Analysis of the Application of Professional Society Screening Guidelines for Colorectal Polyposis Syndromes at a Single Institution.

Several professional society guidelines suggest germline genetic testing for colorectal polyposis syndromes in patients with ≥10 lifetime adenomatous polyps. This study evaluated the factors associated with genetic testing decisions and outcomes when germline testing was recommended per guidelines. Surgical archives revealed 145 patients with a recommendation for germline genetic polyposis testing based on guidelines. Demographic data and medical history were collected to examine their association with testing decisions and results. Germline genetic testing was ordered in 90 out of 145 patients and was ordered in younger patients with more lifetime adenomas. Pathogenic alterations were detected in 12 out of 53 patients who completed testing. Younger ages and higher numbers of lifetime adenomas were not associated with the detection of germline genetic alterations. In fact, patients with a pathogenic germline alteration had higher median ages and fewer lifetime adenomas than those without an alteration. Half of the 12 patients with a pathogenic germline mutation were not White non-Hispanic, although White non-Hispanic patients comprised 75.5% of those tested. This study supports the 10 adenomatous polyp threshold for recommending germline genetic polyposis testing, as an alteration was detected in a sizable proportion (>20%) of patients tested. Although a younger age and a higher number of lifetime adenomas were associated with an increased likelihood of ordered tests, no evidence was found to support these additional factors in testing decisions.

Machine learning models are superior to noninvasive tests in identifying clinically significant stages of NAFLD and NAFLD-related cirrhosis.

BACKGROUND AND AIMS: We assessed the performance of machine learning (ML) models in identifying clinically significant NAFLD-associated liver fibrosis and cirrhosis. APPROACH AND RESULTS: We implemented ML models including logistic regression (LR), random forest (RF), and artificial neural network to predict histological stages of fibrosis using 17 demographic/clinical features in 1370 patients with NAFLD who underwent liver biopsy, FibroScan, and labs within a 6-month period at multiple U.S. centers. Histological stages of fibrosis (≥F2, ≥F3, and F4) were predicted using ML, FibroScan liver stiffness measurements, and Fibrosis-4 index (FIB-4). NASH with significant fibrosis (NAS ≥ 4 + ≥F2) was assessed using ML, FibroScan-AST (FAST) score, FIB-4, and NAFLD fibrosis score (NFS). We used 80% of the cohort to train and 20% to test the ML models. For ≥F2, ≥F3, F4, and NASH + NAS ≥ 4 + ≥F2, all ML models, especially RF, had primarily higher accuracy and AUC compared with FibroScan, FIB-4, FAST, and NFS. AUC for RF versus FibroScan and FIB-4 for ≥F2, ≥F3, and F4 were (0.86 vs. 0.81, 0.78), (0.89 vs. 0.83, 0.82), and (0.89 vs. 0.86, 0.85), respectively. AUC for RF versus FAST, FIB-4, and NFS for NASH + NAS ≥ 4 + ≥F2 were (0.80 vs. 0.77, 0.66, 0.63). For NASH + NAS ≥ 4 + ≥F2, all ML models had lower/similar percentages within the indeterminate zone compared with FIB-4 and NFS. Overall, ML models performed better in sensitivity, specificity, positive predictive value, and negative predictive value compared with traditional noninvasive tests. CONCLUSIONS: ML models performed better overall than FibroScan, FIB-4, FAST, and NFS. ML could be an effective tool for identifying clinically significant liver fibrosis and cirrhosis in patients with NAFLD.

Markedly increased duodenal villous surface apoptosis in patients taking pre-exposure prophylaxis (PrEP) against human immunodeficiency virus.

AIMS: Pre-exposure prophylaxis (PrEP) consists of combination antiretroviral therapy and is increasingly utilized to prevent human immunodeficiency virus (HIV) in high-risk populations. Two index cases noted during routine care showed markedly increased duodenal villous surface apoptosis in patients on PrEP. We sought to examine the prevalence of this finding and identify any clinicopathologic correlations. METHODS: Gastrointestinal biopsy specimens from 23 male patients aged 18-40 years taking PrEP and 23 control patients were reviewed. Patients with HIV, inflammatory gastrointestinal diseases, and celiac disease were excluded. Apoptoses were counted on surface epithelium and deep crypts. The highest apoptotic body count per tissue fragment was recorded. Clusters were defined as groups of ≥5 apoptoses. Apoptotic counts between patients taking PrEP and controls were compared using t-tests. RESULTS: In PrEP patients, the median age was 35 years (range 25-40) and 83% (19/23) were white. The control patients were demographically similar (median age: 32 years [range 23-40]; 70% [16/23] white). Duodenal apoptosis in villous surface epithelium was increased in PrEP patients, with 14/23 (60.9%) patients having ≥10 surface apoptoses compared to 2/23 (8.7%) controls (P = 2.1 × 10-3 ) and 14/23 (61%) having clusters compared to 3/23 (13%) controls (P = 2.0 × 10-3 ). There was no significant association between increased surface apoptosis or clusters and clinical symptoms or duration of PrEP use. CONCLUSION: Markedly increased villous surface apoptosis, particularly in clusters, is often seen in the duodenum of patients taking PrEP. Although the mechanism and significance are unknown, knowledge of this peculiar finding may prevent unnecessary additional testing.

