Management of undifferentiated embryonal sarcoma of the liver: A Pediatric Surgical Oncology Research Collaborative study.

BACKGROUND: Undifferentiated embryonal sarcoma of the liver (UESL) is a rare tumor for which there are few evidence-based guidelines. The aim of this study was to define current management strategies and outcomes for these patients using a multi-institutional dataset curated by the Pediatric Surgical Oncology Research Collaborative. METHODS: Data were collected retrospectively for patients with UESL treated across 17 children's hospitals in North America from 1989 to 2019. Factors analyzed included patient and tumor characteristics, PRETEXT group, operative details, and neoadjuvant/adjuvant regimens. Event-free and overall survival (EFS, OS) were the primary and secondary outcomes, respectively. RESULTS: Seventy-eight patients were identified with a median age of 9.9 years [interquartile range [IQR): 7-12]. Twenty-seven patients underwent resection at diagnosis, and 47 patients underwent delayed resection, including eight liver transplants. Neoadjuvant chemotherapy led to a median change in maximum tumor diameter of 1.6 cm [IQR: 0.0-4.4] and greater than 90% tumor necrosis in 79% of the patients undergoing delayed resection. R0 resections were accomplished in 63 patients (81%). Univariate analysis found that metastatic disease impacted OS, and completeness of resection impacted both EFS and OS, while multivariate analysis revealed that R0 resection was associated with decreased expected hazards of experiencing an event [hazard ratio (HR): 0.14, 95% confidence interval (CI): 0.04-0.6]. At a median follow-up of 4 years [IQR: 2-8], the EFS was 70.0% [95% CI: 60%-82%] and OS was 83% [95% CI: 75%-93%]. CONCLUSION: Complete resection is associated with improved survival for patients with UESL. Neoadjuvant chemotherapy causes minimal radiographic response, but significant tumor necrosis.

Cellular origin and molecular mechanisms of lung metastases in patients with aggressive hepatoblastoma.

BACKGROUND AND AIMS: Lung metastases are the most threatening signs for patients with aggressive hepatoblastoma (HBL). Despite intensive studies, the cellular origin and molecular mechanisms of lung metastases in patients with aggressive HBL are not known. The aims of these studies were to identify metastasis-initiating cells in primary liver tumors and to determine if these cells are secreted in the blood, reach the lung, and form lung metastases. APPROACH: We have examined mechanisms of activation of key oncogenes in primary liver tumors and lung metastases and the role of these mechanisms in the appearance of metastasis-initiating cells in patients with aggressive HBL by RNA-Seq, immunostaining, chromatin immunoprecipitation, Real-Time Quantitative Reverse Transcription PCR and western blot approaches. Using a protocol that mimics the exit of metastasis-initiating cells from tumors, we generated 16 cell lines from liver tumors and 2 lines from lung metastases of patients with HBL. RESULTS: We found that primary HBL liver tumors have a dramatic elevation of neuron-like cells and cancer-associated fibroblasts and that these cells are released into the bloodstream of patients with HBL and found in lung metastases. In the primary liver tumors, the ph-S675-ß-catenin pathway activates the expression of markers of cancer-associated fibroblasts; while the ZBTB3-SRCAP pathway activates the expression of markers of neurons via cancer-enhancing genomic regions/aggressive liver cancer domains leading to a dramatic increase of cancer-associated fibroblasts and neuron-like cells. Studies of generated metastasis-initiating cells showed that these cells proliferate rapidly, engage in intense cell-cell interactions, and form tumor clusters. The inhibition of ß-catenin in HBL/lung metastases-released cells suppresses the formation of tumor clusters. CONCLUSIONS: The inhibition of the ß-catenin-cancer-enhancing genomic regions/aggressive liver cancer domains axis could be considered as a therapeutic approach to treat/prevent lung metastases in patients with HBL.

Critical elements of pediatric liver cancer surgery.

The appropriate management of pediatric liver malignancies, primarily hepatoblastoma and hepatocellular carcinoma, requires an in depth understanding of contemporary preoperative risk stratification, experience with advanced hepatobiliary surgery, and a good relationship with one's local or regional liver transplant center. While chemotherapy regimens have become more effective, operative indications more well-defined, and overall survival improved, the complexity of liver surgery in small children provides ample opportunity for protocol violation, inadequate resection, and iatrogenic morbidity. These guidelines represent the distillation of contemporary literature and expert opinion as a means to provide a framework for preoperative planning and intraoperative decision-making for the pediatric surgeon.

