Management and Outcomes of Wilms Tumor With Suprarenal Intravascular Extension: A Pediatric Surgical Oncology Research Collaborative Study

OBJECTIVE

The purpose of this study was to describe management and outcomes from a contemporary cohort of children with Wilms tumor complicated by inferior vena caval thrombus.

BACKGROUND

The largest series of these patients was published almost 2 decades ago. Since then, neoadjuvant chemotherapy has been commonly used to manage these patients, and outcomes have not been reported.

METHODS

Retrospective review of 19 North American centers between 2009 and 2019. Patient and disease characteristics, management, and outcomes were investigated and analyzed.

RESULTS

Of 124 patients, 81% had favorable histology (FH), and 52% were stage IV. IVC thrombus level was infrahepatic in 53 (43%), intrahepatic in 32 (26%), suprahepatic in 14 (11%), and cardiac in 24 (19%). Neoadjuvant chemotherapy using a 3-drug regimen was administered in 82% and postresection radiation in 90%. Thrombus level regression was 45% overall, with suprahepatic level showing the best response (62%). Cardiopulmonary bypass (CPB) was potentially avoided in 67%. The perioperative complication rate was significantly lower after neoadjuvant chemotherapy [(25%) vs upfront surgery (55%); P =0.005]. CPB was not associated with higher complications [CPB (50%) vs no CPB (27%); P =0.08]. Two-year event-free survival was 93% and overall survival was 96%, higher in FH cases (FH 98% vs unfavorable histology/anaplastic 82%; P =0.73). Neither incomplete resection nor viable thrombus cells affected event-free survival or overall survival.

CONCLUSIONS

Multimodal therapy resulted in excellent outcomes, even with advanced-stage disease and cardiac extension. Neoadjuvant chemotherapy decreased the need for CPB to facilitate resection. Complete thrombectomy may not always be necessary.

Comparison of Outcomes Between Surveillance Ultrasound and Completion Lymph Node Dissection in Children and Adolescents With Sentinel Lymph Node-Positive Cutaneous Melanoma

OBJECTIVE

To determine the impact of nodal basin ultrasound (US) surveillance versus completion lymph node dissection (CLND) in children and adolescents with sentinel lymph node (SLN) positive melanoma.

BACKGROUND

Treatment for children and adolescents with melanoma are extrapolated from adult trials. However, there is increasing evidence that important clinical and biological differences exist between pediatric and adult melanoma.

METHODS

Patients ≤18 years diagnosed with cutaneous melanoma between 2010 and 2020 from 14 pediatric hospitals were included. Data extracted included demographics, histopathology, nodal basin strategies, surveillance intervals, and survival information.

RESULTS

Of 252 patients, 90.1% (n=227) underwent SLN biopsy (SLNB), 50.9% (n=115) had at least 1 positive node. A total of 67 patients underwent CLND with 97.0% (n=65/67) performed after a positive SLNB. In contrast, 46 total patients underwent US observation of nodal basins with 78.3% (n=36/46) of these occurring after positive SLNB. Younger patients were more likely to undergo US surveillance (median age 8.5 y) than CLND (median age 11.3 y; P =0.0103). Overall, 8.9% (n=21/235) experienced disease recurrence: 6 primary, 6 nodal, and 9 distant. There was no difference in recurrence (11.1% vs 18.8%; P =0.28) or death from disease (2.2% vs 9.7%; P =0.36) for those who underwent US versus CLND, respectively.

CONCLUSIONS

Children and adolescents with cutaneous melanoma frequently have nodal metastases identified by SLN. Recurrence was more common among patients with thicker primary lesions and positive SLN. No significant differences in oncologic outcomes were observed with US surveillance and CLND following the identification of a positive SLN.

In Vivo Raman Spectroscopy Reveals Biochemical Composition of the Esophageal Tissue in Pediatric Eosinophilic Esophagitis

INTRODUCTION

Biochemical alterations in the esophagus of patients with eosinophilic esophagitis (EoE) are poorly understood. We used Raman spectroscopy through a pediatric endoscope to identify key Raman features reflective of the esophageal biochemical composition to differentiate between children with EoE from non-EoE controls and between children with active (aEoE) and inactive EoE (iEoE).

METHODS

Spectral measurements were obtained using a customized pediatric endoscope-compatible fiber-optic Raman probe in real time during an esophagogastroduodenoscopy. Chemometric analysis was performed to identify key Raman features associated with EoE. Pearson correlation analysis was used to assess relationship between the key Raman features and EoE activity indices. Their diagnostic utility was ascertained using the receiver operator characteristic curve analysis.

RESULTS

Forty-three children were included in the study (EoE = 32 [74%] and non-EoE control = 11 [26%]; aEoE = 20 [63%] and iEoE = 12 [37%]). Raman intensities assigned to lipids, proteins, and glycogen:protein ratio accurately distinguished children with EoE from those without EoE and aEoE from iEoE. They significantly correlated with EoE activity indices. The Raman peak ratio for lipids had 90.6% sensitivity, 100% specificity, and an area under the curve of 0.95 to differentiate children with EoE from non-EoE controls. The glycogen:protein ratio had 70% sensitivity, 91.7% specificity, and an area under the curve of 0.75 to distinguish children with aEoE from iEoE.

DISCUSSION

Real-time intraendoscopy Raman spectroscopy is an effective method for identifying spectral markers reflective of the esophageal biochemical composition in children with EoE. This technique may aid in the diagnosis and monitoring of EoE and help to elucidate EoE pathogenesis.

Proton Pump Inhibitors Modulate Gene Expression Profile in Esophageal Mucosa and Microbiome

OBJECTIVE

Proton pump inhibitors (PPIs) are commonly used to manage children with upper gastrointestinal symptoms and without a formal diagnosis. We investigated the effect of PPIs on esophageal mucosal transcriptome and active microbiota in children with normal esophagi. Furthermore, we examined whether the differences in host esophageal mucosal gene expression were driven by an underlying esophageal epithelial cell type composition.

METHODS

Using metatranscriptomics, the host transcriptional and active microbial profiles were captured from 17 esophageal biopsy samples (PPI naïve [PPI-], n = 7; PPI exposed [PPI+], n = 10) collected from children without any endoscopic and histologic abnormalities in their esophagus (normal esophagus). Deconvolution computational analysis was performed with xCell to assess if the observed epithelial gene expression changes were related to the cell type composition in the esophageal samples.

RESULTS

The median (IQR) age of our cohort was 14 years (12-16) with female (63%) preponderance. Both groups were similar in terms of their demographics and clinical features. Compared with PPI-, the PPI+ had upregulation of 27 genes including the MUC genes. The cell type composition was similar between the PPI- and PPI+ groups. Prevotella sp and Streptococcus sp were abundant in PPI+ group.

CONCLUSIONS

In children with normal esophagus, PPI exposure can be associated with upregulation of esophageal mucosal homeostasis and epithelial cell function genes in a cell-type independent manner, and an altered esophageal microbiome. Additional studies are warranted to validate our findings and to investigate the causal effect of PPIs on the normal esophageal epithelium and microbial communities.

Hashimoto's Thyroiditis and the Risk of Papillary Thyroid Cancer in Children

The association between Hashimoto's thyroiditis (HT) and pediatric thyroid cancer is controversial. Most studies examining this connection have been based on adults, and larger studies in children are lacking. We performed a retrospective study of all sequential pediatric patients who underwent a thyroidectomy for a neoplasm at our institution over a twenty-year period in order to explore the link between HT and pediatric thyroid cancer. A total of 153 patients, median age 16.5 (interquartile range [IQR] 14.2-18.3) years, underwent thyroid surgery for a neoplasm. Patients were mainly female (80%) and White (84%). Median follow-up was 58.6 (IQR 20.7-105.4) months. Thirty-five (23%) patients had HT. Patients who underwent thyroid surgery and had HT were more likely to harbor a malignant neoplasm (p = 0.05); specifically, papillary thyroid carcinoma (PTC, p = 0.02). There was a difference in the distribution of HT among the subtypes of PTC (p = 0.03). Despite this, there was no difference in terms of survival between patients with/without HT. In conclusion, children with a thyroid malignancy, specifically, PTC, are more likely to have HT. The association between HT and pediatric PTC appears to be subtype-specific but does not seem to affect patient survival.

