67.5%). Children who underwent HSCT at pubertal age (n=100) were at higher risk of endocrine complications than those who received it at prepubertal age (79% vs. 56%, P=0.001). The most common complication was hypogonadism (40%), followed by dyslipidemia (22%). Short stature and diabetes mellitus were more prevalent in the prepubertal group, whereas hypogonadism and osteoporosis were more common in the pubertal group. Being female, pubertal age at HSCT, and glucocorticoid use were predictors of an increased risk for any complication. Radiation exposure increased the risk of short stature and hypothyroidism. Hypogonadism was significantly associated with being female, pubertal age at HSCT, and high-dose radiation. Pubertal age at HSCT also increased the risks of osteoporosis and dyslipidemia.

CONCLUSION

This study demonstrates that long-term endocrine complications are common after HSCT in children and adolescents. Age at HSCT is a critical factor for endocrine complications after HSCT. These findings suggest that surveillance strategies for endocrine complications in childhood cancer survivors should be specified according to age at HSCT.

Ten-Year Trends of Hematopoietic Stem Cell Transplantation in Korean Pediatric Cancer from the National Health Insurance Claims Data

PURPOSE

We aimed to determine the current application and survival trends of hematopoietic stem cell transplantation (HSCT) among Korean children and adolescents with cancer.

MATERIALS AND METHODS

Data of patients aged < 20 years with KCD-10 (Korean Classifications of Diseases, 10th revision) C codes and specific designation codes were collected from the National Health Insurance Service database. Thirty claim codes for HSCT were included, and data from 2009 to 2019 were analyzed.

RESULTS

The operational definition of pediatric cancer yielded an annual average of 2,000, with annual cases decreasing. In 2019, 221 HSCTs were performed, a decrease from the ten-year average of 276. Allografts outnumbered autografts with a ratio of 1.5:1. The source of allograft was bone marrow in 15% of patients in 2009; however, it substantially decreased to 3.3% in 2019. Furthermore, 70.5% of allogeneic HSCT used peripheral blood stem cell (PBSC) grafts, which increased to 89.3% by 2015. Cord blood utilization markedly decreased to 2.7% in 2018. The 5-year overall survival (OS) rate of all patients was 85.1%. Overall mortality decreased among patients who underwent recent HSCT, and they exhibited a higher 5-year OS rate.

CONCLUSION

In Korea, the number of pediatric patients with cancer is declining; however, the ratio of transplants to all patients remains constant. Patients who recently underwent transplantation showed better survival rates, possibly due to HSCT optimization. Korea showed a substantially greater PBSC utilization in pediatric HSCT. An in-depth examination encompassing donor relations and cause of death with a prospective registry is required in future studies.

Local control and toxicity outcomes following consolidative radiation therapy in patients with high-risk neuroblastoma: a 20-year experience at a single center

BACKGROUND

Intensive multimodal treatment can improve survival in patients with high-risk neuroblastoma, and consolidative radiation therapy has contributed to local control. We examined the clinical outcomes of patients who underwent consolidative radiation therapy at our institution.

METHODS

We retrospectively reviewed the records of patients with high-risk neuroblastoma who underwent consolidative radiation therapy from March 2001 to March 2021 at Asan Medical Center. Patients underwent multimodal treatment including high-dose chemotherapy, surgery, stem cell transplantation, and maintenance therapy. Radiation (median, 21.0 Gy; range, 14-36) was administered to the primary site and surrounding lymph nodes.

RESULTS

This study included 37 patients, and the median age at diagnosis was 2.8 years (range, 1.3-10.0). Four patients exhibited local failure, and 5-year free-from locoregional failure rate was 88.7%, with a median followup period of 5.7 years. The 5-year disease-free survival (DFS) and overall survival (OS) rates were 59.1% and 83.6%, respectively. Univariate analysis revealed that patients with neuron-specific enolase levels > 100 ng/mL had significantly worse DFS and OS (P = 0.036, 0.048), and patients with no residual disease before radiation therapy showed superior OS (P = 0.029). Furthermore, patients with 11q deletion or 17q gain exhibited poor DFS and OS, respectively (P = 0.021, 0.011). Six patients experienced grade 1 acute toxicity. Late toxicity was confirmed in children with long-term survival, predominantly hypothyroidism and hypogonadism, typically < grade 3, possibly attributed to combination treatment. Four patients experienced late toxicity ≥ grade 3 with chronic kidney disease, growth hormone abnormality, ileus, premature epiphyseal closure, and secondary tumor, and recovered by hospitalization or surgical treatment.

CONCLUSIONS

In patients with high-risk neuroblastoma, consolidative radiotherapy to the primary tumor site resulted in excellent local control and a tolerable safety profile.

Correction: Immunologic monitoring of cytomegalovirus (CMV) enzyme-linked immune absorbent spot (ELISPOT) for controlling clinically significant CMV infection in pediatric allogeneic hematopoietic stem cell transplant recipients

[This corrects the article DOI: 10.1371/journal.pone.0246191.].

CD19/CD22 bispecific chimeric antigen receptor‑NK‑92 cells are developed and evaluated

Anti-CD19 chimeric antigen receptor (CAR)-T cells have improved the outcomes of patients with B cell leukemia and lymphoma. However, their applications and positive outcomes remain limited. CAR-T cells are currently restricted to autologous blood as their source and their use can lead to downregulation of CD19 expression along with complications such as graft-versus-host disease and cytokine release syndrome. The present study aimed to develop anti-CD19/CD22 bispecific CAR structures using an anti-CD22 monoclonal antibody clone from chickens and analyze them in natural killer (NK)-92 cells, a human NK cell line, in vitro and in vivo. Anti-CD19/CD22 CAR-NK-92 cell cytotoxicity was assessed by the survival of target cells and counted using flow cytometry. Anti-CD22/CD19 and loop-structured anti-CD19/CD22 bi-specific CAR-NK-92 cells showed improved efficacy against OCI-Ly7 cells, a human B cell lymphoma cell line, compared with other CAR structures. These results demonstrate the potential of anti-CD19/CD22 bispecific CAR-NK cells and suggested that optimizing CAR structures in NK cells can improve the efficacy of CAR therapy.

High-dose chemotherapy followed by autologous stem cell transplantation in pediatric patients with relapsed osteosarcoma

BACKGROUND

Patients with relapsed osteosarcoma have poor treatment outcomes. High-dose chemotherapy with autologous stem cell transplantation (HDCT/ASCT) has been used in several high-risk malignant solid tumors; however, few studies have evaluated their role in treating osteosarcoma. We evaluated the effectiveness of HDCT/ASCT in relapsed pediatric osteosarcoma cases.

PROCEDURE

We retrospectively reviewed the medical records of 40 patients diagnosed with and treated for relapsed osteosarcoma at Asan Medical Center and Samsung Medical Center from January 1996 to July 2019.

RESULTS

The median age of this cohort was 13.4 years (range: 6.1-18.2). The cohort's 5-year overall survival (OS) was 51.0% ± 0.1% during a median follow-up period of 67.5 months. Twenty-five patients (62.5%) achieved complete remission (CR) with salvage treatment, and the 5-year OS was 82.4% ± 0.1%, whereas none of the remaining 15 patients who did not achieve CR survived (p < .0001). Of the 25 CR cases, 15 underwent subsequent HDCT/ASCT. We compared the effect of HDCT/ASCT among patients who achieved CR. There were no significant differences in the 5-year OS outcomes between patients who did and did not receive HDCT/ASCT (83.9% ± 0.1%, 13/15 vs. 80.0% ± 0.1%, 8/10, respectively; p = .923).

CONCLUSION

To our knowledge, we report the first comparative cohort study that proved HDCT/ASCT does not significantly improve survival outcomes in relapsed osteosarcoma. Achievement of CR remains the most crucial factor for good survival outcomes.

Comorbidity Differences by Trajectory Groups as a Reference for Identifying Patients at Risk for Late Mortality in Childhood Cancer Survivors: Longitudinal National Cohort Study

BACKGROUND

Childhood cancer has a high long-term morbidity and mortality rate. Five years after the initial cancer diagnosis, approximately two-thirds of childhood cancer survivors experience at least one late complication, with one-quarter experiencing severe, life-threatening complications. Chronic health conditions can impact survivors' life planning and daily activities, reducing their health-related quality of life. Comprehensive and longitudinal data are required for investigations of national claims data.

OBJECTIVE

This study aimed to address clinical and health policy interventions and improved survival rates. A comprehensive categorization of the long-term morbidities associated with childhood cancer survivorship is required. We analyzed the trajectory groups associated with long-term mortality among childhood cancer survivors.