Anti-thymocyte globulin induction with delayed introduction of tacrolimus preserves renal function in pediatric liver transplant recipients.

BACKGROUND: Tacrolimus (TAC)-mediated renal disease occurs in up to 70% of pediatric liver transplant (LT) recipients. The safety and efficacy of renal-sparing immunosuppression using anti-thymocyte globulin (ATG) induction and delayed TAC administration has not been studied in children. We evaluated the safety and efficacy of ATG induction on preserving renal function in children within the first year (Y1) post-LT in a single-center retrospective cohort study. METHODS: Children under age 18 years of who received isolated LT from 2008 to 2020 with a GFR < 70 received renal-sparing (RS) protocol consisting of ATG with methylprednisolone (MP), delayed TAC administration, lower initial TAC trough goals, and mycophenolate mofetil (MMF). The RS group was matched 1:2 by age and LT indication with standard immunosuppression (SI) group. Changes in renal function as well as adverse events within Y1 post-LT were compared. RESULTS: Forty-four pediatric patients were included in the analysis, of which 13 received RS. As expected, the RS group had significantly lower mean TAC trough levels at 30 days (10.3 vs. 13.2, p = .001) post-LT. Renal function was significantly preserved at 6 (-0.26 vs. 0.21, p = .004) and 12 months (-0.33 vs. 0.11, p = .003) post-LT in the RS versus SI group as measured by mean change in serum creatinine, with similar trends observed in eGFR and cystatin C. ACR, sepsis, viremia, graft loss and mortality occurred at similar rates in both RS and SI groups. CONCLUSION: Induction immunosuppression with ATG and delayed TAC administration in children with renal impairment is safe and effectively preserves renal function during Y1 post-LT.

Children undergoing early liver re-transplantation for primary non-function have improved survival.

BACKGROUND: Primary non-function (PNF) in the early post-LT period in children leads to prolonged hospitalization, high graft loss, and significant mortality. However, there is a paucity of data available on the natural history of children relisted for LT due to PNF, including those who recover graft function and survive with their original allograft. METHODS: We interrogated the United Network of Organ Sharing (UNOS) database for pediatric LT recipients who were relisted with a primary diagnosis of PNF from 2000 to 2020. Patients >21-year-old and multiple organ transplants were excluded. Logistic regression and Cox proportional hazard models were employed to identify risk factors for early re-transplantation (within 30 days of relisting) and mortality after adjusting for baseline clinical characteristics. RESULTS: One hundred and eight patients were relisted for LT for PNF during the study period. Twenty-five patients survived beyond 30 days from relisting with their original LT, 76 underwent early re-transplantation, and 7 did not survive. Having a high-risk EBV mismatch (OR 2.03, 95% CI 0.66-6.27) and an elevated donor serum creatinine (OR: 2.19, 95% CI 0.54-8.84) were associated with increased odds of a patient requiring early re-transplantation. Donor characteristics including age, final total bilirubin, final AST/ALT, and final serum sodium, as well as vasopressor use prior to procurement, were not associated with increased odds of early re-transplantation (p > 0.05). Operative characteristics including allograft type and cold-ischemia time were also not associated with early re-transplantation (p > 0.05). Patients undergoing early re-transplantation showed a trend toward improved 1-year graft survival (69% vs 55%, p = 0.24). On multivariable Cox proportional hazards modeling, early re-transplantation was associated with reduced risk of overall patient mortality compared to those who survived with their original LT (HR 0.27, 95% CI 0.12-0.67). CONCLUSION: Early re-transplantation for PNF is associated with improved patient survival compared with patients who survive with their original LT.

Histologic type predicts disparate outcomes in pediatric hepatocellular neoplasms: A Pediatric Surgical Oncology Research Collaborative study.

