Risk-adjusted therapy for pediatric non-T cell ALL improves outcomes for standard risk patients: results of JACLS ALL-02

This study was a second multicenter trial on childhood ALL by the Japan Childhood Leukemia Study Group (JACLS) to improve outcomes in non-T ALL. Between April 2002 and March 2008, 1138 children with non-T ALL were enrolled in the JACLS ALL-02 trial. Patients were stratified into three groups using age, white blood cell count, unfavorable genetic abnormalities, and treatment response: standard risk (SR), high risk (HR), and extremely high risk (ER). Prophylactic cranial radiation therapy (PCRT) was abolished except for CNS leukemia. Four-year event-free survival (4yr-EFS) and 4-year overall survival (4yr-OS) rates for all patients were 85.4% ± 1.1% and 91.2% ± 0.9%, respectively. Risk-adjusted therapy resulted in 4yr-EFS rates of 90.4% ± 1.4% for SR, 84.9% ± 1.6% for HR, and 66.5% ± 4.0% for ER. Based on NCI risk classification, 4yr-EFS rates were 88.2% in NCI-SR and 76.4% in NCI-HR patients, respectively. Compared to previous trial ALL-97, 4yr-EFS of NCI-SR patients was significantly improved (88.2% vs 81.2%, log rank p = 0.0004). The 4-year cumulative incidence of isolated (0.9%) and total (1.5%) CNS relapse were significantly lower than those reported previously. In conclusion, improved EFS in NCI-SR patients and abolish of PCRT was achieved in ALL-02.

Disordered hemostasis associated with severely depressed fibrinolysis demonstrated using a simultaneous thrombin and plasmin generation assay during L-asparaginase induction therapy in pediatric acute lymphoblastic leukemia

BACKGROUND

L-asparaginase (L-Asp)-associated thromboembolisms are serious complications in pediatrics patients with acute lymphoblastic leukemia (ALL), especially at ≥10.0 years old, but the pathogenesis remains to be clarified.

PROCEDURE

We conducted a multicenter, prospective study of 72 patients with ALL aged 1.0 to 15.2 years treated with either a Berlin-Frankfurt-Münster (BFM) 95-ALL oriented regimen or Japan Association of Childhood Leukemia Study ALL-02 protocol. We divided patients into each treatment protocol and investigated the dynamic changes in coagulation and fibrinolysis using simultaneous thrombin and plasmin generation assay. Patients' plasma samples were collected at the prephase (T0), intermittent phase (T1), and postphase of L-Asp therapy (T2), and postinduction phase (T3). Measurements of endogenous thrombin potential (T-EP) and plasmin peak height (P-Peak) were compared to normal plasma.

RESULTS

None of the cases developed thromboembolisms. Median ratios of T-EP and P-Peak for the controls in the JACLS group were 1.06 and 0.87 (T0), 1.04 and 0.71 (T1), 1.02 and 0.69 (T2), and 1.20 and 0.92 (T3), respectively, while those in the BFM group were 1.06 and 1.00 (T0), 1.04 and 0.64 (T1), 1.16 and 0.58 (T2), and 1.16 and 0.85 (T3), respectively. In particular, P-Peak ratios were depressed at T1 and T2 compared to T0 in the BFM group (P < .01). Moreover, P-Peak ratios in patients ≥10.0 years old were lower at T1 in the BFM group (P = .02).

CONCLUSIONS

The results demonstrated that hemostatic dynamics appeared to shift to a hypercoagulable state with marked hypofibrinolysis associated with L-Asp therapy, especially in patients ≥10.0 years old following the BFM regimen.

Clinical characteristics, treatment, and survival outcome in pediatric patients with atypical teratoid/rhabdoid tumors: a retrospective study by the Japan Children's Cancer Group

OBJECTIVE

The prognosis of atypical teratoid/rhabdoid tumors (ATRTs) has improved in recent years with the use of multimodal therapy, mainly in cases not involving metastatic disease. The authors wanted to obtain historical control data and evaluate the suitable treatments in Japanese children with ATRTs that were proven negative for INI-1 immunostaining.

METHODS

The authors retrospectively collected clinical information on 38 pediatric patients with ATRTs treated from 2005 to 2016 and analyzed the data for this series.

RESULTS

The median age of the patient population was 1.3 years, and the male/female ratio was approximately 2:1. Twenty-three patients (60.5%) had metastases. The effects of treatment on prognosis were analyzed for 34 patients after exclusion of 4 patients who could not receive curative treatment. At a median follow-up of 40.9 months, the mean (± SD) progression-free survival (PFS) and overall survival (OS) were 66.6% ± 8.3% and 45.9% ± 8.7% at 2 years and 44.2% ± 9.9% and 34.2% ± 8.9% at 5 years, respectively. The metastasis stage at diagnosis (M0-1 vs M2-4) (HR 2.68, 95% CI 1.08-6.65; p = 0.0338) and gross tumor resection (yes vs no) (HR 3.49, 95% CI 1.01-12.1; p = 0.0481) were prognostic factors for PFS but not for OS. Postoperative chemotherapy was performed in all 34 cases. High-dose chemotherapy was performed in 19 (55.8%) of 34 patients and showed a positive impact on OS (HR 0.31, 95% CI 0.11-0.86; p = 0.0254); the most commonly used regimen was a double-conditioning regimen of thiotepa plus melphalan. Local radiotherapy had a positive impact on both PFS and OS; however, craniospinal irradiation (CSI) performed in 12 patients as the primary therapy was associated with a poor outcome. Disseminated recurrence within 12 months from diagnosis was the most common pattern of treatment failure regardless of CSI.

CONCLUSIONS

There has been an improvement in outcomes for pediatric ATRT patients since the introduction of multimodal therapy in Japan, mainly in patients without metastases. Even if selection bias is taken into consideration, CSI did not contribute to an improved prognosis. Novel treatment approaches are required for pediatric ATRT patients with metastases.

Dynamics of Minimal Residual Disease in Neuroblastoma Patients

Neuroblastoma is a common extracranial solid tumor of neural crest (NC) origin that accounts for up to 15% of all pediatric cancer deaths. The disease arises from a transient population of NC cells that undergo an epithelial-mesenchymal transition (EMT) and generate diverse cell-types and tissues. Patients with neuroblastoma are characterized by their extreme heterogeneity ranging from spontaneous regression to malignant progression. More than half of newly diagnosed patients present highly metastatic tumors and are stratified into a high-risk group with dismal outcome. As many as 20% of high-risk patients have residual disease that is refractory or progressive during induction chemotherapy. Although a majority of high-risk patients achieve remission, larger part of those patients has minimal residual disease (MRD) that causes relapse even after additional consolidation therapy. MRD is composed of drug-resistant tumor cells and dynamically presented as cancer stem cells (CSCs) in residual tumors, circulating tumor cells (CTCs) in peripheral blood (PB), and disseminated tumor cells (DTCs) in bone marrow (BM) and other metastatic sites. EMT appears to be a key mechanism for cancer cells to acquire MRD phenotypes and malignant aggressiveness. Due to the restricted availability of residual tumors, PB and BM have been used to isolate and analyze CTCs and DTCs to evaluate MRD in cancer patients. In addition, recent technical advances make it possible to use circulating tumor DNA (ctDNA) shed from tumor cells into PB for MRD evaluation. Because MRD can be detected by tumor-specific antigens, genetic or epigenetic changes, and mRNAs, numerous assays using different methods and samples have been reported to detect MRD in cancer patients. In contrast to the tumor-specific gene-rearrangement-positive acute lymphoblastic leukemia (ALL) and the oncogenic fusion-gene-positive chronic myelogenous leukemia (CML) and several solid tumors, the clinical significance of MRD remains to be established in neuroblastoma. Given the extreme heterogeneity of neuroblastoma, dynamics of MRD in neuroblastoma patients will hold a key to the clinical validation. In this review, we summarize the biology and detection methods of cancer MRD in general and evaluate the available assays and clinical significance of neuroblastoma MRD to clarify its dynamics in neuroblastoma patients.