METHODS

We collected data from a nationwide claims database of the entire Korean population. Between 2003 and 2007, patients diagnosed with and treated for cancer before the age of 20 years were included. With 8119 patients who survived >10 years, 3 trajectory groups were classified according to yearly changes in the number of diagnoses (the lowest in group 1 and the highest in group 3).

RESULTS

The patterns of most comorbidities and survival rates differed significantly between the trajectory groups. Group 3 had a higher rate of mental and behavioral disorders, neoplasms, and blood organ diseases than the other two groups. Furthermore, there was a difference in the number of diagnoses by trajectory groups over the entire decade, and the disparity increased as the survival period increased. If a patient received more than four diagnoses, especially after the fourth year, the patient was likely to be assigned to group 3, which had the worst prognosis. Group 1 had the highest overall survival rate, and group 3 had the lowest (P<.001). Group 3 had the highest hazard ratio of 4.37 (95% CI 2.57-7.42; P<.001) in a multivariate analysis of late mortality.

CONCLUSIONS

Our findings show that the pattern of comorbidities differed significantly among trajectory groups for late death, which could help physicians identify childhood cancer survivors at risk for late mortality. Patients with neoplasms, blood organ diseases, or mental and behavioral disorders should be identified as having an increased risk of late mortality. Furthermore, vigilance and prompt action are essential to mitigate the potential consequences of a child cancer survivor receiving four or more diagnoses within a year.

Cytotoxicity of Human Hepatic Intrasinusoidal Gamma/Delta T Cells Depends on Phospho-antigen and NK Receptor Signaling

BACKGROUND/AIM

We previously showed that human hepatic intrasinusoidal (HI) natural killer (NK) T cells selectively eliminate hepatocellular carcinoma (HCC) cell lines. In this study, we investigated the underlying mechanisms on how HI γδ T cells, expanded with zoledronate, exhibit a superior cytotoxic effect on HI NK-resistant Huh7 HCC cells.

MATERIALS AND METHODS

γδ T cells were obtained from living liver transplant donors or from peripheral blood mononuclear cells (PBMC) of healthy volunteers and were expanded in the presence of IL-2, IL-15, and zoledronate for 2 weeks. Cytotoxicity was measured using the lactate dehydrogenase (LDH) assay in vitro and by flow cytometry using carboxyfluorescein succinimidyl ester (CFSE) in vivo.

RESULTS

The cytotoxicity of expanded HI γδ T cells against Huh7 cells was associated with a higher pyrophosphate expression in Huh7 cells compared to SNU398 cells. In contrast, the cytotoxicity of HI γδ T cells against SNU398 cells depended on NKG2D. HI γδ T cells expressed less PD-1 than PB γδ T cells. The cytotoxicity of HI γδ T cells against Du145 and PC3 prostate cancer cells was also associated with pyrophosphate expression in these cells, as well as NKG2D and DNAM-1.

CONCLUSION

The expression levels of phospho-antigen in tumor cells determined the cytotoxicity of HI γδ T cells, although the NK activating receptors, death ligands, and immune checkpoint molecules also contribute to their cytotoxicity. γδ T cells are attractive candidates for cancer immune cell therapy.

Epidemiologic and Clinical Outcomes of Pediatric Renal Tumors in Korea: A Retrospective Analysis of The Korean Pediatric Hematology and Oncology Group (KPHOG) Data

PURPOSE

Renal tumors account for approximately 7% of all childhood cancers. These include Wilms tumor (WT), clear cell sarcoma of the kidney (CCSK), malignant rhabdoid tumor of the kidney (MRTK), renal cell carcinoma (RCC), congenital mesoblastic nephroma (CMN) and other rare tumors. We investigated the epidemiology of pediatric renal tumors in Korea.

MATERIALS AND METHODS

From January 2001 to December 2015, data of pediatric patients (0-18 years) newly-diagnosed with renal tumors at 26 hospitals were retrospectively analyzed.

RESULTS

Among 439 patients (male, 240), the most common tumor was WT (n=342, 77.9%), followed by RCC (n=36, 8.2%), CCSK (n=24, 5.5%), MRTK (n=16, 3.6%), CMN (n=12, 2.7%), and others (n=9, 2.1%). Median age at diagnosis was 27.1 months (range 0-225.5) and median follow-up duration was 88.5 months (range 0-211.6). Overall, 32 patients died, of whom 17, 11, 1, and 3 died of relapse, progressive disease, second malignant neoplasm, and treatment-related mortality. Five-year overall survival and event free survival were 97.2% and 84.8% in WT, 90.6% and 82.1% in RCC, 81.1% and 63.6% in CCSK, 60.3% and 56.2% in MRTK, and 100% and 91.7% in CMN, respectively (p < 0.001).

CONCLUSION

The pediatric renal tumor types in Korea are similar to those previously reported in other countries. WT accounted for a large proportion and survival was excellent. Non-Wilms renal tumors included a variety of tumors and showed inferior outcome, especially MRTK. Further efforts are necessary to optimize the treatment and analyze the genetic characteristics of pediatric renal tumors in Korea.

Favorable outcomes with durable chimerism after hematopoietic cell transplantation using busulfan and fludarabine-based reduced-intensity conditioning for pediatric patients with hemophagocytic lymphohistiocytosis

Background

The incorporation of a reduced-intensity conditioning (RIC) regimen in hematopoietic cell transplantation (HCT) for patients with hemophagocytic lymphohistiocytosis (HLH) has decreased early mortality but is associated with a high rate of mixed chimerism and graft failure. Here, we present a successful single-center experience using busulfan and a fludarabine-based RIC regimen for the treatment of HLH.

Methods

The medical records of pediatric patients with HLH who underwent HCT using a busulfan/fludarabine-based RIC regimen between January 2008 and December 2017 were reviewed retrospectively.

Results

Nine patients received HCT with a busulfan/fludarabine-based RIC regimen. Three patients had primary HLH, and the other six patients had secondary HLH with multiple reactivations. All three patients with primary HLH had UNC13D mutations. All patients achieved neutrophil and platelet engraftment at a median of 11 days (range, 10‒21) and 19 days (range, 13‒32), and all eight evaluable patients had sustained complete donor chimerism at the last follow-up. Two patients (22%) experienced grade 2 acute graft-versus-host disease (GVHD). Two patients (22%) developed chronic GVHD, and one died from chronic GVHD. One patient (11%) experienced reactivation 4 months after HCT from a syngeneic donor and died of the disease. The 8-year overall survival and event-free survival rates were 78%. No early treatment-related mortality within 100 days after HCT was observed.

Conclusion

Our experience suggests that a busulfan/fludarabine-based RIC regimen is a viable option for pediatric patients with HLH who require HCT.

Clinical characteristics and treatment outcomes of children and adolescents with aggressive mature B-cell lymphoma: a single-center analysis

Background

Aggressive mature B-cell non-Hodgkin lymphoma (B-NHL) is the most common non-Hodgkin lymphoma in children. The outcome of chemotherapy for B-NHL has improved over decades.

Methods

We reviewed 82 children and adolescents with B-NHL diagnosed at Asan Medical Center between 1993 and 2020. The D-COMP/COMP (daunomycin–cyclophosphamide, doxorubicin, vincristine, and prednisolone), Pediatric Oncology Group (POG)-9219/9315/9317, R-CHOP/CHOP (rituximab–cyclophosphamide, doxorubicin, vincristine, and prednisolone), and Lymphomes Malins B 89 (LMB89)/LMB96 regimens were administered. In 2018, rituximab was added to the LMB protocol (R-LMB) for advanced-staged Burkitt lymphoma (BL). The patients’ clinical features and treatment outcomes were retrospectively analyzed.

Results

The most common subtype was BL (61%), followed by diffuse large B-cell lymphoma (DLBCL) (35%). The median age was 7.8 (range, 1.3‒16.4) years, and the most frequently used regimen was French‒American‒British (FAB)/LMB96 (58 patients, 70.7%). The 5-year overall survival (OS) and event-free survival (EFS) rates were 92.5% and 85.7%, respectively. The EFS rates of patients with BL and DLBCL were 90.0% and 79.3%, respectively. Among the FAB/LMB risk groups, group C (85.7%) had a significantly lower 5-year OS (P=0.037). Eleven events occurred (6 relapses, 3 deaths, and 2 secondary malignancies) during the median follow-up of 7.1 (range, 3.7‒118.5) months. Two patients treated with R-LMB had good outcomes without complications.

