Shengmei Zhou

The alternative lengthening of telomere phenotype is significantly associated with loss of ATRX expression in high-grade pediatric and adult astrocytomas: a multi-institutional study of 214 astrocytomas

Loss-of-function of alpha thalassemia/mental retardation syndrome X-linked (ATRX) protein leads to a phenotype called alternative lengthening of telomeres (ALT) in some tumors. High-grade astrocytomas comprise a heterogeneous group of central nervous system tumors. We examined a large cohort of adult (91) and pediatric (n=88) high-grade astrocytomas as well as lower grade forms (n=35) for immunohistochemical loss of ATRX protein expression and the presence of ALT using telomere-specific fluorescence in situ hybridization, with further correlation to other known genetic alterations. We found that in pediatric high-grade astrocytomas, 29.6% of tumors were positive for ALT and 24.5% were immunonegative for the ATRX protein, these two alterations being highly associated with one another (P<0.0001). In adult high-grade astrocytomas, 26.4% of tumors were similarly positive for ALT, including 80% of ATRX protein immunonegative cases (P<0.0001). Similar frequencies were found in 11 adult low-grade astrocytomas, whereas all 24 pilocytic astrocytomas were negative for ALT. We did not find any significant correlations between isocitrate dehydrogenase status and either ALT positivity or ATRX protein expression in our adult high-grade astrocytomas. In both cohorts, however, the ALT positive high-grade astrocytomas showed more frequent amplification of the platelet-derived growth factor receptor alpha gene (PDGFRA; 45% and 50%, respectively) than the ALT negative counterparts (18% and 26%; P=0.03 for each). In summary, our data show that the ALT and ATRX protein alterations are common in both pediatric and adult high-grade astrocytomas, often with associated PDGFRA gene amplification.

PDGFRA amplification is common in pediatric and adult high-grade astrocytomas and identifies a poor prognostic group in IDH1 mutant glioblastoma

High‐grade astrocytomas (HGAs), corresponding to World Health Organization grades III (anaplastic astrocytoma) and IV (glioblastoma; GBM), are biologically aggressive, and their molecular classification is increasingly relevant to clinical management. PDGFRA amplification is common in HGAs, although its prognostic significance remains unclear. Using fluorescence in situ hybridization (FISH), the most sensitive technique for detecting PDGFRA copy number gains, we determined PDGFRA amplification status in 123 pediatric and 263 adult HGAs. A range of PDGFRA FISH patterns were identified and cases were scored as non‐amplified (normal and polysomy) or amplified (low‐level and high‐level). PDGFRA amplification was frequent in pediatric (29.3%) and adult (20.9%) tumors. Amplification was not prognostic in pediatric HGAs. In adult tumors diagnosed initially as GBM, the presence of combined PDGFRA amplification and isocitrate dehydrogenase 1 (IDH1)R132H mutation was a significant independent prognostic factor (P = 0.01). In HGAs, PDGFRA amplification is common and can manifest as high‐level and focal or low‐level amplifications. Our data indicate that the latter is more prevalent than previously reported with copy number averaging techniques. To our knowledge, this is the largest survey of PDGFRA status in adult and pediatric HGAs and suggests PDGFRA amplification increases with grade and is associated with a less favorable prognosis in IDH1 mutant de novo GBMs.

Expansion of prominin‐1‐expressing cells in association with fibrosis of biliary atresia

