David Carpentieri

Favorable Neuroblastoma Genes and Molecular Therapeutics of Neuroblastoma

Purpose and Experimental Design: Neuroblastoma (NB) is a common pediatric solid tumor that exhibits a striking clinical bipolarity: favorable and unfavorable. Favorable NB genes (EPHB6, EFNB2, EFNB3, NTRK1, and CD44) are genes whose high-level expression predicts favorable NB outcome, and forced expression of these genes inhibits growth of unfavorable NB cells. In this study, we investigated whether favorable NB gene expression could be augmented in unfavorable NB cells by chemical compounds and whether an increased expression of these genes was associated with suppression of NB growth and metastasis. Results: We found that inhibitors of DNA methylation [5-aza-2′-deoxycytidine (5AdC)], histone deacetylase (HDAC) [4-phenylbutyrate (4PB)], and proteasome (MG262) enhanced the expression of favorable NB genes in NB cell lines and inhibited the growth of these cells in vitro (P < 0.0005). The growth-inhibitory effects of 5AdC and 4PB in vitro were in part due to caspase-dependent cell death and inhibition of DNA synthesis. Administration of 5AdC and/or 4PB also suppressed growth of subcutaneous NB xenografts in nude mice (P < 0.001), which was accompanied by enhanced favorable NB gene expression and an increase in apoptosis. Moreover, 4PB suppressed bone marrow and liver metastases of NB cells in severe combined immunodeficient/Beige mice (P = 0.007 and P = 0.008, respectively). The growth-suppressive activity of HDAC inhibitors on NB was further confirmed by the efficacy of trichostatin A, a potent and specific HDAC inhibitor. Conclusions: Collectively, these observations further emphasize the link between the elevated favorable NB gene expression and a benign phenotype of NB.

Langerhans cell histiocytosis: a primary viral infection of bone? Human herpes virus 6 latent protein detected in lymphocytes from tissue of children.

To better understand the etiology of Langerhans cell histiocytosis (LCH), the authors analyzed tissue from 35 children diagnosed with LCH for the presence of viral proteins and DNA by immunohistochemistry (IHC) and in situ hybridization (ISH). Eighteen control biopsies were obtained from patients without LCH. Confirmatory ISH was randomly performed on four positive and two negative cases determined by IHC. Twenty-five (71.4%) tissue samples with LCH involvement stained by IHC with the 101-kDa antibody against human herpesvirus-6 (HHV-6). None were positive with antibodies against the p41/38 or gp110 viral proteins. Five (27.7%) positive control tissues demonstrated presence of the 101-kDa viral protein in a similar fashion. The difference in the prevalence of HHV-6 in LCH-positive tissues (25/35) when compared with control tissues from patients without LCH involvement (5/18) was statistically significant. ISH confirmed the IHC in all six tissues tested. These findings demonstrate an association between HHV-6 and LCH, suggesting a role for the HHV-6B in the etiology of this disease.

Tumor necrosis factor-like weak inducer of apoptosis stimulation of glioma cell survival is dependent on Akt2 function

