Rare Liver Cancer Research Articles

Treatments and prognostic outcomes of combined hepatocellular-cholangiocarcinoma with distant metastasis: an analysis based on SEER data.

Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a rare liver cancer with a poor prognosis, often diagnosed at an advanced stage. The management of cHCC-CCA with distant metastasis remains challenging, and prognostic factors are not well-defined. This study aimed to investigate prognostic factors and treatment outcomes for cHCC-CCA patients with distant metastasis. Retrospective analysis was conducted using data from the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) database. Patients with distant metastasis [stage M1, according to the American Joint Committee on Cancer (AJCC) 7th edition] between January 2010 and December 2020 were included. Their characteristics, clinical profiles, and prognostic information were evaluated. Cox multifactorial survival analysis and Kaplan-Meier survival curves were used for statistical analysis. A total of 130 patients were included, with 78 (60%) receiving chemotherapy. Cox multivariate survival analysis revealed worse prognosis for Black individuals compared to White individuals (P<0.05). The median overall survival was 2 months for Black patients and 5 months for White patients. Chemotherapy significantly improved patient prognosis (P<0.05), while lung metastasis emerged as an independent risk factor (P<0.05). Kaplan-Meier survival curves confirmed the impact of lung metastasis and chemotherapy on overall survival. Patients with lung metastasis had lower survival rates (P<0.05), and those receiving chemotherapy had higher survival rates (P<0.05). Subgroup analysis based on age showed lower survival rates in patients aged 75 years or older compared to those below 75 years. Chemotherapy showed significant beneficial effects on the prognosis of patients below 75 years old, but no significant difference was observed in patients aged 75 years or above. Chemotherapy improves the prognosis of cHCC-CCA patients with distant metastasis, especially for those under 75 years old. Black race and lung metastasis are poor prognostic factors.

Mechanistic Association of Hepatoblastoma with Cerebral Palsy: A Narrative Review.

Hepatoblastoma is a rare liver cancer that occurs most often in children who present with lower birth weight. Cerebral palsy (CP) is a neurodevelopmental disorder distinguished by irregularities in muscle tone, movement, and motor skills. CP is caused by damage to the developing brain and is often associated with secondary complications such as severe constipation. Clinicians must be aware of sudden worsening constipation occurring in CP children because it can also be a sign of hepatoblastoma. The aim of this review is to summarize the current understanding of the risks for hepatoblastoma development in children with CP. Cancer risks likely include dysfunction of the immune system surveillance in CP children. Elevated C-reactive protein and tumor necrosis factor-alpha levels may be higher in children with CP, which weakens their innate immune system. Metabolic disruption increases the risk of some cancers, and poor nutrition and reduced growth that occur in CP patients may have an impact on cancer development through a loss in immune function. Increased mobility and physical activity can increase the T-cell, natural killer cell, and neutrophil population. Children with CP tend to engage poorly in physical activity, and consequently, their immune system is affected. There are multiple factors associated with CP that increase the risk of childhood cancers such as hepatoblastoma.

Increased Protein Kinase A Activity Induces Fibrolamellar Hepatocellular Carcinoma Features Independent of DNAJB1.

Fibrolamellar hepatocellular carcinoma (FLC) is a rare liver cancer that is driven by the fusion of DNAJB1 and PRKACA, the catalytic subunit of protein kinase A (PKA). PKA activity is controlled through regulatory proteins that both inhibit catalytic activity and control localization, and an excess of regulatory subunits ensures PRKACA activity is inhibited. Here, we found an increase in the ratio of catalytic to regulatory units in FLC patient tumors driven by DNAJB1::PRKACA using mass spectrometry, biochemistry, and immunofluorescence, with increased nuclear localization of the kinase. Overexpression of DNAJB1::PRKACA, ATP1B1::PRKACA, or PRKACA, but not catalytically inactive kinase, caused similar transcriptomic changes in primary human hepatocytes, recapitulating the changes observed in FLC. Consistently, tumors in patients missing a regulatory subunit or harboring an ATP1B1::PRKACA fusion were indistinguishable from FLC based on the histopathological, transcriptomic, and drug-response profiles. Together, these findings indicate that the DNAJB1 domain of DNAJB1::PRKACA is not required for FLC. Instead, changes in PKA activity and localization determine the FLC phenotype. Significance: Alterations leading to unconstrained protein kinase A signaling, regardless of the presence or absence of PRKACA fusions, drive the phenotypes of fibrolamellar hepatocellular carcinoma, reshaping understanding of the pathogenesis of this rare liver cancer.

