Nobuyuki Yamamoto

The first report of adolescent TAFRO syndrome, a unique clinicopathologic variant of multicentric Castleman’s disease

BackgroundTAFRO syndrome is a unique clinicopathologic variant of multicentric Castleman’s disease that has recently been identified in Japan. It is characterized by a constellation of symptoms: Thrombocytopenia, Anasarca, reticulin Fibrosis of the bone marrow, Renal dysfunction and Organomegaly (TAFRO). Previous reports have shown that affected patients usually respond to immunosuppressive therapy, but the disease sometimes has a fatal course. TAFRO syndrome occurs in the middle-aged and elderly and there are no prior reports of the disease in adolescents. Here we report the first adolescent case, successfully treated with anti-IL-6 receptor antibody (tocilizumab, TCZ) and monitored with serial cytokine profiles.Case presentationA 15-year-old Japanese boy was referred to us with fever of unknown origin. Whole body computed tomography demonstrated systemic lymphadenopathy, organomegaly and anasarca. Laboratory tests showed elevated C-reactive protein and hypoproteinemia. Bone marrow biopsy revealed a hyperplastic marrow with megakaryocytic hyperplasia and mild reticulin fibrosis. Despite methylprednisolone pulse therapy, the disease progressed markedly to respiratory distress, acute renal failure, anemia and thrombocytopenia. Serum and plasma levels of cytokines, including IL-6, vascular endothelial growth factor, neopterin and soluble tumor necrosis factor receptors I and II, were markedly elevated. Repeated weekly TCZ administration dramatically improved the patient’s symptoms and laboratory tests showed decreasing cytokine levels.ConclusionTo our knowledge, this is the first report of TAFRO syndrome in a young patient, suggesting that this disease can occur even in adolescence. The patient was successfully treated with TCZ. During our patient’s clinical course, monitoring cytokine profiles was useful to assess the disease activity of TAFRO syndrome.

Epigallocatechin gallate inhibits sphere formation of neuroblastoma BE(2)-C cells

ObjectivesA growing number of epidemiological studies have demonstrated that the consumption of green tea inhibits the growth of a variety of cancers. Epigallocatechin gallate (EGCG), the most abundant catechin in green tea, has been shown to have an anti-cancer effect against many cancers. Most cancers are believed to be initiated from and maintained by a small population of tumor-initiating cells (TICs) that are responsible for chemotherapeutic resistance and tumor relapse. In neuroblastoma, an aggressive pediatric tumor that often relapses and has a poor prognosis, TICs were recently identified as spheres grown in a serum-free non-adherent culture used for neural crest stem cell growth. Although EGCG has been reported to induce growth arrest and apoptosis in neuroblastoma cells, its effect on neuroblastoma TICs remains to be defined.MethodsGene expression was analyzed by real-time reverse transcription polymerase chain reaction (RT-PCR). The effects of EGCG on cell proliferation, apoptosis, and sphere formation were determined by cell counting, propidium iodide staining, and sphere (>100xa0μm in diameter) counting, respectively.ResultsNeuroblastoma BE(2)-C cells showed increased expression of stem cell markers (nanog homeobox [NANOG] and octamer-binding transcription factor 4 [OCT4]), as well as decreased expression of neuronal differentiation markers (Cu2+-transporting ATPase alpha polypeptide [ATP7A] and dickkopf homolog 2 [DKK2]) in spheres grown in serum-free non-adherent culture, compared to parental cells grown in conventional culture. Although EGCG induced growth arrest and apoptosis in the parental cells in a dose-dependent manner, it was not effective against spheres. However, EGCG potently inhibited sphere formation in the BE(2)-C cells.ConclusionsThe present results suggest that EGCG may inhibit the development of TICs in BE(2)-C cells.

Involvement of aldehyde dehydrogenase 1A2 in the regulation of cancer stem cell properties in neuroblastoma

Despite the introduction of 13-cis-retinoic acid (13-cis-RA) into the current chemotherapy, more than half of high-risk neuroblastoma patients have experienced tumor relapses driven by chemoresistant cancer stem cells (CSCs) that can be isolated by their ability to grow as spheres. Although aldehyde dehydrogenase (ALDH) has been used to characterize CSCs in certain cancers, ALDH remains elusive in neuroblastoma. In the present study, we determined ALDH activity and expression of its 19 isoforms in spheres and parental cells of neuroblastoma. ALDH activity and several ALDH isoforms were consistently induced in spheres of different neuroblastoma cells. While ALDH1A2, ALDH1L1 and ALDH3B2 expression was consistently induced in spheres and associated with the sphere and colony formation, only ALDH1A2 expression was significantly correlated with the poor prognosis of neuroblastoma patients. ALDH1A2 expression was further associated with the growth and undifferentiation of neuroblastoma xenografts and the resistance of neuroblastoma cells to 13-cis-RA. These results suggest that ALDH1A2 is involved in the regulation of CSC properties in neuroblastoma.