Clinicopathologic Features of Severe Acute Hepatitis Associated With Adenovirus Infection in Children

A recent increase in reports of severe acute hepatitis of unknown etiology in children is under investigation. Although adenovirus has been frequently detected, its role remains unclear, and systematic histopathologic analysis is lacking. We conducted a retrospective study of 11 children hospitalized between October 2021 and May 2022 with unexplained acute hepatitis and concurrent adenovirus infection. Liver biopsies collected shortly after admission demonstrated moderately to severely active hepatitis in 8/11 (73%) cases, characterized by marked portal mixed inflammation, moderate-to-severe interface activity, and milder lobular inflammation. Clusters of plasma cells were present in 6/11 (55%) cases, mimicking autoimmune hepatitis. Semiquantitative scoring of 17 discrete histologic features found that greater degrees of portal inflammation, interface activity, bile duct injury, bile ductular reaction, lobular inflammation, Kupffer cell activation, and hepatocyte focal necrosis were significantly more common in these cases in comparison to the control group of unexplained acute severe hepatitis without adenovirus infection. Liver biopsy immunohistochemistry was negative for adenovirus in all cases. Polymerase chain reaction testing of liver tissue was positive for the enteric adenovirus serotypes 41 (species F) in 10/11 (91%) cases. An immunoprofile study of hepatic infiltrating lymphocytes in 1 patient revealed the presence of large numbers of CD3 + and CD4 + lymphocytes. Nine patients received supportive treatment without steroids and recovered without the need for liver transplantation. In summary, liver injury in children with severe acute hepatitis and adenovirus infection is characterized by a hepatitic pattern that resembles severe autoimmune hepatitis and may represent an immune-mediated process associated with viral infection.

Outcomes and Histological Variations of Neuroblastoma and Ganglioneuroblastoma with Paraneoplastic Syndromes

BACKGROUND

Neuroblastomas are the most common extracranial solid malignancy in children with variable manifestations and complications depending on the presence of paraneoplastic syndromes.

MATERIALS AND METHODS

We performed a single institution retrospective cohort study of all patients less than 18 years old diagnosed with neuroblastoma or ganglioneuroblastoma between January 2002 and July 2022. Patients were identified through the pathology and cancer registry and cross-referenced with pediatric records. Patient demographics, clinical presentation, treatment, and outcomes were collected. A univariate descriptive analysis of the collected data was conducted.

RESULTS

In our study period, 130 children were diagnosed with neuroblastoma, and 15 were diagnosed with ganglioneuroblastoma. There were 12 children with a paraneoplastic syndrome identified, 8 with NBL and 4 with ganglioneuroblastoma (GNBL). The average age at diagnosis was 22 months. All but 1 underwent resection prior to treatment of paraneoplastic syndrome, and 4 children required neoadjuvant therapy. Neurological complications were the most common with 10 children (83%). The average time from symptom onset to diagnosis was 0.7 months. Eight children had complete resolution of their symptoms after treatment and resection, 2 children recently started treatment within a year, 1 had partial resolution, and 1 died during treatment. The presence of tumor-infiltrating lymphocytes occurred in 4 children with neurologic paraneoplastic syndromes. Six children had neuropil rich tumors.

CONCLUSION

The histological profile of paraneoplastic syndromes of neuroblastoma and ganglioneuroblastoma and their treatment across a single institution can be highly variable. The presence of tumor-infiltrating lymphocytes and neuropil may have an impact on paraneoplastic pathology.

Minimally invasive adnexa-sparing surgery for benign ovarian and paratubal masses in children

BACKGROUND

The precision of minimally invasive surgery (MIS) to resect benign ovarian and paratubal masses while preserving adnexa in children is unclear. This study evaluated the integrity of laparoscopy to spare adnexa while resecting benign pathologies in children.

METHODS

The institutional pathology database was queried to identify patients aged 18 years and younger having any ovarian or tubal lesion resected at a comprehensive children's hospital between 2006 and 2021. Adnexa-sparing surgery was defined as preserving both the ovary and tube from which the lesion was resected. Postoperative ultrasounds were reviewed to document ovarian follicles, blood flow, volumes, and lesion recurrence.

RESULTS

Adnexal preservation was implemented in 168 of 328 pathological resections. MIS approach was used in 149 cases. Median age was 13.4 [11.0-15.3]. Among sparing surgeries, MIS associated with benign pathology, shorter operative time (median minutes: 78 MIS [59-111.5]; 130 open [92.8-149.8]; 174 MIS-to-open [132.8-199.5]; p = 0.010), and reduced hospital stay (median days: 1 MIS (Lindfors, 1971; Lovvorn III et al., 1998) [1-2]; 2 open [2-2.9], 2 MIS-to-open [1-3.3]; p = 0.001). Postoperative ovarian volume ipsilateral to the MIS procedure (median, 7.6 ml [4.3-12.1]) was relatively smaller than the contralateral ovary (median, 9.1 ml [5.5-15.0]). Blood flow was documented to the ovary in 70/94 (74.4%) of patients after MIS adnexal-sparing surgery. Distinct follicles were detected in 48/74 (64.8%) of post-menarchal patients after MIS adnexal-sparing surgery. Five ovarian cysts recurred.

CONCLUSIONS

MIS preserves adnexa reliably, with postoperative ovarian follicles and blood flow detected in most patients, and maintains ∼80% of contralateral volume, while achieving definitive tumor resection.

LEVEL OF EVIDENCE

III.

Exploiting embryonic niche conditions to grow Wilms tumor blastema in culture

Introduction

Wilms Tumor (WT), or nephroblastoma, is the most common pediatric kidney cancer. Most WTs display a “favorable” triphasic histology, in which the tumor is comprised of blastemal, stromal, and epithelial cell types. Blastemal predominance after neoadjuvant chemotherapy or diffuse anaplasia (“unfavorable” histology; 5-8%) portend a worse prognosis. Blastema likely provide the putative cancer stem cells (CSCs), which retain molecular and histologic features characteristic of nephron progenitor cells (NPCs), within WTs. NPCs arise in the metanephric mesenchyme (MM) and populate the cap mesenchyme (CM) in the developing kidney. WT blastemal cells, like NPCs, similarly express markers, SIX2 and CITED1. Tumor xenotransplantation is currently the only dependable method to propagate tumor tissue for research or therapeutic screening, since efforts to culture tumors in vitro as monolayers have invariably failed. Therefore, a critical need exists to propagate WT stem cells rapidly and efficiently for high-throughput, real-time drug screening.

Methods

Previously, our lab developed niche conditions that support the propagation of murine NPCs in culture. Applying similar conditions to WTs, we assessed our ability to maintain key NPC "stemness" markers, SIX2, NCAM, and YAP1, and CSC marker ALDHI in cells from five distinct untreated patient tumors.

Results

Accordingly, our culture conditions maintained the expression of these markers in cultured WT cells through multiple passages of rapidly dividing cells.

Discussion

These findings suggest that our culture conditions sustain the WT blastemal population, as previously shown for normal NPCs. As a result, we have developed new WT cell lines and a multi-passage in vitro model for studying the blastemal lineage/CSCs in WTs. Furthermore, this system supports growth of heterogeneous WT cells, upon which potential drug therapies could be tested for efficacy and resistance.

Slow-Growing Pediatric Neck Mass

An 11-year-old girl with no significant medical history was referred to the pediatric otolaryngology department for a painless, left-sided neck mass that had been slowly enlarging for 8 months. What is your diagnosis?

Antiferromagnetic Blume-Capel model of the disordered Fe-Mn-Al ternary system

The magnetic properties and thermodynamical description of the Fe-Mn-Al ternary alloy are studied using the spin 1 antiferromagnetic Blume-Capel (BC) model by the pair approximation based on the Gibbs-Feymann-Bogoliubov inequality for the free energy. The values of the spin operator are +1 for ferromagnetic interaction (Fe-Fe), -1 for the antiferromagnetic one (Mn-Mn, Mn-Fe), and 0 for the magnetic diluter (corresponding to Al). The BC model with antiferromagnetic (AF) next-nearest-neighbor coupling better accurately fit the mean hyperfine field experimental data obtained by Mössbauer spectroscopy. Considering the crystalline field, the predicted temperature as a function of the Al concentration phase diagram, for the fcc lattice, from the numerical solution is remarkably good and significantly improves the traditional Ising and random-site Ising models.

Elective choledochal cyst excision is associated with improved postoperative outcomes in children

PURPOSE

The majority of pediatric patients with choledochal cysts (CDC) are symptomatic prior to undergoing CDC excision. This study investigated the impact of surgical timing of CDC excision on postoperative outcomes among children.

METHODS

We performed a retrospective review of 59 patients undergoing open CDC excision with Roux-Y hepaticojejunostomy between 2000 and 2020. Patients were grouped based on whether they underwent an electively scheduled or urgent CDC excision, as defined as CDC excision within the same admission due to CDC-related symptoms. Patient characteristics and perioperative data were compared between the two groups.