Abstract OT1-05-04: Phase 3 trial of carboplatin in triple negative breast cancer (TNBC) patients with residual invasive carcinoma after neoadjuvant chemotherapy (JONIE4:J-CAT trial)

Background: It is well known that the prognosis of non pCR TNBC patients was poor after anthracycline and taxan treatment. For such patients, capecitabine seems to be effective to reduce recurrence based on the HR 0.58 of the CREATE X trial (Masuda, N. et al. Adjuvant Capecitabine for Breast Cancer after Preoperative Chemotherapy. N Engl J Med. 376, 2147. 2017) . However, the target of capecitabine is still unclear for TNBC. We classified non pCR tumors as BRCAness and Sporadic using BRCAness test(MRC-Holland, Amsterdam, the Netherlands). The recurrence rate of the BRCAness group was about 70%. Carboplatine is expected to be effective against BRCAness tumors, as it is a DNA damaging agent. In this study BRCAness can be checked just before carboplatin treatment using surgical specimens. Then the efficacy of carboplatin will be directly known to make comparison between DFS in the carboplatin group and that of the observation group.

Trial design: This is anopen label, randomized phase III study that will enroll TNBC with residual invasive cancer after surgery with preoperative chemotherapy including both anthracycrine and taxan. Patients are randomly assigned to either the carboplatin group or observation group. The patients in the carboplatin group are treated with carboplatin at AUC 6 and those in the observation group are observed at only 3 years.

Eligibility criteria:

1) ER and PgR&lt;1%, HER2 0, 1+ or 2+ with FISH negative on core needle biopsy before the chemotherapy and surgical specimens.

2) Preoperative chemotherapy including both anthracycrine and taxan.

3) Residual invasive cancer on breast tumors or lymph node metastasis in surgical specimens.

4) 20-79 year old women.

5) No chemotherapy within 5 years.

6) Not bilateral breast cancer, without metastasis, no prior breast cancer.

7) No severe bone marrow suppression.

Specific aims:Primary objective is DFS (Disease Free Survival). Secondary objectives are overall survival and safety.

STATISTICAL METHODS:

The 3 years recurrence rate of the observation group was estimated as 40% and hazard ratio at 0.58 based on the CREATE X trial. For both groups, 135 patients are necessary. This study is powered to approximately 80% to test the superiority of carboplatin group at a 2-sided α=0.05 using a stratified log-rank test.

Activation Date:22ndMarch 2018. No patients had been enrolled till 3rd July.

Citation Format: Tanino H, Suzuki M, Kaise H, Miyashita M, Chishima T, Hayashi M, Miyoshi Y, Futamura M, Ohtani S, Nagahashi M, Ohta T, Kosaka Y, Ishikawa T, Hasegawa Y, Kubota T, Sangai T, Iwatani T, Yamada A, Akazawa K, Kohno N. Phase 3 trial of carboplatin in triple negative breast cancer (TNBC) patients with residual invasive carcinoma after neoadjuvant chemotherapy (JONIE4:J-CAT trial) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT1-05-04.

Pazopanib maintenance therapy after tandem high-dose chemotherapy for disseminated Ewing sarcoma

The dismal prognosis of patients with disseminated Ewing sarcoma necessitates the development of novel treatment strategies. Pazopanib is an oral multi-targeted tyrosine kinase inhibitor that is active against advanced soft tissue sarcoma. However, the clinical activity and feasibility of pazopanib for treating Ewing sarcoma remain poorly understood. Moreover, clinical information on the use of tandem high-dose chemotherapy for Ewing sarcoma is limited. A 14-year-old boy with Ewing sarcoma was transferred to our hospital for treatment. Magnetic resonance imaging, computed tomography scans, and bone scintigraphy revealed multiple lesions in the pubis, ilium, ischium, femur, rib, cranial bone, thoracic vertebrae, sacrum, obturator muscle, adductor magnus muscle, testicular cord, and lungs. Bone scintigraphy after intensive chemotherapies confirmed that multiple abnormal accumulations were still present in the cranial bone and pubis. Subsequently, the patient received tandem high-dose chemotherapy including topotecan, and radiotherapy. Abnormal accumulations have disappeared in bone scintigraphy. Subsequently, pazopanib maintenance therapy was initiated. Despite the presence of innumerable lesions at diagnosis, the patient has been in near-complete remission for the past 1 year with pazopanib administration. This confirms that adding pazopanib maintenance therapy after tandem high-dose chemotherapy is a therapeutic option for cases with disseminated Ewing sarcoma.

Hematopoietic cell transplantation for asymptomatic X-linked lymphoproliferative syndrome type 1

Background

X-linked lymphoproliferative disease type 1 (XLP1) is a rare primary immune deficiency, which is caused by SH2D1A gene mutations. XLP1 is commonly associated with Epstein-Barr virus (EBV)-associated hemophagocytic lymphohistiocytosis, hypogammaglobulinemia, and/or lymphoma. The only curative treatment for XLP1 is allogeneic hematopoietic cell transplantation. However, published data detailing the clinical course of, and indications for, allogeneic hematopoietic cell transplantation in asymptomatic patients with XLP1 is lacking. Although relevant family history could be useful in identifying patients with XLP1 before disease onset, no guidelines have been established on the management of asymptomatic patients with XLP1. Therefore, clinicians and families face dilemmas in balancing between the risk of waiting for the disease onset, and the risk of transplant-related mortality associated with allogeneic hematopoietic cell transplantation, which is often performed at a very young age. We first describe the detailed clinical course of an asymptomatic patient with XLP1 who successfully underwent allogeneic hematopoietic cell transplantation.

Case presentation

A boy was born at 39 weeks of gestation, weighing 3016 g at birth. He appeared fine, but he underwent genetic testing because his maternal cousin had XLP1. He was found to have a novel c.207_208insC (p.Pro70ProfsX4) mutation in exon 3 of SH2D1A, which was also found in his cousin. There was no HLA-identical donor in his family. Immunoglobulin was administered monthly to prevent EBV infection while searching for an alternative donor. He underwent allogeneic bone marrow transplantation (BMT) from an allele HLA 8/8 fully matched, unrelated donor with a reduced-intensity conditioning (RIC) regimen consisting of fludarabine, melphalan, and low-dose total body irradiation (TBI) at 20 months of age. The patient has been doing well for 2 years post transplantation and maintaining complete donor chimerism without any evidence of chronic graft versus host disease.

