EZH2 is a key component of hepatoblastoma tumor cell growth.

BACKGROUND: Enhancer of zeste homolog 2 (EZH2) catalyzes the trimethylation of histone H3 at lysine 27 via the polycomb recessive complex 2 (PRC2) and plays a time-specific role in normal fetal liver development. EZH2 is overexpressed in hepatoblastoma (HB), an embryonal tumor. EZH2 can also promote tumorigenesis via a noncanonical, PRC2-independent mechanism via proto-oncogenic, direct protein interaction, including ß-catenin. We hypothesize that the pathological activation of EZH2 contributes to HB propagation in a PRC2-independent manner. METHODS AND RESULTS: We demonstrate that EZH2 promotes proliferation in HB tumor-derived cell lines through interaction with ß-catenin. Although aberrant EZH2 expression occurs, we determine that both canonical and noncanonical EZH2 signaling occurs based on specific gene-expression patterns and interaction with SUZ12, a PRC2 component, and ß-catenin. Silencing and inhibition of EZH2 reduce primary HB cell proliferation. CONCLUSIONS: EZH2 overexpression promotes HB cell proliferation, with both canonical and noncanonical function detected. However, because EZH2 directly interacts with ß-catenin in human tumors and EZH2 overexpression is not equal to SUZ12, it seems that a noncanonical mechanism is contributing to HB pathogenesis. Further mechanistic studies are necessary to elucidate potential pathogenic downstream mechanisms and translational potential of EZH2 inhibitors for the treatment of HB.

Dr. Allen Oldfather Whipple (1881-1963): Namesake of the pancreaticoduodenectomy.

Allen O. Whipple was an American surgeon who popularized the pancreaticoduodenectomy (Whipple procedure) for periampullary cancer, which remains the gold standard for pancreatic tumor resections. Whipple was educated at Princeton University (B.S., 1904) and Columbia University College of Physicians and Surgeons (M.D., 1908). He swiftly ascended the academic ranks, culminating in his appointment as Professor of Surgery at Columbia and Director of Surgical Services at Presbyterian Hospital in 1921. Whipple published three criteria (Whipple's triad) for evaluating hyperinsulinism secondary to pancreatic insulinoma. He also revived interest in portocaval anastomosis to reduce portal hypertension, determining it to be a consequence of liver disease. During his 40-year career, Whipple introduced the concept of multidisciplinary teams and prospective data collection. He also shaped the structure of surgical training as President of the American Surgical Association and Chairman of the American Board of Surgery. Beyond the walls of the operating room, Whipple was a Renaissance Man whose childhood in Persia (Iran) engendered a lifelong interest in the region's art, culture, history, and medicine. Dr. Allen Oldfather Whipple is remembered as a pioneering physician and surgeon beloved by those who trained under him.

Structural and Functional Impact of Posttranslational Modification of Glypican-3 on Liver Carcinogenesis.

Glypican-3 (GPC3) is a cell-surface glycoprotein that is frequently overexpressed in hepatocellular carcinoma (HCC). GPC3 undergoes extensive posttranslational modification (PTM) including cleavage and glycosylation. This review focuses on the structure and function of GPC3 in liver cancer, highlighting the PTM of the tertiary and quaternary structures of GPC3 as a potential oncogenic regulatory mechanism. We propose that the function of GPC3 in normal development can vary with extensive PTM and that dysregulation of these processes leads to disease. Defining the regulatory impact of these modifications can provide a deeper understanding of the role of GPC3 in oncogenesis, epithelial-mesenchymal transition, and drug development. Through review of current literature, this article provides a unique perspective on the role of GPC3 in liver cancer, focusing on potential regulatory mechanisms of PTM on GPC3 function at the molecular, cellular, and disease level.

