PTEN Deficiency Induces an Extrahepatic Cholangitis-Cholangiocarcinoma Continuum via Aurora kinase A in Mice.

BACKGROUND & AIMS: The PTEN-AKT pathway is frequently altered in extrahepatic cholangiocarcinoma (eCCA). We aim to evaluate the role of PTEN in the pathogenesis of eCCA and find novel therapies for this disease. METHODS: The Pten gene in the biliary epithelial cells were genetically deleted using the Cre-loxp system. The pathologies were evaluated both macroscopically and histologically. The characteristics were further analyzed by immunohistochemistry (IHC), RT-PCR, cell culture, and RNAseq. Some features were compared to those in human eCCA samples. Further mechanistic studies utilized the conditional knockout of Trp53 and Aurora kinase A (Aurka) genes. Experimental therapy was tested using an Aurka inhibitor. RESULTS: We observed that genetic deletion of the Pten gene in the extrahepatic biliary epithelium and peri-ductal glands initiated sclerosing cholangitis-like lesions in mice, resulting in enlarged and distorted extrahepatic bile ducts in mice as early as one month old. Histologically, these lesions exhibited increased epithelial proliferation, inflammatory cell infiltration, and fibrosis. With aging, the lesions progressed from low-grade dysplasia to invasive carcinoma. Trp53 inactivation further accelerated the disease progression, potentially through downregulating senescence. Further mechanistic studies showed that both human and mouse eCCA showed high expressions of AURKA. Notably, the genetic deletion of Aurka completely eliminated Pten deficiency-induced extrahepatic bile duct lesions. Furthermore, pharmacological inhibition of Aurka alleviated disease progression. CONCLUSIONS: Pten deficiency in extrahepatic cholangiocytes and peribiliary glands led to a cholangitis-to-cholangiocarcinoma continuum through an Aurka-dependent manner. These findings offer new insights into preventive and therapeutic interventions for extrahepatic CCA. IMPACT AND IMPLICATIONS: The aberrant PTEN-PI3K-AKT signaling pathway is commonly observed in human extrahepatic cholangiocarcinoma (eCCA), a disease with a poor prognosis. In our study, we developed a mouse model mimicking cholangitis to eCCA progression by conditionally deleting the Pten gene via Pdx1-Cre in epithelial cells and peribiliary glands of the extrahepatic biliary duct. The conditional Pten deletion in these cells led to cholangitis, which gradually advanced to dysplasia, ultimately resulting in eCCA. The loss of Pten heightened Akt signaling, cell proliferation, inflammation, fibrosis, DNA damage, epigenetic signaling, epithelial-mesenchymal transition (EMT), cell dysplasia, and cellular senescence. Genetic deletion or pharmacological inhibition of Aurka successfully halted the disease progression. This model shall be valuable for testing novel therapies and unraveling the mechanisms of eCCA tumorigenesis.

Imaging of Alcohol-Associated Liver Disease.

Alcohol-associated liver disease (ALD) continues to be a global health concern, responsible for a significant number of deaths worldwide. Although most individuals who consume alcohol do not develop ALD, heavy drinkers and binge drinkers are at increased risk. Unfortunately, ALD is often undetected until it reaches advanced stages, frequently associated with portal hypertension and hepatocellular carcinoma (HCC). ALD is now the leading indication for liver transplant. The incidence of alcohol-associated hepatitis (AH) surged during the COVID-19 pandemic. Early diagnosis of ALD is therefore important in patient management and determination of prognosis, as abstinence can halt disease progression. The spectrum of ALD includes steatosis, steatohepatitis, and cirrhosis, with steatosis the most common manifestation. Diagnostic techniques including ultrasound, CT, and MRI provide useful information for identifying ALD and excluding other causes of liver dysfunction. Heterogeneous steatosis and transient perfusion changes on CT and MRI in the clinical setting of alcohol-use disorder are diagnostic of severe AH. Elastography techniques are useful for assessing fibrosis and monitoring treatment response. These various imaging modalities are also useful in HCC surveillance and diagnosis. This review discusses the imaging modalities currently used in the evaluation of ALD, highlighting their strengths, limitations, and clinical applications.