Conclusions

We describe a case of an asymptomatic patient with XLP1, who successfully underwent unrelated BMT with RIC regimen consisting of fludarabine, melphalan, and 3 Gy TBI. That was well tolerated and successfully generated complete chimerism in every subpopulation. This case delineates the option of allogeneic hematopoietic cell transplantation even in asymptomatic patients with XLP1.

Abstract A11: A pediatric ETV6-ABL1-positive acute lymphoblastic leukemia case with ETV6-ABL1-independent resistance to tyrosine kinase inhibitor

Introduction: ETV6-ABL1 fusion represents a rare subgroup of pediatric acute lymphoblastic leukemia (ALL) with unfavorable outcomes. ETV6-ABL1-positive ALL is recently identified in Philadelphia chromosome (Ph)-like ALL and exhibits a gene expression profile similar to BCR-ABL1-positive ALL. Analogous to BCR-ABL1 fusion, ETV6-ABL1 fusion results in the formation of constitutively active non-receptor tyrosine kinases that can also be targeted by selective ATP-competitive tyrosine kinase inhibitors (TKIs). Since TKIs are currently incorporated into the standard treatment of BCR-ABL1-positive ALL, they will be a promising option also for the treatment ETV6-ABL1-positive ALL. However, TKI resistance becomes a common problem in TKI-treated patients, where it is frequently caused by BCR-ABL1-dependent alterations including mutations, genomic amplification, and enhanced expression of BCR-ABL1-fusion kinase. In addition, BCR-ABL1-independent alterations have also been reported to cause TKI resistance. It includes a variety of activating and/or inactivating alterations in RAS, NF-kB, PI3K-AKT, and JAK-STAT signaling pathways that mediate the oncogenic activity of BCR-ABL1 fusion kinase. In contrast, the molecular mechanisms of TKI resistance have been poorly described in ETV6-ABL1-positive ALL, except for T315I mutation of ETV6-ABL1 fusion gene in a single patient and K89M mutation of GNB1 gene in a cell line model.

Patient and Results: A previously healthy 14-year-old girl was admitted to our hospital because of persistent fever. Laboratory data showed white blood cell count of 417,800 /µL and increased LDH level and uric acid level. Bone marrow examination showed nuclear cell count of 855,000 /µL with 90.0% blastic cells of lymphoid morphology. Bone marrow blasts at initial diagnosis were positive for CD10, CD19, CD20, CD34, cyCD79a, cyTdT, HLA-DR, and CD66c; had a karyotype of 45, XX, -7; and were sensitive to TKIs (imatinib and dasatinib) in vitro. A split signal analyzed by ABL1 FISH probe was positive (92.7%), while major and minor BCR-ABL1 fusion transcripts were not detected by RT-qPCR. She was treated with the high-risk protocol based on BFM 95 protocol because of prednisolone poor response. After induction chemotherapy, she achieved complete remission (CR) without ABL1 split signal and IgH gene rearrangement. However, she relapsed 19 months after initial diagnosis, and failed to achieve second CR by alternating administration of dasatinib and antileukemic drugs. Bone marrow blasts at initial diagnosis and after relapse were subjected to whole-transcriptome sequencing. ETV6-ABL1 fusion transcripts were identified in both initial diagnostic and relapsed samples, and their level of expression was not significantly changed. No known alteration in ETV6-ABL1 fusion and GNB1 genes was detected. These results suggested a novel mechanism of TKI resistance in ETV6-ABL1-positive ALL.

Conclusion: To our knowledge, this is a first case of ETV6-ABL1-positive ALL who acquired ETV6-ABL1-independent TKI resistance. It will provide a foundation for the treatment of TKI-resistant ETV6-ABL1-positive ALL.

Citation Format: Suguru Uemura, Daiichiro Hasegawa, Akemi Shono, Khin Kyae Mon Thwin, Nanako Nino, Satoru Takafuji, Takeshi Mori, Akihiro Tamura, Nobuyuki Yamamoto, Atsuro Saito, Kenji Kishimoto, Toshiaki Ishida, Yoshiyuki Kosaka, Kazumoto Iijima, Noriyuki Nishimura. A pediatric ETV6-ABL1-positive acute lymphoblastic leukemia case with ETV6-ABL1-independent resistance to tyrosine kinase inhibitor [abstract]. In: Proceedings of the AACR Special Conference: Pediatric Cancer Research: From Basic Science to the Clinic; 2017 Dec 3-6; Atlanta, Georgia. Philadelphia (PA): AACR; Cancer Res 2018;78(19 Suppl):Abstract nr A11.

Low-dose azacitidine maintenance therapy after allogeneic stem cell transplantation for high-risk pediatric acute myeloid leukemia

The dismal prognosis of pediatric acute myeloid leukemia (AML) relapsing after hematopoietic stem cell transplantation (HSCT) requires exploration of novel strategies to prevent relapse. Azacitidine (AZA) maintenance therapy could potentially reduce the recurrence rate post HSCT. Here, we presents the cases of three children with high-risk AML post HSCT who were treated with low-dose AZA maintenance therapy, demonstrating the feasibility of this therapy. Currently, all three are in complete remission for 13-41 months despite their high-risk characteristics. Our encouraging data warrant larger prospective studies to assess the efficacy and safety of low-dose AZA maintenance therapy post HSCT for pediatric patients with high-risk AML.

Co-occurrence of hypertrophic cardiomyopathy and juvenile myelomonocytic leukemia in a neonate with Noonan syndrome, leading to premature death

We report a case of a neonate with Noonan syndrome presenting with concurrent hypertrophic cardiomyopathy and juvenile myelomonocytic leukemia, which resulted in premature death. Cases with Noonan syndrome diagnosed during the neonatal period might not necessarily show mild clinical course, and premature death is a possible outcome to be considered.

ETV6-ABL1 fusion combined with monosomy 7 in childhood B-precursor acute lymphoblastic leukemia

ETV6-ABL1 fusion is a rare but recurrent oncogenic lesion found in childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL), without an established chromosomal abnormality, and is associated with poor outcome. In ETV6-ABL1-positive cases, an in-frame fusion produced by a complex rearrangement results in constitutive chimeric tyrosine kinase activity. Monosomy 7 is also a rare and unfavorable chromosomal abnormality in childhood BCP-ALL. Here, we report a 14-year-old female BCP-ALL patient with ETV6-ABL1 fusion combined with monosomy 7. She was admitted to our hospital because of persistent fever. Bone marrow nuclear cell count on admission was 855,000/µL with 90.0% blastic cells of lymphoid morphology. Blasts were positive for CD10, CD19, CD20, CD34, cyCD79a, cyTdT, HLA-DR, and CD66c, had a karyotype of 45, XX, - 7 [18/20] and a split signal for ABL1 FISH probe (92.7%), and were sensitive to tyrosine kinase inhibitors, imatinib and dasatinib, in vitro. ETV6-ABL1 fusion transcript was identified by whole transcriptome sequencing and confirmed by RT-PCR. She was treated with the high-risk protocol based on ALL-BFM 95, achieved complete remission (CR) after induction chemotherapy, and maintained CR for 4 months. To our knowledge, this is the first report of ETV6-ABL1 fusion combined with monosomy 7 in childhood BCP-ALL.