10 Year Analysis of Pediatric Surgery Fellowship Match and Operative Experience: Concerning Trends?

OBJECTIVE: This paper aims to evaluate the pediatric surgery training pipeline vis-à-vis the pediatric surgery match and operative experience of pediatric surgery fellows. SUMMARY OF BACKGROUND DATA: Pediatric surgery remains a competitive surgical subspecialty. However, there is concern that operative experience for pediatric surgery fellows is changing. This paper examines the selectivity of the pediatric surgery match, along with the operative experience of pediatric surgery fellows to characterize the state of pediatric surgery training. METHODS: The pediatric surgery fellowship match was analyzed from the National Resident Matching Program data from 2010 to 2019. Selectivity among fellowships was compared using analysis of variance with Dunnett test. Operative log data for pediatric fellows was analyzed using the Accreditation Council for Graduate Medical Education case logs from 2009 to 2019. Linear regression analysis was used to evaluate trends in operative volume over time. RESULTS: Pediatric surgery had the highest proportion of unmatched applicants (47.2% ± 5.3%) and lowest proportion of unfilled positions (1.4% ± 1.6%) when compared to other National Resident Matching Program surgical fellowships. Accreditation Council for Graduate Medical Education case log analysis revealed a statistically significant decrease in cases for graduating fellows (-5.3 cases/year, P < 0.05). Total index cases decreased (-4.7 cases/year, P < 0.01, R 2 = 0.83) such that graduates in 2019 completed 59 fewer index operations than graduates in 2009. CONCLUSION: Although pediatric surgery fellowship remains highly selective there has been a decline in the operative experience for graduating fellows. This highlights the need for evaluation of training paradigms and operative exposure in pediatric surgery to ensure the training of competent pediatric surgeons.

Inhibition of Glypican-3 Cleavage Results in Reduced Cell Proliferation in a Liver Cancer Cell Line.

INTRODUCTION: Glypican-3 (GPC3) is a surface-bound proteoglycan overexpressed in pediatric liver cancer and utilized clinically as an immunohistochemical tumor marker. Furin is a proprotein convertase that is ubiquitously expressed and shown to modify GPC3 post-translationally. In experimental models of epithelial-based cancers, furin inhibition decreased tumor cell migration and proliferation representing a potential therapeutic target. METHODS: Using a synthetic furin inhibitor, we evaluated proliferation, migration, protein, and RNA expression in two liver cancer cell lines, HepG2 (GPC3-positive) and SKHep1 cells (GPC3-negative). Total furin protein and GPC3 protein expression were assessed to evaluate functional levels of furin. RESULTS: There was a reduction in HepG2 proliferation with addition of furin inhibitor at the 48-h timepoint, however there was an increase in HepG2 migration. CONCLUSIONS: GPC3 cleavage in hepatoblastoma (HB) has a role in cell proliferation with therapeutic potential, however furin inhibition is not an appropriate target for GPC3-expressing HB due to increased migration which may enhance metastatic potential.

Association between Elevated Urine Neutrophil Gelatinase-Associated Lipocalin and Postoperative Acute Kidney Injury in Neonates.

OBJECTIVE: To examine the incidence of postoperative neonatal acute kidney injury (AKI) following general surgical procedures and to test the hypothesis that postoperative urine neutrophil gelatinase-associated lipocalin (uNGAL) concentrations predict AKI. The secondary objective was to evaluate for an association between AKI and hospital mortality. STUDY DESIGN: Prospective observational study of infants undergoing abdominal and thoracic surgical procedures in the neonatal intensive care unit from October 2018 to March 2020. The primary outcome was incidence of neonatal AKI (defined by the neonatal modified Kidney Diseases Improving Global Outcomes criteria) following each procedure to postoperative day 5. Severe AKI was defined as stage 2 or 3 AKI. Urine samples were obtained pre- and postoperatively at 6 time points to evaluate for levels of uNGAL. Secondary outcomes were in-hospital mortality and length of stay. RESULTS: Subjects (n = 141) underwent a total of 192 general surgical procedures during the study period. Neonatal AKI and severe AKI occurred following 36 (18%) and 15 (8%) procedures (n = 33 subjects). Percent change of uNGAL from 24 hours preoperatively to 24 hours postoperatively was greater in subjects with neonatal AKI (190.2% [IQR 0.0, 1666.7%] vs 0.7% [IQR -31.2%,140.2%], P = .0374). The strongest association of uNGAL and AKI occurred at 24 hours postoperatively (area under the receiver operator curves of 0.81, 95% CI 0.72, 0.89). Increased mortality risk was observed in subjects with any postoperative AKI (aOR 11.1 95% CI 2.0, 62.8, P = .0063) and severe AKI (aOR 13.8; 95% CI 3.0, 63.1, P = .0007). CONCLUSION: Elevation in uNGAL 24 hours postoperative was associated with AKI. Neonates with postoperative AKI had increased mortality.

