A Surgical Collaborative to Empower Medical Student Research.

Mini abstracts: Faculty at the Baylor College of Medicine have developed a flexible research collaborative through which students gain research skills and individualized mentorship. This division has produced 86 trainee first author publications, 64 manuscripts by 34 different medical students with an average Scimago Journal Rank of 1.293 (range: 1.035-1.551) since 2015.

Genome-wide association study identifies high-impact susceptibility loci for HCC in North America.

BACKGROUND AND AIMS: Despite the substantial impact of environmental factors, individuals with a family history of liver cancer have an increased risk for HCC. However, genetic factors have not been studied systematically by genome-wide approaches in large numbers of individuals from European descent populations (EDP). APPROACH AND RESULTS: We conducted a 2-stage genome-wide association study (GWAS) on HCC not affected by HBV infections. A total of 1872 HCC cases and 2907 controls were included in the discovery stage, and 1200 HCC cases and 1832 controls in the validation. We analyzed the discovery and validation samples separately and then conducted a meta-analysis. All analyses were conducted in the presence and absence of HCV. The liability-scale heritability was 24.4% for overall HCC. Five regions with significant ORs (95% CI) were identified for nonviral HCC: 3p22.1, MOBP , rs9842969, (0.51, [0.40-0.65]); 5p15.33, TERT , rs2242652, (0.70, (0.62-0.79]); 19q13.11, TM6SF2 , rs58542926, (1.49, [1.29-1.72]); 19p13.11 MAU2 , rs58489806, (1.53, (1.33-1.75]); and 22q13.31, PNPLA3 , rs738409, (1.66, [1.51-1.83]). One region was identified for HCV-induced HCC: 6p21.31, human leukocyte antigen DQ beta 1, rs9275224, (0.79, [0.74-0.84]). A combination of homozygous variants of PNPLA3 and TERT showing a 6.5-fold higher risk for nonviral-related HCC compared to individuals lacking these genotypes. This observation suggests that gene-gene interactions may identify individuals at elevated risk for developing HCC. CONCLUSIONS: Our GWAS highlights novel genetic susceptibility of nonviral HCC among European descent populations from North America with substantial heritability. Selected genetic influences were observed for HCV-positive HCC. Our findings indicate the importance of genetic susceptibility to HCC development.

Retrospective Analysis of the Impact of High- and Low-Quality Donor Livers for Patients with High-Acuity Illness.

BACKGROUND Patients with high-acuity liver failure have increased access to marginal and split liver options, owing to historically high waitlist mortality rates. While most research states that donor liver quality has no impact on patients with high-acuity illness, there have been inconsistencies in recent research on how liver quality impacts post-transplant outcomes for these patients. We aimed to quantify donor liver quality with various post-transplantation patient outcomes for patients with high-acuity illness. MATERIAL AND METHODS Using the liver donor risk index (LDRI), model for end stage liver disease (MELD), and clinically relevant recipient factors, we used multivariate logistic regression to analyze how donor liver quality affects varying measures of patient outcomes for 9923 high-acuity patients from June 18, 2013, to June 18, 2022. RESULTS Using LDRI, high-quality livers had a significant protective impact on high-acuity patient mortality, compared with low-quality livers (OR=0.695 [0.549, 0.879], P=0.002). High-quality livers also had significant impact on graft survival (OR=0.706 [0.558, 0.894], P=0.004). Two sensitivity patient mortality analyses, excluding patients with status 1A and hepatocellular carcinoma, showed significant protective findings for high-quality livers. High-quality livers had insignificant outcomes on long-term survivor mortality, length of hospitalization, and primary non-function outcomes, compared with low-quality donor livers. CONCLUSIONS While our findings suggest donor quality has an impact on high-acuity patient outcomes, these findings indicate further research is needed in intent-to-treat analysis on clinical offer data to provide a clearer finding of how donor quality affects patients with high-acuity illness.

Estimating risk of prolonged mechanical ventilation after liver transplantation in children: PROVE-ALT score.