RESULTS

Patients who underwent an elective surgery were older, had more Todani-type 1 CDC, and had decreased postoperative hospital length of stay and opioid use compared to patients who underwent CDC excision within the same admission due to CDC-related symptoms. No significant differences emerged regarding postoperative complications. Multivariable analysis showed that elective cyst excision (HR = 0.55, p = 0.04; HR = 0.59, p = 0.008) and type 1 CDC (HR = 0.32, p = 0.03; HR = 0.12, p < 0.001) were independently associated with decreased opioid use and postoperative hospital length of stay.

CONCLUSIONS

Elective CDC excision is associated with shortened hospital stay and decreased opioid use among children compared to patients who undergo a CDC excision during the same admission for CDC-related symptoms.

Intraoperative Ultrasound Guided Laparoscopic Spleen-Preserving Distal Pancreatectomy for Primitive Neuroendocrine Tumors in a Pediatric Patient with MEN-1

This case details the presentation and surgical management of a 15-year-old male patient with multiple endocrine neoplasia syndrome type 1 (MEN1) who required distal pancreatectomy for multiple nonfunctional pancreatic tumors. An intraoperative ultrasound was utilized to allow for proper location of the distal pancreatectomy, as well as visualization of the splenic vessel relationships and to ensure all lesions were contained within the specimen. Pathology demonstrated 5 well-differentiated neuroendocrine tumors with no evidence of malignancy. This case utilized innovative technology and a multidisciplinary approach in a challenging case to achieve a safe minimally invasive resection. The use of ultrasound intraoperatively provided confidence that all lesions had been identified, as well as demonstration of safe planes separate from the nearby vasculature.

Temperature-Dependent Potential for the Molecular Dynamics of the superionic conductor β-PbF2

Molecular dynamic (MD) calculations were performed to investigate the thermodynamic and structural properties of lead fluoride (PbF₂) by using a proposed inter-ionic temperature-dependent potential. This potential allows calculating with high precision the linear thermal expansivity and the lattice parameter as a temperature function. In addition, the potential can be represented as a sum of two contributions, a temperature-independent potential added to another temperature-dependent potential, considered last as a correction justified by the one-dimensional Newtonian quantum equation. Two fitting regions were considered, the first region from 300 to 700 K and the other one from 700 to 900 K. These regions arise naturally due to the smooth and continuous transition that PbF₂ undergoes until it reaches the superionic state and, allows us to model with high precision the anomaly in the dependence of the lattice parameter with the temperature of this material, a feature that until now under the molecular dynamic method has not been studied. These results are all in good agreement with the experimental measurements.

Oncologic Fidelity of Minimally Invasive Surgery to Resect Neoadjuvant-Treated Wilms Tumors

Background

The Children's Oncology Group recommends upfront resection of Wilms tumor (WT), however, unique scenarios warrant neoadjuvant chemotherapy and delayed resection. We hypothesized that in the context of neoadjuvant chemotherapy, minimally invasive surgery (MIS) to resect WT achieves equivalent oncologic fidelity and better maintains therapy schedules.

Methods

A retrospective analysis of WT treated between 2010-2021 at a free-standing children's hospital was performed. Patient and disease specific characteristics were collected, and pre-resection tumor volumes (TV) were calculated. Impact of MIS or open resection on oncologic fidelity and time to resume chemotherapy was analyzed.

Results

For the study period, 62 patients were treated for 65 WT, and 14 patients (22.6%) received neoadjuvant chemotherapy to treat 17 WT (26.2%): 7 Stage I (all predisposition syndromes), 2 stage III, 7 stage IV, and 1 stage V (bilateral). MIS was utilized to resect 6 WT from 5 patients. For partial nephrectomy, pre-resection TV was 0.38 ml if MIS and 10.38 ml if open ( P = .025). For radical nephrectomy, pre-resection TV was 31.58 ml if MIS and 175.00 ml if open ( P = .101). No significant differences between surgical approach were detected regarding pathologic variables or survival. Epidural use was significantly greater with open procedures ( P = .001). Length of stay was 2.00 days after MIS compared to 6.00 for open resection ( P = .004). Time to resume chemotherapy was 7.00 days after MIS versus 27.00 for open ( P = .004).

Conclusion

After neoadjuvant chemotherapy for WT, MIS partial and radical nephrectomies achieved equivalent oncologic fidelity, reduced epidural use and post-operative stays, and better maintained adjuvant therapy timelines when compared to open resections.

Laparoscopic Resection of Pediatric Solid Pseudopapillary Tumors of the Pancreas

BACKGROUND

Solid pseudopapillary tumors (SPTs) of the pancreas arise rarely in children, are often large, and can associate intimately with splenic vessels. Splenic preservation is a fundamental consideration when resecting distal SPT. Occasionally, the main splenic vessels must be divided to resect the SPT with negative margins, but the spleen can be preserved if the short gastric vessels remain intact (ie, Warshaw procedure). The purpose of this study was to evaluate outcomes of distal pancreatectomy (DP) for SPT in children and to highlight 2 cases of splenic preservation using the Warshaw procedure.

METHODS

Patients 19 years and younger who were treated at a single children's hospital between July 2004 and January 2021 were examined. Patient characteristics were collected from the electronic medical record. A pediatric radiologist calculated SPT and pre- and post-operative (ie, non-infarcted) splenic volumes.

RESULTS

Eleven patients received DP for SPT. Six DPs were performed open and 5 laparoscopically. The spleen was preserved in 3 open and 4 laparoscopic DPs. A laparoscopic Warshaw procedure was performed in 2 patients. Laparoscopic resection associated with less frequent epidural use (P = .015), shorter time to full diet (P = .030), and post-operative length of stay (P = .009), compared to open resection. Average residual splenic volume after the laparoscopic Warshaw procedure was 70% of preoperative volume.

DISCUSSION

Laparoscopic DP for pediatric SPT achieved similar oncologic goals to open resection. Splenic preservation was feasible with laparoscopy in most cases and was successfully supplemented with the Warshaw procedure, which has not been previously reported for SPT resection in children.

Factors Associated With Adequate Lamina Propria Sampling and Presence of Lamina Propria Fibrosis in Children with Eosinophilic Esophagitis

BACKGROUND & AIMS

Esophageal biopsies in children with eosinophilic esophagitis (EoE) are often inadequate for assessment of lamina propria and lamina propria fibrosis (LPF). For children with EoE, little is known about the factors associated with adequate lamina propria (aLP) sampling or the relationship among epithelial features in esophageal biopsies with and without LPF. We aimed to evaluate aLP in esophageal biopsies from children with and without EoE, identify factors associated with aLP and LPF, and examine the relationship among epithelial features in biopsies with and without LPF in children with EoE.

METHODS

In a retrospective study, we analyzed clinical, endoscopic, and histologic data from 217 children (124 with EoE and 94 without EoE [controls]) using descriptive statistics, logistic regression, Spearman's correlation, and receiver operating characteristic curve analysis. Active and inactive EoE were defined per the 2011 consensus guidelines.

RESULTS

aLP was observed in biopsies from higher proportion of children with EoE (69%) than controls (31%) (P = .0001). Active EoE was independently associated with aLP (adjusted odds ratio [aOR], 4.23; 95% CI, 1.00-18.13; P = .05). Patient sex (aOR for boys, 8.37; 95% CI, 1.23-56.74; P = .03) and peak eosinophil count (aOR, 1.02; 95% CI, 1.01-1.04; P = .01) were independently associated with LPF. Epithelial features were strongly interrelated in biopsies with LPF, and the presence of specific epithelial features was associated with LPF.

CONCLUSIONS

aLP was observed in a higher proportion of esophageal biopsies from children with EoE than controls. EoE status, patient sex, and peak eosinophil count were associated with aLP sampling and LPF. Given the intricate relationship between epithelial features and LPF, computational models can be developed to identify children with esophageal biopsies without aLP who are at risk for LPF.

Changes in FXR1 expression after Chemotherapy for Rhabdomyosarcoma

BACKGROUND

Rhabdomyosarcoma (RMS) arises from abnormal muscle development. We reported previously that Fragile-X-Related 1 (FXR1), essential to normal myogenesis, was highly expressed in RMS relative to other embryonal tumors. This current study explored FXR1 expression across RMS disease characteristics and treatment response.

METHODS

RMS patients ≤18 years (1980-2019; n = 152) were categorized according to tumor histology, PAX/FOXO1 translocation, and vital status. FXR1 protein expression was compared before and after chemotherapy. Impact of FXR1 expression on relapse-free (RFS) and overall survival (OS) was analyzed.