Indocyanine green is a sensitive adjunct in the identification and surgical management of local and metastatic hepatoblastoma.

BACKGROUND: Hepatoblastoma is the most common primary pediatric liver malignancy. Indocyanine green (ICG) has been described as an adjunct to resection in small series. Its utility remains undefined in larger cohorts. METHODS: Records for 29 patients diagnosed with hepatoblastoma who received ICG prior to surgical resection from 2017 to 2020 at a single institution were retrospectively reviewed. The primary outcome was correlation between intraoperative ICG-avidity and histologic presence of hepatoblastoma. A secondary outcome included the histologic margin designation for resected liver specimens. RESULTS: ICG sensitivity was 91% for 120 resected thoracic specimens from 21 patients. Specificity was 57%. In 10% of operations, HB-positive specimens were resected solely on ICG-avidity. In an additional 40% of cases, ICG assisted in localizing a preoperatively diagnosed lesion. ICG sensitivity during thoracotomy and thoracoscopic surgery was 95 and 74%, respectively; primary and relapsed disease demonstrated sensitivity of 94 and 73%, respectively. Sensitivity was 92% for 25 resected liver specimens from nine patients with all parenchymal margins grossly negative for disease. Four multifocal lesions were identified with two resected solely by ICG-avidity. CONCLUSIONS: ICG is a sensitive adjunct for identifying local and metastatic hepatoblastoma, including lesions not visualized on preoperative imaging, and delineating margins during liver resection. False positives limit specificity; however, there were no adverse outcomes from additional resections. We noted that thoracoscopic surgery can be completed safely in patients with less significant disease burden, and conversion to thoracotomy, if necessary, is straightforward.

Natural Course of Pediatric Portal Hypertension.

The etiology of portal hypertension (pHTN) in children differs from that of adults and may require different management strategies. We set out to review the etiology, management, and natural history of pHTN at a pediatric liver center. From 2008 to 2018, 151 children and adolescents with pHTN were identified at a free-standing children's hospital. Patients were stratified by etiology of pHTN (intrahepatic disease [IH], defined as cholestatic disease and fibrotic or hepatocellular disease; extrahepatic disease [EH], defined as hepatic vein obstruction and prehepatic pHTN). Patients with EH were more likely to undergo an esophagoduodenscopy for a suspected gastrointestinal bleed (77% vs. 41%; P < 0.01). Surgical interventions differed based on etiology (P < 0.01), with IH more likely resulting in a transplant only (65%) and EH more likely to result in a shunt only (43%); 30% of patients with IH and 47% of patients with EH did not undergo an intervention for pHTN. Kaplan-Meier analysis revealed a significant increase in mortality in the group that received no intervention compared to shunt, transplant, or both and lower mortality in patients with prehepatic pHTN compared to other etiologies (P < 0.01 each). Multivariate analysis revealed increased odds of mortality in patients with refractory ascites (odds ratio [OR], 4.34; 95% confidence interval [CI], 1.00, 18.88; P = 0.05) and growth failure (OR, 13.49; 95% CI, 3.07, 58.99; P < 0.01). Conclusion: In this single institution study, patients with prehepatic pHTN had better survival and those who received no intervention had higher mortality than those who received an intervention. Early referral to specialized centers with experience managing these complex disease processes may allow for improved risk stratification and early intervention to improve outcomes.

The role of surgical shunts in the treatment of pediatric portal hypertension.

