Polycomb group protein BMI1 protects neuroblastoma cells against DNA damage-induced apoptotic cell death.

The overexpression of BMI1, a polycomb protein, correlates with cancer development and aggressiveness. We previously reported that MYCN-induced BMI1 positively regulated neuroblastoma (NB) cell proliferation via the transcriptional inhibition of tumor suppressors in NB cells. To assess the potential of BMI1 as a new target for NB therapy, we examined the effects of reductions in BMI1 on NB cells. BMI1 knockdown (KD) in NB cells significantly induced their differentiation for up to 7 days. BMI1 depletion significantly induced apoptotic NB cell death for up to 14 days along with the activation of p53, increases in p73, and induction of p53 family downstream molecules and pathways, even in p53 mutant cells. BMI1 depletion in vivo markedly suppressed NB xenograft tumor growth. BMI1 reductions activated ATM and increased γ-H2AX in NB cells. These DNA damage signals and apoptotic cell death were not canceled by the transduction of the polycomb group molecules EZH2 and RING1B. Furthermore, EZH2 and RING1B KD did not induce apoptotic NB cell death to the same extent as BMI1 KD. Collectively, these results suggest the potential of BMI1 as a target of molecular therapy for NB and confirmed, for the first time, the shared role of PcG proteins in the DNA damage response of NB cells.

[Congenital leukemia showing lineage switch following induction chemotherapy and attaining long-term remission after HLA-haploidentical stem cell transplantation].

Congenital leukemia is a rare subgroup of childhood leukemia. Lineage switches in leukemic cells are relatively rare events, which have been occasionally reported in congenital leukemia. To the best of our knowledge, the survival of congenital leukemia patients with lineage switch has not been previously documented. This lack of documentation may be attributable to extremely poor prognosis of these patients. We describe a case of a newborn female with initial diagnosis of MLL-AF4 positive B-precursor acute lymphoblastic leukemia, who developed lineage switch to acute monocytic leukemia following the induction therapy. Although morphological remission was temporary, she received an HLA-haploidentical bone marrow transplant from her father with non-remission status because of an early relapse at the age of 4 months. Despite many difficulties such as graft-versus-host disease, growth impairment, and psychomotor retardation, she remained in remission for 3 years and 7 months after the transplant. This successful outcome suggests that the graft-versus-leukemia effect was potentially accomplished in the patient. Taken together, early HLA-haploidentical stem cell transplant following remission is required for congenital leukemia patients with lineage switch, and it may be an effective alternative for refractory patients.

Coexistence of neuroblastoma and ganglioneuroma in a girl with a hemizygous deletion of chromosome 11q14.1-23.3.

Constitutional 11q interstitial deletion syndrome presents with congenital anomalies including microcephaly with craniostenosis, minor dysmorphic features, vitreoretinopathy, and renal anomalies. This syndrome is occasionally associated with neuroblastoma (NB) as a life-threatening complication, which is important for clinical care. Although the corresponding locus to NB has been predicted to exist in 11q22-23 by previous deletion studies related to NB, the causative haploinsufficient genes have not yet been identified. We herein reported for the first time the simultaneous coexistence of adrenal NB and abdominal prevertebral ganglioneuroma in a 6-year-old girl with a constitutional hemizygous 11q14.1-23.3 deletion. Of the 11 haploinsufficient genes predicted with an in silico database, we focused on NCAM1 and CADM1 as the genes accountable for NB and ganglioneuroma. The deletion range, especially the 11q22.3 involvement, needs to be determined in 11q deletion cases in order to predict susceptibility to peripheral nerve tumors involving NB and ganglioneuroma.

Linezolid-resistant Staphylococcus epidermidis associated with long-term, repeated linezolid use in a pediatric patient.

We report an 8-year-old patient with catheter-related bacteremia caused by linezolid-resistant Staphylococcus epidermidis that was isolated after the long-term, repeated use of linezolid. Three S. epidermidis strains isolated from this patient were bacteriologically analyzed. While the strain isolated prior to linezolid initiation was susceptible to linezolid, two strains after linezolid therapy displayed low-level linezolid susceptibility (MIC, 4 mg/L) and linezolid resistance (MIC, 16 mg/L). T2500A mutation in two copies and G2575T mutations in three copies of 23S rRNA were detected in the low-susceptible strain and the resistant strain, respectively. Linezolid-resistant S. epidermidis infection is rare, but may occur with the long-term administration of linezolid.

Coexistence of neuroblastoma detected on staging of Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is a rare proliferative disease accompanied by the accumulation of pathological Langerhans cells, which often spreads into multi-site and multi-organ systems. We here describe a girl with a history of Kawasaki disease and cervical lymphadenopathy who presented with occipital LCH. Adrenal tumor was detected on staging evaluation of LCH and was diagnosed as neuroblastoma on resection using laparoscopic surgery. Neither tumor relapsed following chemotherapy for LCH and resection of neuroblastoma. Although LCH often spreads into multi-organ lesions, invasive biopsy may be needed for tumors with atypical localization for LCH in consideration of the synchronous occurrence of malignancies.