BACKGROUND: Children at high risk for prolonged mechanical ventilation (PMV) after liver transplantation (LT) need to be identified early to optimize pulmonary support, allocate resources, and improve surgical outcomes. We aimed to develop and validate a metric that can estimate risk for Prolonged Ventilation After LT (PROVE-ALT). METHODS: We identified preoperative risk factors for PMV by univariable analysis in a retrospective cohort of pediatric LT recipients between 2011 and 2017 (n = 205; derivation cohort). We created the PROVE-ALT score by mapping multivariable logistic regression coefficients as integers, with cutoff values using the Youden Index. We validated the score by C-statistic in a retrospectively collected separate cohort of pediatric LT recipients between 2018 and 2021 (n = 133, validation cohort). RESULTS: Among total 338 patients, 21% (n = 72) were infants; 49% (n = 167) had cirrhosis; 8% (n = 27) required continuous renal replacement therapy (CRRT); and 32% (n = 111) required management in hospital (MIH) before LT. Incidence of PMV post-LT was 20% (n = 69) and 3% (n = 12) required tracheostomy. Independent risk factors (OR [95% CI]) for PMV were cirrhosis (3.8 [1-14], p = .04); age <1-year (8.2 [2-30], p = .001); need for preoperative CRRT (6.3 [1.2-32], p = .02); and MIH before LT (12.4 [2.1-71], p = .004). PROVE-ALT score ≥8 [Range = 0-21] accurately predicted PMV in the validation cohort with 73% sensitivity and 80% specificity (AUC: 0.81; 95% CI: 0.71-0.91). CONCLUSION: PROVE-ALT can predict PMV after pediatric LT with a high degree of sensitivity and specificity. Once externally validated in other centers, PROVE-ALT will empower clinicians to plan patient-specific ventilation strategies, provide parental anticipatory guidance, and optimize hospital resources.

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.

Survival Benefit of Solid-Organ Transplantation: 10-Year Update.

IMPORTANCE: Transplantation has transformed into a burgeoning field that is rapidly evolving to optimize organ distribution and survival outcomes. The years since 2012 (the last comprehensive study) have seen changes in transplantation, such as advances in immunotherapy and novel indices, that necessitate an updated analysis of survival benefit. DESIGN: Our goal was to determine the survival benefit for solid-organ transplants in the United Network for Organ Sharing (UNOS) database for a three decade period and provide updates on advancements since 2012. Our retrospective analysis examined data containing U.S. patient records from September 1, 1987, to September 1, 2021. RESULTS: We found that 3,430,272 life-years were saved over our transplant period (4.33 life-years saved per patient); kidney-1,998,492 life-years; liver -767,414; heart-435,312; lung-116,625; pancreas-kidney-123,463; pancreas-30,575; intestine-7901. After matching, 3,296,851 life-years were saved. Life-years saved and median survival increased for all organs between 2012 and 2021. Compared to 2012, median survival increased in kidney (from 12.4 to 14.76 years), liver (from 11.6 to 14.59), heart (9.5 to 11.73), lung (5.2 to 5.63), pancreas-kidney (from 14.5 to 16.88), pancreas (from 13.3 to 16.10). When compared to 2012, the percent transplanted increased in kidney, liver, heart, lung, and intestine, while pancreas-kidney and pancreas show decreased percent transplanted. CONCLUSION: Our study underscores the tremendous survival benefits of solid organ transplantation (over 3.4 million life-years saved) and shows improvements since 2012. Our study also highlights areas of transplantation, notably pancreas transplants, that may necessitate reinvigorated attention.

Radiological-histopathological discordance in patients transplanted for HCC and its impact on post-transplant outcomes.

