Targeted therapeutics in treatment of children and young adults with solid tumors: an expert survey and review of the literature.

Although prognosis of children with solid tumors is steadily improving, long-term survival is not achievable in all patients, especially in patients with recurrent or refractory disease. Despite the increasing number of targeted therapeutics (TT), only very few TT have been introduced into clinical protocols. Accordingly, clinical experience concerning the efficacy and safety of these drugs is limited. This may possibly discourage oncologists from administering TT to children.We performed a comprehensive review of the literature to identify TT that may be considered for treatment of children and young adults with solid tumors. Moreover, we interviewed an expert panel of the Society for Pediatric Oncology and Hematology (GPOH) using questionnaires in a modified Delphi process in order to describe the experts' experiences in the use of these TT.Among 30 TT identified to be possibly useful in children and young adults, imatinib, bevacizumab and rapamycin were most widely used. These drugs were reported as having mostly little to no severe adverse events and seem to induce at least partial responses in a subset of patients. In addition, our study confirms and expands the present knowledge about adverse events and the potential efficacy of 5 other commonly used TT in this population.This information may be useful for oncologists when administering these TT to children and young adults with solid tumors. Controlled clinical trials are urgently needed to test their safety and efficacy.

Further evidence for a somatic KRAS mutation in a pilocytic astrocytoma.

Astrocytomas are the most common brain tumors of childhood. However, knowledge of the molecular etiology of astrocytomas WHO grade I and II is limited. Germline mutations in the Ras-guanosine triphosphatase-activating protein, neurofibromin, in individuals with neurofibromatosis type I predispose to pilocytic astrocytomas. This association suggests that constitutive activation of the Ras signaling pathway plays a fundamental role in astrocytoma development. We screened 25 WHO I and II astrocytomas for mutations of PTPN11, NRAS, KRAS, and HRAS genes and identified the somatic G12A KRAS mutation in one pilocytic astrocytoma. These data suggest that Ras is rarely mutated in these tumors. Analyzed astrocytomas without mutations in Ras or neurofibromin may harbor mutations in other proteins of this pathway leading to hyperactive Ras signaling.

[Risk stratification in medulloblastoma: screening for molecular markers]. / Screening molekularbiologischer Marker zur Risikostratifizierung bei Medulloblastomen.

BACKGROUND: The present study evaluates molecular markers for patients at risk of poor or no response to medulloblastoma. The aim of the study is to optimize therapy stratification. PATIENTS AND METHODS: 69 snap-frozen medulloblastoma samples were examined. C-MYC amplification was determined by fluorescence in situ hybridisation (FISH) analysis. Methylation specific PCR revealed the level of promoter methylation status of the tumor suppressor genes CASP8 (Caspase 8), TIMP3, CDH1 (E-Cadherin), CDKN2A (p16) and MGMT. Expression of GAS7 was evaluated by RT-PCR. RESULTS: C-MYC amplification: 4/69 tumors displayed high level amplification; 53/69 tumors displayed low level (< 4 copies) or no amplification; 12/69 samples were not predictive. In patients with c-MYC amplification a tendency towards unfavorable outcome was observed (p = 0.3). Promoter methylation status: CASP8: in 36/40 tumors methylated; TIMP3: 1/38 methylated; MGMT 0/44 methylated; CDKN2A: 1/46 methylated; E-cadherin 3/36 methylated; no association between methylation status and clinical outcome. GAS7: Detection of specific RNA in 20/29 medulloblastoma samples. CONCLUSION: No significant association between amplification of c-MYC and clinical outcome was observed. Promoter methylation of tumor suppressor genes is non-randomly distributed with a high level of methylation of CASP8. Recent studies show that silencing of CASP8 by methylation could be overcome by interferon gamma providing a possible therapeutic mechanism. GAS7 was shown to be a marker of mature neuronal cells with potential antitumorigenic capacity in neuronal tumors. In medulloblastoma 20/29 of the tumors examined express GAS7. Therefore a tumor suppressing function of GAS7 is improbable.

Neonatal mastocytosis with pachydermic bullous skin without c-Kit 816 mutation.

BACKGROUND: Bullous mastocytosis is an unusual variant of mast cell disease with widespread bullae as the main cutaneous feature induced by mast cell proteases that cause dermoepidermal separation. CASE REPORT: A rare case of diffuse cutaneous bullous mastocytosis with pachydermia and unusually extensive skin folding is described in a 3-week-old girl. The diagnosis was confirmed by immunohistochemistry with Giemsa stain, the naphthol ASD chloroacetate esterase reaction and elevated blood levels for tryptase, histamine in serum and histamine and 1.4-methylimidazol acetic acid in the 24-hour urine. Blood cell count was normal, as were thrombocytosis and leukocytosis. FACS analysis of the bone marrow aspiration material showed 1% mast cells. No c-Kit 816 [Asp-->Val] somatic mutation was found. Systemic involvement of other organs was excluded. DISCUSSION: The prognosis of c-Kit-negative diffuse bullous mastocytosis is not known. Regular blood controls are mandatory, and screening for germ cell ovarian cancer and bone marrow controls should be performed as well.

No aberrant methylation of neurofibromatosis 1 gene (NF1) promoter in pilocytic astrocytoma in childhood.