RESULTS

FXR1 was most intensely expressed in the cytosol of undifferentiated rhabdomyoblasts. At diagnosis, FXR1 expression was ubiquitous and strong across all disease characteristics and foremost associated with worse RFS in translocation-positive patients (p = 0.0411). Among embryonal and translocation-negative RMS, survivors showed a significantly greater decrease in FXR1 expression after chemotherapy (p < 0.001) compared to decedents (p = 0.8). In contrast, alveolar and translocation-positive RMS specimens showed insignificant changes in FXR1 expression across therapy. As expected, alveolar histology, translocation presence, stage, and clinical group associated with worse survival.

CONCLUSIONS

FXR1 was expressed strongly across RMS specimens at diagnosis regardless of disease or patient characteristics, and particularly in undifferentiated cells. Reduction in FXR1 expression after chemotherapy associated with improved survival for embryonal and translocation-negative RMS patients.

Key histopathologic features in idiopathic noncirrhotic portal hypertension: an interobserver agreement study and proposal for diagnostic criteria

Histologic features of idiopathic noncirrhotic portal hypertension (INCPH), loosely termed as obliterative portal venopathy (OPV), are heterogenous, often subtle, and overlap with other entities. To this date, no consensus histopathologic diagnostic criteria have been established for INCPH. For these reasons, rendering a reproducible consensus histologic diagnosis of OPV on a liver biopsy may often be challenging even for experienced hepatopathologists. We report herein a two-phase interobserver agreement study on the diagnosis of OPV and assessed the relative value of histologic features in 104 liver biopsies in distinguishing between INCPH and non-INCPH with the goal to obtain a consensus on specific practical diagnostic criteria. Six hepatopathologists blinded to clinical information and original pathologic diagnosis reviewed internet-based case study sets with high-resolution whole-slide images. The initial interobserver agreement on OPV was expectedly low, but significantly improved (moderate agreement in most categories) upon adopting a consensus view recognizing portal vein sclerosis as the only strong independent histologic predictor for INCPH, and that contrary to the conventional view, aberrant portal/periportal vessels does not significantly contribute to the positive assignment of OPV status. We propose a three-tiered classification with diagnostic criteria to facilitate the histologic assignment of OPV status for the evaluation of INCPH. Furthermore, we have validated the performance of the proposed criteria either based on histology alone or coupled with clinicopathologic correlation. This classification may aid in practical histologic assessment of liver biopsies with or without portal hypertension and help to improve diagnostic consistency and accuracy.

Correlation of endoscopic signs and mucosal alterations in children with eosinophilic esophagitis

BACKGROUND AND AIMS

In children with eosinophilic esophagitis (EoE), the relationship among the endoscopic reference score (EREFS), the histology scoring system (EoEHSS), and the peak eosinophil count (PEC) is incompletely described. Our aim was to determine the relationship among EREFS, EoEHSS, and PEC and develop a predictive model using components of EREFS and EoEHSS for EoE activity.

METHODS

We analyzed 189 paired EREFSs, EoEHSSs, and PECs. Active EoE (aEoE; n = 98) was defined as ≥15 eosinophils per high-power field and inactive EoE (iEoE; n = 91) as <15 eosinophils per high-power field. Spearman correlation (r) with Bonferroni correction was used to assess the relationship between EREFS, EoEHSS and PEC, and a back-transformed average Fisher test was used to determine the statistical significance of the differences. Receiver operating characteristic analysis was used to develop the predictive model.

RESULTS

The relationship between total EREFS and EoEHSS was modest (r = 0.61) but significantly stronger than the correlation between total EREFS and PEC (r = 0.55; P = .04). The relationship between total EREFS and EoEHSS tended to be stronger in aEoE compared with iEoE (r = 0.41 vs 0.24; P = .09). Compared with EREFS, EoEHSS had a significantly higher area under the curve (0.78 vs 0.92; P = .04) to predict aEoE. A combination of furrows, eosinophilic inflammation, basal cell hyperplasia, eosinophilic abscess, and dilated intercellular spaces had an area under the curve of 0.97, accuracy of 98%, sensitivity of 97%, and specificity of 98% to predict aEoE.

CONCLUSIONS

The endoscopy score modestly correlates with the histologic scoring system. Thus, the endoscopy score is not a reliable marker of tissue involvement in EoE. A panel of individual endoscopic and histologic signs hold promise to accurately predict EoE activity.

Noninvasive Follicular Thyroid Neoplasm With Papillary-Like Nuclear Features in Children: An Institutional Experience and Literature Review

BACKGROUND

Papillary thyroid carcinoma (PTC) in children has a distinctive set of clinicopathologic features and molecular signature compared to their adult counterparts. The recent recommendation to reclassify encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC) without invasion as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is based on evidence derived almost exclusively from studies in adults. Clinicopathologic studies restricted to pediatric NIFTP are limited.

METHODS

We retrospectively analyzed all pediatric PTC and NIFTP diagnosed and treated in our institution from 1999 to 2016 (n = 31).

RESULTS

Using recently published consensus diagnostic criteria, we identified 3 NIFTP and 2 infiltrative follicular variants of papillary thyroid carcinoma (FVPTC) among 31 cases. Two of the NIFTP cases were initially diagnosed as EFVPTC. All 3 patients with NIFTP had unifocal tumors of lower American Joint Committee on Cancer (AJCC) classification (T2 or lower) and were free of lymph node or distant metastasis. Total (n = 1) or completion (n = 2) thyroidectomy was performed in all cases, and only 1 NIFTP patient received subsequent radioablative therapy. No residual or recurrent disease has been observed during follow-up (15-138 months) in patients with NIFTP.

CONCLUSIONS

Our experience with NIFTP in children is similar to outcomes reported in adult studies, suggesting that pediatric NIFTP behave indolently as evidenced by the absence of local recurrence in our cohort.

Dataset for correlation in γ-RbAg4I5 between ionic conductivity relaxation and specific heat

Using the ac-calorimetry technique and the electric modulus formalism for analysis of ionic conductivity relaxation in crystalline γ-RbAg₄I₅, close to the γ to β phase transition at 120 K, the temperature derivative of microscopic interaction energy for a single-mobile ion is proportional to the specific heat. The two different experimental techniques show that cooperative behavior drives the phase transition at 120 K (obey the same mechanism).

Identification of α-N-catenin as a novel tumor suppressor in neuroblastoma

The lost expression of α-catenin has been found in cancers, and reinstalling α-catenin inhibits tumor growth. Here we hypothesized that the α-N-catenin, a homologous member of α-catenin and neural-specific expressed, functions as a novel tumor suppressor in neural crest-derived tumor, neuroblastoma. We correlated CTNNA2 (encodes α-N-catenin) expression to neuroblastoma disease relapse-free survival probability using publicly accessible human neuroblastoma datasets in R2 platform. The result showed that it negatively correlated to relapse-free survival probability significantly in patients with neuroblastoma with non-MYCN amplified tumor. Conversely, overexpressing CTNNA2 suppressed the neuroblastoma cell proliferation as measuring by the clonogenesis, inhibited anchorage-independent growth with soft agar colony formation assay. Forced expression of CTNNA2 decreased cell migration and invasion. Further, overexpression of CTNNA2 reduced the secretion of angiogenic factor IL-8 and HUVEC tubule formation. Our results show, for the first time, that α-N-catenin is a tumor suppressor in neuroblastoma cells. These findings were further corroborated with in vivo tumor xenograft study, in which α-N-catenin inhibited tumor growth and reduced tumor blood vessel formation. Interestingly, this is only observed in SK-N-AS xenografts lacking MYCN expression, and not in BE(2)-C xenografts with MYCN amplification. Mechanistically, α-N-catenin attenuated NF-κB responsive genes by inhibiting NF-κB transcriptional activity. In conclusion, these data demonstrate that α-N-catenin is a tumor suppressor in non-MYCN-amplified neuroblastomas and it inhibits NF-κB signaling pathway to suppress tumor growth in human neuroblastomas. Therefore, restoring the expression of α-N-catenin can be a novel therapeutic approach for neuroblastoma patients who have the deletion of CTNNA2 and lack of MYCN amplification.

Abstract LB-041: Targeting AKT2 and ERK decline the drug/radiation resistance in neuroblastoma

Introduction: Neuroblastoma is highly heterogeneous, containing cancer cells with very different molecular characteristics. Activation of distinct signal transduction pathways can induce neuroblastoma cells to transform cells with neuronal, chromaffin, or schwannian phenotypes, further supporting the existence of cancer stem cells. We previously demonstrated that AKT2 plays critical roles in regulation of neuroblastoma tumorigenesis. Here we hypotheize that targeting AKT2 would block the signal transduction pathways enhanced in drug/radiation resistant neuroblastoma cancer stem cells.