Conclusion

Various treatment regimens have favorable outcomes in pediatric patients with B-NHL. However, further studies are needed to improve survival in high-risk patients. In addition, careful monitoring for acute toxicity or secondary malignancy due to intensive multidrug chemotherapy is required.

Case Report: Mevalonic Aciduria Complicated by Acute Myeloid Leukemia After Hematopoietic Stem Cell Transplantation

Mevalonic aciduria (MA) is the most severe clinical subtype of mevalonate kinase deficiency (MKD) caused by an inherited defect in the mevalonate pathway. The treatment of MKD focuses on the suppression of recurrent hyperinflammatory attacks using anti-inflammatory drugs. Recently, allogeneic hematopoietic stem cell transplantation (HCT) was shown to successfully ameliorate autoinflammatory attacks in patients with MKD. Here, we report a case of an infant who showed severe recurrent systemic inflammation and was diagnosed with MA. Although she responded to steroids, her symptoms relapsed after the dose was tapered, and organ deterioration occurred. Therefore, at the age of 11 months, HCT from a matched, unrelated donor was performed for curative treatment. However, at 50 days after transplantation, acute myeloid leukemia was diagnosed, which was chemo-refractory. A second HCT from her haploidentical father was performed to treat the acute myeloid leukemia, but the patient died of sepsis on day 4 after transplantation. This is the first report of malignancy following HCT for MA. Our findings suggest that normalizing the mevalonate pathway after HCT in patients with MKD impacts patients differently depending on the clinical spectrum and severity of disease.

Outcomes of intracranial germinoma-A retrospective multinational Asian study on effect of clinical presentation and differential treatment strategies

BACKGROUND

This multinational study was conducted to report clinical presentations and treatment strategies in patients with intracranial germinomas across selected Asian centers, including failure patterns, risk factors, and outcomes.

METHODS

A retrospective data collection and analysis of these patients, treated between 1995 and 2015 from eight healthcare institutions across four countries was undertaken.

RESULTS

From the results, 418 patients were analyzed, with a median follow-up of 8.9 years; 79.9% of the patients were M0, and 87.6% had β-human chorionic gonadotropin values <50 mIU/mL. The 5/10-year overall survival (OS) and recurrence-free survival (RFS) rates were 97.2%/96.2% and 89.9%/86.9%, respectively. RFS was predicted by the radiotherapy (RT) field, with focal RT having the worst outcome, whereas chemotherapy usage had no impact on survival. Among patients who received chemotherapy, response to chemotherapy did not predict survival outcomes. In M0 patients, primary basal ganglia tumors predicted a worse RFS. In patients with bifocal tumors, an extended field RT was associated with better outcomes. In multivariable analysis, only RT fields were associated with RFS. In relapsed patients, salvage rates were high at 85.7%. Additionally, patients who received salvage RT had a better outcome (91.6% vs. 66.7%).

CONCLUSIONS

Survival outcomes of patients with germinoma were excellent. Thus, the focus of treatment for intracranial germinoma should be on survivorship. Further studies are warranted to find the optimal intensity and volume of radiation, including the role of chemotherapy in the survival of patients with intracranial germinomas, considering age, primary tumor location, and extent of disease.

Characteristics of Human Peripheral Blood γδ T Cells Expanded With Zoledronate

BACKGROUND/AIM

This study aimed to investigate the characteristics of human peripheral blood γδ T cells, which were expanded ex vivo in the presence of zoledronate (ZOL).

MATERIALS AND METHODS

Human peripheral blood cells were cultured with IL-2 and IL-15 in the presence or absence of ZOL, which was added as a phospho-antigen, and their phenotypes were assessed by flow cytometry. Expanded γδ T cells were transduced with CD19 CAR vector, and the cytotoxicity was evaluated in vitro and in vivo by flow cytometry.

RESULTS

Ex vivo expansion did not hamper the expression of activating receptors. Interestingly, ZOL promoted the expression of CD226 (DNAM-1), TRAIL, and FAS-L in the Vδ1 subset of γδ T cells. Expanded γδ T cells containing CD19 CAR⁺ γδ T cells removed B cell lymphoma cells effectively in vivo.

CONCLUSION

γδ T cells could be a promising immunotherapeutic for cancer.

Prognostic factors of pediatric hematopoietic stem cell transplantation recipients admitted to the pediatric intensive care unit

Background

Pediatric patients who received hematopoietic stem cell transplantation (HSCT) tend to have high morbidity and mortality. While, the prognostic factors of adult patients received bone marrow transplantation were already known, there is little known in pediatric pateints. This study aimed to identify the prognostic factor for pediatric intensive care unit (PICU) mortality of critically ill pediatric patients with HSCT.

Methods

Retrospectively reviewed that the medical records of patients who received HSCT and admitted to PICU between January 2010 and December 2019. Mortality was defined a patient who expired within 28 days.

Results

A total of 131 patients were included. There were 63 boys (48.1%) and median age was 11 years (interquartile range, 4–15 years). The most common HSCT type was haploidentical (38.9%) and respiratory failure (44.3%) was the most common reason for PICU admission. Twenty-eight–day mortality was 22.1% (29/131). In comparison between survivors and non-survivors, the number of HSCTs received, sepsis, oncological pediatric risk of mortality-III (OPRISM-III), pediatric risk of mortality-III (PRISM-III), pediatric Sequential Organ Failure Assessment (pSOFA), serum lactate, B-type natriuretic peptide (BNP) and use of mechanical ventilator (MV) and vasoactive inotropics were significant predictors (P<0.05 for all variables). In multivariate logistic regression, the number of HSCTs received, use of MV, OPRISM-III, PRISM-III and pSOFA were independent risk factors of PICU mortality. Moreover, three scoring systems were significant prognostic factors of 28-day mortality.

Conclusions

The number of HSCTs received and use of MV were more accurate predictors in pediatric patients received HSCT.

Physeal Abnormalities in Children With High-risk Neuroblastoma Intensively Treated With/Without 13-Cis-Retinoic Acid

BACKGROUND

This study aimed to investigate the presence of physeal abnormality and its effect on growth in children with high-risk neuroblastoma treated by intensive multimodal treatment with/without 13-cis-retinoic acid (13-CRA).

METHODS

Fifteen patients diagnosed with high-risk neuroblastomas at the age of 1 to 10 years, who received treatment such as high-dose chemotherapy and autologous stem cell transplantation with/without 13-CRA, and with complete data during their >2-year follow-up were retrospectively reviewed. The physeal abnormalities were investigated by whole-body magnetic resonance imaging, serially performed every 3 to 6 months. The patients' height growth was also investigated and compared with that of age-and-sex-matched patients with brain tumors who also underwent high-dose chemotherapy and autologous stem cell transplantation.

RESULTS

Six of 15 patients presented multifocal physeal abnormalities during follow-up, and all lesions occurred in patients with 13-CRA use. The lesions in 3 patients completely resolved spontaneously without any adverse effect on growth, but some lesions in the other 3 patients progressed to disturb the bony growth. Height growth of matched patients with brain tumors were not significantly different, and none of the matched controls showed definite bony deformity during the follow-up.

CONCLUSIONS

Some children who were treated for high-risk neuroblastomas experienced multifocal physeal insults, probably due to the use of 13-CRA. Most lesions resolved spontaneously, but some led to bony deformity. If the lesions are not followed by premature physeal closure, there seems to be no further adverse effect of 13-CRA on leg length growth. Routine periodic screening for physeal status is needed for the patients with high-risk neuroblastomas using 13-CRA.

LEVEL OF EVIDENCE

Level IV-prognostic study.

Granulocytic and Monocytic Myeloid-Derived Suppressor Cells are Functionally and Prognostically Different in Patients with Chronic Myeloid Leukemia

Myeloid-derived suppressor cells (MDSCs) represent phenotypically heterogeneous populations that suppress tumor-specific T-cell responses. MDSCs are produced from myeloid precursors in emergent states and are increased in several hematologic malignancies. We evaluated the differences in the levels and prognostic significance of MDSCs according to the clinical status of chronic myeloid leukemia (CML). The percentages and numbers of granulocytic (g)MDSCs and monocytic (m)MDSCs in peripheral blood (PB) and bone marrow (BM) aspirates were determined by five-color flow cytometry (HLA-DR/CD11b/CD15/CD33/CD14). The median BM-gMDSC% and PB-gMDSC% of the CML group were lower than those of the complete hematologic response (CHR) and control groups (P<0.001). In the CHR group, patients with major molecular response (MMR) showed higher median BM-gMDSC% than those without MMR (P=0.039). Conversely, the PB-mMDSC number of the CML group was higher than those of the CHR and control groups (P<0.001). Patients with high PB-gMDSC number exhibited superior survival to those with low PB-gMDSC number (P=0.021), and patients with high PB-mMDSC% showed inferior survival to those with low PB-mMDSC%, but there was no statistical significance (P=0.182). Increased gMDSCs at CHR may reflect non-leukemic granulopoiesis, and a high number of PB-gMDSCs suggests better prognosis in CML. However, mMDSCs may be associated with malignant conditions and poor prognosis.