Minimal residual disease monitoring in neuroblastoma patients based on the expression of a set of real-time RT-PCR markers in tumor-initiating cells

Minimal residual disease (MRD) is derived from tumor-initiating cells (TICs) and is responsible for tumor relapse. Neuroblastoma is characterized by extreme tumor heterogeneity, and more than half of high-risk patients experience tumor relapse. To overcome tumor heterogeneity and achieve more sensitive detection of MRD, several sets of real-time RT-PCR markers have been reported for MRD monitoring in neuroblastoma patients from different centers. However, these markers vary across centers and are still being validated. In the present study, we validated the ability of 14xa0commonly used real-time RT-PCR markers to detect MRD based on their expression in neuroblastoma TICs, and we developed a novel MRD detection protocol, which scored the samples as MRD-positive when the expression of one of the 11xa0real-time RT-PCR markers (CHRNA3, CRMP1, DBH, DCX, DDC, GABRB3, GAP43, ISL1, KIF1A, PHOX2B and TH) exceeded the normal range. By using this protocol, we prospectively monitored MRD in 73xa0bone marrowxa0(BM), 12xa0peripheral blood stem cell and 8xa0peripheral blood samples from 14 neuroblastoma patients treated at a single center. We scored 100, 56, 56 and 57% BM cytology-positive, elevated vanillylmandelic acid (VMA), elevated homovanillic acid (HVA) and elevated neuron-specific enolase (NSE) samples as MRD-positive, respectively. MRD was also positive in 48, 45, 46 and 43% of the BM cytology-negative and normal VMA, normal HVA and normal NSE samples, respectively. These results suggest that the present MRD detection protocol based on the expression of a set of 11xa0real-time RT-PCR markers in neuroblastoma TICs achieves sensitive MRD monitoring in neuroblastoma patients.

Rab15 alternative splicing is altered in spheres of neuroblastoma cells

Neuroblastoma is an aggressive pediatric tumor that accounts for 15% of cancer-related deaths in children. More than half of high-risk neuroblastoma patients develop tumor relapse that is lethal in most cases. A small population of tumor-initiating cells (TICs), recently identified from high-risk neuroblastoma patients as spheres, is believed to be responsible for tumor relapse. Rab family small G proteins are essential in controlling membrane traffic and their misregulation results in several cancers. Rab15 was originally isolated as a brain-specific Rab protein regulating the endocytic recycling pathway and was recently identified as a downstream target of the neural transcription factor Atoh1. Previously, we identified two alternatively spliced Rab15 isoforms in neuroblastoma cells and showed a significant correlation between Rab15 expression and neuronal differentiation. As aberrant alternative splicing is intimately associated with an increasing number of cancers, its use as a new diagnostic and/or prognostic biomarker has attracted considerable attention. In the present study, we explored cancer-associated changes of Rab15 alternative splicing in neuroblastoma TICs. We found that Rab15 alternative splicing generated two novel isoforms designated as Rab15(AN2) and Rab15(AN3) in addition to two known isoforms designated as Rab15(CN) and Rab15(AN1). Although both Rab15(AN2) and Rab15(AN3) contained premature termination codons, they were detected in not only neuroblastoma cells but also in normal human tissues. One isoform was predominantly expressed in the brain and testis, while the other isoform was more specifically expressed in the brain. In neuroblastoma, Rab15 isoform balance measured by the Rab15(CN)/Rab15(AN1+AN2+AN3) ratio was significantly decreased in spheres compared to parental cells. These results suggest that Rab15 alternative splicing may serve as a biomarker to discriminate TICs from non-TICs in neuroblastoma.

The emergence of CD20-/CD19- tumor cells after rituximab therapy for Epstein-Barr virus-associated post-transplant lymphoproliferative disorder complicated with hemophagocytic lymphohistiocytosis.