Human CD134 (OX40) expressed on T cells plays a key role for human herpesvirus 6B replication after allogeneic hematopoietic stem cell transplantation

BACKGROUND

CD134 (OX40), which is a cellular receptor for human herpesvirus-6B (HHV-6B) and expresses on activated T cells, may play a key role for HHV-6B replication after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

OBJECTIVES

Therefore, we examined the CD134 expression on T cells and HHV-6B replication after allo-HSCT, and analyzed the correlation between them.

STUDY DESIGN

Twenty-three patients after allo-HSCT were enrolled. The percentages of CD134-positive cells within the CD4⁺ and CD8⁺ cell populations were measured by flow cytometry, and the viral copy number of HHV-6B was simultaneously quantified by real-time PCR. The correlation between CD134 and HHV-6B viral load was then statistically analyzed.

RESULTS

HHV-6B reactivation occurred in 11 of 23 patients (47.8%). CD134 expression was seen on T cells and was coincident with the time of peak viral load. The percentage of CD134-positive cells decreased significantly when HHV-6B DNA disappeared (p = .005 in CD4⁺ T cells, p = .02 in CD8⁺ T cells). In the 4 patients who underwent umbilical cord blood transplantation (UCBT), the viral load varied with the percentage of CD134-positive cells. In the comparison between the HHV-6B reactivation group and non-reactivation group, maximum percentages of CD134-positive cells among CD4⁺ T cells in reactivation group were significantly higher than those in non-reactivation group (p = .04).

CONCLUSIONS

This is the first study to show that a correlation of CD134 expression on T cells with HHV-6B replication after allo-HSCT, especially in UCBT. The results possibly indicate that CD134 on T cells plays a key role for HHV-6B replication after allo-HSCT.

Abstract PD8-03: ESR1 gene fusions drive endocrine therapy resistance and metastasis in breast cancer

Background. Dysregulation of the estrogen receptor gene (ESR1) is an established mechanism of inducing endocrine therapy resistance. We previously discovered a chromosomal translocation event generating an estrogen receptor gene fused in-frame to C-terminal sequences of YAP1 (ESR1-YAP1) that contributed to endocrine therapy resistance in estrogen receptor positive (ER+) breast cancer models. This study compares functional, transcriptional, and pharmacological properties of additional ESR1 gene fusion events of both early stage (ESR1-NOP2) late stage (ESR1-YAP1 and ESR1-PCDH11x) breast cancers to gain a better understanding of therapeutic resistance and metastasis. Understanding the role of ESR1 fusions in inducing metastasis is critical, since the primary cause of death in breast cancer patients is through metastasis to distant sites.

Methods. RNA-seq screens identified ESR1 fusions from early and late stage, endocrine therapy resistant breast tumor samples. Functional experiments were conducted using ER+ breast cancer cell lines, xenograft, and PDX models to test the ability of ESR1 fusions to induce therapeutic resistance and metastasis. ChIP-seq and RNA-seq were performed to examine transcriptional properties and differential gene expression induced by the fusions which directed subsequent pharmacological experiments with a CDK4/6 inhibitor.

Results. ESR1-YAP1 and ESR1-PCDH11x promoted estrogen-independent and fulvestrant-resistant growth in vitro and induced greater tumor growth and increased metastatic capacity to the lungs of xenografted mice. In contrast, the ESR1-NOP2 fusion was sensitive to low estrogen conditions in vitro, and did not promote tumor growth. RNA-seq profiling revealed E2F targets pathway as the most highly enriched pathway induced by the ESR1 fusions. IHC revealed higher levels of pRb in ESR1-YAP1 and ESR1-PCDH11x xenograft tumors and subsequent CDK4/6 inhibition completely blocked tumor growth in an ESR1-YAP1 PDX model. Integrating RNA-seq with ChIP-seq data, we discovered a set of EMT and metastasis genes bound by all ESR1 fusions and WT-ER, but whose expression was strongly and uniquely up-regulated only by the ESR1-YAP1 and ESR1-PCDH11x fusions. These studies also revealed gained sites bound only by the ESR1-YAP1 and ESR1-PCDH11x fusions, not bound by WT-ER nor ESR1-NOP2. Genes mapping to these sites have a role in metastatic biology and were highly up-regulated by the YAP1 and PCDH11x fusions, potentially mediated by long range transcriptional activation.

Conclusion. ESR1-YAP1 and ESR1-PCDH11x are driver fusions that occur in drug-resistant, advanced stage breast cancer and are a new class of recurrent somatic mutation that can cause acquired endocrine therapy resistance, yet can be treated with CDK4/6 inhibition. These driver fusions also confer increased metastatic ability through their ability to drive expression of genes that contribute to EMT and metastasis. In contrast, ESR1-NOP2 did not produce functional protein and appears to be a passenger event. These studies may provide pre-clinical rationale for targeting ESR1 translocated breast tumors, since the presence of an ESR1 driver fusion places a patient in a therapeutic category where none of the currently available endocrine therapies are likely to be effective.

Citation Format: Lei JT, Shao J, Zhang J, Iglesia M, Chan DW, Cao J, Anurag M, Singh P, Haricharan S, Kavuri SM, Matsunuma R, Schmidt C, Kosaka Y, Crowder R, Hoog J, Phommaly C, Goncalves R, Ramalho S, Rodrigues-Peres RM, Lai W-C, Hampton O, Rogers A, Tobias E, Parikh P, Davies S, Ma C, Suman V, Hunt K, Watson M, Hoadley KA, Thompson A, Perou CM, Creighton CJ, Maher C, Ellis MJ. ESR1 gene fusions drive endocrine therapy resistance and metastasis in breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD8-03.

Low Incidence of Osteonecrosis in Childhood Acute Lymphoblastic Leukemia Treated With ALL-97 and ALL-02 Study of Japan Association of Childhood Leukemia Study Group

Purpose Osteonecrosis (ON) is a serious complication of the treatment of childhood acute lymphoblastic leukemia (ALL); however, data relating to ON in Asian pediatric patients with ALL are scarce. Therefore, we performed a retrospective analysis of cohorts of Japanese patients with ALL to clarify the incidence, clinical characteristics, and risk factors of ON. Patients and Methods The incidence and characteristics of ON were determined in patients with ALL (n = 1,662) enrolled in two studies from the Japan Association of Childhood Leukemia Study (JACLS) group (n = 635 and n = 1,027 patients treated with the ALL-97 and ALL-02 protocols, respectively). Results In total, 24 of 1,662 patients suffered from ON, of which 12 of 635 and 12 of 1,027 patients were treated with the ALL-97 and the ALL-02 protocol, respectively. Of the 24 patients, 23 were older than 10 years. In multivariate analysis, age (≥ 10 years) was the sole significant risk factor for ON ( P < .001). Separate evaluation of patients ≥ 10 years of age indicated a 5-year cumulative incidence of ON of 7.2% (95% CI, 4.0% to 12.6%) and 5.9% (95% CI, 3.3% to 10.4%) in the ALL-97 and the ALL-02 protocol, respectively, which was lower than reported previously, despite an administration of dexamethasone (DEX) similar to that in comparable studies; however, concomitant administration of DEX and l-asparaginase was reduced in the JACLS protocols. Conclusion We identified a low frequency of ON in the JACLS ALL-97 and ALL-02 studies. Although the sole risk factor for ON was age (≥ 10 years), even among high-risk patients, ON incidence was significantly lower than that reported in previous studies. These results suggest that, not only the total amount of DEX, but also how DEX and l-asparaginase are administered, which affects the clearance of DEX, may be associated with ON incidence in patients with ALL.