Malignant gliomas are the most common primary brain tumors. Despite intensive clinical investigation and significant technical advances in surgical and radiation treatment, the impact on clinical outcome for patients with malignant gliomas is disappointing. We have previously shown that tumor necrosis factor–like weak inducer of apoptosis (TWEAK), a member of the tumor necrosis factor superfamily, can stimulate glioma cell survival via binding to the Fn14 receptor, activation of the NF-κB pathway, and upregulation of BCL-XL gene expression. Here, we show that TWEAK treatment of glioma cells leads to phosphorylation of Akt and BAD. TWEAK stimulation results in the phosphorylation of both Akt1 and Akt2. However, small interfering RNA (siRNA)–mediated depletion of either Akt1 or Akt2 showed that BAD serine 136 phosphorylation is dependent specifically on Akt2 function. Depletion of Akt2 expression by siRNA also abrogates TWEAK-stimulated glioma cell survival, whereas no effect on glioma cell survival was observed after siRNA-mediated depletion of Akt1 expression. Surprisingly, although siRNA-mediated depletion of BAD in glioma cells abrogates cytotoxic- and chemotherapy-induced apoptosis, TWEAK still displays a strong protective effect, suggesting that BAD serine 136 phosphorylation plays a minor role in TWEAK-Akt2–induced glioma cell survival. We also report here that AKT2 gene expression levels increased with glioma grade and inversely correlate with patient survival. Additionally, immunohistochemical analysis showed that Akt2 expression positively correlates with Fn14 expression in glioblastoma multiforme specimens. We hypothesize that the TWEAK-Fn14 signaling axis functions, in part, to enhance glioblastoma cell survival by activation of the Akt2 serine/threonine protein kinase. (Mol Cancer Res 2009;7(11):1871–81)

Central nervous system Sjögren's syndrome in a child: case report and review of the literature.

We describe a case of pediatric Sjögrens syndrome with progressive neurologic involvement. At age 4 years, she had been diagnosed with Melkersson-Rosenthal syndrome. After being stable with facial diplegia and swelling for 5 years, she acutely presented with diplopia, vertigo, and ataxia. Cranial magnetic resonance imaging (MRI) showed a left dorsal midbrain lesion. Serologic and histopathologic findings confirmed primary Sjögrens syndrome. She responded well to intravenous methylprednisolone, with subsequent clinical improvement and MRI resolution. This report reviews the pediatric literature and underscores the importance of considering Sjögrens syndrome in a child with unexplained facial weakness and in the differential diagnosis of pediatric stroke. (J Child Neurol 2001;16:683-685).

Successful treatment of recurrent pediatric inflammatory myofibroblastic tumor in a single patient with a novel chemotherapeutic regimen containing celecoxib.

Inflammatory myofibroblastic tumors are rare tumors characterized as low-to-intermediate grade sarcomas. This is a case of a 7-year-old male with a 5-cm lung mass, which recurred 11 months after complete resection. The recurrence manifested as multifocal metastatic disease involving the ipsilateral parietal and visceral pleura. A novel chemotherapeutic regimen, which included vincristine, ifosfamide, doxorubicin, and celecoxib was utilized for the disease recurrence. The patient had complete and durable remission of the disease and has been disease-free for >4 years. This novel regimen including a cyclooxygenase 2 inhibitor may be an effective regimen for metastatic inflammatory myofibroblastic tumors.

Malignant Peritoneal Mesothelioma in an Adolescent Male With BAP1 Deletion.

Diffuse malignant peritoneal mesotheliomas in children are uncommon, aggressive tumors with a grave prognosis. We herein report the clinical, radiologic, and pathologic findings of a 16-year-old male. The adolescent presented with a history of abdominal pain, nausea and daily, nonbilious, nonbloody emesis for 3 weeks. Radiographic imaging suggested small bowel obstruction. The diagnostic work-up and differential diagnoses are discussed. Histologically, the tumor was composed of epithelioid cells with a papillary and glandular architectural pattern. A few glands appeared to produce mucinous material. Histochemistry revealed PAS diastase resistant mucin, an inconspicuous finding in diffuse malignant peritoneal mesothelioma. An extensive immunohistochemistry panel (calretinin, WT-1, D2-40, CK 7, CAM 5.2, CK 5/6, CEA, B72.3, CK 20, CD10, CD30, CD15, CD117, PLAP, S100, TFE3, and EMA) confirmed the diagnosis. Of special interest, BAP1 staining was cytoplasmic and consistent with 3p deletion detected by conventional cytogenetics. The ultrastructural analysis demonstrated long microvilli, desmosomes, and intercellular junctions which further supported the diagnosis.

Detection of an atypical teratoid rhabdoid brain tumor gene deletion in circulating blood using next-generation sequencing.