BACKGROUND: Hepatocellular carcinoma (HCC) is a rare cancer in children, with various histologic subtypes and a paucity of data to guide clinical management and predict prognosis. METHODS: A multi-institutional review of children with hepatocellular neoplasms was performed, including demographic, staging, treatment, and outcomes data. Patients were categorized as having conventional HCC (cHCC) with or without underlying liver disease, fibrolamellar carcinoma (FLC), and hepatoblastoma with HCC features (HB-HCC). Univariate and multivariate analyses identified predictors of mortality and relapse. RESULTS: In total, 262 children were identified; and an institutional histologic review revealed 110 cHCCs (42%; 69 normal background liver, 34 inflammatory/cirrhotic, 7 unknown), 119 FLCs (45%), and 33 HB-HCCs (12%). The authors observed notable differences in presentation and behavior among tumor subtypes, including increased lymph node involvement in FLC and higher stage in cHCC. Factors associated with mortality included cHCC (hazard ratio [HR], 1.63; P = .038), elevated α-fetoprotein (HR, 3.1; P = .014), multifocality (HR, 2.4; P < .001), and PRETEXT (pretreatment extent of disease) stage IV (HR, 5.76; P < .001). Multivariate analysis identified increased mortality in cHCC versus FLC (HR, 2.2; P = .004) and in unresectable tumors (HR, 3.4; P < .001). Disease-free status at any point predicted survival. CONCLUSIONS: This multi-institutional, detailed data set allowed a comprehensive analysis of outcomes for children with these rare hepatocellular neoplasms. The current data demonstrated that pediatric HCC subtypes are not equivalent entities because FLC and cHCC have distinct anatomic patterns and outcomes in concert with their known molecular differences. This data set will be further used to elucidate the impact of histology on specific treatment responses, with the goal of designing risk-stratified algorithms for children with HCC. LAY SUMMARY: This is the largest reported granular data set on children with hepatocellular carcinoma. The study evaluates different subtypes of hepatocellular carcinoma and identifies key differences between subtypes. This information is pivotal in improving understanding of these rare cancers and may be used to improve clinical management and subsequent outcome in children with these rare malignancies.

Clinical heterogeneity of pediatric hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is often a chemoresistant neoplasm with a poor prognosis. Pediatric HCC may reflect unique biological and clinical heterogeneity. PROCEDURE: An IRB-approved retrospective institutional review of patients with HCC treated between 2004 and 2015 was undertaken. Clinical, radiographic, and histologic data were collected from all patients. RESULTS: Thirty-two patients with HCC, median age 11.5 years (range 1-20) were identified. Seventeen patients had a genetic or anatomic predisposition. Histology was conventional HCC (25) and fibrolamellar HCC (7). Evans staging was 1 (12); 2 (1); 3 (10); 4 (9). Sixteen patients underwent resection at diagnosis and five patients after neoadjuvant chemotherapy. Surgical procedures included liver transplantation (LT, 11), hemihepatectomy (9), and segmentectomy (1). Eighteen patients had medical therapy (13 neoadjuvant, 5 adjuvant). Most common initial medical therapy included sorafenib alone (7) and cisplatin/doxorubicin-based therapy (8). Overall, 14 (43.8%) patients survived with a median follow-up of 58.8 months (range 26.5-157.6). Cause of death was most often linked to lack of primary tumor surgery (11). Of the survivors, Evans stage was 1 (11), 2 (1), and 3 (2, both treated with LT). Four of 18 patients (22%) who received medical therapy, 8 of 17 patients with a predisposition (47%), and 14 of 21 patients (66%) who underwent surgery remain alive. CONCLUSIONS: Genetic and anatomic predisposing conditions were seen in over half of this cohort. Evans stage 1 or 2 disease was linked to improved survival. LT trended toward improved survival. Use of known chemotherapy agents may benefit a smaller group of pediatric HCC and warrants formal prospective study through cooperative group trials.