Abstract 2710: Combination CXCR4 and PD-1 blockade increases T cell infiltration and effector function in fibrolamellar carcinoma (FLC)

Abstract Introduction: Fibrolamellar carcinoma (FLC), a rare liver cancer affecting young patients without cirrhosis, has a poor prognosis and few systemic therapy options. Current evidence implicates an immunosuppressive tumor microenvironment (TME), including our preliminary data suggesting preferential localization of T cells in stromal bands. We hypothesized that dual blockade of C-X-C chemokine receptor type 4 (CXCR4) and programmed cell death protein (PD-1) would enhance T cell infiltration and activation, respectively, and thereby increase tumor killing. Methods: Flow cytometry and single-nuclear RNA sequencing (snRNA-seq) were used to analyze immune cells and evaluate gene expression, respectively, in patient-derived FLC and non-tumor liver (NTL). Immunohistochemistry (IHC) was used to assess CD3+ T cell localization in relation to CXCL12, the chemokine ligand of CXCR4. Tumor slice cultures (TSCs) from fresh FLC resection specimens (n=11) were treated with control (IgG1), a small molecule CXCR4 inhibitor (AMD3100), anti-PD-1 blocking antibody (αPD-1), or combination CXCR4 and PD-1 blockade (AMD3100/αPD-1). IHC, RNA expression (Nanostring), and live microscopy were used to evaluate T cell mobilization and function. Results: Flow cytometry analysis demonstrated fewer CD45+ cells (16% vs 54% of live cells, p=0.01) and heterogenous PD-1 expression on T cells in FLC compared with NTL. SnRNA-seq analysis showed that CXCR4 expression is upregulated in FLC lymphocyte and macrophage populations relative to NTL (15% vs 10% and 20% vs 5% expressed), and CXCL12 is expressed primarily in stellate cells. CD3+ T cells colocalized with CXCL12 in the FLC stroma on IHC. Multiplex IHC of treated TSCs revealed more T cells in the carcinoma (CK7+) than the stromal (SMA+) compartment after AMD3100 compared with IgG1 (63% vs 34% T cells in CK7+ compartment, p=0.05). Nanostring indicated upregulation of effector pathways (apoptosis, cytotoxicity, lymphocyte activation) after AMD3100/αPD-1 compared with IgG1. Time-lapse live microscopy revealed a greater percentage of apoptotic carcinoma cells (SR-FLICA+CK7+) colocalized with CD3+ T cells (37% vs 18%, p=0.005) and longer CD3+ T cell track length (27 vs 22 μm, p=0.03) after AMD3100/αPD-1 than before treatment. Cleaved caspase-3 (CC3) IHC demonstrated significantly increased tumor apoptosis after AMD3100/αPD-1 compared with IgG1 and monotherapy (53% vs 32% (IgG1), 39% (AMD3100), and 42% (αPD-1) CC3+ cells, p=0.002, p=0.03, p=0.04). Conclusion: The CXCR4/CXCL12 axis mediates T cell exclusion in the FLC TME. Combination CXCR4 and PD-1 blockade overcomes immunosuppression in FLC by mobilizing T cells into the carcinoma compartment and activating their effector function, with resultant tumor apoptosis. These findings support consideration of clinical trials testing drugs targeting CXCR4 and PD-1 in FLC. Citation Format: Lindsay K. Dickerson, Renske van den Bijgaart, Xiuyun Jiang, Sara K. Daniel, Jason A. Carter, Alaa Farghli, Kevin M. Sullivan, Yongjun Liu, Heidi L. Kenerson, Raymond S. Yeung, Teresa S. Kim, Ian N. Crispe, Praveen Sethupathy, Kevin C. Barry, Venu G. Pillarisetty. Combination CXCR4 and PD-1 blockade increases T cell infiltration and effector function in fibrolamellar carcinoma (FLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2710.

DNAJB1-PRKACA fusion protein-regulated LINC00473 promotes tumor growth and alters mitochondrial fitness in fibrolamellar carcinoma.