BACKGROUND AND AIMS: Contrast-enhanced cross-sectional imaging is the cornerstone in the diagnosis, staging, and management of HCC, including eligibility for liver transplantation (LT). Radiological-histopathological discordance may lead to improper staging and may impact patient outcomes. We aimed to assess the radiological-histopathological discordance at the time of LT in HCC patients and its impact on the post-LT outcomes. METHODS: We analyzed further the effect of 6-month waiting policy on the discordance. Using United Network for Organ Sharing-Organ Procurement and Transplantation Network (UNOS-OPTN) database, we examined the discordance between pre-LT imaging and explant histopathology for all adult HCC patients who received liver transplants from deceased donors between April 2012 and December 2017. Kaplan-Meier methods and Cox regression analyses were used to evaluate the impact of discordance on 3-year HCC recurrence and mortality. RESULTS: Of 6842 patients included in the study, 66.7% were within Milan criteria on both imaging and explant histopathology, and 33.3% were within the Milan based on imaging but extended beyond Milan on explant histopathology. Male gender, increasing numbers of tumors, bilobar distribution, larger tumor size, and increasing AFP are associated with increased discordance. Post-LT HCC recurrence and death were significantly higher in patients who were discordant, with histopathology beyond Milan (adj HR 1.86, 95% CI 1.32-2.63 for mortality and 1.32, 95% CI 1.03-1.70 for recurrence). Graft allocation policy with 6-month waiting time led to increased discordance (OR 1.19, CI 1.01-1.41), although it did not impact post-LT outcome. CONCLUSION: Current practice for staging of HCC based on radiological imaging features alone results in underestimation of HCC burden in one out of three patients with HCC. This discordance is associated with a higher risk of post-LT HCC recurrence and mortality. These patients will need enhanced surveillance to optimize patient selection and aggressive LRT to reduce post-LT recurrence and increase survival.

Surgical Management and Outcomes of Patients with Multifocal Hepatoblastoma.

OBJECTIVE: To compare the outcomes of patients with multifocal hepatoblastoma (HB) treated at our institution with either orthotopic liver transplant (OLTx) or hepatic resection to determine outcomes and risk factors for recurrence. BACKGROUND: Multifocality in HB has been shown to be a significant prognostic factor for recurrence and worse outcome. The surgical management of this type of disease is complex and primarily involves OLTx to avoid leaving behind microscopic foci of disease in the remnant liver. METHODS: We performed a retrospective chart review on all patients <18 years of age with multifocal HB treated at our institution between 2000 and 2021. Patient demographics, operative procedure, post-operative course, pathological data, laboratory values, short- and long-term outcomes were analyzed. RESULTS: A total of 41 patients were identified as having complete radiologic and pathologic inclusion criteria. Twenty-three (56.1%) underwent OLTx and 18 (43.9%) underwent partial hepatectomy. Median length of follow-up across all patients was 3.1 years (IQR 1.1-6.6 years). Cohorts were similar in rates of PRETEXT designation status identified on standardized imaging re-review (p = .22). Three-year overall survival (OS) estimate was 76.8% (95% CI: 60.0%-87.3%). There was no difference in rates of recurrence or overall survival in patients who underwent either resection or OLTx (p = .54 and p = .92 respectively). Older patients (>72 months), patients with a positive porta hepatis margin, and patients with associated tumor thrombus experienced worse recurrence rates and survival. Histopathology demonstrating pleomorphic features independently associated with worse rates of recurrence. CONCLUSIONS: Through proper patient selection, multifocal HB was adequately treated with either partial hepatectomy or OLTx with comparable outcome results. HB with pleomorphic features, increased patient age at diagnosis, involved porta hepatis margin on pathology, and the presence of associated tumor thrombus may be associated with worse outcomes regardless of the local control surgery offered. LEVEL OF EVIDENCE: III.

Selecting DCD Recipients Using Predictive Indices.

