John A. Sandoval

Incidence, risk factors, and treatment patterns for deep venous thrombosis in hospitalized children: An increasing population at risk

OBJECTIVE The optimal prophylactic strategy and treatment regimen for deep venous thrombosis (DVT) in hospitalized pediatric patients is not clearly established. This study assessed the incidence, risk factors, and treatment patterns for DVT among pediatric patients admitted to a hospital ward. METHODS Children (aged <17 years) admitted to a single tertiary-care hospital during a 14-year period who developed or presented with DVT were retrospectively identified. Patient demographic and clinical data were analyzed retrospectively. Patients who developed DVT in the hospital were stratified according to the Wells clinical probability scoring system from criteria noted before the diagnosis. Treatment patterns and outcomes were evaluated between the two time intervals of 1992 to 2001 (group I) and 2002 to 2005 (group II). RESULTS Between 1992 and 2005, 358 children were evaluated for DVT, and 99 (52 boys, 47 girls) were admitted to the hospital and were determined to have DVT by confirmatory imaging. A prior DVT (12 total) was present in eight of the 21 patients admitted for DVT treatment; of the remaining, only seven received DVT prophylaxis on admission. In those developing a DVT, the inpatient clinical probability score was 21% (low), 40% (moderate), and 39% (high). The most common risk factor in those with prehospital DVT was a prior DVT (38%) or thrombophilic condition (33%), whereas inpatients had a central catheter (45%), with nearly 50% in the femoral vein. Children acquiring an inpatient DVT had concomitant severe respiratory (17%), oncologic (14%), and/or infectious (15%) diseases and required a prolonged intensive care unit (12.7 days) stay. Prehospital DVT was lower extremity predominant (90%) and statistically different from inpatient-acquired DVT (62%, P = .01). Treatment patterns between periods I and II revealed a trend to more low-molecular-weight heparin and less unfractionated heparin use (P = .09). Three patients died (one fatal pulmonary embolism). The number of recognized cases per 10,000 admissions increased from 0.3 to 28.8 from 1992 to 2005. CONCLUSION The incidence of DVT in hospitalized children is increasing. Those presenting with DVT typically have prior DVT, thrombophilia, or lower extremity disease. Our study suggests that children admitted with severe medical conditions who require a prolonged intensive care unit stay in addition to central venous access (especially via the femoral vein) should be considered candidates for DVT prophylaxis. A clinical probability scoring system alone cannot stratify patients sufficiently to forgo prophylaxis in hopes of a rapid clinical diagnosis. Childhood-specific level 1 trials aimed at determining guidelines for DVT prophylaxis are urgently required.

Annular Pancreas: Dramatic Differences Between Children and Adults

BACKGROUND Annular pancreas is rare; only 737 cases have been reported in the English literature. In addition, no large analysis has compared children and adults. Recently, prenatal diagnosis and advances in imaging have led to increased experience with this condition. STUDY DESIGN Data from 103 patients (48 children, 55 adults) with annular pancreas, managed from 1992 to 2006, were reviewed. Patients with isolated duodenal atresia, stenosis, or webs were excluded. RESULTS Median ages at diagnosis were 1 day in children and 47 years in adults. Annular pancreas was more common in girls and women (children, 58%; adults, 69%). Congenital anomalies were more frequent (p < 0.01) in children (71%) than in adults (16%); Down syndrome, cardiac, and intestinal anomalies were most common. Prenatal diagnosis was suspected in 56% of infants, and adults presented with pain (75%), vomiting (24%), pancreatitis (22%), or abnormal liver tests (11%). All children were managed with duodenal bypass. Children were more likely (p < 0.01) to require surgery for associated anomalies. In contrast, adults had fewer duodenal bypass procedures (24%) but more often required endoscopic pancreatobiliary procedures (67%), cholecystectomy (56%), and other pancreatobiliary surgery (20%; p < 0.01). Adults more commonly (p < 0.01) had pancreas divisum (29%) and pancreatobiliary neoplasia (11%). Five children (6%) with multiple anomalies died; all adults survived their operations. Late deaths occurred in 2 children (4%) with multiple anomalies and 3 adults (5%) with pancreatobiliary cancer. CONCLUSIONS Annular pancreas is associated with a spectrum of disease that differs in children and adults. Congenital anomalies are more common in children with annular pancreas; complex pancreatobiliary disorders and malignancy are more frequent in adults.