Phase I study of perifosine monotherapy in patients with recurrent or refractory neuroblastoma

PURPOSE

Perifosine is an alkylphospholipid analog that inhibits or modulates signaling through signal transduction pathways such as Akt, which is enhanced in neuroblastoma (NB) by activation of tyrosine kinase receptors. We conducted a phase I study of perifosine in Japanese patients with recurrent or refractory NB.

EXPERIMENTAL DESIGN

All patients enrolled were over 2 years of age; all had refractory or relapsed NB and a performance status of greater than 50%. Perifosine was orally administered at a loading dose (100-300 mg) on day 1 and at a maintenance dose (50-150 mg) from day 2 onward. Dose-limiting toxicity (DLT) and pharmacokinetics were assessed in Step 1 and safety and efficacy in Step 2.

RESULTS

Nineteen patients were recruited. No DLT was observed. Adverse reactions occurring in more than 30% of the patients were vomiting (63%), nausea (53%), and diarrhea (37%). The mean plasma concentration of perifosine was 27.5 ± 9.8 μM on day 15 and 27.3 ± 11.5 μM on day 29. The response rate (RR) in 18 patients evaluable according to modified International Neuroblastoma Response Criteria was 0%; the disease control rate (DCR) was 56%. Median progression-free survival (PFS) was 122 days. In 11 patients evaluable according to the Response Evaluation Criteria in Solid Tumors, the RR and DCR were 9% and 55%, respectively. The median PFS was not reached.

CONCLUSIONS

Perifosine monotherapy was well tolerated in Japanese patients with recurrent/refractory NB. Further investigations in combination with other anticancer or molecular targeted agents are warranted.

Fludarabine, cytarabine, granulocyte colony-stimulating factor and idarubicin for relapsed childhood acute myeloid leukemia

BACKGROUND

The combination of fludarabine (Flu), high-dose cytarabine (Ara-C) and granulocyte colony-stimulating factor (G-CSF; FLAG), with anthracyclines has become standard chemotherapy for refractory acute myeloid leukemia (AML) in European children and adults. To clarify the efficacy and the safety of FLAG-idarubicin (IDA) for children prospectively, we planned a multicenter phase II study (AML-R11) by the Japanese Pediatric Leukemia/Lymphoma Study Group.

METHODS

Patients with AML aged between 2 and 20 years old, who had the first bone marrow (BM) relapse or induction failure, were enrolled. The FLAG-IDA regimen consisted of Flu 30 mg/m² for 5 days, Ara-C 2 g/m² for 5 days, G-CSF (lenograstim) 5 μg/kg for 6 days and IDA 10 mg/m² for 3 days. The primary endpoint was remission rate after therapy.

RESULTS

Due to drug supply issues, the trial was suspended after the inclusion of seven eligible patients. There were six cases of early relapse within 1 year of the first remission. All seven patients completed the therapy and no early death was observed. Hematological toxicity was common, and one patient developed grade 4 non-hematological toxicity of bacterial meningitis. Although only one patient with late relapse achieved complete remission, minimal residual disease was positive on both flow cytometry and Wilms' tumor 1 mRNA. Two patients were alive in remission following hematopoietic stem cell transplantation, whereas the other five patients died of either the disease or treatment-related causes.

CONCLUSION

FLAG-IDA might be tolerable for children with refractory AML although the efficacy should be further investigated.

Prevention of chemotherapy-induced vomiting in children receiving multiple-day cisplatin chemotherapy: A hospital-based, retrospective cohort study

BACKGROUND

Optimal prevention of chemotherapy-induced vomiting (CIV) has not been established for patients receiving cisplatin in divided doses. The aim of this study was to describe the incidence and risk factors of CIV in children who received multiple-day cisplatin chemotherapy.

PROCEDURE

A total of 24 consecutive pediatric patients (age 0-19 years) who received multiple-day cisplatin chemotherapy in our hospital were enrolled. Patients with relapsed disease or primary intracranial tumor and those who received concurrent radiation therapy were excluded. The number of chemotherapy cycles reviewed was 107, with a median of five per patient. All patients received granisetron. Dexamethasone and NK-1 receptor antagonists (NK1RA) were used as additional antiemetics for prophylaxis of CIV.

RESULTS

CIV was observed in 22 of 24 (92%) patients, and 61 of 107 (57%) cycles. Patients who developed CIV had a higher incidence of other chemotherapy-related adverse events (87 vs. 41%, P < 0.001). The incidence of CIV was lower in patients administered with NK1RA than those without (32 vs. 68%, P < 0.001). Multivariate logistic regression identified age less than or equal to 2 years (odds ratio [OR] = 0.25, 95% confidence interval [CI] = 0.10-0.63) and administration of NK1RA (OR = 0.16, 95% CI = 0.06-0.43) as independent factors for CIV.

CONCLUSIONS

These results suggest that NK1RA is crucial to reduce CIV in children who receive multiple-day cisplatin chemotherapy.

Long-term outcomes of 95 children with moderate aplastic anemia treated with horse antithymocyte globulin and cyclosporine

BACKGROUND

Currently, the standard management of moderate aplastic anemia (MAA) has not been well described, although the superiority of the combination of antithymocyte globulin (ATG) and cyclosporine (CyA) over CyA alone has been demonstrated in terms of hematological responses and failure-free survival (FFS).

PROCEDURE

We adopted this therapeutic strategy and treated 95 children with MAA who were enrolled in two consecutive prospective studies between October 1992 and August 2009.

RESULTS

For these patients, the 6-month response rate was 54.7% (complete response, 13.7%; partial response, 41.1%). There were no statistically significant differences in the overall response rates between the transfusion-dependent (48.8%, n = 41) and transfusion-independent groups (59.3%, n = 54; P = 0.4). Treatment failure was defined as the requirement of salvage treatment, and was observed in 52 patients. The 10-year FFS was 44.0% (95% confidence interval [CI], 32.9%-54.6%). Of the 22 patients who underwent a second immunosuppressive therapy (IST), 12 responded. Forty patients underwent hematopoietic stem cell transplantation as second- or third-line therapy and three died of complications. Consequently, the 10-year overall survival rate was 96.0% (95% CI, 88.0%-98.7%) with a median follow-up period of 103 months (range, 29-221 months).

CONCLUSIONS

Although current guidelines recommend only observation for patients with transfusion-independent MAA, the results of our study justify early intervention with ATG and CyA in those patients. A prospective randomized trial is warranted to clarify the risks and benefits of early intervention with IST and observation alone until progression to severe AA in patients with MAA.