Fibrolamellar carcinoma (FLC) is a rare liver cancer that disproportionately affects adolescents and young adults. Currently, no standard of care is available and there remains a dire need for new therapeutics. Most patients harbor the fusion oncogene DNAJB1-PRKACA (DP fusion), but clinical inhibitors are not yet developed and it is critical to identify downstream mediators of FLC pathogenesis. Here, we identify long noncoding RNA LINC00473 among the most highly upregulated genes in FLC tumors and determine that it is strongly suppressed by RNAi-mediated inhibition of the DP fusion in FLC tumor epithelial cells. We show by loss- and gain-of-function studies that LINC00473 suppresses apoptosis, increases the expression of FLC marker genes, and promotes FLC growth in cell-based and in vivo disease models. Mechanistically, LINC00473 plays an important role in promoting glycolysis and altering mitochondrial activity. Specifically, LINC00473 knockdown leads to increased spare respiratory capacity, which indicates mitochondrial fitness. Overall, we propose that LINC00473 could be a viable target for this devastating disease.

GalNAc-conjugated siRNA targeting the DNAJB1-PRKACA fusion junction in fibrolamellar hepatocellular carcinoma

Fibrolamellar hepatocellular carcinoma (FLC) is a rare liver cancer caused by a dominant recurrent fusion of the heat shock protein (DNAJB1) and the catalytic subunit of protein kinase A (PRKACA). Current therapies such as chemotherapy and radiation have limited efficacy, and new treatment options are needed urgently. We have previously shown that FLC tumors are dependent on the fusion kinase DNAJB1::PRKACA, making the oncokinase an ideal drug target. mRNA degrading modalities such as antisense oligonucleotides or small interfering RNAs (siRNAs) provide an opportunity to specifically target the fusion junction. Here, we identify a potent and specific siRNA that inhibits DNAJB1::PRKACA expression. We found expression of the asialoglycoprotein receptor in FLC to be maintained at sufficient levels to effectively deliver siRNA conjugated to the GalNAc ligand. We observe productive uptake and siRNA activity in FLC patient-derived xenografts (PDX) models invitro and invivo. Knockdown of DNAJB1::PRKACA results in durable growth inhibition of FLC PDX in vivo with no detectable toxicities. Our results suggest that this approach could be a treatment option for FLC patients.

S3602 A Rare and Aggressive Liver Cancer With Atypical Presentation: Primary Hepatic Angiosarcoma Presenting With Hypercalcemia

S3602 A Rare and Aggressive Liver Cancer With Atypical Presentation: Primary Hepatic Angiosarcoma Presenting With Hypercalcemia

Ex-vivo analysis of programmed cell death on fibrolamellar carcinoma.

4103 Background: Fibrolamellar carcinoma (FLC) is a rare liver cancer with surgery as the only established treatment. Relapse is common (&gt;80%) and with 40% unresectable, there is a need for rationale systemic therapy. Empiric combinations, especially with lenvatinib (LEN) and gemcitabine (GEM), show promise, but are lacking a CLIA licensed laboratory rationale. Ex-Vivo Analysis of Programmed Cell Death (EVA-PCD), from Nagourney Cancer Institute, is an attempt to meet this need. Methods: Nagourney Institute analyzed FLC tissue (as previously described), with a panel of 34 single/26 combinations of available/promising agents from 18 drug classes. Drug concentration with 50% cell death (LC50), below, within, or above 1-standard deviation of the mean (n ≥ 15), define Highly-Sensitive/Intermediate/Resistant, respectively. Active/Moderate/Inactive are similarly defined but with n &lt; 15. Actionable defines clinically available drug(s), not resistant/inactive and ≥ 6 assays. Results: Forty-four samples from 40 patients (17M,23F, age 6-56, 23 states/4 countries) were analyzed: 80% were viable and 69% of high quality for a total of 378 assays (avg 12/patient). However, all patients had actionable agents, and 78% of the assays showed activity in at least some patients. All the universally resistant/inactive assays (22%) were single agent. 76% of assays were actionable in at least one patient (100% for combinations compared to 62% for single agents). EVA-PCD replicate FLC studies and experience, such as the failure of monotherapy and the importance of LEN. Of 11 patients who had treatment that matched testing, 72% responded as predicted, including 6 with 100% response to LEN and/or QUE as predicted. Overall LEN/QUE, LEN/EVE, TRE, REG, QUE, 5FU/INF performed the best, while single agent ALP, CAB, LAR, VOR, GEM, DAS and IBR all showed 0% activity when tested &gt; 5 times. The largest challenge is the need for an adequate amount of viable tissue to arrive within 24 hours. However our experience demonstrates that it is feasible from other countries and across the US. Conclusions: This is the first demonstration of CLIA approved human FLC tumor testing. Data are in line with literature and correlates clinically. Prospective data are needed to fully incorporate EVA-PCD testing into the clinic. [Table: see text]