Three-dimensional neuroblastoma cell culture: Proteomic analysis between monolayer and multicellular tumor spheroids

IntroductionSolid tumors, such as neuroblastoma (NB), are associated with a heterogeneous cell environment. Multicellular tumor spheroid (MCTS) cultures have been shown to better mimic growth characteristics of in vivo solid tumors. Because tumor spheroid growth patterns may be quite different from standard two-dimensional culture systems, we sought to compare the protein expression profiles of two- and three-dimensional in vitro NB cultures, i.e., monolayers and MCTS.Materials and methodsHuman NB cells were grown as both monolayers and spheres. Nuclear and cytosolic proteins were analyzed for differentially secreted proteins by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and selected polypeptides were identified by mass spectrometry (LC-MS/MS).ResultsSeveral metabolic (transketolase, triosephosphate isomerase, pyruvate kinase M1/M2, alpha enolase, and phosphoglycerate mutase-1), cell stress response (heat shock proteins (HSP) 90, 70, and 60; antioxidant, thioredoxin), cell structure (septin 2, adenyl cyclase-associated protein-1), tubulin β-2 chain, actin, translationally controlled tumor protein and cofilin), signal transduction (peptidyl prolyl cis/trans isomerase A), biosynthetic (phosphoserine aminotransferase) and transport (cellular retinoic acid binding protein 1) polypeptides were overexpressed in spheroids. Several protein groups were differentially expressed between NB monolayers and spheroids.ConclusionThe altered proteins among NB spheroids may represent an important link between monolayer cell cultures and in vivo experiments and thus a more ideal in vitro culture system for determining the precise threedimensional microenvironment of NB.

Applications of emerging molecular technologies in glioblastoma multiforme

Glioblastoma multimorme (GBM) is the most common primary brain tumor in adults. Median survival from the time of diagnosis is less than a year, with less than 5% of patients surviving 5 years. These tumors are thought to arise through two different pathways. Primary GBMs represent de novo tumors, while secondary GBMs represent the malignant progression of lower-grade astrocytomas. Moreover, despite improvements in deciphering the complex biology of these tumors, the overall prognosis has not changed in the past three decades. The hope for improving the outlook for these glial-based malignancies is centered on the successful clinical application of current high-throughput technologies. For example, the complete sequencing of the human genome has brought both genomics and proteomics to the forefront of cancer research as a powerful approach to systematically identify large volumes of data that can be utilized to study the molecular and cellular basis of oncology. The organization of these data into a comprehensive view of tumor growth and progression translates into a unique opportunity to diagnose and treat cancer patients. In this review, we summarize current genomic and proteomic alterations associated with GBM and how these modalities may ultimately impact treatment and survival.

Proteomic Analysis of Neuroblastoma Microenvironment: Effect of the Host–Tumor Interaction on Disease Progression

BACKGROUND Children with advanced-stage neuroblastoma (NB) traditionally experience poor outcomes. Because early detection of advanced-stage disease may impact survival, finding new targets for early diagnosis is crucial. Evidence suggests the tumor microenvironment may have profound effects on cancer progression. METHODS As little is known concerning the NB-host microenvironment, this study applied proteomic techniques, two-dimensional polyacrylamide gel electrophoresis (2D PAGE) combined with matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry to determine protein differences between cell cultured NB and tumors grown in mice for 2, 4, and 5 wk. RESULTS We found an increase in proteins in cultured NB compared with implanted mouse tumors during tumor progression. Additionally, analyzing in vivo tumors to cultured NB, we observed less expressed proteins. However, 16 out of 19 proteins were of mouse origin, thus inferring host-derived factors contributing to tumor growth. CONCLUSION We show that the dynamic relationship between NB and host microenvironment is important for tumor growth and better understanding of this milieu maybe relevant towards finding unique approaches for identifying advanced-stage disease.