Circulating biomarkers such as somatic chromosome mutations are novel diagnostic tools to detect cancer noninvasively. We describe focal deletions found in a patient with atypical teratoid rhabdoid tumor, a highly aggressive early childhood pediatric tumor. First, we used magnetic resonance imaging (MRI) and histopathology to study the tumor anatomy. Next, we used whole genome sequencing (Next Gen Sequencing) and Bioinformatics interrogation to discover the presence of 3 focal deletions in tumor tissue and 2 of these 3 focal deletions in patient’s blood also. About 20% of the blood DNA sequencing reads matched the tumor DNA reads at the SMARCB1 gene locus. Circulating, tumor-specific DNA aberrations are a promising biomarker for atypical teratoid rhabdoid tumor patients. The high percentage of tumor DNA detected in blood indicates that either circulating brain tumor cells lyse in the blood or that contents of brain tumor cells traverse a possibly compromised blood-brain barrier in this patient.

Atypical presentation of Wilson disease.

A 15-year-old Caucasian female on human chorionic gonadotropin (HCG) diet presented with fever, cholestasis, coagulopathy, hemolytic anemia, and acute renal dysfunction. Imaging of the biliary system and liver were normal. She responded to intravenous antibiotics, vitamin K and blood transfusions but experienced relapse upon discontinuation of antibiotics. She had remission with reinstitution of antibiotics. Liver biopsy revealed pronounced bile ductular reaction, bridging fibrosis, and hepatocytic anisocytosis and anisonucleosis with degenerative enlarged eosinophilic hepatocytes, suggestive of Wilson disease. Diagnosis of Wilson disease was further established based on the low serum ceruloplasmin, increased urinary and hepatic copper and presence of Kayser-Fleischer rings. The multisystem involvement of the liver, kidney, blood, and brain are consistent with Wilson disease; however, the clinical presentation of cholangitis and reversible coagulopathy is uncommon, and may result from concurrent acute cholangitis and/or the HCG diet regimen the patient was on.

Lysinuric protein intolerance in a family of Mexican ancestry with a novel SLC7A7 gene deletion. Case report and review of the literature

Lysinuric protein intolerance (LPI) is a rare autosomal recessive disorder caused by mutations in the SLC7A7 located on the chromosome 14q11.2. LPI is most prevalent in Finland (1:50,000), Northern Japan (1:60,000) and Italy. Cases have also been reported in Spain and the United States. Here we report two siblings of Mexican descent. The older child was diagnosed at the age of three with severe chronic respiratory insufficiency leading to her demise. In contrast, the younger child was diagnosed soon after birth and dietary therapy has led to a stable life. Genetic analysis revealed a previously unreported deletion in the SLC7A7 gene. Additional research is needed to clarify the role of lysine in the pathophysiology of pulmonary proteinosis and herpes infections.

Ectomesenchymoma with embryonal rhabdomyosarcoma and ganglioneuroma, arising in association with benign triton tumor of the tongue

Soft-tissue tumors known as “triton” tumors are rare lesions containing neural tissue and skeletal muscle at varying levels of maturity and malignant potential. Benign triton tumors, also called “neuromuscular choristomas” or “neuromuscular hamartomas,” consist of neural tissue containing mature skeletal muscle in intimate relationship with peripheral nerve. These tumors are rare in the head and neck in children. Ectomesenchymomas are similar tumors consisting of a malignant mesenchymal component, usually embryonal rhabdomyosarcoma, and a neuroectodermal component represented by mature ganglion cells or primitive neuroblastic/neuroectodermal foci (primitive ectomesenchymoma). Benign triton tumors have been regarded as benign, whereas ectomesenchymomas have been operationally considered to be variants of rhabdomyosarcoma. We present here a unique case that combines features of these 2 entities in a recurrent lesion on the tongue of a 35-month-old girl. This lesion raises questions about the “benign” nature of benign triton tumor and its possible relationship to ectomesenchymoma.