BACKGROUND: Portal diversion by surgical shunt plays a major role in the treatment of medically refractory portal hypertension. We evaluate our center's experience with surgical shunts for the treatment of pediatric portal hypertension. METHODS: All patients who underwent surgical shunt at a single institution from 2008 to 2017 were reviewed. The primary outcome was intervention-free shunt patency. RESULTS: In this study, 34 pediatric patients underwent portal shunt creation. The median age was 7.7 years (interquartile range 4.3-12.0). Twenty-nine patients (85%) had prehepatic portal hypertension and 5 patients (15%) had intrahepatic portal hypertension. The primary manifestations of portal hypertension were esophageal varices (97%) and gastrointestinal bleeding (77%). Eighteen patients (53%) underwent meso-Rex bypass, 10 patients (29%) underwent splenorenal shunt, and 6 patients (18%) underwent mesocaval shunt. Outcomes were notable for minimal wound complications (9%), rebleeding events (12%), and mortality (3%). In the postoperative setting, 10 patients (29%) experienced a shunt complication (occlusion or stenosis), 4 of which occurred in the early postoperative period and required urgent intervention. The 1-year and 5-year "primary patency" patency rates were 71% and 66%, respectively. CONCLUSION: Children suffer significant morbidity from the sequelae of portal hypertension. Our experience reinforces the feasibility of surgical shunts as an effective treatment option associated with low rates of morbidity and mortality.

Surgical management of locally-advanced and metastatic hepatoblastoma.

Advanced stage hepatoblastoma, including both locally advanced primary tumors as well as metastatic disease, poses unique clinical challenges. Despite substantial advances in chemotherapeutics, surgical extirpation remains the mainstay of cure for this tumor. Locally advanced tumors that involve multiple hepatic lobes and/or invade significant vascular structures can be managed either by complex hepatic resections or liver transplantation. We review the indications, roles, and outcomes of these surgical approaches as well as those for the resection of pulmonary metastases.

Esophageal dysmotility: An intrinsic feature of megacystis, microcolon, hypoperistalsis syndrome (MMIHS).

OBJECTIVES: Megacystis-microcolon-hypoperistalsis syndrome (MMIHS) also called Berdon's Syndrome, is a smooth muscle myopathy that results in an enlarged bladder, microcolon, and small bowel hypoperistalsis. In our series of six patients with this disorder, all had disordered swallowing. Therefore, we prospectively characterized esophageal structure and function in all. METHODS: Diagnoses had been established by contrast radiography, small bowel manometry, and urodynamic studies. To investigate the esophagus, we endoscoped and biopsied the esophagus of each patient on multiple occasions. All patients also underwent water soluble contrast esophagography and esophageal manometry. RESULTS: Upon careful questioning, all patients had swallowing dysfunction, and the majority of their enteral intake was via gastrostomy or gastrojejunostomy. All took some oral alimentation, but eating was slow and none could aliment themselves completely by the oral route, receiving 50% or less of their calories by mouth. Four had megaesophagus whereas the esophagus of the two youngest was of normal caliber. All had eosinophilic esophagitis and/or esophageal Candidiasis from time to time, but successful treatment of these findings failed to improve their symptoms. Manometry revealed normal lower esophageal sphincter (LES) resting tone and normal LES relaxation, but for all, peristalsis was absent in the esophageal body. CONCLUSIONS: This series expands the spectrum of findings in MMIHS, to include a primary motility disorder of the esophageal body. As patients age, the esophageal caliber appears to increase. Successful treatment of neither esophageal eosinophilia nor Candidiasis is effective in ameliorating the motility disorder. If our findings are confirmed in more patients with MMIHS, this disorder should be renamed, megacystis-microcolon-intestinal-and esophageal hypoperistalsis syndrome. TYPE OF STUDY: Prognosis study, Level IV (case series).

Hepatoblastoma-The Evolution of Biology, Surgery, and Transplantation.

The most common primary malignant liver tumor of childhood, hepatoblastoma has increased in incidence over the last 30 years, but little is still known about its pathogenesis. Discoveries in molecular biology provide clues but have yet to define targeted therapies. Disease-free survival varies according to stage, but is greater than 90% in favorable risk populations, in part due to improvements in chemotherapeutic regimens, surgical resection, and earlier referral to liver transplant centers. This article aims to highlight the principles of disease that guide current treatment algorithms. Surgical treatment, especially orthotopic liver transplantation, will also be emphasized in the context of the current Children's Oncology Group international study of pediatric liver cancer (AHEP-1531).