Clinical utility of an international multidisciplinary virtual tumor board for fibrolamellar carcinoma.

e18624 Background: Fibrolamellar carcinoma (FLC) is a rare liver cancer with approximately 1500 new cases per year, worldwide. The lack of expertise locally often incurs significant travel for patients (pts). Virtual consults have improved access to expertise but identifying the best experts for an ultra-rare condition is difficult for pts and families and multidisciplinary tumor boards of experts offer better clinical guidance. Foundations and advocacy groups play a vital role in navigation and support for pts with rare cancers. Methods: Pts with FLC and their local treating oncologists were engaged by the FibroFighters Foundation and offered a multidisciplinary virtual tumor board (VTB) review. Each VTB included the local treating oncologist, a patient advocate, a molecular pharmacologist, and international experts in the clinical management of FLC including at least one medical oncologist, one radiation oncologist, one interventional radiologist, and one surgical oncologist. Each VTB reviewed the pts’ clinical history and relevant imaging and discussed surgical, radiological, and systemic approaches. Pts consented to the observational research protocol XCELSIOR ( NCT03793088 ) to enable longitudinal clinical summaries to be prepared and for outcomes to be annotated. Results: Between August 4th 2022 and February 9th, 2023, the VTB held a total of 71 discussions for 59 unique pts (12 discussed more than once): 12 new diagnoses, 28 relapses, 14 treatment failures, and 5 ongoing care. Median age at diagnosis of pts was 18 years (range 6-44 years). Pts were seen at 44 institutions/practices across 22 states and 4 countries (USA, Australia, Switzerland, and the Netherlands). A total of 36 unique treatment regimens were discussed, with 21 unique consensus top-ranked options delivered to treating oncologists. The most common consensus options included regimens of gemcitabine, lenvatinib, and nivolumab (13), interventional radiology (IR, 11), surgical resection (6), and a regimen of gemcitabine, oxaliplatin, and lenvatinib (6). The primary team implemented the VTB recommendations 60 times out of 71 (85%): change in systemic therapy (33), IR (11), continue current regimen (11), surgery (6), radiation oncology (2). Conclusions: This is the first demonstration of a patient-focused international multidisciplinary VTB for FLC. The high rate of recommendation adoption by local treating oncologists suggests this is a valuable service to improve patient care. Outcomes are being collected prospectively in a master observational research protocol to better define clinical utility.

Abstract 1516: Bulk and spatial single-cell transcriptomic characterization of fibrolamellar hepatocellular carcinoma

Abstract Fibrolamellar Hepatocellular Carcinoma (FLC) is a rare liver cancer affecting adolescents and young adults, with no gender or ethnicity predilection and without history of underlying viral hepatitis, cirrhosis, or other known risk factors. Almost all FLC patients present a somatic heterozygous deletion in chromosome 19p13.12, DNAJB1::PRKACA, which is sufficient to drive FLC in mice. A few studies comparing FLC tumors with adjacent non-transformed liver (normal) samples revealed many transcriptional differences. However, there were done in very small datasets and analyzed using different bioinformatic methods, resulting in just 18-47% agreement between them. This study aims to comprehensively characterize the transcriptome of FLC at bulk and spatial single-cell resolution. The whole transcriptome of 109 FLC frozen patient samples, the largest RNA-seq dataset of FLC to date, was sequenced using different library preparation and ribosomal depletion methods. Only paired tumor and normal tissue samples resected from the same patient were used and divided into two groups: exploration (3 datasets, 67 samples) and testing (2 datasets, 17 samples). Additionally, as external validation datasets, RNA-seq samples from previously published studies were collected, including Sorenson et al. (FLC: 26, normal: 9, paired: 8), the TCGA-LIHC study (FLC: 6, normal: 1, paired: 1), Hirsch et al. (FLC: 15, normal: 3, paired: 0) and Francisco et al. (FLC: 27, normal: 10, paired: 9). All were reanalyzed using state-of-the-art bioinformatic methods: mapped to the Human Genome GRCh38.103 and transcripts quantified using Salmon 1.6.0, unsupervised clustering exploration using PCA, tSNE and UMAP, differential expression calculated using DESeq2 1.28.1, and checking for detectability and consistency among datasets. We found 857 up- and 988 down-regulated genes presenting the same dysregulation in the exploration datasets and confirmed in the testing and external datasets. We call these genes the transcriptional FLC signature. The FLC signature was further characterized by comparing it with the genes differentially expressed in other liver cancers: hepatocellular carcinoma (41 paired samples), hepatoblastoma (22 paired samples), and cholangiocarcinoma (27 paired samples). We found 276 up- and 352 down-regulated genes altered in other liver cancers as well as FLC, but 156 up- and 68 down-regulated only in FLC. The 112 genes with the strongest dysregulation (56 up and 56 down) were used for a MERFISH screening, providing for the first time a single-cell spatial transcriptomic characterization of FLC. This showed clear differential expression patterns in tumor, normal, stromal, and infiltrating immune cells, allowing the identification of how different cell types contribute to the transcriptional FLC signature. Citation Format: David Requena, Aldhair Medico, Luis F. Soto, Mahsa Shirani, James A. Saltsman, Gadi Lalazar, Michael P. LaQuaglia, Sanford M. Simon. Bulk and spatial single-cell transcriptomic characterization of fibrolamellar hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1516.