Dissecting the PI3K Signaling Axis in Pediatric Solid Tumors: Novel Targets for Clinical Integration.

Children with solid tumors represent a unique population. Recent improvements in pediatric solid tumor survival rates have been confined to low- and moderate-risk cancers, whereas minimal to no notable improvement in survival have been observed in high-risk and advanced-stage childhood tumors. Treatments for patients with advanced disease are rarely curative, and responses to therapy are often followed by relapse, which highlights the large unmet need for novel therapies. Recent advances in cancer treatment have focused on personalized therapy, whereby patients are treated with agents that best target the molecular drivers of their disease. Thus, a better understanding of the pathways that drive cancer or drug resistance is of critical importance. One such example is the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway, which is activated in many solid cancer patients and represents a target for therapy. PI3K/Akt/mTOR pathway activation has also been observed in tumors resistant to agents targeting upstream receptor tyrosine kinases (RTKs). Agents that target this pathway have the potential to shut down survival pathways, and are being explored both in the setting of pathway-activating mutations and for their ability to restore sensitivity to upstream signaling targeted agents. Here, we examine the role of the PI3K/Akt/mTOR pathway in pediatric solid tumors, review the novel agents being explored to target this pathway, and explore the potential role of the inhibition of this pathway in the clinical development of these agents in children.

Oxidative status in neuroblastoma: a source of stress?

AIM OF STUDY Reactive oxygen species have been shown to be initiators/promotors of tumorigenesis. Because evidence supports the role of increased oxidative stress in solid tumors, we sought to establish this relationship in neuroblastoma (NB). The aim of the study was to investigate the extent of oxidative DNA damage and antioxidative status in a progressive animal model of human NB. METHODS Tumors were induced in the left kidneys of nude mice by the injection of cultured human NB cells (10(6)). Blood was collected from tumor-bearing mice and controls at 2, 4, and 6 weeks. Peripheral blood leukocyte oxidative DNA damage was determined using single-cell gel electrophoresis (comet assay), and plasma antioxidant capacity was assessed by the Trolox equivalent antioxidant capacity method. MAIN RESULTS Levels of oxidative DNA damage in peripheral blood leukocytes of NB-bearing mice were increased by 166%, 110%, and 87% as compared with healthy controls at 2, 4, and 6 weeks, respectively. Plasma total antioxidant values for tumor-bearing mice were not significantly different from control mice. CONCLUSIONS Our results indicate an increase of oxidative stress in an animal model of human NB, especially in the early stages of growth. Yet, we did not observe an appreciable response in plasma antioxidant activity. Because an altered redox status has been implicated in tumor maintenance and progression, these findings support the notion of a complex oxidant-antioxidant imbalance contributing to NB growth.

Acute Phase Proteins as Cancer Biomarkers

Interactions between tumor cells and the host microenvironment have been shown to play a significant role in the initiation, progression, and invasiveness of human cancer. The complex changes in the tumor microenvironment have been shown to modulate the activation of the different arms of the host immune system including the acute phase response. Acute phase changes are mediated by several serum proteins [acute phase proteins (APP)] whose concentrations may increase (positive APP) or decrease (negative APP) as a result of varied clinical conditions, including cancer. To date, a body of evidence suggests APP may have a profound impact on cancer growth and appear to court a protective immune response by co-opting the body’s innate immune system. In this review, we discuss the impact of the host tumor response in relation to acute phase proteins and examine literature characterizing APP as helpful cancer biomarkers. Insights gained into the mechanism of action of acute-phase reactants towards malignancy and how they are induced could be exploited for the future development of more specific and targeted cancer biomarker strategies.