CRP Versus SAA for Identification of Inflammatory Hepatic Adenomas.

Subtyping hepatic adenomas is important for patient management due to differing complication risks. Immunohistochemical staining with C-reactive protein (CRP) and serum amyloid-A (SAA) is widely accepted as a surrogate for molecular classification to identify inflammatory hepatocellular adenomas. Limited data, however, has been published on how these 2 stains compare for sensitivity. We conducted a large, multicenter, retrospective study to examine the sensitivity and staining characteristics of CRP and SAA in inflammatory hepatic adenomas, with focal nodular hyperplasia (FNHs) as a control group. Inflammatory adenomas were identified in 133 patients (average age 37 years, 109 were female). In all, 69.9% of cases were resection specimens and 90.2% of all cases showed positive staining for both CRP and SAA; 10 (7.5%) were positive for CRP only and 3 (2.3%) were positive for SAA only. CRP was more sensitive than SAA (97.74% vs. 92.48%, P -value = 0.0961) and showed more extensive and intense staining, with a significantly higher modified H-score ( P <0.001). Focal nodular hyperplasia can also show positive CRP and SAA staining but with a lower modified H-score ( P <0.0001). Based on beta-catenin and glutamine synthetase staining, 26 of inflammatory adenomas also had beta-catenin activation (19.5%). All 3 cases with positive SAA and negative CRP staining were beta-catenin activated. In contrast, the proportion of cases that were CRP positive and SAA negative was similar regardless of beta-catenin activation. The data affirms the strategy of using both CRP and SAA immunostains for hepatic adenoma subtyping and raises the awareness of the highly variable nature of SAA staining characteristics.

Therapeutic Efficacy of Temsirolimus in a Patient-derived Model of Metastatic Fibrolamellar Hepatocellular Carcinoma.

BACKGROUND/AIM: Fibrolamellar hepatocellular carcinoma (FLHCC) is a rare tumor presenting in younger patients without chronic liver disease. Up to 80-100% develop recurrent disease, necessitating additional surgery or systemic treatment. Systemic options and pre-clinical treatment studies are lacking. We previously described patient-derived xenograft (PDX) development, allowing for pre-clinical studies. Herein, we develop FLHCC PDX models and utilize these to define tumor characteristics and determine the efficacy of systemic agents. MATERIALS AND METHODS: Primary and lymph node metastatic tumor tissues were obtained at the time of FLHCC resection in two patients. Tumor lysates were screened for protein upregulation. Cell lines were generated from metastatic and primary tumor tissue. The viability of the cell lines was assessed after treatment with temsirolimus, gemcitabine/oxaliplatin, and FOLFIRINOX. Two PDX models were developed from metastatic tissue. For in vivo studies, tumor-bearing mice were treated with temsirolimus, FOLFIRINOX, and Gemcitabine/oxaliplatin. RESULTS: PDX models were successfully generated from metastatic FLHCC, which closely recapitulated the original tumor. Upregulation of mTOR was seen in metastatic tissue compared to primary tumors. Cell lines from metastatic tissue demonstrated significant sensitivity to temsirolimus. In vivo testing of PDX models demonstrated a significant response to single-agent temsirolimus with minimal toxicity. CONCLUSION: Herein, we demonstrate the feasibility of developing PDX models that closely recapitulate FLHCC. Upregulation of mTOR was seen in metastatic tissue compared to primary tissue. The efficacy of mTOR inhibition with temsirolimus treatment suggests that the upregulation of the mTOR pathway may be a significant mechanism for growth in metastatic lesions and a potential target for therapeutics.

Hepatic Angiosarcomas With Sinusoidal Growth Patterns.