Case Report: Choledocholithiasis as Risk Factor for Klatskin Tumor: A Rare Cholangiocarcinoma

Background: Klatskin tumor is a rare liver cancer that involves the bile ducts. Its incidence begins to increase over time and is usually only diagnosed in patients who are already at an advanced stage. The annual incidence of klatskin tumors is not more than 1:100,000. Klatskin tumor is suspected based on signs of biliary obstruction, ultrasonography showing a stricture or bile mass, cholangiography with ERCP and MRCP, abnormal liver function tests, and elevated tumor marker CA 19-9. Case Report: A 65-year-old man presented to the hospital with complaints of yellowing of the eyes and body that began one month ago, as well as a lump in the right upper abdomen that had grown larger over the previous five months. Physical examination revealed yellow eyes, and a palpable lump in the upper quadrant of the patient's abdomen. The patient defecates looked like putty and urinates looked like tea. The diagnosis leaded to a klatskin tumor because the results of MRCP showed a mass in the hilar region of the liver that extended to the proximal common bile duct, which described the appearance of a klatskin tumor. There were an increasing CA 19-9 level and liver function tests. Conclusion: Patient has been diagnosed with klatskin tumors, has choledocholithiasis risk factor, supported by appropriate MRCP images and increasing CA 19-9 level

The impact of lymphadenectomy on intrahepatic cholangiocarcinoma management and prognosis: a comprehensive review

Intrahepatic cholangiocarcinoma (iCCA) is a rare liver cancer generally associated with poor patient outcomes. Curative intent liver resection has been established as a standard treatment of care of resectable disease. However, the role of lymphadenectomy, including the extent of resection and therapeutic value, continues to be an area of controversy. The objective of this review was to highlight the role of lymph node dissection (LND) relative to therapeutic value and prognosis in the surgical management of iCCA. A comprehensive review was performed using MEDLINE/PubMed. Search terms included “intrahepatic cholangiocarcinoma”, “bile duct cancer”, lymphadenectomy”, “lymph node metastasis”, and lymph node staging”. Treatment for iCCA should include an R0 resection with regional lymphadenectomy. The prognostic and therapeutic value of regional lymphadenectomy has been an increased area of research and debate. An increased number of lymph node metastases has correlated with inferior overall survival versus lymph node-negative disease. In addition to surgical resection, regional lymphadenectomy with the removal of at least six lymph nodes in the appropriate nodal basins based on primary tumor location should be standard. The identification of lymph node metastasis provides additional important information to guide providers in determining adjuvant therapy and surveillance strategies.

Rare liver cancer complicated with hereditary hemorrhagic telangiectasia

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Developing a competing risk nomogram that predicts the survival of patients with a primary hepatic neuroendocrine tumor.