Pediatric pancreas transplantation, including total pancreatectomy with islet autotransplantation.

Unlike other solid-organ transplants, whole pancreas transplantation in children is relatively rare, and it occurs more frequently in the context of multivisceral or composite organ transplantation. Because children only infrequently suffer severe sequelae of type 1 diabetes mellitus, pancreas transplantation is rarely indicated in the pediatric population. More commonly, pediatric pancreas transplant occurs in the setting of incapacitating acute recurrent or chronic pancreatitis, specifically islet autotransplantation after total pancreatectomy. In this clinical scenario, total pancreatectomy removes the nidus of chronic pain and debilitation, while autologous islet transplantation aims to preserve endocrine function. The published experiences with pediatric total pancreatectomy with islet autotransplantation (TPIAT) in children has demonstrated excellent outcomes including liberation from chronic opioid use, as well as improved mental and physical quality of life with good glycemic control. Given the complexity of the operation, risk of postoperative complication, and long-term physiologic changes, appropriate patient selection and comprehensive multidisciplinary care teams are critical to ensuring optimal outcomes.

The beneficial impact of revision of Kasai portoenterostomy for biliary atresia: an institutional study.

OBJECTIVE: To determine whether portoenterostomy (PE) revision in patients afflicted with biliary atresia (BA) is a viable treatment option and, if so, identify which patients may benefit. BACKGROUND: BA, the most common cause of neonatal liver disease, results in biliary tract obstruction and hepatic fibrosis. Kasai PE is the initial surgical intervention performed and, if successful, restores drainage and preserves the native liver. Portoenterostomy failure warrants liver transplantation, but because of complications related to transplantation, treatment strategies to salvage the native liver may be beneficial. Using uniformly applied criteria, we have revised PEs to delay or avoid transplantation. METHODS: A retrospective review of medical records of patients diagnosed with BA since 1983 was performed. Patient demographics, symptoms, indications for revision, laboratory values, and outcomes were recorded. A cohort of patients who underwent revision after initial PE was identified. Survival rates were assessed using the Kaplan-Meier method. For patients who required transplantation, operative data from the revised PE cohort were compared with those from the unrevised PE cohort. A Cox proportional hazards model was used to determine covariates predictive of a favorable outcome. RESULTS: Of 181 children who underwent PE, 24 underwent revision. Adequate biliary drainage, as evidenced by normalized conjugated bilirubin levels, was achieved in 75% of revised patients. Overall survival in patients who underwent revision, regardless of transplantation, was 87%. Among patients who underwent PE revision, 46% have survived with their native liver. CONCLUSION: Experience at our center suggests that with appropriate patient selection, PE revision may delay the need for liver transplanation yielding encouraging patient outcomes.

Prevention of the murine model of biliary atresia after live rotavirus vaccination of dams.

PURPOSE: Biliary atresia (BA) is a neonatal disease that results in the obliteration of the biliary tree. The murine model of BA has been established where rhesus rotavirus (RRV) infection of newborn mice leads to an obstructive cholangiopathy. We determined whether maternal postconception rotavirus vaccination could prevent the murine model of BA. MATERIALS AND METHODS: Female mice were mated and injected intraperitoneally with one of the following materials: purified rotavirus strains RRV or Wa, high or low-dose Rotateq (Merck and Co Inc, Whitehouse Station, NJ) (a pentavalent rotavirus vaccine [PRV]), purified recombinant viral antigens of rotavirus (VP6) or influenza (NP), or saline. B-cell-deficient females also underwent postconception PRV injection. RESULTS: Maternal vaccination with PRV improves survival of pups infected with RRV. Serum rotavirus IgG, but not IgA, levels were increased in pups delivered from dams who received RRV, Wa, PRV, or VP6, but in the case of the Wa, PRV, and VP6 groups, these antibodies were not neutralizing. Postconception injection of high-dose PRV did not improve survival of pups born to B-cell-deficient dams. CONCLUSION: Maternal vaccination against RRV can prevent the rotavirus-induced murine model of BA in newborn mouse pups.