Surgical management of children and adolescents with upfront completely resected hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is an aggressive malignant neoplasm that is often chemoresistant. Complete surgical resection remains the mainstay of therapy. The role of liver transplantation (LT) in pediatric HCC is in evolution, as is the role of adjuvant chemotherapy for stage I disease. METHODS: A retrospective review of patients < 18 years of age with completely resected HCC treated with surgical intervention alone at our institution from 2004 to 2015 was conducted. RESULTS: Twelve patients with a median age of 12 years (range = 1-17; number of females = 7) with upfront resected HCC (Evans stage I) were identified. Four patients had HCC without identifiable risk factors (fibrolamellar-HCC = 2; early HCC arising in focal nodular hyperplasia = 1, well-differentiated [wd] HCC = 1). Four patients had early or wd-HCC in the context of portosystemic shunts (Abernethy = 2; mesocaval shunt and portal vein thrombosis = 2). Four patients had moderate to wd-HCC in the context of pre-existing liver disease with cirrhosis (progressive familial intrahepatic cholestasis type-2 = 2, alpha-1 antitrypsin deficiency = 1, Alagille syndrome = 1). Seven patients underwent LT (multifocal = 5; solitary = 2); five exceeded Milan criteria (MC) by imaging. Five patients underwent complete resection (segmentectomy = 2; hemihepatectomy = 3). Ten patients received no adjuvant chemotherapy. All patients are alive without evidence of disease with a median follow-up of 54.1 months (range = 28.1-157.7 months). CONCLUSIONS: Pediatric and adolescent patients with upfront, completely resected HCC can be effectively treated without chemotherapy. LT should be considered for nonmetastatic HCC, especially in the context of pre-existing chronic liver disease, even when the tumor exceeds MC. Distinct pediatric selection criteria are needed to identify patients most suitable for LT.

Cholangiocyte secretion of chemokines in experimental biliary atresia.

UNLABELLED: Biliary atresia (BA) is a disease of the newborn that results in obstruction of the biliary tree. The cause of BA remains unknown; however, recent studies using the murine model of biliary atresia have found that rotavirus infection of the biliary epithelial cell (cholangiocyte) triggers an inflammatory response. We hypothesized that rotavirus infection of cholangiocytes results in the release of chemokines, important mediators of the host immune response. METHODS: In vivo, Balb/c pups were injected with rhesus rotavirus (RRV) or saline, and, their extrahepatic bile ducts were microdissected 2, 5, 7, and 14 days after injection. Next, an immortalized cholangiocyte cell line (mCl) was incubated with RRV or serum-free media. Qualitative and quantitative chemokine assessment was performed using enzyme-linked immunosorbent assay, polymerase chain reaction, and immunohistochemistry. RESULTS: In vivo, increased levels of the chemokines macrophage inflammatory protein 2, monocyte chemotactic protein 1, KC and Regulated upon Activation, Normal T Expressed and Secreted were found in RRV-infected murine bile ducts. In vitro, infected mCl cells produced increasing amounts of these same chemokines in relation to dose and time. CONCLUSION: These novel results suggest that chemokine expression by RRV-infected cholangiocytes may trigger a host inflammatory process that causes bile duct obstruction. Understanding how viral infection initiates this response may shed light on the pathogenesis of biliary atresia.

Cholangiocyte expression of alpha2beta1-integrin confers susceptibility to rotavirus-induced experimental biliary atresia.

Inoculation of BALB/c mice with rhesus rotavirus (RRV) in the newborn period results in biliary epithelial cell (cholangiocyte) infection and the murine model of biliary atresia. Rotavirus infection of a cell requires attachment, which is governed in part by cell-surface expression of integrins such as alpha2beta1. We hypothesized that cholangiocytes were susceptible to RRV infection because they express alpha2beta1. RRV attachment and replication was measured in cell lines derived from cholangiocytes and hepatocytes. Flow cytometry was performed on these cell lines to determine whether alpha2beta1 was present. Cholangiocytes were blocked with natural ligands, a monoclonal antibody, or small interfering RNA against the alpha2-subunit and were infected with RRV. The extrahepatic biliary tract of newborn mice was screened for the expression of the alpha2beta1-integrin. Newborn mice were pretreated with a monoclonal antibody against the alpha2-subunit and were inoculated with RRV. RRV attached and replicated significantly better in cholangiocytes than in hepatocytes. Cholangiocytes, but not hepatocytes, expressed alpha2beta1 in vitro and in vivo. Blocking assays led to a significant reduction in attachment and yield of virus in RRV-infected cholangiocytes. Pretreatment of newborn pups with an anti-alpha2 monoclonal antibody reduced the ability of RRV to cause biliary atresia in mice. Cell-surface expression of the alpha2beta1-integrin plays a role in the mechanism that confers cholangiocyte susceptibility to RRV infection.