Biliary atresia (BA), the most common cause of end‐stage liver disease and the leading indication for pediatric liver transplantation, is associated with intrahepatic ductular reactions within regions of rapidly expanding periportal biliary fibrosis. Whereas the extent of such biliary fibrosis is a negative predictor of long‐term transplant‐free survival, the cellular phenotypes involved in the fibrosis are not well established. Using a rhesus rotavirus‐induced mouse model of BA, we demonstrate significant expansion of a cell population expressing the putative stem/progenitor cell marker, PROMININ‐1 (PROM1), adjacent to ductular reactions within regions of periportal fibrosis. PROM1positive (pos) cells express Collagen‐1α1. Subsets of PROM1pos cells coexpress progenitor cell marker CD49f, epithelial marker E‐CADHERIN, biliary marker CYTOKERATIN‐19, and mesenchymal markers VIMENTIN and alpha‐SMOOTH MUSCLE ACTIN (αSMA). Expansion of the PROM1pos cell population is associated with activation of Fibroblast Growth Factor (FGF) and Transforming Growth Factor‐beta (TGFβ) signaling. In vitro cotreatment of PROM1‐expressing Mat1a−/− hepatic progenitor cells with recombinant human FGF10 and TGFβ1 promotes morphologic transformation toward a myofibroblastic cell phenotype with increased expression of myofibroblastic genes Collagen‐1α1, Fibronectin, and α‐Sma. Infants with BA demonstrate similar expansion of periportal PROM1pos cells with activated Mothers Against Decapentaplegic Homolog 3 (SMAD3) signaling in association with increased hepatic expression of FGF10, FGFR1, and FGFR2 as well as mesenchymal genes SLUG and SNAIL. Infants with perinatal subtype of BA have higher tissue levels of PROM1 expression than those with embryonic subtype. Conclusion: Expansion of collagen‐producing PROM1pos cells within regions of periportal fibrosis is associated with activated FGF and TGFβ pathways in both experimental and human BA. PROM1pos cells may therefore play an important role in the biliary fibrosis of BA. (Hepatology 2014;60:941–953)

Subcutaneous nerve activity and spontaneous ventricular arrhythmias in ambulatory dogs

BACKGROUND Stellate ganglion nerve activity (SGNA) is important in ventricular arrhythmogenesis. However, because thoracotomy is needed to access the stellate ganglion, it is difficult to use SGNA for risk stratification. OBJECTIVE The purpose of this study was to test the hypothesis that subcutaneous nerve activity (SCNA) in canines can be used to estimate SGNA and predict ventricular arrhythmia. METHODS We implanted radiotransmitters to continuously monitor left stellate ganglion and subcutaneous electrical activities in 7 ambulatory dogs with myocardial infarction, complete heart block, and nerve growth factor infusion to the left stellate ganglion. RESULTS Spontaneous ventricular tachycardia (VT) or ventricular fibrillation (VF) was documented in each dog. SCNA preceded a combined 61 episodes of VT and VF, 61 frequent bigeminy or couplets, and 61 premature ventricular contractions within 15 seconds in 70%, 59%, and 61% of arrhythmias, respectively. Similar incidence of 75%, 69%, and 62% was noted for SGNA. Progressive increase in SCNA [48.9 (95% confidence interval [CI] 39.3-58.5) vs 61.8 (95% CI 45.9-77.6) vs 75.1 (95% CI 57.5-92.7) mV-s] and SGNA [48.6 (95% CI 40.9-56.3) vs 58.5 (95% CI 47.5-69.4) vs 69.0 (95% CI 53.8-84.2) mV-s] integrated over 20-second intervals was demonstrated 60 seconds, 40 seconds, and 20 seconds before VT/VF (P <.05), respectively. The Pearson correlation coefficient for integrated SCNA and SGNA was 0.73 ± 0.18 (P <.0001 for all dogs, n = 5). Both SCNA and SGNA exhibited circadian variation. CONCLUSION SCNA can be used as an estimate of SGNA to predict susceptibility to VT and VF in a canine model of ventricular arrhythmia and sudden cardiac death.

Renal Cell Carcinoma Occurring in Patients With Prior Neuroblastoma: A Heterogenous Group of Neoplasms

Renal cell carcinoma (RCC) associated with neuroblastoma (NB) was included as a distinct entity in the 2004 World Health Organization classification of kidney tumors. A spectrum of RCC subtypes has been reported in NB survivors. We herein describe a series of 8 RCCs diagnosed in 7 patients with a history of NB. Microscopic evaluation, immunohistochemical staining for PAX8, cathepsin K, and succinate dehydrogenase subunit B (SDHB), and fluorescence in situ hybridization (FISH) for TFE3 and TFEB were performed. Four distinct morphologic subtypes were identified: 3 tumors were characterized by cells with abundant oncocytoid cytoplasm and irregular nuclei; 3 showed features of microphthalmia transcription factor family translocation RCC (MiTF-RCC); 1 had features of hybrid oncocytic-chromophobe tumor; 1 had papillary RCC histology. All RCCs expressed PAX8 and retained SDHB expression. Cathepsin K was positive in 2 MiTF-RCCs, 1 was TFEB FISH positive, and the other was indeterminate. Cathepsin K was negative in a third MiTF-RCC with TFE3 rearrangement. TFE3 FISH was negative in 4 and insufficient in 1 of the other 5 RCCs. While a subset of RCCs associated with NB is characterized by cells with prominent oncocytoid cytoplasm, other RCC subtypes also occur in post-NB patients. Renal neoplasms occurring in patients with a history of NB do not represent a single entity but a heterogenous group of RCCs. SDHB mutations do not explain the subset of nontranslocation RCCs with oncocytoid features; therefore, further studies are needed to clarify whether they may represent a distinct entity with unique molecular abnormalities or may belong to other emerging RCC subtypes.