Refractory double-hit lymphoma/leukemia in childhood mimicking B-precursor acute lymphoblastic leukemia at initial presentation

A 10-year-old girl was referred to our hospital with left preauricular adenopathy and gingival swelling. She was diagnosed with B-cell precursor acute lymphoblastic leukemia (BCP-ALL) based on being positive for expressions of CD10, CD19, TdT and HLA-DR. She showed no CD20 expression at the time of diagnosis. Based on the initial diagnosis of BCP-ALL, induction chemotherapy for BCP-ALL was initiated. However, the blasts did not disappear from her peripheral blood. Bone marrow examination on day 33 identified 81.3% residual blasts with positive expressions of CD19, 20 and HLA-DR and negative CD10 and TdT expressions; these cells were morphologically and phenotypically different from those at the initial diagnosis. Based on cytogenetic studies, the final diagnosis was double-hit lymphoma/leukemia (DHL) with IgH-BCL2 and Igλ-MYC. Although dose intensive chemotherapy, including rituximab, led to complete remission, bone marrow and central nervous system relapse occurred. At relapse, blasts expressed CD10, CD19 and HLA-DR, but not CD20, findings the same as those at the onset. The patient died of the disease 44 days after cord blood transplantation with non-remission status. DHL in childhood is extremely rare and its prognosis is poor. The establishment of an effective treatment for DHL is highly anticipated.

Abstract PD2-03: Recurrent functionally diverse in-frame ESR1 gene fusions drive endocrine resistance in breast cancer

Background. We previously reported an alternative ESR1 somatic gain-of-function chromosomal translocation event in a patient presenting with aggressive, endocrine therapy resistant estrogen receptor (ER) positive disease, producing an in-frame fusion gene consisting of N-terminal ESR1 and the C-terminus of the Hippo pathway coactivator YAP1 (ESR1-YAP1). We recently identified another ESR1 fusion through RNA sequencing (RNA-seq) in advanced stage ER+ disease from a chest wall recurrence in a male patient that was refractory to multiple lines of treatment. Two examples of fusions discovered in primary breast cancer samples include ESR1 fused in-frame to C-terminal sequences from NOP2 (ESR1-NOP2), identified in a resistant cohort from a RNA-seq screen focused on 81 primary breast cancers from aromatase inhibitor clinical trials, and a second ESR1 fusion, fused in-frame to the entire coding sequence of POLH (ESR1-POLH), that was identified from RNA-seq analysis of 728 Cancer Genome Atlas breast samples. This current study extends our previous characterization of ESR1-YAP1 by comparing functional and pharmacological properties of these three additional ESR1 gene fusion events of both early stage and advanced breast cancers.

Methods. In vitro and in vivo experiments were conducted to test ESR1 fusions to induce therapeutic resistance, and metastasis. The transcriptional and binding properties of each fusion was also examined. Pharmacological inhibition with Palbociclib, a cyclin-dependent kinase 4/6 inhibitor, was utilized to assess drug sensitivity in ESR1 fusion containing breast cancer cells and in a patient derived xenograft (PDX) model expressing ESR1-YAP1 (WHIM18).

Results. The YAP1 and PCDH11x fusions conferred estrogen-independent and fulvestrant-resistant growth. Immunohistochemistry revealed significantly higher numbers of ER+ cells in lungs of mice xenografted with T47D cells expressing the YAP1 and PCDH11x fusions compared to YFP control, NOP2 and POLH fusions. Results from ChIP-seq and microarray studies suggest that these two fusions promote proliferation and metastasis through genomic action by binding estrogen response elements (ERE) and subsequent gene activation. We thereby define these fusions as “canonical” fusions compared to “non-canonical” NOP2 and POLH fusions, which demonstrated dramatically decreased genomic binding ability. The non-canonical fusions induced genes associated with basal-like breast cancer and promoted HER2, EGFR, and MAPK gene expression signatures in contrast to genes associated with cell cycle/proliferation induced by canonical fusions. The proliferative ability of canonical fusion-containing ER+ cells was inhibited by Palbociclib in a dose-dependent manner. In vivo WHIM18 tumors in mice fed with Palbociclib-containing chow demonstrated significantly reduced tumor volume, growth rate, and weight compared to tumors in mice on control chow.

Conclusions. In-frame ERE activating canonical fusions occur in end-stage drug resistant advanced breast cancer and can be added to ESR1 point mutations as a class of recurrent somatic mutation that may cause acquired resistance. Growth induced by these fusions can be antagonized by Palbociclib and is potentially clinically helpful.

Citation Format: Lei JT, Shao J, Zhang J, Iglesia M, Cao J, Chan DW, He X, Kosaka Y, Schmidt C, Matsunuma R, Haricharan S, Crowder R, Hoog J, Phommaly C, Goncalves R, Ramalho S, Lai W-C, Hampton O, Rogers A, Tobias E, Parikh P, Davies S, Ma C, Suman V, Hunt K, Watson M, Hoadley KA, Thompson A, Chen X, Perou CM, Creighton CJ, Maher C, Ellis MJ. Recurrent functionally diverse in-frame ESR1 gene fusions drive endocrine resistance in breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr PD2-03.

Abstract P5-16-04: A randomized phase II neoadjuvant study comparing docetaxel and cyclophosphamide (TC) with 5-fluorouracil, epirubicin, and cyclophosphamide followed by docetaxel (FEC-D) for hormone receptor-negative breast cancer: The Kanagawa breast oncology group (KBOG) 1101 study

Purpose: This study aimed to evaluate response to neoadjuvant chemotherapy (NAC) for patients with hormone receptor-negative (HR-negative) breast cancer (BC) to identify subtypes that require anthracycline treatment.

Methods: In total, 103 patients with operable HR-negative BC were registered. They were randomely assigned to administration of 6 cycles of docetaxel (75mg/m2) and cyclophosphamide (600 mg/m2) (TC6) or 3 cycles of 5-fluorouracil (500 mg/m2), epirubicin (100mg/m2), and cyclophosphamide (500mg/m2) followed by 3 cycles of docetaxel (100mg/m2) (FEC-D). Cytokeratin (CK) 5/6 and EGFR expression were used to identify basal and non-basal triple-negative (TN) BC. The primary endpoint was pathological complete response (pCR); secondary endpoints were safety, breast-conserving surgery, disease-free survival, and overall survival. Predictive factors of pCR for each regimen were also evaluated.

Results:

The pCR rate was 36% for FEC-D and 25.5% for TC6, which did not differ significantly (P=0.265). When TN BC was subdivided into basal and non-basal subtypes, the pCR rate in the basal subtype was significantly lower for TC6 (13.6%) than for FEC-D (42.9%) (P=0.033), but did not significantly differ in the non-basal (TC6, 36.4%; FEC-D, 25.0%) and HER2-positive (TC6, 41.7%; FEC-D, 35.7%) cases.

The relative dose intensities of epirubicin and docetaxel in FEC-D and docetaxel in TC6 were 96.3±13.0%, 93.5±14.6%, and 93.9±16.3% (mean±SD), respectively. Occurrence of grade ≥2 adverse events was significant in FEC-D-treated patients. Poor appetite (P&lt;0.001), nausea (P&lt;0.001), vomiting (P&lt;0.001), dysgeusia (P=0.03), and fatigue (P=0.05) were significantly more common for FEC-D than TC6. Patients treated with FEC-D experienced significantly more febrile neutropenia and anemia (P=0.016 and 0.017, respectively).