Hepatic angiosarcomas are aggressive malignant tumors of the liver with variable morphology. One of the rare morphologies is that of the sinusoidal growth pattern, which is challenging to diagnose because of its subtle imaging and morphologic findings. This retrospective study characterizes the clinical, histologic, and immunohistochemical features of sinusoidal hepatic angiosarcomas. Thirteen cases were included in the study, comprising 12 (92.3%) needle core biopsies and 1 wedge biopsy; one of the needle biopsies also had a subsequent resection specimen available for review. Multiple biopsies were needed to make the diagnosis in 4 cases. At least moderate sinusoidal dilatation was seen in 53.8% of cases. Increased cellularity within the sinusoids was seen at both low-power and high-power magnification (69.2% and 84.6%, respectively). Cytologic atypia ranged from mild to marked. Multinucleated tumor cells were present in most cases (10/13 cases) but were often sparse. Mitotic activity was identified in 5/13 cases. ERG immunostains were more reliable than CD31 and CD34 in identifying the tumor cells. Ki-67 proliferative index ranged from 5% to 30%. p53 immunostains were available in 9 cases and c-MYC in 7 cases; they were positive in 62.5% and 33.3% of cases, respectively and had a mutually exclusive staining pattern. In summary, this rare pattern of hepatic angiosarcoma is challenging to diagnose but has distinctive morphologic findings that can be supplemented with immunostains to establish the diagnosis.

Disruption of proteome by an oncogenic fusion kinase alters metabolism in fibrolamellar hepatocellular carcinoma.

Fibrolamellar hepatocellular carcinoma (FLC) is a usually lethal primary liver cancer driven by a somatic dysregulation of protein kinase A. We show that the proteome of FLC tumors is distinct from that of adjacent nontransformed tissue. These changes can account for some of the cell biological and pathological alterations in FLC cells, including their drug sensitivity and glycolysis. Hyperammonemic encephalopathy is a recurrent problem in these patients, and established treatments based on the assumption of liver failure are unsuccessful. We show that many of the enzymes that produce ammonia are increased and those that consume ammonia are decreased. We also demonstrate that the metabolites of these enzymes change as expected. Thus, hyperammonemic encephalopathy in FLC may require alternative therapeutics.

Unique Morphologic Findings in the Liver After Stereotactic Radiation for Cholangiocarcinoma.

Newer radiotherapy techniques, such as stereotactic body radiation, have been increasingly used as part of the treatment of cholangiocarcinomas, particularly as a bridge to liver transplantation. Although conformal, these high-dose therapies result in tissue injury in the peritumoral liver tissue. This retrospective study characterized the morphologic changes in the liver after stereotactic body radiation in a series of liver explant specimens with perihilar cholangiocarcinoma. The morphologic changes in the irradiated zone were compared against the nonirradiated background liver parenchyma to control for chemotherapy-related changes. Of the 21 cases studied, 16 patients (76.2%) had underlying primary sclerosing cholangitis, and 13 patients (61.9%) had advanced liver fibrosis. The average duration between completion of radiotherapy and liver transplantation was 33.4 weeks (range: 6.29 to 67.7). Twelve patients (57.1%) had no residual tumor in the liver. The most frequent histologic changes in the peritumoral irradiated liver tissue were sinusoidal congestion (100%), sinusoidal edematous stroma (100%), and hepatocellular atrophy (100%), followed by partial/complete occlusion of central veins (76.2%), sinusoidal cellular infiltrates (76.2%), and hepatocyte dropout (66.7%). The findings in the radiated areas were more extensive than in the background liver ( P <0.01). Sinusoidal edematous stroma was striking and dominated the histologic findings in some cases. Over time, there was less sinusoidal congestion but more hepatocyte dropout (r s =-0.54, P =0.012 and r s =0.64, P =0.002, respectively). Uncommon findings, such as foam cell arteriopathy in the liver hilum, were also observed. In summary, postradiation liver specimens have distinctive morphologic findings.

Imaging Features in the Liver after Stereotactic Body Radiation Therapy.