Primary hepatic neuroendocrine tumor (PHNET) is rare liver cancer and related prognostic factors are unclear. The aim of this study was to analyze the prognostic risk factors of patients with PHNETs and establish an assessment model for prognosis. The clinical information of 539 patients with PHNETs who met the criteria for inclusion was extracted from the Surveillance, Epidemiology, and End Results (SEER) database. These patients were randomly assigned to the training (269 cases) and validation sets (270 cases). Prognostic factors in patients with PHNETs were screened using the Cox proportional regression model and Fine-Gray competing risk model. Based on the training set analysis using the Fine-Gray competing risk model, a nomogram was constructed to predict cumulative probabilities for PHNET-specific death. The performance of the nomogram was measured by using receiver operating characteristic curves, the concordance index (C-index), calibration curves, and decision curve analysis (DCA). No differences in clinical baseline characteristics between the training and validation sets were observed, and the Fine-Gray analysis showed that surgery and more than one primary malignancy were associated with a low cumulative probability of PHNET-specific death. The training set nomograms were well-calibrated and had good discriminative ability, and good agreement between predicted and observed survival was observed. Patients with PHNETs with a high-risk score had a significantly increased risk of PHNET-specific death and non-PHNET death. Surgical treatment and the number of primary malignancies were found to be independent protective factors for PHNETs. The competing risk nomogram has high accuracy in predicting disease-specific survival (DSS) for patients with PHNETs, which may help clinicians to develop individualized treatment strategies.

Generative adversarial networks (GAN)-based data augmentation of rare liver cancers: The SFR 2021 Artificial Intelligence Data Challenge

PurposeThe 2021 edition of the Artificial Intelligence Data Challenge was organized by the French Society of Radiology together with the Centre National d’Études Spatiales and CentraleSupélec with the aim to implement generative adversarial networks (GANs) techniques to provide 1000 magnetic resonance imaging (MRI) cases of macrotrabecular-massive (MTM) hepatocellular carcinoma (HCC), a rare and aggressive subtype of HCC, generated from a limited number of real cases from multiple French centers. Materials and methodsA dedicated platform was used by the seven inclusion centers to securely upload their anonymized MRI examinations including all three cross-sectional images (one late arterial and one portal-venous phase T1-weighted images and one fat-saturated T2-weighted image) in compliance with general data protection regulation. The quality of the database was checked by experts and manual delineation of the lesions was performed by the expert radiologists involved in each center. Multidisciplinary teams competed between October 11th, 2021 and February 13th, 2022. ResultsA total of 91 MTM-HCC datasets of three images each were collected from seven French academic centers. Six teams with a total of 28 individuals participated in this challenge. Each participating team was asked to generate one thousand 3-image cases. The qualitative evaluation was performed by three radiologists using the Likert scale on ten randomly selected cases generated by each participant. A quantitative evaluation was also performed using two metrics, the Frechet inception distance and a leave-one-out accuracy of a 1-Nearest Neighbor algorithm. ConclusionThis data challenge demonstrates the ability of GANs techniques to generate a large number of images from a small sample of imaging examinations of a rare malignant tumor.

Abstract 2495: Clinical and demographic predictors of survival for fibrolamellar hepatocellular carcinoma patients - A patient-community registry-based study

Abstract Fibrolamellar Carcinoma (FLC), a rare liver cancer, has yet no specific tools to evaluate its prognosis. This study aims, in partnership with the patient community, to search for associations between various demographic and clinical factors and overall survival of patients, to assess prognostic factors. We performed a retrospective analysis on a community-based patient registry (The Fibrolamellar Registry http://fibroregistry.org) to examine relations between survival and different variables. The variables examined were demographic (gender), clinical (age at diagnosis, tumor size, number of tumors inside the liver, presence of positive lymph nodes or distant metastasis) as well as treatment modalities (surgery or systemic therapy). Kaplan-Meier survival plots were created for the overall research population and for stratifying by unadjusted variables. Cox proportional hazards model was used for multivariable analysis of hazard ratio (HR) for death at any time among groups, adjusting for variables found significant in the univariate analysis. Among 150 patients, (89 females and 61 males), median overall survival time from diagnosis to death or loss of follow-up was 8 years and 2 months. Features with independent positive effect on survival were female gender, as well as being treated with surgery alone. In contrast, having 10 or more tumors inside the liver had a negative effect on survival. Positive lymph nodes at diagnosis, and distant metastasis at diagnosis, were both associated with poorer prognosis, though did not remain independent when adjusting for covariables. We could not find an effect of age at diagnosis or tumor size at its largest measurement, on survival. In conclusion, our study suggests gender is a significant prognostic factor for FLC patients, with females having a better outcome than males. Surgical removal of the tumor, without additional systemic therapy is a positive prognostic factor as well. Having a large number of tumors of 10 and above, despite all being inside the liver, is a negative prognostic factor. Citation Format: Amichai Berkovitz, Rachael D. Migler, Adam Qureshi, Roger Vaughan, Erin L. Marcotte, Sanford M. Simon. Clinical and demographic predictors of survival for fibrolamellar hepatocellular carcinoma patients - A patient-community registry-based study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2495.