Tumors of the central nervous system are the most frequent solid tumors in childhood. With 30-40% of this heterogenous group, low-grade astrocytomas represent the most common subtype. Neurofibromatosis type 1 (NF1) is strongly associated with the development of pilocytic astrocytoma (PA), frequently appearing as optic glioma. Neurofibromatosis 1 gene (NF1 ) fulfills the criteria of a tumor suppressor gene and is deleted or mutated heterozygously in patients with NF1. This suggests an involvement in the development of PA. To clarify whether silencing of NF1 by promoter methylation plays a role in PA and especially in optic glioma, the authors investigated the methylation status in 30 PA, 6 of which had optic glioma. However, no methylation was found at the NF1 promoter region in PA. To rule out that silencing of NF1 by promoter methylation is restricted to higher-grade astrocytomas, 15 pediatric WHO II degree and IV degree astrocytomas were analyzed: 12 astrocytomas II and 3 glioblastomas displayed no NF1 promoter methylation. The authors conclude that NF1 silencing by methylation plays no role in low-grade astrocytoma.

Mycoplasma pneumoniae associated organising pneumonia in a 10 year old boy.

We describe a 10 year old boy with organising pneumonia associated with acute Mycoplasma pneumoniae infection. The diagnosis of organising pneumonia was made by open lung biopsy and the M pneumoniae infection was proven serologically. Antibiotic and long term corticosteroid treatment resulted in steadily improving pulmonary function monitored by spirometry. The introduction of anti-inflammatory treatment with NSAIDs/immunosuppressive agents in order to spare steroids was well tolerated and resulted in further improvement of the pulmonary function. To our knowledge this is the first documented case of Mycoplasma pneumoniae associated organising pneumonia to be reported in a child.

Isochromosome 1q as an early genetic event in a child with intracranial ependymoma characterized by molecular cytogenetics.

Data concerning cytogenetic features of childhood ependymoma are rare. In this article, a gain of 1q was identified as the sole alteration in a primary childhood infratentorial ependymoma by comparative genomic hybridization (CGH). A recurrence of this brain tumor was studied using multiplex-fluorescence in situ hybridization (M-FISH) in addition to CGH and G-banding analysis. In accordance with the primary tumor, a gain of 1q corresponding to an isochromosome 1q was observed indicating an early event in the tumor development. Furthermore, M-FISH classified several other rearranged chromosomes including 6q and 17p that have previously been found to be involved in the development and progression of childhood ependymoma.

Identification of seven novel mutations including the first two genomic rearrangements in SLC26A3 mutated in congenital chloride diarrhea.

Congenital chloride diarrhea (CLD) is an autosomal recessive disorder characterized by defective intestinal electrolyte absorption, resulting in voluminous osmotic diarrhea with high chloride content. A variety of mutations in the solute carrier family 26, member 3 gene (SLC26A3, previously known as CLD or DRA) are responsible for the disease. Since the identification of the SLC26A3 gene and the determination of its genomic structure, altogether three founder and 17 private mutations have been characterized within miscellaneous ethnic groups. We screened for mutations in seven unrelated families with CLD. The diagnoses were confirmed by fecal chloride measurements. The combined PCR-SSCP and sequencing analyses revealed altogether seven novel mutations including two missense mutations (S206P, D468V), two splicing defects (IVS12-1G>C, IVS13-2delA), one nonsense mutation (Q436X), one insertion/deletion mutation (2104-2105delGGins29-bp), and an intragenic deletion of SLC26A3 exons 7 and 8. Two previously identified mutations were also found. This is the first report of rearrangement mutations in SLC26A3. Molecular features predisposing SLC26A3 for the two rearrangements may include repetitive elements and palindromic-like sequences. The increasingly wide diversity of SLC26A3 mutations suggests that mutations in the SLC26A3 gene may not be rare events.

Cytogenetic and histopathologic studies of congenital supratentorial primitive neuroectodermal tumors: a case report.

Primitive neuroectodermal tumors (PNET) represent about 25% of primary central nervous system tumors in childhood, but congenital PNETs are rare. Cytogenetic studies and studies on molecular pathology have identified several genetic alterations in medulloblastoma, but molecular investigations on supratentorial PNETs are infrequent. We present a male newborn with a large congenital PNET of the right cerebral hemisphere and the molecular analysis of the tumor. Tumor tissue was investigated by routine histology and immunohistochemistry. Fluorescence in-situ hybridization was carried out on native tumor tissue to investigate deletions on chromosome 17p and to analyze c-Myc or N-Myc amplifications. Histologic examination revealed a primitive neuroectodermal tumor with massive extension covering almost the entire right hemisphere. Genetic analysis of the native tumor tissue of our patient excluded a deletion of chromosome 17p. An amplification of the c-Myc or N-Myc oncogene was absent using fluorescence in-situ hybridization. Despite unremarkable genetic analysis in our case prognosis was poor, suggesting that there are additional, yet unknown constitutional genetic aberrations in the pathogenesis of congenital supratentorial PNET.

Chronic autoimmune thrombopenia/neutropenia in a boy with persistent parvovirus B19 infection.

OBJECTIVE: We report an 11-year-old boy presenting with splenomegaly, chronic thrombocytopenia and concordant neutropenia. RESULTS: In contrast to autoantibodies against platelets, there were no detectable neutrophil-specific autoantibodies present in this patient. Extensive serologic investigations revealed increased IgM- and IgG-antibody titers against parvovirus B19. A nested polymerase chain reaction (PCR) showed parvovirus B19-specific sequences in the patient's bone-marrow cells but not in the serum. Specific antibodies against the structural proteins VP1 and VP2 in addition to those against non-structural protein NS1 of parvovirus B19 were detected by Western blot analysis. Thrombocytopenia and neutropenia responded to immunosuppressive therapy and subsequent splenectomy, the latter being necessary due to severe side-effects of steroid medication. CONCLUSION: Autoimmune thrombocytopenia/neutropenia may have been triggered and/or sustained by a chronic parvovirus B19 infection. Patients with this very rare disorder should be screened for this virus.