Histological features of primary tumors after induction or high-dose chemotherapy in high-risk neuroblastoma.

PURPOSE: In the recent years in Japan, an increasing number of patients with neuroblastoma (NB) are being treated by the "delayed local treatment (DL)" policy, undergoing surgery after the completion of high-dose chemotherapy with hematopoietic stem cell rescue (HDC). We reviewed the histopathological findings of second-look operations, including those of patients treated with DL. PATIENTS: From 1998 to 2013, 26 patients with high-risk NB underwent radical operation following chemotherapy. Surgery was performed after induction chemotherapy in 17 cases (standard; STD), whereas 9 cases completed induction chemotherapy and HDC before undergoing tumor resection (DL). The amount of necrosis and the degree of differentiation within the post-treatment tumor were assessed. RESULTS: Eighty-eight percent of the tumors showed necrosis in more than 1/3 of the specimen. Two DL cases showed complete disappearance of viable tumor cells. Amount of necrosis did not affect the prognosis of the patient. Tumors with immature, poorly differentiated phenotypes showed an extremely aggressive thereafter. Though not statistically proven, (123)I-MIBG (metaiodobenzylguanidine) uptake may be correlated with the amount of viable cells remaining within the tumor, but not with the degree of differentiation. CONCLUSIONS: Our results support the previous reports advocating that tumors that sustain unfavorable histology after chemotherapy behave aggressively thereafter.

Trametinib for a child with refractory Rosai-Dorfman-Destombes disease harboring a novel somatic mutation in MAP2K1.

Rosai-Dorfman-Destombes disease (RDD) is a rare histiocytosis characterized by accumulation of S100 + , CD68 + , and CD1a- histiocytes, with emperipolesis. It occurs predominantly in black adolescents and young adults, but rarely in Japanese children. Recently, oncogenic mutations in mitogen-activated protein kinase (MAPK) pathway genes were reported in 30-50% of patients with RDD, and several studies have described treatment of adult patients with MAPK inhibitors. Here, we present the case of a Japanese boy with refractory RDD without signs of cardiofaciocutaneous (CFC) syndrome who harbored MAP2K1 p.Lys59del and responded to trametinib. The patient had lymph node, nasal cavity, kidney, upper respiratory tract, and intracranial involvement. RDD progressed after multi-agent chemotherapy, but responded to trametinib (0.025 mg/kg). Trametinib did not eliminate the mass lesions, but trametinib plus minimal prednisolone (0.1 mg/kg) resulted in a good outcome for more than 15 months, without significant adverse effects. MAP2K1 p.Lys59del has been described as a germline mutation in a patient with CFC syndrome, but not as a somatic mutation in patients with malignancies. Trametinib may be a promising drug for children with RDD that is refractory to multi-agent chemotherapy. Its long-term efficacy and safety alone and in combination with chemotherapy should be investigated.

Optimal surgical treatment and urological outcomes in boys with pelvic and urogenital rhabdomyosarcomas and soft tissue sarcomas.

BACKGROUND: Soft tissue sarcomas (STS) of pelvic origin in boys often involve the urogenital organs. The optimal extensiveness of radical surgery has long been an issue of discussion, since exenterative surgeries result in severe urogenital adverse effects. We conducted a retrospective review of patients with pelvic STS treated in two regional center hospitals and assessed the radicality of surgery and the functional outcome of the bladder. PATIENTS: Medical records and surgical reports of nine cases (embryonal rhabdomyosarcoma 6, malignant triton tumor 2, suspected rhabdomyosarcoma 1) treated within 1997-2012 were reviewed. Site of origin was prostate in seven, retroperitoneal in two. Average follow-up period was 96 months. TREATMENT AND OUTCOME: All cases were subjected to neoadjuvant chemotherapy. Response was PR in four, SD in two, and PD in two. Radical surgery resulted in gross total resection in eight, and partial resection in one. Three underwent cystoprostatectomy, two cases underwent prostatectomy, and bladder-preserving tumor resection was carried out in four cases. At the last follow-up, three retained a functional bladder. Two required augmentation cystoplasty with intestinal conduits. CONCLUSIONS: The majority of the on-going clinical trials recommend conservative surgery for bladder/prostate rhabdomyosarcoma, and to preserve the bladder function particularly in chemosensitive tumors. Some other groups, however, advocate the importance of radical surgery to prevent local relapse. These reports include heterogenous group of patients in the cohort, and therefore it is difficult to draw a conclusion of which approach truly contributes to the survival of the patients better. Future studies should evaluate bladder and sexual function objectively to establish reliable evidence regarding the benefit and adverse effects of different surgical approaches. These data would be informative to optimize the treatment balance for children with pelvic rhabdomyosarcomas.

Bmi1 regulates cell fate via tumor suppressor WWOX repression in small-cell lung cancer cells.