Donation after circulatory death (DCD) allografts might represent one of the largest untapped sources of liver allografts. Our aim was to identify independent recipient risk factors that predict mortality in DCD allograft recipients to preselect optimal candidates for successful transplantation. Furthermore, we compared the application of our newly constructed DCD Recipient Selector Index (RSI) score to previously developed models to determine superiority in predicting recipient survival. Methods: Using the Organ Procurement and Transplantation Network database, we performed univariate and multivariate retrospective analyses on 4228 DCD liver allograft recipients. Results: We identified 8 significant factors and incorporated them into the weighted RSI to predict 3-mo survival following DCD liver transplantation with a C-statistic of 0.6971. The most significant recipient risk factors were recipient serum sodium levels >150 mEq/L at transplant, recipient albumin <2.0 g/dL at transplant, and a history of portal vein thrombosis. Because Model for End-Stage Liver Disease (MELD) score components were included as individual predictors, the DCD RSI predicts survival independently of MELD. Upon comparison with 3 previous recipient risk scores-Balance of Risk, Renal Risk Index, Patient-Survival Outcomes Following Liver Transplantation-the DCD RSI was determined to be superior at selecting optimal candidates pre-DCD transplantation, yielding a C-statistic of 0.6971. Conclusions: After verifying the performance of predictive indices for selection of DCD recipients, the DCD RSI is best used to preselect patients for optimized outcomes after DCD transplantation. This can increase utilization of DCD donors by improving outcomes.

Innate immune cell dysfunction and systemic inflammation in children with chronic liver diseases undergoing transplantation.

Advanced liver diseases (ALD) can affect immune function and compromise host defense against infections. In this study, we examined the phenotypic and functional alterations in circulating monocyte and dendritic cells (DCs) in children with ALD undergoing liver transplantation (LT). Children were stratified into 2 clusters, C1 (mild) and C2 (severe), on the basis of laboratory parameters of ALD and compared with healthy pediatric controls. Children in C2 had a significant reduction in frequencies of nonclassical monocytes and myeloid DCs. Children in C2 displayed monocyte and DC dysfunction, characterized by lower human leucocyte antigen DR expression and reduced interleukin 12 production, and had an increased incidence of infections before and after LT. Children in C2 demonstrated immune dysregulation with elevations of pro- and anti-inflammatory cytokines in plasma. Alterations of innate immune cells correlated with multiple laboratory parameters of ALD, including plasma bile acids. In vitro, monocytes cultured with specific bile acids demonstrated a dose-dependent reduction in interleukin 12 production, similar to alterations in children with ALD. In conclusion, a cohort of children with ALD undergoing LT exhibited innate immune dysfunction, which may be related to the chronic elevation of serum bile acids. Identifying at-risk patients may permit personalized management pre- and post-transplant, thereby reducing the incidence of infection-related complications.

Acute liver failure and unique challenges of pediatric liver transplantation amidst a worldwide cluster of adenovirus-associated hepatitis.

Investigation into a recent cluster of acute hepatitis in children from the southeastern United States identified human adenovirus (HAdV) DNAemia in all 9 cases. Molecular genotyping in 5 of 9 (56%) children identified HAdV type 41 in all cases (100%). Importantly, 2 children from this cluster progressed rapidly to pediatric acute liver failure (PALF) and required liver transplantation. HAdV type 41, a known cause of self-limited gastroenteritis, has not previously been associated with severe cholestatic hepatitis and liver failure in healthy children. Adenovirus polymerase chain reaction assay and sequencing of amplicons performed on DNA extracted from formalin-fixed, paraffin-embedded liver tissue also identified adenovirus species F (HAdV type 40 or 41) in these 2 children with PALF. Transplant considerations and successful liver transplantation in such situations remain scarce. In this report, we describe the clinical course, laboratory results, liver pathology, and treatment of 2 children with PALF associated with HAdV type 41, one of whom developed secondary hemophagocytic lymphohistiocytosis. Their successful posttransplant outcomes demonstrate the importance of early multidisciplinary medical management and the feasibility of liver transplantation in some children with PALF and HAdV DNAemia.

Long-term outcomes and trends in liver transplantation for hereditary hemochromatosis in the United States.