Hematopoietic Stem Cell Transplantation-Associated Neurological Complications and Their Brain MR Imaging Findings in a Pediatric Population

Simple Summary

Neurologic complications following a hematopoietic stem cell transplantation (HSCT) can be caused by various etiologies and significantly contribute to morbidity and mortality. The aim of our retrospective study was to determine the prognostic indicators for HSCT-associated neurological complications in pediatric HSCT recipients using their clinical characteristics and brain magnetic resonance imaging (MRI) lesions. The demographics, received treatments, treatment-related morbidities, laboratory findings and brain MRI findings were reviewed and compared among 51 patients who had underwent a brain MRI due to newly developed neurological symptoms or infection signs during HSCT and follow-up period. Children with neurologic complications associated with infectious causes, malignant disease or severe brain MRI abnormalities were more likely to have poor outcome.

Abstract

Purpose: To determine the prognostic indicators for hematopoietic stem cell transplantation (HSCT)-associated neurological complications, the clinical characteristics and brain magnetic resonance imaging (MRI) lesions in pediatric HSCT recipients were reviewed. Methods: This retrospective study included 51 patients who had underwent a brain MRI due to newly developed neurological symptoms or infection signs during chemotherapy or HSCT. We reviewed the demographics, received treatments, treatment-related morbidities, laboratory findings and brain MRI findings, which were compared between good and poor neurologic outcome groups. Results: Thirty-seven patients (72.5%) fully recovered from the neurologic deficits and fourteen (27.5%) persisted or aggravated. The children with an underlying malignant disease had significantly poorer neurological outcomes (p = 0.015). The neurologic complications associated with infection were more frequent in the poor outcome group (p = 0.038). In the neuroimaging findings, the extent of the white matter lesions was significantly higher in the poor outcome group, as was that of abnormal enhancement, ventriculomegaly, cortical change, deep gray matter abnormalities and cerebellar abnormalities. Conclusion: Most children with neurologic complications and neuroimaging abnormalities during HSCT had recovered. However, children with neurologic complications associated with infectious causes, malignant disease or severe brain MRI abnormalities should be more carefully monitored during HSCT.

Genetic Confirmation and Identification of Novel Variants for Glanzmann Thrombasthenia and Other Inherited Platelet Function Disorders: A Study by the Korean Pediatric Hematology Oncology Group (KPHOG)

The diagnosis of inherited platelet function disorders (IPFDs) is challenging owing to the unavailability of essential testing methods, including light transmission aggregometry and flow cytometry, in several medical centers in Korea. This study, conducted by the Korean Pediatric Hematology Oncology Group from March 2017 to December 2020, aimed to identify the causative genetic variants of IPFDs in Korean patients using next-generation sequencing (NGS). Targeted exome sequencing, followed by whole-genome sequencing, was performed for diagnosing IPFDs. Of the 11 unrelated patients with suspected IPFDs enrolled in this study, 10 patients and 2 of their family members were diagnosed with Glanzmann thrombasthenia (GT). The variant c.1913+5G>T of ITGB3 was the most common, followed by c.2333A>C (p.Gln778Pro) of ITGB2B. Known variants of GT, including c.917A>C (p.His306Pro) of ITGB3 and c.2975del (p.Glu992Glyfs*), c.257T>C (p.Leu86Pro), and c.1750C>T (p.Arg584*) of ITGA2B, were identified. Four novel variants of GT, c.1451G>T (p.Gly484Val) and c.1595G>T (p.Cys532Phe) of ITGB3 and c.1184G>T (p.Gly395Val) and c.2390del (p.Gly797Valfs*29) of ITGA2B, were revealed. The remaining patient was diagnosed with platelet type bleeding disorder 18 and harbored two novel RASGRP2 variants, c.1479dup (p.Arg494Alafs*54) and c.813+1G>A. We demonstrated the successful application of NGS for the accurate and differential diagnosis of heterogeneous IPFDs.

Interplay between IL6 and CRIM1 in thiopurine intolerance due to hematological toxicity in leukemic patients with wild-type NUDT15 and TPMT

NUDT15 and TPMT variants are strong genetic determinants of thiopurine-induced hematological toxicity. Despite the impact of homozygous CRIM1 on thiopurine toxicity, several patients with wild-type NUDT15, TPMT, and CRIM1 experience thiopurine toxicity, therapeutic failure, and relapse of acute lymphoblastic leukemia (ALL). Novel pharmacogenetic interactions associated with thiopurine intolerance from hematological toxicities were investigated using whole-exome sequencing for last-cycle 6-mercaptopurine dose intensity percentages (DIP) tolerated by pediatric ALL patients (N = 320). IL6 rs13306435 carriers (N = 19) exhibited significantly lower DIP (48.0 ± 27.3%) than non-carriers (N = 209, 69.9 ± 29.0%; p = 0.0016 and 0.0028 by t test and multiple linear regression, respectively). Among 19 carriers, 7 with both heterozygous IL6 rs13306435 and CRIM1 rs3821169 showed significantly decreased DIP (24.7 ± 8.9%) than those with IL6 (N = 12, 61.6 ± 25.1%) or CRIM1 (N = 94, 68.1 ± 28.4%) variants. IL6 and CRIM1 variants showed marked inter-ethnic variability. Four-gene-interplay models revealed the best odds ratio (8.06) and potential population impact [relative risk (5.73), population attributable fraction (58%), number needed to treat (3.67), and number needed to genotype (12.50)]. Interplay between IL6 rs13306435 and CRIM1 rs3821169 was suggested as an independent and/or additive genetic determinant of thiopurine intolerance beyond NUDT15 and TPMT in pediatric ALL.

Recent improvement in survival outcomes and reappraisal of prognostic factors in hepatoblastoma

Background

Prognostic factors in hepatoblastoma need to be reevaluated considering the advances in treatment modalities. The study aimed to evaluate current outcomes of hepatoblastoma and reappraise the association of prognostic factors, including pre‐treatment extent of tumor (PRETEXT) stage with annotation factors and Children's Hepatic tumors International Collaboration‐Hepatoblastoma Stratification (CHIC‐HS) system, with survival outcomes.

Methods

We evaluated 103 consecutive patients with hepatoblastoma retrospectively according to the treatment period based on the introduction of a liver transplantation program.

Results

The 5‐year overall survival (OS), event‐free survival (EFS), and transplant‐free survival rates were 80.2%, 74.2%, and 61.8%, respectively. EFS and OS were improved significantly from 58.6% to 81.6% (P = 0.024) and from 58.6% to 90.8% (P < 0.001), respectively, in the late period (N = 74) compared with the early period (N = 29). The PRETEXT stage was significant or marginally significant for EFS and OS in the early period but not in the late period. The P, F, R, and C factors were significant for OS and EFS in the early period. However, in the late period, only the P factor was significant for OS, and the F and M factors were significant for EFS. The CHIC‐HS system was significant or marginally significant for EFS in both the early and late periods; however, it was significant for OS only in the early period.

Conclusion

Survival rates were significantly improved in children with hepatoblastoma, especially in those with advanced PRETEXT stages with positive annotation factors and in a high‐risk CHIC‐HS group. Prognostic factors had different clinical implications with evolved treatment modalities.

Recent advances in the understanding of the molecular pathogenesis and targeted therapy options in Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is the most common histiocytic disorder caused by the clonal expansion of myeloid precursors that differentiate into CD1a+/CD207+ cells in the lesion. Advances in genomic sequencing techniques have improved our understanding of the pathophysiology of LCH. Activation of the mitogen-activated protein kinase (MAPK) pathway is a key molecular mechanism involved in the development of LCH. Recurrent BRAF mutations and MAP2K1 mutations are the major molecular alterations involved in the activation of the MAPK pathway. Recent studies have supported the “misguided myeloid differentiation model” of LCH, where the extent of disease is defined by the differentiation stage of the cell in which the activating somatic MAPK mutation occurs, suggesting LCH. Several studies have advocated the efficacy of targeted therapy using BRAF inhibitors with a high response rate, especially in patients with high-risk or refractory LCH. However, the optimal treatment scheme for children remains unclear. This review outlines recent advances in LCH, focusing on understanding the molecular pathophysiology, emerging targeted therapy options, and their clinical implications.