Methods: We generated cisplatin (CDDP) resistant and radiation (Rad) resistant neuroblastoma cells under the treatment or irradiation with a concentration of IC 50 of CDDP and 137Cs irradiator respectively. Cell viability was assessed with CCK-8 kit daily. Extreme limiting dilution analysis (ELDA) was performed for quantification of tumor sphere formation. Immunoblotting detected the expression of stem cell markers CD133, Sox2, ALDH, ALDH, Nestin, Oct4 and Nanog, as well as survival signaling pathway key molecules AKT2, MAPK and P38 MAPK.

Results: We founded that two important cell proliferation and survival signaling pathways mTOR, downstream of AKT2 and MAPK enhanced in CDDP-resistant and Rad-resistant neuroblastoma cells. Blocking these two pathways with chemical inhibitors, CCT128930, AKT2 selective inhibitor and PD98059, MEK inhibitor decreased cell proliferation, angiogenesis, cell migration and soft agar conoly growth in these resistant cells. We further demonstrated that these resistant cells showed higher capacity of sphere-forming with increased expression of stem cell markers CD133, Sox2, ALDH, ALDH, Nestin, Oct4 and Nanog. Improtantly, the sphere formation of these resistant cells is sensitive to the inhibitors of AKT2 and MAPK.

Conclusion: Our results suggest that selected CDDP-resistant and radiation-resistant neuroblastoma cells might serve as an useful tool to improve understanding of the molecular mechanisms of therapeutic resistance and develop more effective novel treatment strategies, and further to reaching better clinical outcomes of patients with neuroblastoma.

Citation Format: Kwang Woon Kim, Dai Chung, Jingbo Qiao, Julia Kim, Camille Poewers, Hernan Correa, Kyungho Park, Sora Lee. Targeting AKT2 and ERK decline the drug/radiation resistance in neuroblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-041.

FXR1 expression domain in Wilms tumor

BACKGROUND/PURPOSE

Wilms tumor (WT) is the most common childhood kidney cancer globally. Our prior unbiased proteomic screen of WT disparities revealed increased expression of Fragile X-Related 1 (FXR1) in Kenyan specimens where survival is dismal. FXR1 is an RNA-binding protein that associates with poor outcomes in multiple adult cancers. The aim of this study therefore was to validate and characterize the FXR1 expression domain in WT.

METHODS

Quantitative FXR1 gene expression was compared between WT, adjacent, adult, and fetal kidney specimens. The cellular and subcellular expression domain of FXR1 was characterized across these tissues using immunoperoxidase staining. RNA-sequencing of FXR1 was performed from WT and other pediatric malignancies to examine its broader target potential.

RESULTS

FXR1 was detected in all clinical WT specimens evaluated (n = 82), and as a result appeared independent of demographic, histology, or adverse event. Specific cytosolic staining was strongest in blastema, intermediate and variable in epithelia, and weakest in stroma. When present, areas of skeletal muscle differentiation stained strongly for FXR1. qPCR revealed increased FXR1 expression in WT compared to adult and adjacent kidney (p < 0.0002) but was similar to fetal kidney (p = 0.648). RNA-sequencing revealed expression of FXR1 in multiple pediatric tumors, greatest in rhabdomyosarcoma and WT.

CONCLUSIONS

FXR1 was expressed consistently across this broad sampling of WT and most robustly in the primitive blastema. Notably, FXR1 labeled a specific self-renewing progenitor population of the fetal kidney.

Molecular and epidemiologic characterization of Wilms tumor from Baghdad, Iraq

BACKGROUND

Wilms tumor (WT) is the most common childhood kidney cancer worldwide, yet its incidence and clinical behavior vary according to race and access to adequate healthcare resources. To guide and streamline therapy in the war-torn and resource-constrained city of Baghdad, Iraq, we conducted a first-ever molecular analysis of 20 WT specimens to characterize the biological features of this lethal disease within this challenged population.

METHODS

Next-generation sequencing of ten target genes associated with WT development and treatment resistance (WT1, CTNNB1, WTX, IGF2, CITED1, SIX2, p53, N-MYC, CRABP2, and TOP2A) was completed. Immunohistochemistry was performed for 6 marker proteins of WT (WT1, CTNNB1, NCAM, CITED1, SIX2, and p53). Patient outcomes were compiled.

RESULTS

Mutations were detected in previously described WT "hot spots" (e.g., WT1 and CTNNB1) as well as novel loci that may be unique to the Iraqi population. Immunohistochemistry showed expression domains most typical of blastemal-predominant WT. Remarkably, despite the challenges facing families and care providers, only one child, with combined WT1 and CTNNB1 mutations, was confirmed dead from disease. Median clinical follow-up was 40.5 months (range 6-78 months).

CONCLUSIONS

These data suggest that WT biology within a population of Iraqi children manifests features both similar to and unique from disease variants in other regions of the world. These observations will help to risk stratify WT patients living in this difficult environment to more or less intensive therapies and to focus treatment on cell-specific targets.

Reversible deficits in apical transporter trafficking associated with deficiency in diacylglycerol acyltransferase

Deficiency in diacylglycerol acyltransferase (DGAT1) is a rare cause of neonatal diarrhea, without a known mechanism or in vitro model. A patient presenting at our institution at 7 weeks of life with failure to thrive and diarrhea was found by whole-exome sequencing to have a homozygous DGAT1 truncation mutation. Duodenal biopsies showed loss of DGAT1 and deficits in apical membrane transporters and junctional proteins in enterocytes. When placed on a very low-fat diet, the patient's diarrhea resolved with normalization of brush border transporter localization in endoscopic biopsies. DGAT1 knockdown in Caco2-BBe cells modeled the deficits in apical trafficking, with loss of apical DPPIV and junctional occludin. Elevation in cellular lipid levels, including diacylglycerol (DAG) and phospholipid metabolites of DAG, was documented by lipid analysis in DGAT1 knockdown cells. Culture of the DGAT1 knockdown cells in lipid-depleted media led to re-establishment of occludin and return of apical DPPIV. DGAT1 loss appears to elicit global changes in enterocyte polarized trafficking that could account for deficits in absorption seen in the patient. The in vitro modeling of this disease should allow for investigation of possible therapeutic targets.

Distinct mucosal microbial communities in infants with surgical necrotizing enterocolitis correlate with age and antibiotic exposure

OBJECTIVE

Necrotizing enterocolitis (NEC) is the most common surgical emergency in preterm infants, and pathogenesis associates with changes in the fecal microbiome. As fecal samples incompletely represent microbial communities in intestinal mucosa, we sought to determine the NEC tissue-specific microbiome and assess its contribution to pathogenesis.

DESIGN

We amplified and sequenced the V1-V3 hypervariable region of the bacterial 16S rRNA gene extracted from intestinal tissue and corresponding fecal samples from 12 surgical patients with NEC and 14 surgical patients without NEC. Low quality and non-bacterial sequences were removed, and taxonomic assignment was made with the Ribosomal Database Project. Operational taxonomic units were clustered at 97%. We tested for differences between NEC and non-NEC samples in microbiome alpha- and beta-diversity and differential abundance of specific taxa between NEC and non-NEC samples. Additional analyses were performed to assess the contribution of other demographic and environmental confounding factors on the infant tissue and fecal microbiome.

RESULTS

The fecal and tissue microbial communities were different. NEC was associated with a distinct microbiome, which was characterized by low diversity, higher abundances of Staphylococcus and Clostridium_sensu_stricto, and lower abundances of Actinomyces and Corynebacterium. Infant age and vancomycin exposure correlated with shifts in the tissue microbiome.

CONCLUSION

The observed low diversity in NEC tissues suggests that NEC is associated with a bacterial bloom and a distinct mucosal bacterial community. The exact bacterial species that constitute the bloom varied by infant and were strongly influenced by age and exposure to vancomycin.

Gestational diabetes mellitus is associated with increased CD163 expression and iron storage in the placenta

PROBLEM

GDM has been associated with disturbances in iron homeostasis and exaggerated immune activation. We sought to investigate the extent to which placental iron storage and macrophage accumulations were altered in GDM.

METHOD OF STUDY

We conducted a retrospective, case-control study of archived placental tissues obtained from 22 pregnancies complicated by GDM and 22 unaffected controls. Controls were matched to cases based on maternal age, gestational age at birth, and method of delivery. Placental tissues were assessed for altered histology and CD68 and CD163 staining. Tissue iron was assessed using Prussian blue staining.