Historically, radiation therapy was not considered in treatment of liver tumors owing to the risk of radiation-induced liver disease. However, development of highly conformed radiation treatments such as stereotactic body radiation therapy (SBRT) has increased use of radiation therapy in the liver. SBRT is indicated in treatment of primary and metastatic liver tumors with outcomes comparable to those of other local therapies, especially in treatment of hepatocellular carcinoma. After SBRT, imaging features of the tumor and surrounding background hepatic parenchyma demonstrate a predictable pattern immediately after treatment and during follow-up. The goals of SBRT are to deliver a lethal radiation dose to the targeted liver tumor and to minimize radiation dose to normal liver parenchyma and other adjacent organs. Evaluation of tumor response after SBRT centers on changes in size and enhancement; however, these changes are often delayed secondary to the underlying physiologic effects of radiation. Knowledge of the underlying pathophysiologic mechanisms of SBRT should allow better understanding of the typical imaging features in detection of tumor response and avoid misinterpretation from common pitfalls and atypical imaging findings. Imaging features of radiation-induced change in the surrounding liver parenchyma are characterized by a focal liver reaction that can potentially be mistaken for no response or recurrence of tumor. Knowledge of the pattern and chronology of this phenomenon may allay any uncertainty in assessment of tumor response. Other pitfalls related to fiducial marker placement or combination therapies are important to recognize. The authors review the basic principles of SBRT and illustrate post-SBRT imaging features of treated liver tumors and adjacent liver parenchyma with a focus on avoiding pitfalls in imaging evaluation of response. Online supplemental material is available for this article. ©RSNA, 2022.

Clinical and demographic predictors of survival for fibrolamellar carcinoma patients-A patient community, registry-based study.

Fibrolamellar hepatocellular carcinoma (FLC) is a rare primary liver cancer that affects primarily adolescents and young adults. It is associated with a poor overall prognosis. There is a need to better define risk factors, but small sample size has limited such studies. An FLC patient registry now provides data sufficient for statistically robust inferences. We leveraged a unique patient community-based FLC registry to analyze the prognostic impact of demographic and clinical characteristics evident at diagnosis. Variables were analyzed using Cox proportional hazards regression to calculate hazard ratios (HRs) and 95% confidence intervals (CIs). In multivariable models of 149 patients (88 females and 61 males), female gender was associated with statistically significant improved survival with HR of 0.52 (95% CI 0.29-0.93). Factors evident at diagnosis that are associated with worse survival included the presence of 10 or more tumors within the liver (HR 7.1; 95% CI 2.4-21.04), and metastases at diagnosis (HR 2.17; 95% CI 1.19-3.94). Positive lymph nodes at diagnosis, despite being found significantly associated with worse survival in a univariate analysis, did not remain significant when adjusted for covariates in a multivariable analysis. We found no statistically significant effect of age at diagnosis nor tumor size at diagnosis on survival. Female gender may confer a favorable prognosis in FLC. Established high-risk prognostic factors that we confirmed in this Registry included the diagnostic presence of numerous intrahepatic tumors, and metastases. This is the first study derived from a FLC patient community-based registry, and highlights how registries of rare tumors can empower patients to meaningfully advance clinical and scientific discoveries.

Human liver organoids for disease modeling of fibrolamellar carcinoma.

Fibrolamellar carcinoma (FLC) is a rare, often lethal, liver cancer affecting adolescents and young adults, for which there are no approved therapeutics. The development of therapeutics is hampered by a lack of in vitro models. Organoids have shown utility as a model system for studying many diseases. In this study, tumor tissue and the adjacent non-tumor liver were obtained at the time of surgery. The tissue was dissociated and grown as organoids. We developed 21 patient-derived organoid lines: 12 from metastases, three from the liver tumor and six from adjacent non-tumor liver. These patient-derived FLC organoids recapitulate the histologic morphology, immunohistochemistry, and transcriptome of the patient tumor. Patient-derived FLC organoids were used in a preliminary high-throughput drug screen to show proof of concept for the identification of therapeutics. This model system has the potential to improve our understanding of this rare cancer and holds significant promise for drug testing and development.

Eosinophilic Disorders of the Gastrointestinal Tract and Associated Abdominal Viscera: Imaging Findings and Diagnosis.