There have been conflicting data regarding liver transplantation (LT) outcomes for hereditary hemochromatosis (HH), with no recent data on LT outcomes in patients with HH in the past decade. Using the United Network for Organ Sharing registry, we evaluated waitlist and post-LT survival in all adult patients listed for HH without concomitant liver disease from 2003 to 2019. Post-LT survival for HH was compared with a propensity-matched (recipient and donor factors) cohort of recipients with chronic liver disease (CLD). From 2003 to 2019, 862 patients with HH were listed for LT, of which 55.6% ( n = 479) patients underwent LT. The 1- and 5-year post-LT survival rates in patients with HH were 88.7% (95% confidence interval [CI], 85.4%-91.4%) and 77.5% (95% CI, 72.8%-81.4%), respectively, and were comparable with those in the propensity-matched CLD cohort ( p value = 0.96). Post-LT survival for HH was lower than for Wilson's disease, another hereditary metabolic liver disease with similar LT volume ( n = 365). Predictors for long-term (5-year) post-LT mortality included presence of portal vein thrombosis (hazard ratio [HR], 1.96; 95% CI, 1.07-3.58), obesity measurements greater than Class II (HR, 1.98; 95% CI, 1.16-3.39), and Karnofsky performance status (HR, 0.98; 95% CI, 0.97-0.99) at the time of LT. The leading cause of post-LT death ( n = 145) was malignancy (25.5%), whereas cardiac disease was the cause in less than 10% of recipients. In conclusion, short- and long-term survival rates for HH are excellent and comparable with those of other LT recipients. Improving extrahepatic metabolic factors and functional status in patients with HH prior to LT may improve outcomes.

Improved Survival After Liver Transplantation for Patients With Human Immunodeficiency Virus (HIV) and HIV/Hepatitis C Virus Coinfection in the Integrase Strand Transfer Inhibitor and Direct-Acting Antiviral Eras.

BACKGROUND: People with human immunodeficiency virus (HIV) with and without hepatitis C virus (HCV) coinfection had poor outcomes after liver transplant (LT). Integrase strand transfer inhibitors (INSTIs) and direct-acting antivirals (DAAs) have changed the treatment landscape for HIV and HCV, respectively, but their impact on LT outcomes remains unclear. METHODS: This retrospective analysis of adults with HIV monoinfection (n = 246) and HIV/HCV coinfection (n = 286) who received LT compared mortality in patients with HIV who received LT before versus after approval of INSTIs and in patients with HIV/HCV coinfection who received LT before versus after approval of DAAs. In secondary analysis, we compared the outcomes in the different eras with those of propensity score-matched control cohorts of LT recipients without HIV or HCV infection. RESULTS: LT recipients with HIV monoinfection did not experience a significant improvement in survival between the pre-INSTI and INSTI recipients with HIV (adjusted hazard ratio [aHR], 0.70 [95% confidence interval {CI}, .36-1.34]). However, recipients with HIV/HCV coinfection in the DAA era had a 47% reduction (aHR, 0.53 [95% CI, .31-9.2] in 1-year mortality compared with coinfected recipients in the pre-DAA era. Compared to recipients without HIV or HCV, HIV-monoinfected recipients had higher mortality during the pre-INSTI era, but survival was comparable between groups during the INSTI era. HIV/HCV-coinfected recipients also experienced comparable survival during the DAA era compared to recipients without HCV or HIV. CONCLUSIONS: Post-LT survival for people with HIV monoinfection and HIV/HCV coinfection has improved with the introduction of INSTI and DAA therapy, suggesting that LT has become safer in these populations.

A new chapter in an evolving pandemic: Successful pediatric liver transplantation with SARS-CoV-2+ donors.

BACKGROUND: Amid a viral pandemic with poorly understood transmissibility and pathogenicity in the pediatric patient, we report the first pediatric liver transplants utilizing allografts from SARS-CoV-2+ donors. METHODS: We describe the outcomes of two pediatric liver transplant recipients who received organs from SARS-CoV-2 nucleic acid test-positive (NAT+) donors. Data were obtained through the respective electronic medical record system and UNet DonorNet platform. RESULTS: The first donor was a 3-year-old boy succumbing to head trauma. One of four nasopharyngeal (NP) swabs and 1 of 3 bronchoalveolar lavage (BAL) NAT tests demonstrated SARS-CoV-2 infection before organ procurement. The second donor was a 16-month-old boy with cardiopulmonary arrest of unknown etiology. Three NAT tests (2 NP swab/1 BAL) prior to procurement failed to detect SARS-CoV-2. The diagnosis was made when the medical examiner repeated 2 NP swab NATs and an archive plasma NAT, all positive for SARS-CoV-2. Both 2-year-old recipients continue to do well 8 months post-transplant, with excellent graft function and no evidence of SARS-CoV-2 transmission. CONCLUSIONS: This is the first report to describe successful pediatric liver transplantation from SARS-CoV-2+ donors. These data reinforce the adult transplant experience and support the judicious use of SARS-CoV-2+ donors for liver transplantation in children. With SARS-CoV-2 becoming endemic, the concern for donor-derived viral transmission must now be weighed against the realized benefit of life-saving transplantation in the pediatric population as we continue to work toward donor pool maximization.