RESULTS

Maternal hematocrit levels were higher in GDM participants compared to controls (P = 0.02). The presence of meconium-laden macrophages was significantly greater within the amnion of GDM cases (adjusted odds ratio (OR) 12.51). Although the total abundance of CD68-expressing macrophages was not significantly different between groups, we detected a significantly greater abundance of CD163 expression within the chorion and decidua of cases. The total area staining positive for iron was 24% (95% confidence intervals of 2%-46%) greater in GDM placentae versus controls.

CONCLUSION

GDM is associated with altered placental histology and increases in meconium-laden macrophages. Greater iron stores within the placentae of women with GDM is consistent with reports that iron excess is associated with an increased risk for GDM. The higher level of expression of CD163 on macrophage-like cells of the chorion and decidua in GDM suggests an increase in M2-like macrophages. Overall, our results add to growing evidence that GDM has direct effects on placental structure.

Mesangial cells, specialized renal pericytes and cytomegalovirus infectivity: Implications for HCMV pathology in the glomerular vascular unit and post-transplant renal disease

Background

Human Cytomegalovirus (HCMV) infection is problematic after kidney transplantation. Human mesangial cells along with human glomerular endothelial cells and podocytes constitute the renal glomerular vascular unit (GVU). HCMV infection of the GVU is poorly understood.

Methods

GVU cells infectivity was analysed by microscopy and immunofluorescence. Cytokines profiles were measured by Luminex assays. Renal tissue analysis for HCMV infection was performed by immunohistochemistry.

Results

Mesangial cells and glomerular endothelial cells but not podocytes were permissive for both lab adapted and clinical strains of HCMV. Luminex analysis of cytokines expressed by mesangial cells exposed to the SBCMV clinical strain was examined. A Tricell infection model of the GVU maintains >90% viability with a unique cytokine profile. Finally, we show αSMA stained mesangial cells permissive for HCMV in renal tissue from a transplant patient.

Conclusions

HCMV infection of mesangial cells induces angiogenic and proinflammatory cytokines that could contribute to glomerular inflammation.

Optimizing surgical resection of the bleeding Meckel diverticulum in children

PURPOSE

Meckel diverticula containing gastric heterotopia predispose to local hyperacidity, mucosal ulceration, and gastrointestinal bleeding in children. Eradication of acid-producing oxyntic cells is performed by either of two surgical methods: segmental enterectomy including the diverticulum or diverticulectomy only.

METHODS

Retrospective review of all children having surgical resection of a Meckel diverticulum at a tertiary-referral children's hospital from 2002 to 2016 was performed. Demographic data, surgical method, pathological specimens, and outcomes were evaluated.

RESULTS

102 children underwent surgical resection of a Meckel diverticulum during the study period. 27 (26.5%) children presented with bleeding, of which 16 (59%) had diverticulectomy only, and 11 (41%) had segmental ileal resection. All Meckel diverticula in children presenting with bleeding contained gastric heterotopia, and resection margins were free of gastric mucosa. Histologically, 19 specimens showed microscopic features of ulceration, on average 2.95mm (SD 4.49) from the nearest gastric mucosa (range: 0-16mm). Mean length of hospitalization after ileal resection was 4.0days (SD 1.2) compared to 1.6days (SD 0.9) for diverticulectomy only (p<0.001), with no re-bleeding occurrences.

CONCLUSION

In the operative management of children having a bleeding Meckel diverticulum, diverticulectomy-only completely eradicates gastric heterotopia without increased risk of continued bleeding or complications and significantly shortens hospitalization.

LEVEL OF EVIDENCE

Treatment Study: Level III.

Elevated TIMP-1 expression is associated with a prometastatic phenotype, disease relapse, and poor survival in neuroblastoma

Approximately two-thirds of patients with neuroblastoma are found to have metastatic disease at time of diagnosis with frequent skeletal, lymph node, central nervous system, and liver involvement. Using a serial in vivo splenic injection model, we have isolated an aggressive subclone (BE(2)-C/LM2) from MYCN-amplified neuroblastomas that demonstrate an enhanced propensity to develop metastatic liver lesions. BE(2)-C/LM2 subclone cells demonstrate increased adherent, soft agar colony and tumorsphere growth in vitro. Components of the tumor microenvironment regulate cancer progression, via networks of cytokines and growth factors. Cytokine array analysis identified increased TIMP-1 in the plasma of mice injected with BE(2)-C/LM2 subclone cells, leading us to hypothesize that TIMP-1 may play a role in our observed prometastatic phenotype. Immunoblotting and ELISA demonstrated enhanced endogenous TIMP-1 expression in our isolated neuroblastoma subclone. Silencing endogenous TIMP-1 successfully blocked in vitro proliferation, soft agar colony formation and tumorsphere formation by BE(2)-C/LM2 cells. Stable RNA interference of endogenous TIMP-1 failed to reverse the prometastatic phenotype of our BE(2)-C/LM2 subclone in our liver metastasis model, suggesting that endogenous TIMP-1 levels may not be an essential component of this in vivo behavior. Notably, tissue microarray analysis and Kaplan-Meier by gene expression demonstrates that elevated TIMP-1 expression is correlated with increased disease relapse and mortality in patients with neuroblastoma. Taken together, our study identifies TIMP-1 as a novel soluble factor that is associated with a prometastatic phenotype in our in vivo model and adverse outcomes in patients with neuroblastoma.

Placental pericytes and cytomegalovirus infectivity: Implications for HCMV placental pathology and congenital disease

PROBLEM

Placental pericytes are essential for placental microvascular function, stability, and integrity. Mechanisms of human cytomegalovirus (HCMV) pathogenesis incorporating placental pericytes are unknown.

METHOD OF STUDY

HCMV-infected placental tissue was stained by dual-labeled immunohistochemistry. Primary placental pericytes, cytotrophoblasts, and villous fibroblasts were exposed to HCMV; and infectivity was analyzed by microscopy and immunofluorescence. Cytokine expression was examined by Luminex assay. A HCMV-GFP recombinant virus was used to examine replication kinetics.

RESULTS

Immunohistochemistry showed HCMV in trophoblast and the villous core with T-cell and macrophage infiltration. Primary HCMV isolate from a patient (SBCMV)- infected pericytes showed dysregulation of proinflammatory and angiogenic cytokines when compared to control cells. A tri-cell model of the villous floor showed a unique expression profile. Finally, we show pericytes infected in vivo with HCMV in placental tissue from a congenitally infected child.

CONCLUSION

Placental pericytes support HCMV replication, inducing proinflammatory and angiogenic cytokines that likely contribute to viral dissemination, placenta inflammation, and dysregulation of placental angiogenesis.

Functional KRAS mutations and a potential role for PI3K/AKT activation in Wilms tumors

Wilms tumor (WT) is the most common renal neoplasm of childhood and affects 1 in 10 000 children aged less than 15 years. These embryonal tumors are thought to arise from primitive nephrogenic rests that derive from the metanephric mesenchyme during kidney development and are characterized partly by increased Wnt/β-catenin signaling. We previously showed that coordinate activation of Ras and β-catenin accelerates the growth and metastatic progression of a murine WT model. Here, we show that activating KRAS mutations can be found in human WT. In addition, high levels of phosphorylated AKT are present in the majority of WT. We further show in a mouse model and in renal epithelial cells that Ras cooperates with β-catenin to drive metastatic disease progression and promotes in vitro tumor cell growth, migration, and colony formation in soft agar. Cellular transformation and metastatic disease progression of WT cells are in part dependent on PI3K/AKT activation and are inhibited via pharmacological inhibition of this pathway. Our studies suggest both KRAS mutations and AKT activation are present in WT and may represent novel therapeutic targets for this disease.