Eosinophilic gastrointestinal disorders (EGIDs) are inflammatory conditions of the gastrointestinal tract that are characterized by tissue eosinophilia and end-organ dysfunction or damage. Primary EGIDs are associated with atopy and other allergic conditions, whereas secondary EGIDs are associated with underlying systemic diseases or hypereosinophilic syndrome. Within the spectrum of EGIDs, eosinophilic esophagitis is the most prevalent. Eosinophilic gastroenteritis and eosinophilic colitis are relatively uncommon. Eosinophilic infiltration of the liver, biliary tree, and/or pancreas also can occur and mimic other inflammatory and malignant conditions. Although endoscopic evaluation is the method of choice for eosinophilic esophagitis, radiologic evaluation of the esophagus plays an important role in the assessment of disease severity. CT and MR enterography are the modalities of choice for demonstrating specific forms of eosinophilic gastroenteritis. CT and MRI are important in the detection of abdominal visceral involvement in EGIDs. Diagnosis is often challenging and relies on symptoms, imaging findings, histologic confirmation of tissue eosinophilia, and correlation with peripheral eosinophilia. Imaging is crucial for identifying characteristic organ-specific findings, although imaging findings are not specific. When promptly treated, EGIDs usually have a benign clinical course. However, a delayed diagnosis and associated surgical interventions have been associated with morbidity. Therefore, a radiologist's knowledge of the imaging findings of EGIDs in the appropriate clinical settings may aid in early diagnosis and thereby improve patient care. An overview of the clinical features and imaging findings of EGIDs and the eosinophilic disorders of associated abdominal viscera is provided. Online supplemental material is available for this article. ©RSNA, 2022.

Hepatic Adenomas in Patients 60 and Older Are Enriched for HNF1A Inactivation and Malignant Transformation.

Hepatic adenomas occur most commonly in women between the ages of 20 and 40 years, but rarely they occur in older aged persons, including those 60 years of age or older. This group of adenomas, however, has not been systemically examined. Twenty-six hepatic adenomas in persons 60 years of age or older were studied, along with a control group of 50 hepatic adenomas in persons aged 30 to 39. Hepatic adenomas in persons 60 or more years of age were found in 21 women and 5 men, while the control group had 44 women and 6 men. Subtyping the adenomas in persons 60 years or older showed the following results: 18 HNF1A-inactivated adenomas (69%), 4 inflammatory adenomas (15%), and 4 unclassified adenomas (15%). In contrast, the control group showed a significantly different pattern (P=0.003), with a greater percentage of inflammatory adenomas (28, 56%), fewer HNF1A-inactivated adenomas (8, 16%), and more unclassified adenomas (14, 28%). Atypia and malignant transformation within the hepatic adenomas was studied next. Of the hepatic adenomas in persons age 60 or greater, 3 (12%) showed atypical histologic features, and 6 (23%) had a malignant transformation. In contrast, for hepatic adenomas in the control group, only 4 (8%) adenomas showed atypical histologic features, and 3 (6%) had undergone malignant transformation. In addition, the hepatic adenomas that were atypical or showed early malignant transformation were less likely to have beta-catenin activation in patients over 60 (2/9 cases) compared with those between 30 and 39 years (5/7 cases). Myxoid change and heavy lipofuscin deposition were also more common in adenomas in older aged persons. In conclusion, hepatic adenomas in persons 60 years of age or older are enriched for HNF1A-inactivated adenomas and have a higher frequency of malignant transformation. Malignant transformation, however, is less likely to develop through activation of the beta-catenin pathway.

Hepatocellular neoplasms with loss of liver fatty acid binding protein: Clinicopathologic features and molecular profiling.