Recipient Age Predicts 20-Year Survival in Pediatric Liver Transplant.

Introduction: Pediatric liver transplant recipients have demonstrated excellent long-term survival. The purpose of this analysis is to investigate factors associated with 20-year survival to identify areas for improvement in patient care. Methods: Kaplan-Meier with log-rank test as well as univariate and multivariate logistic regression methods were used to retrospectively analyze 4,312 liver transplant recipients under the age of 18 between September 30, 1987 and March 9, 1998. Our primary endpoint was 20-year survival among one-year survival. Results: Logistic regression analysis identified recipient age as a significant risk factor, with recipients below 5 years old having a higher 20-year survival rate (p < 0.001). A preoperative primary diagnosis of a metabolic dysfunction was found to be protective compared to other diagnoses (OR 1.64, CI 1.20-2.25). African-American ethnicity (OR 0.71, CI 0.58-0.87) was also found to be a risk factor for mortality. Technical variant allografts (neither living donor nor cadaveric) were not associated with increased or decreased rates of 20-year survival. Conclusions: Our analysis suggests that long-term survival is inversely correlated with recipient age following pediatric liver transplant. If validated with further studies, this conclusion may have profound implications on the timing of pediatric liver transplantation.

Do Patients with Autoimmune Conditions Have Less Access to Liver Transplantation despite Superior Outcomes?

Orthotopic liver transplantation (OLT) is a lifesaving therapy for patients with irreversible liver damage caused by autoimmune liver diseases (AutoD) including autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC). Currently, it is unclear how access to transplantation differs among patients with various etiologies of liver disease. Our aim is to evaluate the likelihood of transplant and the long-term patient and graft survival after OLT for each etiology for transplantation from 2000 to 2021. We conducted a large retrospective study of United Network for Organ Sharing (UNOS) liver transplant patients in five 4-year eras with five cohorts: AutoD (PBC, PSC, AIH cirrhosis), alcohol-related liver disease (ALD), hepatocellular carcinoma (HCC), viral hepatitis, and nonalcoholic steatohepatitis (NASH). We conducted a multivariate analysis for probability of transplant. Intent-to-treat (ITT) analysis was performed to assess the 10-year survival differences for each listing diagnosis while accounting for both waitlist and post-transplant survival. Across all eras, autoimmune conditions had a lower adjusted probability of transplant of 0.92 (0.92, 0.93) compared to ALD 0.97 (0.97, 0.97), HCC 1.08 (1.07, 1.08), viral hepatitis 0.99 (0.99, 0.99), and NASH 0.99 (0.99, 1.00). Patients with AutoD had significantly better post-transplant patient and graft survival than ALD, HCC, viral hepatitis, and NASH in each and across all eras (p-values all < 0.001). Patients with AutoD had superior ITT survival (p-value < 0.001, log rank test). In addition, the waitlist survival for patients with AutoD compared to other listing diagnoses was improved with the exception of ALD, which showed no significant difference (p-value = 0.1056, log rank test). Despite a superior 10-year graft and patient survival in patients transplanted for AutoD, patients with AutoD have a significantly lower probability of receiving a liver transplant compared to those transplanted for HCC, ALD, viral hepatitis, and NASH. Patients with AutoD may benefit from improved liver allocation while maintaining superior waitlist and post-transplant survival. Decreased access in spite of appropriate outcomes for patients poses a significant risk for increased morbidity for patients with AutoD.

Trends in marginal lung allograft survival: Advanced-age donors improve.