The rates of breast-conserving surgery were 68.0 and 72.3% for FEC-D and TC6, respectively (P=0.641).

Patients achieved pCR had better DFS (log rank test, P = 0.287) and OS (log rank test, P = 0.069), though not significant. Patients treated with FEC-D had better DFS (log rank test, P = 0.107) and OS (log rank test, P = 0.159), though not significant. Among patients with TN BC, those treated with FEC-D had significantly better DFS (log rank test, P = 0.016) and OS (log rank test, P = 0.034) than treated with TC6.

Low ALDH1 expression and high topo IIα protein expression were strongly correlated with pCR in FEC-D, with odds ratios (ORs) of 4.33 [95% CI, 1.02–18.38] and 4.08 [0.97–17.2], respectively. ALDH1 was also associated with pCR in TC, OR=3.50 [0.84–14.6]. Other factors, including age, tumor size, nodal status, tumor grade, Ki67, p53, and TOP 2A status were not associated with pCR in either regimen.

Conclusions:We found that TC6 was less effective than FEC-D for treating HR-negative BC because it was insufficient for TNBC, particularly for basal BC. This suggests that anthracycline is more important than taxane for basal BC. Additionally, ALDH1 could be a marker for resistance to conventional chemotherapy.

Citation Format: Narui K, Ishikawa T, Shimizu D, Tanabe M, Sasaki T, Oba MS, Morita S, Nawata S, Kida K, Mogaki M, Doi T, Tsugawa K, Ogata H, Ota T, Kosaka Y, Sengoku N, Kuranami M, Saito Y, Suzuki Y, Suto A, Arioka H, Chishima T, Ichikawa Y, Endo I, Tokuda Y. A randomized phase II neoadjuvant study comparing docetaxel and cyclophosphamide (TC) with 5-fluorouracil, epirubicin, and cyclophosphamide followed by docetaxel (FEC-D) for hormone receptor-negative breast cancer: The Kanagawa breast oncology group (KBOG) 1101 study [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-16-04.

Predictive factor for intraoperative tumor rupture of Wilms tumor

PURPOSE

For Wilms tumor, intraoperative tumor rupture with wide tumor spillage during surgical manipulation raises the classification to stage 3. Then, postoperative chemotherapy must be more intensive, and abdominal radiotherapy is added. Therefore, intraoperative tumor rupture should be avoided if possible. However, predictive factors for intraoperative tumor rupture have not been sufficiently described. Here we examined the risk factors for intraoperative tumor rupture.

METHODS

Patients with Wilms tumor who underwent treatment according to the National Wilms Tumor Study or the Japanese Wilms Tumor Study protocol at our institution were reviewed retrospectively. Collected cases were categorized into two groups: the ruptured group and the non-ruptured group. Risk factors for intraoperative tumor rupture, including the ratio of the tumor area to the abdominal area in a preoperative single horizontal computed tomography slice (T/A ratio), were investigated in both groups.

RESULTS

The two groups were not different in age, body weight, tumor laterality, sex, or histological distribution. The T/A ratio in the ruptured group was significantly higher than that in the non-ruptured group. Receiver operating characteristic curve analysis identified a discriminative value for a T/A ratio >0.5.

CONCLUSION

The T/A ratio can be a predictive factor for intraoperative tumor rupture of Wilms tumor.

Collaboration of cancer-associated fibroblasts and tumour-associated macrophages for neuroblastoma development

Neuroblastoma is the most common extracranial solid tumour in children and is histologically classified by its Schwannian stromal cells. Although having fewer Schwannian stromal cells is generally associated with more aggressive phenotypes, the exact roles of other stromal cells (mainly macrophages and fibroblasts) are unclear. Here, we examined 41 cases of neuroblastoma using immunohistochemistry for the tumour-associated macrophage (TAM) markers CD68, CD163, and CD204, and a cancer-associated fibroblast (CAF) marker, alpha smooth muscle actin (αSMA). Each case was assigned to low/high groups on the basis of the number of TAMs or three groups on the basis of the αSMA-staining area for CAFs. Both the number of TAMs and the area of CAFs were significantly correlated with clinical stage, MYCN amplification, bone marrow metastasis, histological classification, histological type, and risk classification. Furthermore, TAM settled in the vicinity of the CAF area, suggesting their close interaction within the tumour microenvironment. We next determined the effects of conditioned medium of a neuroblastoma cell line (NBCM) on bone marrow-derived mesenchymal stem cells (BM-MSCs) and peripheral blood mononuclear cell (PBMC)-derived macrophages in vitro. The TAM markers CD163 and CD204 were significantly up-regulated in PBMC-derived macrophages treated with NBCM. The expression of αSMA by BM-MSCs was increased in NBCM-treated cells. Co-culturing with CAF-like BM-MSCs did not enhance the invasive ability but supported the proliferation of tumour cells, whereas tumour cells co-cultured with TAM-like macrophages had the opposite effect. Intriguingly, TAM-like macrophages enhanced not only the invasive abilities of tumour cells and BM-MSCs but also the proliferation of BM-MSCs. CXCL2 secreted from TAM-like macrophages plays an important role in tumour invasiveness. Taken together, these results indicate that PBMC-derived macrophages and BM-MSCs are recruited to a tumour site and activated into TAMs and CAFs, respectively, followed by the formation of favourable environments for neuroblastoma progression. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Successful non-myeloablative allogenic bone marrow transplantation in a child with severe congenital neutropenia complicated by chronic pulmonary infection

We herein describe a 2-year-old boy with severe congenital neutropenia (SCN) who was successfully treated with reduced-intensity bone marrow transplantation (HSCT). He had suffered recurrent episodes of bacterial pneumonia from 12 months of age, and was found to have severe neutropenia with white blood cell counts below 100/μl. The patient harbored a heterozygous missense mutation in ELANE exon 4 (p.Gln134Pro, NM_001972.2: c.401A>C). This was a novel mutation. Due to intractable pneumonia and severe persistent neutropenia, reduced-intensity HSCT was performed from an HLA-matched sibling donor. The preparative regimen consisted of melphalan, fludarabine, and 4 Gy of total body irradiation. Hematopoietic engraftment was rapidly obtained, i.e., by day +14, and complete donor chimerism was subsequently achieved. The lung complications observed pre-transplantation markedly improved after neutrophil recovery, i.e., by day +60. We concluded that HSCT is a useful treatment for SCN patients, especially for those at high risk of leukemic transformation. Fludarabine-based reduced-intensity HSCT may represent a safe and effective therapeutic option for patients with SCN who need HSCT even if they have intractable infectious complications.