HNF1A-inactivated hepatocellular adenomas (H-HCA) show steatosis, no atypia and loss of liver fatty acid binding protein (LFABP). LFABP loss also occurs in hepatocellular carcinoma (HCC). This study examines 68 LFABP-negative tumors: 33 typical H-HCA, 10 atypical hepatocellular neoplasms (AHN), 7 well-differentiated (WD) HCC, 18 moderately or poorly differentiated (MD/PD) HCC. Capture based sequencing was performed in 13 cases (8 AHN, 5 WD-HCC). Patients with HCA, AHN and WD-HCC were nearly all women. AHN and WD-HCC resembled H-HCA but had higher degree of atypia and/or reticulin loss. Variant features like inconspicuous fat (59% vs. 12%, p = 0.03), predominance of eosinophilic cells (59% vs. 21%, p = 0.01) and pseudoacini were more common in AHN and WD-HCC. Myxoid change and prominent lipofuscin were more common in WD-HCC (29% each) than H-HCA and AHN combined (2% and 7% respectively). Compared to WD-HCC, LFABP-negative MD/PD HCC were more commonly associated with male gender, viral hepatitis and cirrhosis. Biallelic HNF1A alterations were seen in all 13 (100%) sequenced cases. Additional mutations and/or copy number alterations were observed in 38% of AHN and 100% of WD-HCC. Diffuse glutamine synthetase (GS) staining was seen in 13% of cases, with no nuclear ß-catenin or Wnt signaling alterations. In conclusion, variant features such as lack of fat, peliosis, myxoid change, pseudoacini and abundant lipofuscin are more common in AHN and/or WD-HCC. LFABP-negative MD/PD HCC have different clinicopathologic features compared to WD-HCC. The significance of diffuse GS in a subset of these cases is unclear.

Liver fibrosis quantification.

Liver fibrosis (LF) is the wound healing response to chronic liver injury. LF is the endpoint of chronic liver disease (CLD) regardless of etiology and the single most important determinant of long-term liver-related clinical outcomes. Quantification of LF is important for staging, to evaluate response to treatment and to predict outcomes. LF is traditionally staged by liver biopsy. However, liver biopsy is invasive and suffers from sampling errors when biopsy size is inadequate; therefore, non-invasive tests (NITs) have found important roles in clinical care. NITs include simple laboratory-based serum tests, panels of serum tests, and imaging biomarkers. NITs are validated against the liver biopsy and will be used in the future for evaluation of nearly all CLDs with invasive liver biopsy reserved for some cases. Both serum tests and some imaging biomarkers such as elastography are currently used clinically as surrogate markers for LF. Several other imaging biomarkers are still considered research and awaiting clinical application in the future. As the evaluation of imaging biomarkers will likely become the norm in the future, understanding pathogenesis of LF is important. Knowledge of properties measured by imaging biomarkers and its correlation with LF is important to understand the application of NITs by abdominal radiologists. In this review, we present a brief overview of pathogenesis of LF, spatiotemporal evolution of LF in different CLD, and severity assessment with liver biopsy. This will be followed by a brief discussion on properties measured by imaging biomarkers and their relationship to the LF.

PSMA as a Theranostic Target in Hepatocellular Carcinoma: Immunohistochemistry and 68 Ga-PSMA-11 PET Using Cyclotron-Produced 68 Ga.

Prostate-specific membrane antigen (PSMA) is a validated target for molecular diagnostics and targeted radionuclide therapy. Our purpose was to evaluate PSMA expression in hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA), and hepatic adenoma (HCA); investigate the genetic pathways in HCC associated with PSMA expression; and evaluate HCC detection rate with 68 Ga-PSMA-11 positron emission tomography (PET). In phase 1, PSMA immunohistochemistry (IHC) on HCC (n = 148), CCA (n = 111), and HCA (n = 78) was scored. In a subset (n = 30), messenger RNA (mRNA) data from the Cancer Genome Atlas HCC RNA sequencing were correlated with PSMA expression. In phase 2, 68 Ga-PSMA-11 PET was prospectively performed in patients with treatment-naïve HCC on a digital PET scanner using cyclotron-produced 68 Ga. Uptake was graded qualitatively and semi-quantitatively using standard metrics. On IHC, PSMA expression was significantly higher in HCC compared with CCA and HCA (P < 0.0001); 91% of HCCs (n = 134) expressed PSMA, which principally localized to tumor-associated neovasculature. Higher tumor grade was associated with PSMA expression (P = 0.012) but there was no association with tumor size (P = 0.14), fibrosis (P = 0.35), cirrhosis (P = 0.74), hepatitis B virus (P = 0.31), or hepatitis C virus (P = 0.15). Overall survival tended to be longer in patients without versus with PSMA expression (median overall survival: 4.2 vs. 1.9 years; P = 0.273). FGF14 (fibroblast growth factor 14) mRNA expression correlated positively (rho = 0.70; P = 1.70 × 10-5 ) and MAD1L1 (Mitotic spindle assembly checkpoint protein MAD1) correlated negatively with PSMA expression (rho = -0.753; P = 1.58 × 10-6 ). Of the 190 patients who met the eligibility criteria, 31 patients with 39 HCC lesions completed PET; 64% (n = 25) lesions had pronounced 68 Ga-PSMA-11 standardized uptake value: SUVmax (median [range] 9.2 [4.9-28.4]), SUVmean 4.7 (2.4-12.7), and tumor-to-liver background ratio 2 (1.1-11). Conclusion: Ex vivo expression of PSMA in neovasculature of HCC translates to marked tumor avidity on 68 Ga-PSMA-11 PET, which suggests that PSMA has the potential as a theranostic target in patients with HCC.