Mortality from lung cancer is important worldwide. Recently, epigenetic aberration of lung cancer, not only genomic DNA methylation but also chromatin modification, has become an important target for lung cancer research, although previous research has demonstrated that lung cancer develops as a result of both environmental and genetic factors. Here, we demonstrated that an epigenetic regulator/polycomb group protein Bmi1 is more highly expressed in small-cell lung cancer (SCLC) than in non-small-cell lung cancer by immunohistochemical analysis. In vitro experiments indicated that Bmi1 reduction by lentivirus-derived shRNA significantly suppressed proliferation, colony formation and in vivo tumor formation. Importantly, apoptosis was induced by Bmi1 depletion in small-cell lung cancer cells. Furthermore, a tumor suppressor WWOX was identified as a Bmi1 target in the cells by a chromatin immunoprecipitation assay and a quantitative real-time PCR assay; WWOX had a role as a tumor suppressor in SCLC cells; therefore, the Bmi1/WWOX pathway could be a new candidate for a new therapeutic approach for SCLC.

Expression of CD203c on basophils as a marker of immunoglobulin E-mediated (L)-asparaginase allergy.

Immediate allergy to l-asparaginase (ASP) is a major obstacle in treating lymphoid malignancies. ASP-specific immunoglobulin G (ASP-IgG) has been used as a surrogate marker. Recently, the CD203c-basophil activation test (BAT) was found to be useful in diagnosing IgE-mediated allergies. We compared the diagnostic utility of the CD203c-BAT to that of ASP-IgG levels in determining ASP allergies in children. Eight ASP allergic reactions occurred over 75 ASP treatment courses. The sensitivity, specificity and area under the receiver operating characteristic curve of CD203c-BAT were similar to the ASP-IgG levels (0.75 vs. 0.85, 0.82 vs. 0.78 and 0.81 vs. 0.85, respectively). Positive skin prick test results in patients with ASP allergy suggested that ASP-IgE was one of the key players in ASP allergy. A combination of the BAT with the ASP-IgG level had the highest specificity (0.95) and positive predictive value (0.62), which permitted us to identify ASP allergy more effectively.

Adamantinoma-like Ewing family tumor of soft tissue associated with the vagus nerve: a case report and review of the literature.

Adamantinoma-like Ewing family tumor (EFT) is a rare subset of EFTs showing mixed features of Ewing sarcoma and adamantinoma of the long bones. All currently reported cases of the adamantinoma-like type have been associated with bone. Recently, a unique type of EFT was reported showing complex epithelial differentiation associated with the vagus nerve. Here we describe another unique type of EFT arising in the soft tissue of the neck associated with the vagus nerve. An 11-year-old girl presented to our hospital with a neck tumor on her right side. Surgical resection was performed, and histopathologic examination demonstrated a high-grade malignant neoplasm. The tumor was composed of sheets of small round proliferating cells, basaloid tumor nests with marked squamous differentiation, biphasic growth pattern with epithelioid tumor nests, and spindle cell proliferation. Immunohistochemically, the tumor cells showed diffuse expression of CD99 and FLI-1. In addition, small round cells and basaloid/squamoid components were immunoreactive for AE1/AE3, CAM5.2, cytokeratin 5/6, high-molecular weight keratin, p63, and p40 (ΔNp63). Reverse transcription polymerase chain reaction and direct sequencing analysis revealed that the tumor harbored a t(11;22) translocation, involving EWSR1 and FLI-1, which are characteristic of EFTs. According to these findings, our case has characteristics of both a subset of adamantinoma-like EFT and EFT with complex epithelial differentiation. We suggest that EFT with complex epithelial differentiation is in a common spectrum with the adamantinoma-like type and that adamantinoma-like EFTs can arise in soft tissue, leading to difficulty in differential diagnosis with malignant epithelial tumors.

Reversible cerebral vasoconstriction syndrome associated with brain parenchymal hemorrhage.

We described a 7-year-old girl with reversible cerebral vasoconstriction syndrome associated with brain parenchymal hemorrhage. She initially presented with high fever and pancytopenia, leading to a diagnosis of most severe type aplastic anemia. We treated her with cyclosporine, methylprednisolone and anti-thymocyte globulin. Thereafter she recurrently complained of a very severe headache called as thunderclap, and finally exhibited loss of consciousness. Brain imaging revealed massive parenchymal hemorrhage between the left occipital and parietal lobes on computed tomography, and diffuse cerebral vasoconstriction on magnetic resonance angiography. The cerebral vasoconstriction resolved within two months, and thus we diagnosed her as having reversible cerebral vasoconstriction syndrome associated with brain parenchymal hemorrhage. This syndrome has been frequently reported in adult females, but rarely in children. However, even in children, a so called thunderclap headache may become a clue for the diagnosis of reversible cerebral vasoconstriction syndrome, especially in cases taking immunosuppressive agents. Immediate magnetic resonance angiography is essential to diagnose this syndrome, and a prompt application of calcium channel inhibitors should be considered to resolve constriction of the vessels and to prevent subsequent brain damage.