INTRODUCTION: Although lung demand continues to outpace supply, 75% of potential donor lungs are discarded without being transplanted in the United States. To identify the discarded cohorts best suited to alleviate the lung shortage and reduce waitlist mortality, we explored changes in survival over time for five marginal donor definitions: age >60 years, smoking history >20 pack-years, PaO2 /FiO2  < 300 mmHg, purulent bronchoscopic secretions, and chest radiograph infiltrates. METHODS: Our retrospective cohort study separated 27 803 lung recipients in the UNOS Database into three 5-year eras by transplant date: 2005-2009, 2010-2014, and 2015-2019. Multivariable Cox proportional hazards regression and Kaplan-Meier analysis with log-rank test were used to compare survival across the eras. RESULTS: Three definitions-low PaO2 /FiO2 , purulent bronchoscopic secretions, and abnormal chest radiographs-did not bear out as truly marginal, demonstrating lack of significantly elevated risk. Advanced donor age demonstrated considerable survival improvement (HR (95% CI): 1.47 (1.26-1.72) in 2005-2009 down to 1.14 (.97-1.35) for 2015-2019), with protective factors being recipients <60 years, moderate recipient BMI, and low Lung Allocation Score (LAS). Donors with smoking history failed to demonstrate any significant improvement (HR (95% CI): 1.09 (1.01-1.17) in 2005-2009 increasing to 1.22 (1.08-1.38) in 2015-2019). CONCLUSIONS: Advanced donor age, previously the most significant risk factor, has improved to near-benchmark levels, demonstrating the possibility for matching older donors to healthier non-elderly recipients in selected circumstances. Low PaO2 /FiO2 , bronchoscopic secretions, and abnormal radiographs demonstrated survival on par with standard donors. Significant donor smoking history, a moderate risk factor, has failed to improve.

Hepatoblastomas with carcinoma features represent a biological spectrum of aggressive neoplasms in children and young adults.

BACKGROUND & AIMS: Hepatoblastoma (HB) and hepatocellular carcinoma (HCC) are the predominant liver cancers in children, though their respective treatment options and associated outcomes differ dramatically. Risk stratification using a combination of clinical, histological, and molecular parameters can improve treatment selection, but it is particularly challenging for tumors with mixed histological features, including those in the recently created hepatocellular neoplasm not otherwise specified (HCN NOS) provisional category. We aimed to perform the first molecular characterization of clinically annotated cases of HCN NOS. METHODS: We tested whether these histological features are associated with genetic alterations, cancer gene dysregulation, and outcomes. Namely, we compared the molecular features of HCN NOS, including copy number alterations, mutations, and gene expression profiles, with those in other pediatric hepatocellular neoplasms, including HBs and HCCs, as well as HBs demonstrating focal atypia or pleomorphism (HB FPAs), and HBs diagnosed in older children (>8). RESULTS: Molecular profiles of HCN NOS and HB FPAs revealed common underlying biological features that were previously observed in HCCs. Consequently, we designated these tumor types collectively as HBs with HCC features (HBCs). These tumors were associated with high mutation rates (∼3 somatic mutations/Mb) and were enriched with mutations and alterations in key cancer genes and pathways. In addition, recurrent large-scale chromosomal gains, including gains of chromosomal arms 2q (80%), 6p (70%), and 20p (70%), were observed. Overall, HBCs were associated with poor clinical outcomes. CONCLUSIONS: Our study indicates that histological features seen in HBCs are associated with combined molecular features of HB and HCC, that HBCs are associated with poor outcomes irrespective of patient age, and that transplanted patients are more likely to have good outcomes than those treated with chemotherapy and surgery alone. These findings highlight the importance of molecular testing and early therapeutic intervention for aggressive childhood hepatocellular neoplasms. LAY SUMMARY: We molecularly characterized a class of histologically aggressive childhood liver cancers and showed that these tumors are clinically aggressive and that their observed histological features are associated with underlying recurrent molecular features. We proposed a diagnostic algorithm to identify these cancers using a combination of histological and molecular features, and our analysis suggested that these cancers may benefit from specialized treatment strategies that may differ from treatment guidelines for other childhood liver cancers.