Clinical Characteristics and Treatment Outcomes of Childhood Acute Promyelocytic Leukemia in Korea: a Nationwide Multicenter Retrospective Study by Korean Pediatric Oncology Study Group

Purpose

Acute promyelocytic leukemia (APL) is a rare disease in children and there are some different characteristics between children and adult. We aimed to evaluate incidence, clinical characteristics and treatment outcomes of pediatric APL in Korea.

Materials and Methods

Seventy-nine pediatric APL patients diagnosed from January 2009 to December 2016 in 16 tertiary medical centers in Korea were reviewed retrospectively.

Results

Of 801 acute myeloid leukemia children, 79 (9.9%) were diagnosed with APL. The median age at diagnosis was 10.6 years (range, 1.3 to 18.0). Male and female ratio was 1:0.93. Thirty patients (38.0%) had white blood cell (WBC) count greater than 10×10⁹/L at diagnosis. All patients received induction therapy consisting of all-trans retinoic acid and chemotherapy. Five patients (6.6%) died during induction chemotherapy and 66 patients (86.8%) achieved complete remission (CR) after induction chemotherapy. The causes of death were three intracranial hemorrhage, one cerebral infarction, and one sepsis. Five patients (7.1%) suffered a relapse during or after maintenance chemotherapy. The estimated 4-year event-free survival and overall survival (OS) rates were 82.1%±4.4%, 89.7%±5.1%, respectively. The 4-year OS was significantly higher in patients with initial WBC < 10×10⁹/L than in those with initial WBC ≥ 10×10⁹/L (p=0.020).

Conclusion

This study showed that the CR rates and survival outcomes in Korean pediatric APL patients were relatively good. The initial WBC count was the most important prognostic factor and most causes of death were related to serious bleeding in the early stage of treatment.

Children's Hepatic Tumors International Collaboration-Hepatoblastoma Stratification (CHIC-HS) System for Pediatric Patients with Hepatoblastoma: A Retrospective, Hospital-Based Cohort Study in South Korea

Purpose

In 2017, the Children's Hepatic Tumors International Collaboration-Hepatoblastoma Stratification (CHIC-HS) system was introduced. We aimed to evaluate the accuracy of Children's Hepatic Tumors International Collaboration-Hepatoblastoma Stratification (CHIC-HS) System for the prediction of event-free survival in Korean pediatric patients with hepatoblastoma.

Materials and Methods

This two-center retrospective study included consecutive Korean pediatric patients with histopathologically confirmed hepatoblastoma from March 1988 through September 2019. We compared event-free survival (EFS) among four risk groups according to the CHIC-HS system. Discriminatory ability of CHIC-HS system was also evaluated using optimism-corrected C-statistics. Factors associated with EFS were explored using multivariable Cox regression analysis.

Results

We included 129 patients (mean age, 2.6±3.3 years; female:male, 63:66). The 5-year EFS rates in the very low, low, intermediate, and high-risk groups, according to the CHIC-HS system were 90.0%, 82.8%, 73.5%, and 51.3%, respectively. The CHIC-HS system aligned significantly well with EFS outcomes (p=0.004). The optimism-corrected C index of CHIC-HS was 0.644 (95% CI, 0.561-0.727). Age ≥8 (vs. age ≤2; HR, 2.781; 95% CI, 1.187-6.512; p=0.018), PRE-Treatment EXTent of tumor (PRETEXT) stage IV (vs. PRETEXT I or II; HR, 2.774; 95% CI, 1.228-5.974; p=0.009), and presence of metastasis (HR, 2.886; 95% CI, 1.457-5.719; p=0.002), which are incorporated as the first three nodes in the CHIC-HS system, were independently associated with EFS.

Conclusion

The CHIC-HS system aligned significantly well with EFS outcomes in Korean pediatric patients with hepatoblastoma. Age group, PRETEXT stage, and presence of metastasis were independently associated with EFS.

Immunologic monitoring of cytomegalovirus (CMV) enzyme-linked immune absorbent spot (ELISPOT) for controlling clinically significant CMV infection in pediatric allogeneic hematopoietic stem cell transplant recipients

The dynamics of recovery of cytomegalovirus (CMV)-specific cell-mediated immunity (CMI) and its impact on controlling clinically significant CMV infections following hematopoietic stem cell transplant (HSCT) are rarely reported in pediatric HSCT recipients. In this study, dynamics of recovery of CMV-specific CMI and its clinical significance in controlling CMV viremia and clinically significant CMV infections were assessed in pediatric allogeneic HSCT recipients. All subjects underwent CMV pp65- and IE1-specific enzyme-linked immune absorbent spot (ELISPOT) assays just before transplantation and then monthly until the detection of CMV-specific CMI with ≥ 5 spot-forming cells (SFC) / 2.0 × 105 cells. Clinically significant CMV infections were defined as CMV diseases, prolonged CMV infections, recurrent CMV infections or late onset CMV infections. Among 52 recipients, 88.5% of recipients recovered CMV-specific CMI with ≥ 5 SFC/ 2.0 × 105 cells at a median of 34 days (interquartile range [IQR]: 29-95 days) following HSCT, 55.8% at 30 days following HSCT, and 73.1% at 90 days following HSCT. The presence of CMV-specific CMI before HSCT was the significant factors for the reconstitution of CMV specific CMI after HSCT (adjusted odds ratio [aOR] = 13.33; 95% confidence interval [CI] = 1.21-142.86). After HSCT, 30 recipients experienced CMV viremia, of which 20 were clinically significant CMV infections. The full recovery of CMV-specific CMI with ≥ 50 SFC / 2.0 × 105 cells after HSCT was the protective factor for the development of clinically significant CMV infections (aOR = 0.13; 95% CI = 0.22-0.71). In the haploidentical HSCT recipients, 82.1% recovered CMV-specific CMI at a median of 65 days after HSCT (IQR: 34-118 days) with a tendency to recover their CMV-specific CMI later than did those from non-haploidentical donors (65 days vs. 30 days; P = 0.001). Clinically significant CMV infections tended to occur more frequently in the haploidentical HSCT recipients compared to those with matched donor HSCT (46.4% vs. 29.2%; P = 0.205). The full recovery of CMV-specific CMI with ≥ 50 SFC/2.0 × 105 cells after HSCT also lowered the risk of development of clinically significant CMV infections (aOR = 0.08; 95% CI = 0.01-0.90). However, transplantation from haploidentical donors was a significant risk factor hampering recovery of CMV-specific CMI (aOR = 0.08; 95% CI = 0.01-0.86) and full recovery of CMV-specific CMI (aOR = 0.05; 95% CI = 0.01-0.50). Pre-transplant CMV-specific CMI influenced the recovery of CMV-specific CMI, and the full recovery of CMV-specific CMI could be a surrogate marker for preventing clinically significant CMV infections in pediatric HSCT recipients. Immunologic monitoring using ELISPOT assay before and after HSCT helps in identifying patients with a high risk of CMV infection and in controlling CMV infection.

Effectiveness and Safety of Clofarabine Monotherapy or Combination Treatment in Relapsed/Refractory Childhood Acute Lymphoblastic Leukemia: A Pragmatic, Non-interventional Study in Korea

Purpose

Effectiveness and safety of clofarabine (one of the treatment mainstays in pediatric patients with relapsed/refractory acute lymphoblastic leukemia [ALL]) was assessed in Korean pediatric patients with ALL to facilitate conditional coverage with evidence development.

Materials and Methods

In this multicenter, prospective, observational study, patients receiving clofarabine as mono/combination therapy were followed up every 4–6 weeks for 6 months or until hematopoietic stem cell transplantation (HSCT). Response rates, survival outcomes, and adverse events were assessed.