Morphologic and Molecular Findings in Myxoid Hepatic Adenomas.

Myxoid hepatic adenomas are a rare subtype of hepatic adenomas with distinctive deposition of extracellular myxoid material between the hepatic plates. A total of 9 cases were identified in 6 women and 3 men with an average of 59±12 years. The myxoid adenomas were single tumors in 5 cases and multiple in 4 cases. In 1 case with multiple adenomas, the myxoid adenoma arose in the background of GNAS-mutated hepatic adenomatosis. Myxoid hepatic adenomas had a high frequency of malignant transformation (N=5 cases). They were characterized at the molecular level by HNF1A inactivating mutations, leading to loss of LFABP protein expression. In addition, myxoid adenomas had recurrent mutations in genes within the protein kinase A (PKA) pathway or in genes that regulate the PKA pathway: GNAS, CDKN1B (encodes p27), and RNF123. In sum, myxoid adenomas are rare, occur in older-aged persons, have a high risk of malignant transformation, and are characterized by the combined inactivation of HNF1A and additional mutations that appear to cluster in the PKA pathway.

Pediatric Hepatocellular Adenomas: The Influence of Age and Syndrome on Subtype.

Hepatocellular adenomas are rare in children. A large study focused on pediatric patients has not been undertaken. A natural language search was performed at 5 institutions for hepatocellular adenomas in patients younger than 21 years old. Clinical characteristics as well as immunohistochemical staining profile was reviewed and adenomas subtyped per standard classification. Patients were divided into prepubescent and postpubescent age group. Thirty-one patients were included. Eleven (35%) were male and 10 (32%) were prepubescent. Fifteen (54%) of 28 patients with known clinical histories had adenomas associated with a syndrome. The percentage of the different adenoma subtypes was: 16% ß-catenin activated, 10% combined inflammatory and ß-catenin activated, 29% HFN1α-inactivated, 35% inflammatory, and 10% unclassified subtype by immunohistochemical staining. Interestingly 53% of patients with syndromes were male, while 85% of patients in the nonsyndromic group were female. The total number of ß-catenin activated tumors was greater in the syndromic group (5/15, 33%) and prepubescent group (5/10, 50%) than in the nonsyndromic group (2/13, 16%) and postpubescent group (3/21, 14%), P=0.4 and 0.07, respectively. Inflammatory type adenoma was more frequent in the postpubescent (10/21, 48%) than in the prepubescent group (1/10, 10%), P=0.06, trending toward significance. Pediatric patients with hepatocellular adenomas frequently have syndromes, especially in the prepubescent group. In patients with syndromes a greater percentage of adenomas were ß-catenin activated. In patients without a known syndrome the distribution of hepatocellular adenoma subtypes appears similar to adults.

Identification of Novel Therapeutic Targets for Fibrolamellar Carcinoma Using Patient-Derived Xenografts and Direct-from-Patient Screening.