Post-transplant lymphoproliferative disorder (PTLD) is a well-recognized aggressive disease commonly associated with Epstein–Barr virus (EBV) infection after hematopoietic stem cell transplantation (HSCT). Although rituximab (RTX) is incorporated into the first-line therapy for EBV-PTLD patients, the outcome of the clinically overt disease is still not optimal mainly due to the regrowth of tumor cells. The proliferation of CD20−/CD19+ tumor cells is increasingly reported in RTX-treated EBV-PTLD patients, whereas the emergence of CD20−/CD19− tumor cells is barely recognized. Here, we report a fatal case of an 18-year-old patient who developed EBV-PTLD after allogeneic HSCT for anaplastic large-cell lymphoma. On day 60 after HSCT, the patient developed abdominal pain, watery diarrhea, and low-grade fever. Colon biopsy revealed the proliferation of CD20+/CD19+/EBV-encoded RNA (EBER)+ tumor cells, and an increase of EBV DNA was detected in peripheral blood (PB). He was treated with RTX for EBV-PTLD and was cleared of EBV DNA in PB. However, he manifested high-grade fever, pancytopenia, and elevated soluble interleukin-2 receptor with a prominent hemophagocytosis in bone marrow aspirates and was treated with etoposide for hemophagocytic lymphohistiocytosis (HLH) complication. He then developed EBV DNA positivity in PB and finally died of Bacteroides fragilis sepsis subsequent to bloody stool and ileus on day 163. Autopsy revealed erosion and bleeding in the whole colon with the proliferation of CD20−/CD19−/EBER+ tumor cells. Immunohistochemical analysis uncovered the CD3−/CD56−/CD79a+/CD79b+ B-cell origin of tumor cells. This case clinically demonstrates the removal of both CD20 and CD19 antigens from EBER+ B cells in an RTX-treated EBV-PTLD patient with HLH complication.

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, −xa07 [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 4xa0months. To our knowledge, this is the first report of ETV6–ABL1 fusion combined with monosomy 7 in childhood BCP-ALL.

Absolute lymphocyte count at the end of induction therapy is a prognostic factor in childhood acute lymphoblastic leukemia

Recent studies have reported that the absolute lymphocyte count (ALC) during induction therapy is predictive of treatment outcome in de novo acute lymphoblastic leukemia (ALL); however, the significance of ALC on outcomes remains controversial. In the present study, we assessed the significance of ALC at day 29 (ALC-29), the end of induction therapy, on outcomes in our Japanese cohort. The outcomes of 141 patients aged ≤18xa0years with newly diagnosed ALL who were enrolled on the JACLS ALL-02 at our hospitals were analyzed in terms of ALC-29. Patients with ALC-29 ≥750/μL (nxa0=xa081) had a superior 5-year EFS (95.2xa0±xa02.7 vs 84.3xa0±xa04.8xa0%, Pxa0=xa00.016) and OS (100 vs 87.0xa0±xa04.7xa0%, Pxa0=xa00.0062). A multivariate analysis identified ALC-29 ≥750/μL as a significant predictor of improved EFS and OS after controlling for confounding factors. A multiple linear regression model revealed a significant inverse relationship between the percentage of blasts in bone marrow on day 15 and ALC-29 (Pxa0=xa00.005). These results indicate that ALC is a simple prognostic factor in childhood ALL, and, thus, has the potential to refine current risk algorithms.

Primary pediatric endobronchial Ewing sarcoma family of tumors

Summary Background: Ewing sarcoma family of tumors is the second most common primary bone tumor of childhood. Extraosseous Ewing sarcoma family of tumors is rare. We present a pediatric case of primary endobronchial Ewing sarcoma family of tumors. Case Report: A 12-year-old boy presented with dyspnea and chest radiography showed right pulmonary atelectasis. Chest computed tomography demonstrated tumor in the right main bronchus. Histopathological examination of the resected tumor demonstrated Ewing sarcoma family of tumors. No other lesions were detected throughout the body and the right main bronchus was thought to be the primary site. As of 1 year and 6 months after further resection of residual tumor followed by chemotherapy and radiotherapy, the patient remains disease-free. Conclusions: Extraosseous Ewing sarcoma family of tumors arises in soft tissues of the trunk or extremities, but primary endobronchial Ewing sarcoma family of tumors has rarely been reported. Although quite rare, Ewing sarcoma family of tumors should be considered among the differential diagnoses for pediatric bronchial tumor.

Transient hyperphosphatasemia in three pediatric patients treated with cyclosporine

Transient hyperphosphatasemia (TH) is defined as marked elevation of serum alkaline phosphatase (ALP), predominantly its bone or liver isoform. It is a rare condition and is usually detected on laboratory examination in patients without any clinical symptoms. In typical patients with TH, ALP spontaneously normalizes, but no apparent cause of TH has been identified. Some drugs are suspected triggers of TH, but no clear evidence of their association with TH has been shown to date. We herein report three cases of TH in pediatric patients. Two patients were treated with cyclosporine for frequently relapsing nephrotic syndrome, and one was also taking cyclosporine for aplastic anemia. Interestingly, ALP immediately decreased after termination of cyclosporine in two patients, whereas TH lasted 4 months in the one patient who continued cyclosporine. Clearly, cyclosporine is associated with the pathophysiology of TH in children.