Integrated Phosphoproteomics for Identifying Substrates of Human Protein Kinase A (PRKACA) and Its Oncogenic Mutant DNAJB1-PRKACA.

The DNAJB1-PRKACA fusion is the signature genetic event of fibrolamellar hepatocellular carcinoma (FL-HCC), a rare but lethal liver cancer that primarily affects adolescents and young adults. A deletion fuses the first exon of the HSP40 gene (DNAJB1), with exons 2-10 of protein kinase A (PRKACA), producing the chimeric kinase DNAJB1-PKAca (J-PKAca). The HSP40 portion's scaffolding/chaperone function has been implicated in redirecting substrate recognition to upregulate oncogenic pathways, but the direct substrates of this fusion are not fully known. We integrated cell-based and in vitro phosphoproteomics to identify substrates targeted directly by PKA and J-PKAca, comparing phosphoproteome profiles from cells with in vitro rephosphorylation of peptides and proteins from lysates using recombinant enzymes. We identified a subset of phosphorylation sites in both cell-based and in vitro experiments, as well as altered pathways and proteins consistent with observations from related studies. We also treated cells with PKA inhibitors that function by two different mechanisms (rpcAMPs and PKI) and examined phosphoproteome profiles, finding some substrates that persisted in the presence of inhibitors and revealing differences between WT and chimera. Overall, these results provide potential insights into J-PKAca's oncogenic activity in a complex cellular system and may provide candidate targets for therapeutic follow-up.

Novel systemic therapies in the treatment of fibrolamellar carcinoma.

e16161 Background: Fibrolamellar carcinoma (FLC) is an exceedingly rare liver cancer affecting children and young adults without underlying liver disease. Complete surgical resection is the primary treatment option, but recurrence is common. There are currently no established systemic therapies. We have treated patients in both the neoadjuvant and adjuvant setting with three novel combination therapies: 5-fluorouracil/interferon/nivolumab (“Triple Therapy” or TT), gemcitabine/oxaliplatin/lenvatinib (GOL), and nivolumab/lenvatinib/quercetin (NLQ). The purpose of this study was to evaluate objective responses and tolerability of three multi-agent systemic therapies in the treatment of FLC. Methods: Data from all patients with FLC who received TT, GOL, or NLQ between May 2018 and February 2021 were reviewed. Patients who received a minimum of six cycles of systemic therapy with follow up scans at least two months after initiation were assessed based on objective response, survival, and toxicity. Results: Twenty-nine patients with FLC who were treated with novel multi-agent systemic therapy were evaluable based on the above criteria. Median age at start of treatment was 20 (7-52; 16F, 12M, 1 non-disclosed). Twenty-three patients received one combination therapy (13 TT, 8 GOL, 2 NLQ), five received two different lines (3 TT/NLQ, 2 TT/GOL), and one patient received all three novel combinations. Between our 29 patients, they had relapsed 36 total times, and 11 had already tried 2+ systemic therapies. Best RECIST 1.1 objective response (clinical remission + partial response) and tumor control rate (clinical remission + partial response + stable disease) were 58%/95%, 55%/100%, and 33%/83% for TT, GOL, and NLQ respectively. The median longest Progression Free Survival (PFS) on any novel multi-agent regimen was 9 months (2-29; 9.5 for TT, 7 for GOL, 6.5 for NLQ), with 18 patients still receiving the therapy extending their PFS. Of those with previous relapses, 56% have a PFS longer than their previous longest remission and 69% have a PFS longer than their previous shortest time to relapse. Half of patients with previous relapses are still receiving the treatment responsible for their longest PFS. Fever, chills, and nausea were the most common adverse effects experienced throughout all three regimens. Seven patients experienced 1+ grade 3 adverse event. There were no toxic deaths or organ failure. Two patients died as a result of disease; their longest PFS (1 on GOL, 1 on TT) were nine and 10 months. Conclusions: FLC is a devastating cancer with patients often relapsing even after successful surgical remission. There is a strong need for effective and tolerable systemic therapies for those with unresectable, relapsed, progressive, or metastatic disease. We have had promising results in treating FLC and prolonging survival with minimal toxicities using novel multi-agent regimens.