Results

Sixty patients (2–26 years old; 65% B-cell ALL, received prior ≥ 2 regimen, 68.3% refractory to previous regimen) were enrolled and treated with at least one dose of clofarabine; of whom 26 (43.3%) completed 6 months of follow-up after the last dose of clofarabine. Fifty-eight patients (96.7%) received clofarabine combination therapy. Overall remission rate (complete remission [CR] or CR without platelet recovery [CRp]) was 45.0% (27/60; 95% confidence interval [CI], 32.4 to 57.6) and the overall response rate (CR, CRp, or partial remission [PR]) was 46.7% (28/60; 95% CI, 34.0 to 59.3), with 11 (18.3%), 16 (26.7%), and one (1.7%) patients achieving CR, CRp, and PR, respectively. The median time to remission was 5.1 weeks (95% CI, 4.7 to 6.1). Median duration of remission was 16.6 weeks (range, 2.0 to 167.6 weeks). Sixteen patients (26.7%) proceeded to HSCT. There were 24 deaths; 14 due to treatment-emergent adverse events.

Conclusion

Remission with clofarabine was observed in approximately half of the study patients who had overall expected safety profile; however, there was no favorable long-term survival outcome in this study.

Endocrine Complications in Children and Adolescents With Non-Central Nervous System Solid Tumors

BACKGROUND

Due to remarkable progress in cancer treatment, endocrine complications are now the major medical issues facing childhood cancer survivors. Although non-central nervous system solid tumors (NCSTs) account for approximately 40% of all pediatric cancers, there have been few studies on endocrine complications associated with NCSTs. This study investigated endocrinopathies following the treatment of pediatric NCSTs.

DESIGN AND SETTING

Retrospective study in a single academic center.

METHODS

This study analyzed 253 survivors of childhood NCSTs who were diagnosed between January of 2000 and December of 2018. The medical charts were reviewed regarding the frequency of endocrinopathies and treatment modalities. The hazard ratios were assessed by multivariable Cox regression analysis. The final height-SDS were analyzed by multivariable linear regression analysis.

RESULTS

There were 76 patients (30%) that developed at least one endocrine complication. Forty-four patients (17.4%) experienced endocrine complications within five years of their cancer diagnosis. The most common endocrine complication was growth failure (n = 35), followed by obesity (n = 18), and primary gonadal failure (n = 16). High cumulative doses of alkylating agents increased the risk of developing at least one endocrine complication. Hematopoietic stem cell transplantation was an important risk factor for primary gonadal failure.

CONCLUSIONS

This study described the comprehensive endocrine outcomes, including growth failure, obesity, primary gonadal failure, primary hypothyroidism, dyslipidemia, and osteoporosis, following the treatment of childhood NCSTs. As endocrinopathies occurred within five years of primary tumor diagnosis, surveillance for endocrine dysfunction is required for early intervention and management.

Long-term treatment outcomes of children and adolescents with lymphoblastic lymphoma treated with various regimens: a single-center analysis

Background

Lymphoblastic lymphoma (LBL) is the second most common subtype of pediatric non-Hodgkin lymphoma. Modified treatments derived from the LSA2-L2 regimen resulted in encouraging survival, but toxicities and long-term sequelae have been problematic. At present, the acute lymphoblastic leukemia (ALL)-type protocol has demonstrated efficacy in LBL. We analyzed the outcomes of children and adolescents with LBL treated with various regimens.

Methods

From 1991‒2018, this study enrolled 63 patients diagnosed with LBL at Asan Medical Center. Medical records were retrospectively analyzed.

Results

Among 63 patients, most patients (38.1%) presented with stage IV at diagnosis, and two had central nervous system (CNS) involvement. At a median follow-up of 160 months, the 5-year event free survival (EFS), overall survival (OS), and relapse free survival (RFS) were 68.8%, 79.3%, and 71.3%, respectively. Among 61 patients who received chemotherapy, 27 patients (44.3%) received the NY protocol, and 14 (23.0%) received the ALL-type protocol. There was no significant difference in 5-yr OS (85.2%/78.6%), EFS (73.5%/78.6%), and RFS (73.5%/78.6%) between the NY and ALL protocol groups, regardless of immunophenotype. Thirteen patients (21.3%) received prophylactic cranial radiotherapy with no difference in the incidence of CNS relapse based on irradiation.

Conclusion

This study showed no difference in outcome between the NY and ALL-type protocols, regardless of stage or immunophenotype. In addition to improving the effectiveness of treatment, it is necessary to continuously appraise the appropriate chemotherapy regimen, considering toxicities and long-term prognosis, for pediatric LBL.

The BTLA and PD-1 signaling pathways independently regulate the proliferation and cytotoxicity of human peripheral blood γδ T cells

Background

B‐ and T‐lymphocyte attenuator (BTLA) and programmed cell death‐1 (PD‐1) inhibit γδ T cell homeostasis and activation. This study aimed to determine whether BTLA and PD‐1 signaling pathways were convergent or independent in human peripheral blood γδ T cells. Herein we demonstrate that the signalings of BTLA and PD‐1 regulated proliferation and cytotoxicity of human γδ T cells, respectively.

Methods

Human peripheral blood γδ T cells were cultured with inactivated Jurkat cells in the presence of interleukin‐2 and zoledronate (Zol) for 14 days. Flow cytometry was performed to evaluate the phenotypes and functions of γδ T cells.

Results

The proliferation of the γδ T cells was increased when PBMCs were cocultured with inactivated herpes virus entry mediator (HVEM)^low Jurkat cells. The cytotoxicity of the expanded γδ T cells was not affected by coculture with inactivated HVEM^low Jurkat cells and was further increased in the presence of anti‐PD‐L1 mAb. These results suggest that the inactivation of the BTLA signaling pathway during expansion could help produce more γδ T cells without compromising γδ T cell function. The inhibition of BTLA or PD‐1 signaling repressed phosphorylation of the src homology region 2‐containing protein tyrosine phosphatase 2 and increased the phosphorylation of protein kinase B in γδ T cells. However, there were no synergistic or additive effects by a combination of BTLA and PD‐1 blockade.

Conclusion

These results suggest that BTLA signaling is crucial in regulating γδ T cell proliferation and function and that the BTLA and PD‐1 signaling pathways act independently on the proliferation and cytotoxicity of human peripheral γδ T cells.

Genetic Alterations Detected by Targeted Next-generation Sequencing and Their Clinical Implications in Neuroblastoma

BACKGROUND/AIM

This study was conducted to evaluate the clinical usefulness of panel next-generation sequencing (NGS) and to investigate the spectrum of genetic alterations and their clinical implications in neuroblastoma.

PATIENTS AND METHODS

Formalin-fixed, paraffin-embedded archival samples from 41 cases of neuroblastoma were used for targeted sequencing.

RESULTS

A total of 145 somatic mutations were identified, including 51 synonymous, 86 missense, 3 nonsense, 2 frameshift deletion, 2 splice-site, and 1 in-frame deletion mutations. The most frequently mutated gene was ALK (9 missense mutations). The common copy number variations (CNVs) were amplification at 2p24.2 and deletion at 11q22.3 and 1p36.21. ALK mutations were more frequent in patients with stage 4 or 4S (0% vs. 33.3%, p=0.017). Among 27 patients with high-risk disease, the 5-year overall survival was inferior in patients with ALK mutations to those without (25.0% vs. 67.0%, p=0.009).

CONCLUSION

Genetic analysis using targeted NGS was feasible and helpful in detecting point mutations and CNVs in neuroblastoma. Targeted NGS could predict prognosis and be used to find molecular target-based therapies for neuroblastoma.

Atypical Teratoid/Rhabdoid Tumor of the Central Nervous System in Children under the Age of 3 Years

Purpose

Atypical teratoid/rhabdoid tumor (ATRT) is a highly aggressive malignancy with peak incidence in children aged less than 3 years. Standard treatment for central nervous system ATRT in children under the age of 3 years have not been established yet. The objective of this study was to analyze characteristics and clinical outcomes of ATRT in children aged less than 3 years.

Materials and Methods

A search of medical records from seven centers was performed between January 2005 and December 2016.

Results

Forty-three patients were enrolled. With a median follow-up of 90 months, 27 patients (64.3%) showed at least one episode of disease progression (PD). The first date of PD was at 160 days after diagnosis. The 1- and 3-year progression-free survivals (PFS) were 51.2% and 28.5%, respectively. The 1- and 3-year overall survivals were 61.9% and 38.1%, respectively. The 3-year PFS was improved from 0% in pre-2011 to 47.4% in post-2011. Excluding one patient who did not receive any further therapy after surgery, 27 patients died due to PD (n=21), treatment-related toxicity (n=5), or unknown cause (n=1). In univariate analysis, factors associated with higher 3-year PFS were no metastases, diagnosis after 2011, early adjuvant radiotherapy, and high-dose chemotherapy (HDCT). In multivariate analysis, the use of HDCT and adjuvant radiotherapy remained significant prognostic factors for PFS (both p < 0.01).