Inflammatory myofibroblastic tumors in childhood.

Inflammatory myofibroblastic tumor (IMT) is a rare tumor of intermediate malignant potential that can occur anywhere in the body. Surgical resection is the principal treatment. We report on nine children diagnosed with IMT at our institution over a 10-year period. Presenting symptoms were reflective of tumor location. Complete surgical resection was curative. Local recurrence occurred in the presence of involved surgical margins. One patient with metastatic disease achieved long-term remission with chemotherapy alone. Severe inflammatory response and death occurred in one patient. The 3-year event free and overall survivals (OS) were 58 ± 20% and 89 ± 10% respectively.

Quantification of glypican 3, β‐catenin and claudin‐1 protein expression in hepatoblastoma and paediatric hepatocellular carcinoma by colour deconvolution

To identify an immunohistochemical panel for paediatric malignant epithelial liver tumours.

High dose alkylator therapy for extracranial malignant rhabdoid tumors in children.

Extracranial malignant rhabdoid tumor (MRT) is a rare pediatric cancer with a poor prognosis. The kidney is the most common site. Isolated reports have shown improvements in patient survival, but no specific treatment regimen has shown efficacy over others.

De novo congenital melanoma: analysis of 2 cases with array comparative genomic hybridization.

Congenital melanoma is extraordinarily rare, and 3 types have been described: transplacental metastases from the mother, de novo congenital melanoma, and melanoma occurring in association with a congenital melanocytic nevus. We describe 2 reports of array comparative genomic hybridization analysis of de novo congenital melanoma. The first patient was male, and the second was female; both had a scalp lesion present at birth, which grew quickly. The scalp mass from patient 1 showed a heterogeneous, anaplastic melanocytic neoplasm with large size and depth, high mitotic rate, ulceration, and necrosis. The scalp mass from patient 2 showed a broad melanocytic neoplasm with single cell and junctional nested proliferation at the dermal-epidermal junction and cellular, confluent aggregates of highly atypical melanocytes in the dermis with high mitotic rate. Patient 1 had lung and liver metastases detected by radiologic imaging and was treated with cisplatin, vinblastine, and dacarbazine but expired at the age of 5 months. Patient 2 developed a metastasis to the right neck with similar histologic features, and pulmonary metastases were also detected by imaging. Patient 2 is currently alive at the age of 4 years. Array comparative genomic hybridization analysis of the first case revealed loss of chromosomes 3p26.3-p21.31, 5p15.33-q23.1, 11q15.5-q13.2, 14 (complete deletion), and 15q11.1-q22.31. The second case displayed gains in chromosomes 1q21.1-q44, 2p25.3-p11.1, 2q11.1-q37.3, 6p25.3-p11.1, 7p22.3-p11.2, 7q11.1-q36.3, 8p23.3-p11.1, 8q11.1-q24.3, 9p24.3-p11.2, 9q12-q34.3, 11q13.2-q13.4, 13q11-q34, 18p11.32-p11.21, 19p13.3-p11, 19q11-q13.43, 20p13-p11.1, and 20q11.21-q13.33. In both cases, the presence of multiple chromosomal aberrations corroborated the diagnosis of melanoma.

Cardiac neural remodeling and its role in arrhythmogenesis

Cardiac innervation comes from both extrinsic and intrinsic sources. The extrinsic sympathetic innervation arises from the stellate ganglia and paravertebral sympathetic ganglia. The vagal nerves are sources of extrinsic parasympathetic nerves that innervate the heart. In addition to the extrinsic cardiac nervous system, there is also an extensive intrinsic cardiac nervous system1 that includes collections of ganglionated plexuses (or “ganglionated plexi”, or GP). Each GP contains both sympathetic and parasympathetic neurons that are associated with complex synaptology. In addition to efferent nerves, the GP also contains afferent nerves. While GP at different locations of the heart have different specialized functions (such as controlling sinoatrial node, atrioventricular node etc), they are also known to communicate among each other and with the extrinsic nervous system.