Early detection of tumor relapse/regrowth by consecutive minimal residual disease monitoring in high-risk neuroblastoma patients

Neuroblastoma is an aggressive pediatric tumor accounting for ~15% of cancer-associated mortalities in children. Despite the current intensive therapy, >50% of high-risk patients experience tumor relapse or regrowth caused by the activation of minimal residual disease (MRD). Although several MRD detection protocols using various reverse transcription-quantitative polymerase chain reaction (RT-qPCR) markers have been reported to evaluate the therapeutic response and disease status of neuroblastoma patients, their clinical significance remains elusive. The present study reports two high-risk neuroblastoma patients, whose MRD was consecutively monitored using 11 RT-qPCR markers (CHRNA3, CRMP1, DBH, DCX, DDC, GABRB3, GAP43, ISL1, KIF1A, PHOX2B and TH) during their course of treatment. The two patients initially responded to the induction therapy and reached MRD-negative status. The patients' MRD subsequently became positive with no elevation of their urinary homovanillic acid, urinary vanillylmandelic acid and serum neuron-specific enolase levels at 13 or 19 weeks prior to the clinical diagnosis of tumor relapse or regrowth. The present cases highlight the possibility of consecutive MRD monitoring using 11 markers to enable an early detection of tumor relapse or regrowth in high-risk neuroblastoma patients.

Randomized study of granulocyte colony stimulating factor for childhood B-cell non-Hodgkin lymphoma: a report from the Japanese pediatric leukemia/lymphoma study group B-NHL03 study

The objective of this study was to assess the impact of the primary prophylaxis of granulocyte colony-stimulating factor (G-CSF) in the management of childhood B-cell non-Hodgkin lymphoma (B-NHL). Patients with advanced-stage mature B-NHL were randomized to receive prophylactic G-CSF (G-CSF+) or not receive G-CSF (G-CSF-) based on protocols of the B-NHL03 study. The G-CSF group received 5 μg/kg/d Lenograstim from day 2 after each course of six chemotherapy courses. Fifty-eight patients were assessable, 29 G-CSF + and 29 G-CSF-. G-CSF + patients showed a positive impact on the meantime to neutrophil recovery and hospital stay. On the other hand, they had no impact in the incidences of febrile neutropenia, serious infections, stomatitis and total cost. Our study showed that administration of prophylactic G-CSF through all six chemotherapy courses for childhood B-NHL showed no clinical and economic benefits for the management of childhood B-NHL treatment.

Identification of novel kinase fusion transcripts in paediatric B cell precursor acute lymphoblastic leukaemia with IKZF1 deletion

Activating tyrosine kinase mutations or cytokine receptor signalling alterations have attracted attention as therapeutic targets for high-risk paediatric acute lymphoblastic leukaemia (ALL). We identified two novel kinase fusions, OFD1-JAK2 and NCOR1-LYN, in paediatric ALL patients with IKZF1 deletion, by mRNA sequencing. The patient with CSF2RA-CRLF2 also harboured IGH-EPOR. All these patients had high-risk features, such as high initial white blood cell counts and initial poor response to prednisolone. The functional analysis of these novel fusions is on-going to determine whether these genetic alterations can be targeted by drugs.

Differential expression of minimal residual disease markers in peripheral blood and bone marrow samples from high-risk neuroblastoma patients

Neuroblastoma is an aggressive solid tumor that leads to tumor relapse in more than half of high-risk patients. Minimal residual disease (MRD) is primarily responsible for tumor relapses and may be detected in peripheral blood (PB) and bone marrow (BM) samples. To evaluate the disease status and treatment response, a number of MRD detection protocols based on either common or distinct markers for PB and BM samples have been reported. However, the correlation between the expression of MRD markers in PB and BM samples remains elusive in the clinical samples. In the present study, the expression of 11 previously validated MRD markers (CHRNA3, CRMP1, DBH, DCX, DDC, GABRB3, GAP43, ISL1, KIF1A, PHOX2B and TH) was determined in 23 pairs of PB and BM samples collected from seven high-risk neuroblastoma patients at the same time point, and the sample was scored as MRD-positive if one of the MRD markers exceeded the normal range. Although the number of MRD-positive samples was not significantly different between PB and BM samples, the two most sensitive markers for PB samples (CRMP1 and KIF1A) were different from those for BM samples (PHOX2B and DBH). There was no statistically significant correlation between the expression of MRD markers in the PB and BM samples. These results suggest that MRD markers were differentially expressed in PB and BM samples from high-risk neuroblastoma patients.

Protracted Administration of L-Asparaginase in Maintenance Phase Is the Risk Factor for Hyperglycemia in Older Patients with Pediatric Acute Lymphoblastic Leukemia

Although L-asparaginase related hyperglycemia is well known adverse event, it is not studied whether the profile of this adverse event is affected by intensification of L-asparaginase administration. Here, we analyzed the profile of L-asparaginase related hyperglycemia in a 1,176 patients with pediatric acute lymphoblastic leukemia treated according to the Japan Association of Childhood Leukemia Study ALL-02 protocol using protracted L-asparaginase administration in maintenance phase. We determined that a total of 75 L-asparaginase related hyperglycemia events occurred in 69 patients. Although 17 events (17/1176, 1.4%) developed in induction phase, which was lower incidence than those (10–15%) in previous reports, 45 events developed during the maintenance phase with protracted L-asparaginase administration. Multivariate analysis showed that older age at onset (≥10 years) was a sole independent risk factor for L-asparaginase-related hyperglycemia (P<0.01), especially in maintenance phase. Contrary to the previous reports, obesity was not associated with L-asparaginase-related hyperglycemia. These findings suggest that protracted administration of L-asparaginase is the risk factor for hyperglycemia when treating adolescent and young adult acute lymphoblastic leukemia patients.

Comparison of long-term outcomes between children with aplastic anemia and refractory cytopenia of childhood who received immunosuppressive therapy with antithymocyte globulin and cyclosporine

The 2008 World Health Organization classification proposed a new entity in childhood myelodysplastic syndrome, refractory cytopenia of childhood. However, it is unclear whether this morphological classification reflects clinical outcomes. We retrospectively reviewed bone marrow morphology in 186 children (median age 8 years; range 1-16 years) who were enrolled in the prospective study and received horse antithymocyte globulin and cyclosporine between July 1999 and November 2008. The median follow-up period was 87 months (range 1-146 months). Out of 186 patients, 62 (33%) were classified with aplastic anemia, 94 (49%) with refractory cytopenia of childhood, and 34 (18%) with refractory cytopenia with multilineage dysplasia. Aplastic anemia patients received granulocyte colony-stimulating factor more frequently and for longer durations than other patients (P<0.01). After six months, response rates to immunosuppressive therapy were not significantly different among the 3 groups. Acquisition of chromosomal abnormalities was observed in 5 patients with aplastic anemia, 4 patients with refractory cytopenia of childhood, and 3 patients with refractory cytopenia with multilineage dysplasia. Although the cumulative incidence of total clonal evolution at ten years was not significantly different among the 3 groups, the cumulative incidence of monosomy 7 development was significantly higher in aplastic anemia than in the other groups (P=0.02). Multivariate analysis revealed that only granulocyte colony-stimulating factor administration duration of 40 days or more was a significant risk factor for monosomy 7 development (P=0.02). These findings suggest that even the introduction of a strict morphological distinction from hypoplastic myelodysplastic syndrome cannot eradicate clonal evolution in children with aplastic anemia.