Conclusion

Aggressive therapy including early adjuvant radiotherapy and HDCT could be considered to improve outcomes of ATRT in children under the age of 3 years.

Feasibility and effectiveness of treatment strategy of tandem high-dose chemotherapy and autologous stem cell transplantation in combination with 131 I-MIBG therapy for high-risk neuroblastoma

This study was performed to evaluate the safety and effectiveness of tandem HDCT/ASCT combined with targeted radiotherapy using ¹³¹ I-MIBG for high-risk neuroblastoma. Patients with high-risk neuroblastoma were treated with 8 to 10 cycles of induction chemotherapy before tandem HDCT/ASCT. Patients received ¹³¹ I-MIBG treatment before the second HDCT/ASCT. Local radiotherapy and maintenance therapy were performed after tandem HDCT/ASCT. Between 2012 and 2016, 19 patients were diagnosed with high-risk neuroblastoma in our institution and 18 of them received tandem HDCT/ASCT combined with ¹³¹ I-MIBG therapy. For the first HDCT/ASCT regimen, 12 patients received busulfan/melphalan and six patients received melphalan/etoposide/carboplatin. The second HDCT included ThioCy. The median dose of ¹³¹ I-MIBG was 17.2 mCi/kg for the first eight patients, while 12 patients in the latter period of the study received reduced dose of 10.7 mCi/kg. The 5-year OS and EFS rates were 79% and 61%, respectively, for all 19 patients with high-risk neuroblastoma, and 83% and 64%, respectively, for 18 patients who completed tandem HDCT/ASCT combined with ¹³¹ I-MIBG therapy. Six patients experienced disease relapse and five patients died. Treatment-related mortality was not observed. Among 15 evaluable patients, 11 patients (73%) developed hypothyroidism, six patients (40%) had CKD, and six patients (40%) had growth failure. Hypothyroidism and growth failure were less frequent in patients who received reduced doses of ¹³¹ I-MIBG therapy. Tandem HDCT/ASCT combined with HD ¹³¹ I-MIBG therapy could be feasible for patients with high-risk neuroblastoma with acceptable toxicity profiles and favorable outcomes.

Improved outcomes of allogeneic hematopoietic stem cell transplantation including haploidentical transplantation for childhood myelodysplastic syndrome

This retrospective study aimed to investigate the outcomes of allogeneic hematopoietic stem cell transplantation (HSCT) for childhood myelodysplastic syndrome (MDS). Thirty-six patients (low-grade MDS, 24; advanced MDS, 12) received HSCT at the Asan Medical Center over two decades (early period, 1997-2007; recent period, 2008-2017). The transplantation outcomes were analyzed according to disease status, conditioning regimen, various donor types, and period of HSCT. During a median follow-up of 5.6 (range, 1.4-21.1) years, the probability of overall survival (OS) and failure-free survival was 77% and 69%, respectively. The cumulative incidence of transplantation-related mortality (TRM) was 12%. Significantly reduced TRM and improved OS were observed in patients who received HSCT during the recent period vs. the early period (TRM, 4% vs. 30%, P = 0.021; OS, 87% vs. 50%, P = 0.006). Comparable outcomes were observed for HSCT from haploidentical family donors vs. HLA-identical donors (TRM, 10% vs. 14%, P= 0.837; OS, 86% vs. 79%, P = 0.625). This study identified the improved outcomes of allogeneic HSCT for childhood MDS over time, in addition, the feasible outcomes of haploidentical HSCT suggested its use as an attractive alternative in the future procedures.

Expression of Immune Checkpoint Receptors on T-Cells and Their Ligands on Leukemia Blasts in Childhood Acute Leukemia

BACKGROUND

Possible correlations between the expression of immune checkpoint molecules and prognosis in childhood acute leukemia were investigated.

MATERIALS AND METHODS

The expression of programmed-death 1 (PD1), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), and B- and T-lymphocyte attenuator (BTLA) was determined by flow cytometry on peripheral αβ⁺ and γδ⁺ T-cells from patients with newly diagnosed acute lymphoblastic leukemia (ALL) (n=9) or acute myeloid leukemia (AML) (n=12), and from healthy volunteers (n=7). The expression of programmed-death ligand 1 (PD-L1), B7-1, B7-2, human leukocyte antigen-ABC (HLA-ABC), and herpesvirus-entry mediator (HVEM) ligands was determined on leukemia blasts.

RESULTS

PD1 expression on αβ⁺ and γδ⁺ T-cells was significantly higher in patients with ALL than in those with AML (p=0.0019 and 0.0239, respectively). CTLA-4 expression was moderately higher on αβ⁺ and γδ⁺ T-cells in ALL (p=0.077 and 0.077, respectively), whereas HLA-ABC expression was significantly higher in AML blast cells (p=0.0182). The expression of CTLA-4 on γδ⁺ T-cells and the B7-2 ligand on blasts was higher in patients with high-risk ALL (p=0.02 and 0.02, respectively). In AML, PD1 expression on αβ⁺ T-cells was higher in the intermediate-risk group (p=0.05), whereas HVEM expression was significantly higher in the low-risk group (p=0.02). Expression of CTLA-4 on γδ+ T-cells and PD-L1 on blasts were both associated with poor relapse-free survival outcomes in ALL (p=0.049).

CONCLUSION

The higher expression of immune checkpoint molecules, in particular, CTLA-4 and PD-L1 are associated with a poorer prognosis in ALL, suggesting that selective use of the immune checkpoint blockade might improve the clinical outcomes in patients with ALL.

Prognostic Factors for Event-Free Survival in Pediatric Patients with Hepatoblastoma Based on the 2017 PRETEXT and CHIC-HS Systems

This study aimed to evaluate the prognostic value of variables used in the 2017 PRE-Treatment EXTent of tumor (PRETEXT) system and the Children's Hepatic tumors International Collaboration-Hepatoblastoma Stratification (CHIC-HS) system in pediatric patients with hepatoblastoma. A retrospective analysis of data from the pediatric hepatoblastoma registry of a tertiary referral center was conducted to evaluate the clinical and imaging variables (annotation factors) of the PRETEXT staging system. The primary outcome was event-free survival (EFS). Data from 84 patients (mean age: 2.9 ± 3.5 years) identified between 1998 and 2017 were included. Univariable Cox proportional hazards analysis revealed that PRETEXT annotation factors P (portal vein involvement), F (multifocality of tumor), and M (distant metastasis) showed a significant negative association with EFS. Multivariable Cox proportional hazard analysis showed that factor F was the strongest predictor (HR (hazard ratio), 2.908; 95% CI (confidence interval), 1.061-7.972; p = 0.038), whereas factor M showed borderline significance (HR, 2.416; 95% CI, 0.918-6.354; p = 0.074). The prediction model based on F and M (F + M) showed good performance to predict EFS (C-statistic, 0.734; 95% CI, 0.612-0.854). In conclusion, the PRETEXT annotation factor F was the strongest predictor of EFS, and the F + M model showed good performance to predict EFS in pediatric patients with hepatoblastoma.

Comparable Outcome with a Faster Engraftment of Optimized Haploidentical Hematopoietic Stem Cell Transplantation Compared with Transplantations from Other Donor Types in Pediatric Acquired Aplastic Anemia

Haploidentical family donors have been used as an alternative source in hematopoietic cell transplantation for patients with severe aplastic anemia. We evaluated and compared the outcomes of transplantation in pediatric acquired severe aplastic anemia based on donor type. Sixty-seven patients who underwent transplantation between 1998 and 2017 were included. Fourteen patients received grafts from matched sibling donors, 21 from suitable unrelated donors, and 32 from haploidentical family donors. Ex vivo CD3⁺ or αβ⁺ T cell-depleted grafts were used for haploidentical transplantation. Sixty-five patients (97.0%) achieved neutrophil engraftment at a median of 11 days. Haploidentical transplantation resulted in significantly faster neutrophil engraftment at a median of 10 days, compared with 14 days in cases of matched sibling donors and 12 days in cases of unrelated donor recipients. Nine patients experienced graft failure, and 5 of 7 who underwent a second transplantation are alive. There was no difference in the incidence of acute or chronic graft-versus-host disease based on donor type. The 5-year overall survival and failure-free survival rates were 93.8% ± 3.0% and 83.3% ± 4.6%, respectively, and there was no significant survival difference based on donor type. The survival outcomes of haploidentical transplantation in patients were comparable with those of matched sibling or unrelated donor transplantation. Optimized haploidentical transplantation using selective T cell depletion and conditioning regimens including low-dose total body irradiation for enhancing engraftment may be a realistic therapeutic option for pediatric patients with severe aplastic anemia.