Proceedings of the 2016 Childhood Arthritis and Rheumatology Research Alliance (CARRA) Scientific Meeting : Toronto, Canada. 14-17 April 2016

P1 Serologic evidence of gut-driven systemic inflammation in juvenile idiopathic arthritis Lampros Fotis, Nur Shaikh, Kevin Baszis, Anthony French, Phillip Tarr P2 Oral health and anti-citrullinated peptide antibodies (ACPA) in juvenile idiopathic arthritis Sriharsha Grevich, Peggy Lee, Sarah Ringold, Brian Leroux, Hannah Leahey, Megan Yuasa, Jessica Foster, Jeremy Sokolove, Lauren Lahey, William Robinson, Joshua Newsom, Anne Stevens P3 Novel autoantigens for endothelial cell antibodies in pediatric rheumatic diseases identified by proteomics Rie Karasawa, Mayumi Tamaki, Megumi Tanaka, Toshiko Sato, Kazuo Yudoh, James N. Jarvis P4 Transcriptional profiling reveals monocyte signature associated with JIA patient poor response to methotrexate Halima Moncrieffe, Mark F. Bennett, Monica Tsoras, Lorie Luyrink, Huan Xu, Sampath Prahalad, Paula Morris, Jason Dare, Peter A. Nigrovic, Margalit Rosenkranz, Mara Becker, Kathleen M. O’Neil, Thomas Griffin, Daniel J. Lovell, Alexei A. Grom, Mario Medvedovic, Susan D. Thompson P5 A multi-dimensional genomic map for polyarticular juvenile idiopathic arthritis Lisha Zhu, Kaiyu Jiang, Laiping Wong, Michael J Buck, Yanmin Chen, Halima Moncrieffe, Laura Brungs, Tao Liu, Ting Wang, James N Jarvis P6 Tocilizumab for treatment of children with refractory JIA Khaled Alsaeid, Jasim Alfailakawi, Hamid Alenezi, Hazim Alsaeed P7 Clinical characteristics of the initial patients enrolled in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry Tim Beukelman, Marc Natter, Norm Ilowite, Kelly Mieszkalski, Grendel Burrell, Brian Best, Helen Bristow, Shannon Carr, Anne Dennos, Rachel Kaufmann, Yukiko Kimura, Laura Schanberg P8 Comparative performance of small and large clinical centers in a comprehensive pediatric rheumatology disease registry Peter R Blier P9 Clinical characteristics of children with membranous lupus nephritis: The Childhood Arthritis and Rheumatology Research Alliance Legacy Registry Alexis Boneparth, Scott E. Wenderfer, L. Nandini Moorthy, Suhas M. Radhakrishna, Anna Carmela P. Sagcal-Gironella, Emily von Scheven P10 Rituximab use in pediatric lupus anticoagulant hypoprothrombinemia syndrome - a two center experience Kader Cetin Gedik, Salma Siddique, Cassyanne L. Aguiar, Doruk Erkan P11 Predictors of complementary and alternative medicine use and response in children with musculoskeletal conditions Ezra Cohen, Yvonne Lee, Michelle Dossett, Darshan Mehta, Roger Davis P12 Comparison of pediatric rheumatology and nephrology survey results for the treatment of refractory proliferative lupus nephritis and renal flare in juvenile SLE Mileka Gilbert, Beatrice Goilav, Esra Meidan, Joyce Hsu, Alexis Boneparth, Anabelle Chua, Stacy Ardoin, Scott E. Wenderfer, Emily Von Scheven, Natasha M. Ruth P13 Transitioning lupus patients from pediatric to adult rheumatology Joyce Hui-Yuen, Kader Cetin Gedik, Liza Bermudez, Ashlea Cook, Lisa Imundo, Amy Starr, Andrew Eichenfield, Anca Askanase P14 The systemic juvenile idiopathic arthritis cohort of the Childhood Arthritis & Rheumatology Research Alliance Registry Ginger Janow, Laura E. Schanberg, Soko Setoguchi, Victor Hasselblad, Elizabeth D. Mellins, Rayfel Schneider, Yukiko Kimura, The CARRA Legacy Registry Investigators P15 Results of the pilot study of the Childhood Arthritis and Rheumatology Research Alliance (CARRA) consensus treatment plans for new-onset systemic juvenile idiopathic arthritis Yukiko Kimura, Sriharsha Grevich, Timothy Beukelman, Esi Morgan, T Brent Graham, Maria Ibarra, Yonit Sterba Ruas, Marisa Klein-Gitelman, Karen Onel, Sampath Prahalad, Marilynn Punaro, Sarah Ringold, Dana Toib, Heather Van Mater, Jennifer E. Weiss, Pamela F. Weiss, Kelly Mieszkalski, Laura E. Schanberg P16 A systemic review of pain relief modalities in juvenile idiopathic arthritis: First step in developing a novel decision support intervention Timothy S. H. Kwok, Jacinthe Bisaillon, Christine Smith, Lucie Brosseau, Jennifer Stinson, Adam M. Huber, Ciaran M. Duffy, Karine Toupin April P17 Barriers and facilitators to care retention for pediatric systemic lupus erythematous patients in South Africa: A qualitative study Laura B Lewandowski, Christiaan Scott P18 Evaluating the feasibility of conducting comparative effectiveness studies in juvenile Localized Scleroderma (jLS) Suzanne C. Li, Kathryn S. Torok, C. Egla Rabinovich, Sandy D. Hong, Mara L Becker, Fatma Dedeoglu, Maria F. Ibarra, Polly J Ferguson, Rob C. Fuhbrigge, Katie G. Stewart, Elena Pope, Ronald M. Laxer, Thomas G. Mason, Gloria C. Higgins, Xiaohu Li, Marilynn G. Punaro, George Tomlinson, Eleanor Pullenayegum, John Matelski, Laura Schanberg, Brian M. Feldman P19 Tonsillar histology in patients with periodic fever, aphthous stomatitis, pharyngitis, adenitis (PFAPA) syndrome Kalpana Manthiram, Hernan Correa, Kathryn Edwards P20 Clinical course of juvenile dermatomyositis presenting as skin predominant disease Edward J. Oberle, Michelle Bayer, Dominic O. Co, Hatice Ezgi Baris, Yvonne Chiu, Adam Huber, Susan Kim P21 A Survey of musculoskeletal ultrasound practices of pediatric rheumatologists in North America Edward J Oberle, Timothy Beukelman P22 Assessment, classification and treatment of calcinosis as a complication of juvenile dermatomyositis: A survey of pediatric rheumatologists by the Childhood Arthritis and Rheumatology Research Alliance Amir B. Orandi, Kevin W. Baszis, Vikas Dharnidharka, Mark F. Hoeltzel, for the CARRA JDM Committee P23 CARRA dermatomyositis CTP pilot study Ann Reed, Adam Huber, George Tomlinson, Eleanor Pullenayegum, John Matelski, Y. Ingrid Goh, Laura Schanberg, Brian M. Feldman P24 Unexpectedly high incidences and prolonged disease activity in children with chronic non-bacterial osteomyelitis (CNO) as compared to bacterial osteomyelitis Anja Schnabel, Ursula Range, Gabriele Hahn, Timo Siepmann, Reinhard Berner, Christian Michael Hedrich P25 Juvenile systemic sclerosis cohort within the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Legacy Registry: Follow up characteristics Brandi Stevens, Kathryn S. Torok, Suzanne Li, Nicole Hershey, Megan Curran, Gloria Higgins, Katharine Moore, Egla Rabinovich, Anne M. Stevens, for the CARRA Registry Investigators P26 Development and usability testing of an iPad and desktop psycho-educational game for children with Juvenile Idiopathic Arthritis and their parents Jennifer Stinson, Mark Connelly, Adam Huber, Nadia Luca, Lynn Spiegel, Argerie Tsimicalis, Stephanie Luca, Naweed Tajuddin, Roberta Berard, Julia Barsalou, Sarah Campillo, Paul Dancey, Ciaran Duffy, Brian Feldman, Nicole Johnson, Patrick McGrath, Natalie Shiff, Shirley Tse, Lori Tucker, Charles Victor P27 iCanCope^TM: User-centred design and development of a smartphone app to support self-management for youth with arthritis pain Jennifer Stinson, Chitra Lalloo, Lauren Harris, Joseph Cafazzo, Lynn Spiegel, Brian Feldman, Nadia Luca, Ronald Laxer P28 Accessing pediatric rheumatology care: Despite barriers, few parents prefer telemedicine Danielle R. Bullock, Richard K. Vehe, Lei Zhang, Colleen K. Correll¹ P29 Exploration of factors contributing to time to achieve clinically inactive disease (CID) in juvenile idiopathic arthritis (JIA): A preliminary report Suhas Ganguli, Max Shenberger, Ritesh Korumilli, Beth Gottlieb P30 Pediatric rheumatology referral patterns: Presenting complaints of new patients at a large, urban academic center Martha Rodriguez, Deirdre de Ranieri, Karen Onel, Linda Wagner-Weiner, Melissa Tesher P31 Quality improvement (QI) initiatives in childhood systemic lupus erythematosus (cSLE) Elizabeth Roth Wojcicki, Kristyn L. Maletta, Dominic O. Co, Marsha Malloy, Sarah Thomson, Judyann C. Olson P32 Proliferative lupus nephritis in juvenile SLE: Support from the pediatric nephrology community for the definitions of responsiveness and flare in the 2012 consensus treatment plans Scott E. Wenderfer, Mileka Gilbert, Joyce Hsu, Sangeeta Sule, Tamar B. Rubinstein, Beatrice Goilav, Daryl M. Okamura, Annabelle Chua, Laurence A. Greenbaum, Jerome C. Lane, Emily von Scheven, Stacy P. Ardoin, Natasha M. Ruth P33 The steroid taper app: Making of a mobile app Jennifer M. P. Woo, Marsha M. Malloy, James A. Jegers, Dustin J. Hahn, Mary K. Hintermeyer, Stacey M. Martinetti, Gretchen R. Heckel, Elizabeth L. Roth-Wojcicki, Dominic O. Co