To repurpose therapeutics for fibrolamellar carcinoma (FLC), we developed and validated patient-derived xenografts (PDX) from surgical resections. Most agents used clinically and inhibitors of oncogenes overexpressed in FLC showed little efficacy on PDX. A high-throughput functional drug screen found primary and metastatic FLC were vulnerable to clinically available inhibitors of TOPO1 and HDAC and to napabucasin. Napabucasin's efficacy was mediated through reactive oxygen species and inhibition of translation initiation, and specific inhibition of eIF4A was effective. The sensitivity of each PDX line inversely correlated with expression of the antiapoptotic protein Bcl-xL, and inhibition of Bcl-xL synergized with other drugs. Screening directly on cells dissociated from patient resections validated these results. This demonstrates that a direct functional screen on patient tumors provides therapeutically informative data within a clinically useful time frame. Identifying these novel therapeutic targets and combination therapies is an urgent need, as effective therapeutics for FLC are currently unavailable. SIGNIFICANCE: Therapeutics informed by genomics have not yielded effective therapies for FLC. A functional screen identified TOPO1, HDAC inhibitors, and napabucasin as efficacious and synergistic with inhibition of Bcl-xL. Validation on cells dissociated directly from patient tumors demonstrates the ability for functional precision medicine in a solid tumor.This article is highlighted in the In This Issue feature, p. 2355.

Sulfatase 2 (SULF2) Monoclonal Antibody 5D5 Suppresses Human Cholangiocarcinoma Xenograft Growth Through Regulation of a SULF2-Platelet-Derived Growth Factor Receptor Beta-Yes-Associated Protein Signaling Axis.

BACKGROUND AND AIMS: Existing therapeutic approaches to treat cholangiocarcinoma (CCA) have limited effectiveness, prompting further study to develop therapies for CCA. We report a mechanistic role for the heparan sulfate editing enzyme sulfatase 2 (SULF2) in CCA pathogenesis. APPROACH AND RESULTS: In silico analysis revealed elevated SULF2 expression in human CCA samples, occurring partly through gain of SULF2 copy number. We examined the effects of knockdown or overexpression of SULF2 on tumor growth, chemoresistance, and signaling pathway activity in human CCA cell lines in vitro. Up-regulation of SULF2 in CCA leads to increased platelet-derived growth factor receptor beta (PDGFRß)-Yes-associated protein (YAP) signaling activity, promoting tumor growth and chemotherapy resistance. To explore the utility of targeting SULF2 in the tumor microenvironment for CCA treatment, we tested an anti-SULF2 mouse monoclonal antibody, 5D5, in a mouse CCA xenograft model. Targeting SULF2 by monoclonal antibody 5D5 inhibited PDGFRß-YAP signaling and tumor growth in the mouse xenograft model. CONCLUSIONS: These results suggest that SULF2 monoclonal antibody 5D5 or related agents may be potentially promising therapeutic agents in CCA.

Hepatocellular carcinoma: making sense of morphological heterogeneity, growth patterns, and subtypes.

Hepatocellular carcinomas are not a homogenous group of tumors but have multiple layers of heterogeneity. This heterogeneity has been studied for many years with the goal to individualize care for patients and has led to the identification of numerous hepatocellular carcinoma subtypes, defined by morphology and or molecular methods. This article reviews both gross and histological levels of heterogeneity within hepatocellular carcinoma, with a focus on histological findings, reviewing how different levels of histological heterogeneity are used as building blocks to construct morphological hepatocellular carcinoma subtypes. The current best practice for defining a morphological subtype is outlined. Then, the definition for thirteen distinct hepatocellular carcinoma subtypes is reviewed. For each of these subtypes, unresolved issues regarding their definitions are highlighted, including recommendations for these problematic areas. Finally, three methods for improving the research on hepatocellular carcinoma subtypes are proposed: (1) Use a systemic, rigorous approach for defining hepatocellular carcinoma subtypes (four-point model); (2) Once definitions for a subtype are established, it should be followed in research studies, as this common denominator enhances the ability to compare results between studies; and (3) Studies of subtypes will be more effective when morphological and molecular results are used in synergistic and iterative study designs where the results of one approach are used to refine and sharpen the results of the other. These and related efforts to better understand heterogeneity within hepatocellular carcinoma are the most promising avenue for improving patient care by individualizing patient care.