The Combination of Flavokawain B and Daunorubicin Induces Apoptosis in Human Myeloid Leukemic Cells by Modifying NF-κB

BACKGROUND/AIM

Flavokawain B (FKB), is a natural chalcone isolated from kava root that induces apoptosis in cancer cells. Herein we investigated the effects of combination of FKB and daunorubicin (DNR) on human leukemic cells.

MATERIALS AND METHODS

Cell viability and death were assessed by the MTS assay and flow cytometry. NK-κB was detected by western blotting.

RESULTS

FKB alone and in combination with DNR reduced the viable cell numbers of four leukemic cell lines. FKB itself induced apoptosis of an acute myeloid cell line, HL-60. Because the additive effect of DNR and FKB was most obvious in HL-60 cells, subsequent experiments were performed with HL-60 cells. Combined treatment of the two compounds increased NF-κB activation at 12 h.

CONCLUSION

A combination treatment of DNR and FKB may improve the anticancer effects of DNR in DNR-resistant acute myeloid leukemia.

Risk Factor Analysis for Secondary Malignancy in Dexrazoxane-Treated Pediatric Cancer Patients

Purpose

Dexrazoxane has been used as an effective cardioprotector against anthracycline cardiotoxicity. This study intended to analyze cardioprotective efficacy and secondary malignancy development, and elucidate risk factors for secondary malignancies in dexrazoxane-treated pediatric patients.

Materials and Methods

Data was collected from 15 hospitals in Korea. Patients who received any anthracyclines, and completed treatment without stem cell transplantation were included. For efficacy evaluation, the incidence of cardiac events and cardiac event-free survival rates were compared. Data about risk factors of secondary malignancies were collected.

Results

Data of total 1,453 cases were analyzed; dexrazoxane with every anthracyclines group (D group, 1,035 patients) and no dexrazoxane group (non-D group, 418 patients). Incidence of the reported cardiac events was not statistically different between two groups; however, the cardiac event-free survival rate of patients with more than 400 mg/m² of anthracyclines was significantly higher in D group (91.2% vs. 80.1%, p=0.04). The 6-year cumulative incidence of secondary malignancy was not different between both groups after considering follow-up duration difference (non-D, 0.52%±0.37%; D, 0.60%±0.28%; p=0.55). The most influential risk factor for secondary malignancy was the duration of anthracycline administration according to multivariate analysis.

Conclusion

Dexrazoxane had an efficacy in lowering cardiac event-free survival rates in patients with higher cumulative anthracyclines. As a result of multivariate analysis for assessing risk factors of secondary malignancy, the occurrence of secondary malignancy was not related to dexrazoxane administration.

Long-term endocrine effects and trends in body mass index changes in patients with childhood-onset brain tumors

As survival rates have improved owing to advances in management strategies for pediatric brain tumors, long-term complications such as endocrine dysfunction, have emerged as a major issue. This study investigated the long-term endocrine effects of childhood-onset brain tumors in a large number of patients. This study included 151 patients with brain tumors diagnosed between January 1995 and December 2016. The following data were retrospectively reviewed: tumor location, tumor histology, endocrine abnormalities, hypothalamic involvement on brain imaging, treatment modalities, and trends in body mass index. The mean age at diagnosis of patients with sellar/suprasellar (SE/SUP-SE) tumors and supra/infratentorial (ST/IT) tumors was 9.9 ± 4.5 and 6.5 ± 4.2 years, respectively. In patient with prepubertal age at diagnosis, height standard deviation score was lower in patients with SE/SUP-SE tumors at diagnosis (P = 0.031), which was lower in patients with ST/IT tumors at the final visit (P < 0.001). The prevalence of combined pituitary hormone deficiencies was higher among patients with SE/SUP-SE tumors than in those with ST/IT tumors (81.7 vs. 36.1%, P < 0.001). Among 98 non-obese patients with SE/SUP-SE tumors, 36.7% developed obesity. The prevalence of combined pituitary hormone deficiencies and obesity was higher in patients with SE/SUP-SE tumors than in those with tumors in other locations; growth impairment was more severe in patients with ST/IT tumors.

Acute Kidney Injury in Pediatric Patients Receiving Allogeneic Hematopoietic Cell Transplantation: Incidence, Risk Factors, and Outcomes

Acute kidney injury (AKI) is a common adverse event after hematopoietic cell transplantation (HCT). AKI is associated with early death or chronic kidney disease among transplant survivors. However, large-scale pediatric studies based on standardized criteria are lacking. We performed a retrospective analysis of 1057 pediatric patients who received allogeneic HCT to evaluate the incidence and risk factors of AKI according to AKI Network criteria within the first 100 days of HCT. We also determined the effect of AKI on patient survival. The 100-day cumulative incidences of all stages of AKI, stage 3 AKI, and AKI requiring renal replacement therapy (RRT) were 68.2% ± 1.4%, 25.0% ± 1.3%, and 7.6% ± .8%, respectively. Overall survival at 1 year was not different between patients without AKI and those with stage 1 or 2 AKI (66.1% versus 73.4% versus 63.9%, respectively) but was significantly different between patients without AKI and patients with stage 3 AKI with or without RRT requirement (66.1% versus 47.3% versus 7.5%, respectively; P < .001). Age, year of transplantation, donor type, sinusoidal obstruction syndrome (SOS), and acute graft-versus-host disease (GVHD) were independent risk factors for stages 1 through 3 AKI. Age, donor, conditioning regimen, number of HCTs, SOS, and acute GVHD were independent risk factors for AKI requiring RRT. Our study revealed that AKI was a prevalent adverse event, and severe stage 3 AKI, which was associated with reduced survival, was common after pediatric allogeneic HCT. All patients receiving allogeneic HCT, especially those with multiple risk factors, require careful renal monitoring according to standardized criteria to minimize nephrotoxic insults.

Hematopoietic stem cell transplantation in pediatric patients with acute myeloid leukemia without favorable cytogenetics

Intensified chemotherapy, HSCT, and supportive care improve the survival of pediatric patients with AML. However, no consensus has been reached regarding the role of HSCT in patients without favorable cytogenetics. We evaluated OS and EFS according to prognostic factors that affect clinical outcomes, including cytogenetics risk group, conditioning regimen, donor type, disease status at the time of HSCT, and number of chemotherapy cycles prior to HSCT in 65 pediatric patients with AML without favorable cytogenetics who underwent HSCT. Fifteen of the 65 patients died: three of TRM and 12 of disease-related mortality. The 5-year OS and EFS were 78.0% and 72.0%, respectively, and the 5-year cumulative relapse and TRM rates were 26.9% and 5.1%, respectively. Survival rates were not influenced by cytogenetic group (intermediated vs. poor), donor type (related vs. unrelated), transplant type (myeloablative vs. reduced-intensity conditioning), or number of pretransplant chemotherapy cycles (≤3 vs. >3 cycles). The low TRM rate and encouraging outcomes suggest that HSCT may be a feasible treatment for pediatric patients with AML without favorable cytogenetics.

Frequency and Clinicopathologic Features of RUNX1 Mutations in Patients With Acute Myeloid Leukemia Not Otherwise Specified

OBJECTIVES

To evaluate the frequency and clinicopathologic characteristics of RUNX1 mutations, focusing on patients with acute myeloid leukemia not otherwise specified (AML NOS).

METHODS

Diagnostic samples from 219 patients with AML NOS were analyzed for RUNX1 mutations using standard polymerase chain reaction and direct sequencing.

RESULTS

Thirty-one RUNX1 mutations were detected in 33 (15.1%) patients. Mutations clustered in the Runt homology (61.3%) and transactivation domains (25.8%). Frameshift mutations were most common (51.6%), followed by missense (41.9%) and nonsense (6.5%) mutations. Patients with RUNX1 mutations had a lower platelet count (P = .013) and shorter relapse-free survival (P = .045) than those without. The presence of RUNX1 and NPM1 or CEBPA mutations was mutually exclusive. A literature review, including our study, showed that patients with RUNX1 mutations were associated with intermediate risk; coexisting mutations such as FLT3-ITD, ASXL1, TET2, and DNMT3A; and a relatively cytogenetic heterogeneity.

CONCLUSIONS

Our findings strengthen previous data concerning RUNX1 mutations in AML and support the notion that RUNX1 mutational status should be integrated into a diagnostic workup of AML, particularly for AML NOS or an intermediate-risk group.