Genetic and chromosomal alterations in Kenyan Wilms Tumor

Wilms tumor (WT) is the most common childhood kidney cancer worldwide and poses a cancer health disparity to black children of sub-Saharan African ancestry. Although overall survival from WT at 5 years exceeds 90% in developed countries, this pediatric cancer is alarmingly lethal in sub-Saharan Africa and specifically in Kenya (36% survival at 2 years). Although multiple barriers to adequate WT therapy contribute to this dismal outcome, we hypothesized that a uniquely aggressive and treatment-resistant biology compromises survival further. To explore the biologic composition of Kenyan WT (KWT), we completed a next generation sequencing analysis targeting 10 WT-associated genes and evaluated whole-genome copy number variation. The study cohort was comprised of 44 KWT patients and their specimens. Fourteen children are confirmed dead at 2 years and 11 remain lost to follow-up despite multiple tracing attempts. TP53 was mutated most commonly in 11 KWT specimens (25%), CTNNB1 in 10 (23%), MYCN in 8 (18%), AMER1 in 5 (11%), WT1 and TOP2A in 4 (9%), and IGF2 in 3 (7%). Loss of heterozygosity (LOH) at 17p, which covers TP53, was detected in 18% of specimens examined. Copy number gain at 1q, a poor prognostic indicator of WT biology in developed countries, was detected in 32% of KWT analyzed, and 89% of these children are deceased. Similarly, LOH at 11q was detected in 32% of KWT, and 80% of these patients are deceased. From this genomic analysis, KWT biology appears uniquely aggressive and treatment-resistant.

Diagnostic utility of PHOX2B in primary and treated neuroblastoma and in neuroblastoma metastatic to the bone marrow

CONTEXT

Neuroblastoma (NB) is the most common extracranial tumor of childhood. Although most cases have a distinctive histology, a subset of primitive cases require immunohistochemical studies to distinguish them from other small round blue cell tumors of childhood. Immunohistochemistry is also used to detect small amounts of tumor metastatic to the bone marrow and in posttreatment samples with obscuring fibrosis, calcification, or inflammation. The transcription factor PHOX2B is essential for the differentiation and survival of sympathetic neurons and chromaffin cells, and therefore is highly specific for the peripheral autonomic nervous system.

OBJECTIVE

To determine the diagnostic utility of PHOX2B immunohistochemistry as a marker of primary, treated, and metastatic NB.

DESIGN

Neuroblastoma tissue microarrays were stained with PHOX2B, CD57, and synaptophysin. Arrays containing rhabdomyosarcoma, Ewing sarcoma, and Wilms tumor were stained with PHOX2B, and negative bone marrow samples were stained with PHOX2B and CD57.

RESULTS

PHOX2B and CD57 were similar to synaptophysin in their ability to detect NB. PHOX2B and CD57 similarly showed robust staining in posttreatment NB and NB metastatic to the bone marrow. In contrast to the cytoplasmic staining pattern seen with synaptophysin and CD57, clear and strong nuclear PHOX2B permitted identification of individual tumor cells. PHOX2B staining was absent in all cases of rhabdomyosarcoma, Ewing sarcoma, and Wilms tumor, and in the negative bone marrow.

CONCLUSIONS

PHOX2B and CD57 are useful markers of NB. PHOX2B is specific for NB in its differential diagnosis with other small round cell tumors, and its nuclear staining may be helpful for accurate bone marrow tumor quantification.

Enteric neuron imbalance and proximal dysmotility in ganglionated intestine of the Sox10Dom/+ Hirschsprung mouse model

BACKGROUND & AIMS

In Hirschsprung disease (HSCR), neural crest-derived progenitors (NCPs) fail to completely colonize the intestine so that the enteric nervous system (ENS) is absent from distal bowel. Despite removal of the aganglionic region, many HSCR patients suffer from residual intestinal dysmotility. To test the hypothesis that inappropriate lineage segregation of NCPs in proximal ganglionated regions of the bowel could contribute to such postoperative disease, we investigated neural crest (NC)-derived lineages and motility in ganglionated, postnatal intestine of the Sox10Dom/+ HSCR mouse model.

METHODS

Cre-mediated fate-mapping was applied to evaluate relative proportions of NC-derived cell types. Motility assays were performed to assess gastric emptying and small intestine motility while colonic inflammation was assessed by histopathology for Sox10Dom/+ mutants relative to wildtype controls.

RESULTS

Sox10Dom/+ mice showed regional alterations in neuron and glia proportions as well as Calretinin+ and nNOS+ neuronal subtypes. In the colon, imbalance of enteric NC derivatives correlated with the extent of aganglionosis. All Sox10Dom/+ mice exhibited reduced small intestinal transit at 4-weeks of age, and at 6-weeks, Sox10Dom/+ males had increased gastric emptying rates. Sox10Dom/+ mice surviving to 6-weeks of age had little or no colonic inflammation when compared to wildtype littermates, suggesting that these changes in GI motility are neurally mediated.

CONCLUSIONS

The Sox10Dom mutation disrupts the balance of NC-derived lineages and affects GI motility in the proximal, ganglionated intestine of adult animals. This is the first report identifying alterations in enteric neuronal classes in Sox10Dom/+ mutants, which suggests a previously unrecognized role for Sox10 in neuronal subtype specification.

Exploring the diversity and metabolic potential of actinomycetes from temperate marine sediments from Newfoundland, Canada

Marine sediments from Newfoundland, Canada were explored for biotechnologically promising Actinobacteria using culture-independent and culture-dependent approaches. Culture-independent pyrosequencing analyses uncovered significant actinobacterial diversity (H'-2.45 to 3.76), although the taxonomic diversity of biotechnologically important actinomycetes could not be fully elucidated due to limited sampling depth. Assessment of culturable actinomycete diversity resulted in the isolation of 360 actinomycetes representing 59 operational taxonomic units, the majority of which (94 %) were Streptomyces. The biotechnological potential of actinomycetes from NL sediments was assessed by bioactivity and metabolomics-based screening of 32 representative isolates. Bioactivity was exhibited by 41 % of isolates, while 11 % exhibited unique chemical signatures in metabolomics screening. Chemical analysis of two isolates resulted in the isolation of the cytotoxic metabolite 1-isopentadecanoyl-3β-D-glucopyranosyl-X-glycerol from Actinoalloteichus sp. 2L868 and sungsanpin from Streptomyces sp. 8LB7. These results demonstrate the potential for the discovery of novel bioactive metabolites from actinomycetes isolated from Atlantic Canadian marine sediments.

Early life establishment of site-specific microbial communities in the gut

Fecal sampling is widely utilized to define small intestinal tissue-level microbial communities in healthy and diseased newborns. However, this approach may lead to inaccurate assessments of disease or therapeutics in newborns because of the assumption that the taxa in the fecal microbiota are representative of the taxa present throughout the gastrointestinal tract. To assess the stratification of microbes in the newborn gut and to evaluate the probable shortcoming of fecal sampling in place of tissue sampling, we simultaneously compared intestinal mucosa and fecal microbial communities in 15 neonates undergoing intestinal resections. We report three key results. First, when the site of fecal and mucosal samples are further apart, their microbial communities are more distinct, as indicated by low mean Sørensen similarity indices for each patient's fecal and tissue microbiota. Second, two distinct niches (intestinal mucosa and fecal microbiota) are evident by principal component analyses, demonstrating the critical role of sample source in defining microbial composition. Finally, in contrast to adult studies, intestinal bacterial diversity was higher in tissue than in fecal samples. This study represents an unprecedented map of the infant microbiota from intestinal mucosa and establishes discernable biogeography throughout the neonatal gastrointestinal tract. Our results question the reliance on fecal microbiota as a proxy for the developing intestinal microbiota. Additionally, the robust intestinal tissue-level bacterial diversity we detected at these early ages may contribute to the maturation of mucosal immunity.