Evaluation of neratinib (N), pembrolizumab (P), everolimus (E), and nivolumab (V) in patients (pts) with fibrolamellar carcinoma (FLC).

310 Background: FLC, a rare liver cancer of young adults, has no effective systemic therapies. Surgical resection is used extensively with non-curative intent. FLC is associated with a DNAJB1- PRKACA chimeric transcript that produces a fusion protein with retained kinase activity and increased expression of several oncogenic signaling pathways including, but not limited to, HER2 ( ERBB2). Methods: N (240 mg oral daily) was studied in FLC pts in the SUMMIT study (NCT01953926); and later under compassionate use for N-based combinations (combo): P (2 mg/kg q3w), E (7.5 mg daily), and V (240 mg q2w) in doublet or triplet regimens. Eligible pts: ≥12y; histologically confirmed FLC; adequate organ function; any number of prior therapies. Primary endpoint: objective response rate (ORR; RECIST v1.1). Secondary endpoints: duration of response; clinical benefit rate (CBR); safety (CTCAE v4.0); somatic and germline sequencing (MSK IMPACT). Results: As of 03-Sep-2020, 15 pretreated pts received N in SUMMIT (confirmed ORR 0%; CBR 13%). Efficacy data for 5 pts from SUMMIT and 2 more pts receiving combo under compassionate use (4 male, 3 female, median age 26 years, median 0 [range 0–4] prior systemic therapies) are in shown in the table. The most common adverse events (AE) with single-agent N (n = 5) were diarrhea (grade 1 80%; grade 2 20%) and nausea (grade 1 60%); other AEs were grade ≤1 in ≤20% of pts. Conclusions: N monotherapy had limited benefit as a single agent in FLC pts. Several case studies evaluating N-based combo with checkpoint inhibitors administered under compassionate use demonstrated that NP led to 1 PR, and the triplet of NPE to prolonged SD. These are case-limited observations but are critical and worth evaluating further in upcoming clinical trials given the continued lack of a standard of care therapy for pts with FLC. Clinical trial information: NCT01953926. [Table: see text]

Insights Into the Somatic Mutation Burden of Hepatoblastomas From Brazilian Patients.

Hepatoblastoma is a very rare embryonal liver cancer supposed to arise from the impairment of hepatocyte differentiation during embryogenesis. In this study, we investigated by exome sequencing the burden of somatic mutations in a cohort of 10 hepatoblastomas, including a congenital case. Our data disclosed a low mutational background and pointed out to a novel set of candidate genes for hepatoblastoma biology, which were shown to impact gene expression levels. Only three recurrently mutated genes were detected: CTNNB1 and two novel candidates, CX3CL1 and CEP164. A relevant finding was the identification of a recurrent mutation (A235G) in two hepatoblastomas at the CX3CL1 gene; evaluation of RNA and protein expression revealed upregulation of CX3CL1 in tumors. The analysis was replicated in two independents cohorts, substantiating that an activation of the CX3CL1/CX3CR1 pathway occurs in hepatoblastomas. In inflammatory regions of hepatoblastomas, CX3CL1/CX3CR1 were not detected in the infiltrated lymphocytes, in which they should be expressed in normal conditions, whereas necrotic regions exhibited negative labeling in tumor cells, but strongly positive infiltrated lymphocytes. Altogether, these data suggested that CX3CL1/CX3CR1 upregulation may be a common feature of hepatoblastomas, potentially related to chemotherapy response and progression. In addition, three mutational signatures were identified in hepatoblastomas, two of them with predominance of either the COSMIC signatures 1 and 6, found in all cancer types, or the COSMIC signature 29, mostly related to tobacco chewing habit; a third novel mutational signature presented an unspecific pattern with an increase of C>A mutations. Overall, we present here novel candidate genes for hepatoblastoma, with evidence that CX3CL1/CX3CR1 chemokine signaling pathway is likely involved with progression, besides reporting specific mutational signatures.