Glycogenic hepatopathy is associated with type 1 diabetes mellitus in only a minority of cases in a contemporary adult population.

OBJECTIVES: This study examines the clinical-pathological profiles of patients with glycogenic hepatopathy in a contemporary cohort of patients at an adult acute care hospital. METHODS: Liver biopsies with glycogenic hepatopathy were retrieved from the departmental surgical pathology database, the histological findings were studied, and the clinical findings were reviewed. RESULTS: Five cases of glycogenic hepatopathy were found, including cases associated with type 1 diabetes mellitus (n = 1), type 2 diabetes mellitus (n = 1), corticosteroids (n = 2), and anorexia (n = 2, including the patient with type 1 diabetes). AST and ALT were normal to mildly elevated (13-115 U/L and 7-126 U/L, respectively). Trace ascites was present in two patients. Hepatomegaly was only present in the patient with type 1 diabetes at the time of diagnosis. CONCLUSIONS: Four of five cases were associated with etiologies other than type 1 diabetes, which is widely reported as the most common etiology of glycogenic hepatopathy. This study suggests that etiologies currently only rarely recognized may actually be more common causes of glycogenic hepatopathy than type 1 diabetes in a contemporary adult population. It is important not only to recognize that these rarely reported causes of glycogenic hepatopathy may be underrecognized, but that the clinical presentation may also be mild.

MRI-based (MAST) score accurately identifies patients with NASH and significant fibrosis.

BACKGROUND & AIMS: Among the large population of patients with non-alcoholic fatty liver disease (NAFLD), identifying those with fibrotic non-alcoholic steatohepatitis (Fibro-NASH) is a clinical priority, as these patients are at the highest risk of disease progression and will benefit most from pharmacologic treatment. MRI-based proton density fat fraction (MRI-PDFF) and MR elastography (MRE) can risk-stratify patients with NAFLD by assessing steatosis and fibrosis, respectively. We developed a highly specific MRI-based score to identify patients with Fibro-NASH. METHODS: This analysis included derivation (n = 103) and validation (n = 244) cohorts of patients who underwent MRI, liver biopsy, transient elastography, and laboratory testing for NAFLD from 2016-2020 in 2 tertiary care centers. To identify Fibro-NASH, a formula was developed based on MRI-PDFF, MRE, and a third variable with highest balanced accuracy per logistic regression. The MRI-aspartate aminotransferase (MAST) score was created and compared to NAFLD fibrosis (NFS), Fibrosis-4 (FIB-4), and FibroScan-aspartate aminotransferase (FAST) scores. RESULTS: The MAST score demonstrated high performance and discrimination in the validation cohort (AUC 0.93; 95% CI 0.88-0.97). In the validation cohorts, the 90% specificity cut-off of 0.242 corresponded to a sensitivity of 75.0%, positive predictive value (PPV) of 50.0% and negative predictive value (NPV) of 96.5%, whereas the 90% sensitivity cut-off of 0.165 corresponded to a specificity of 72.2%, PPV of 29.4%, and NPV of 98.1%. Compared to NFS and FIB-4, MAST resulted in fewer patients having indeterminate scores and an overall higher AUC. Compared to FAST, MAST exhibited a higher AUC and overall better discrimination. CONCLUSION: The MAST score is an accurate, MRI-serum-based score that outperforms previous scores in non-invasively identifying patients at higher risk of Fibro-NASH. LAY SUMMARY: Identifying patients with non-alcoholic steatohepatitis and significant fibrosis - who need treatment and are at risk of clinical liver-related outcomes - is a clinical priority. We developed a more accurate score using MRI-based technologies and a laboratory blood test (aspartate aminotransferase) that outperforms previous non-invasive scores for the identification of patients at higher risk of liver disease progression.

Consensus recommendations for histological criteria of autoimmune hepatitis from the International AIH Pathology Group: Results of a workshop on AIH histology hosted by the European Reference Network on Hepatological Diseases and the European Society of Pathology: Results of a workshop on AIH histology hosted by the European Reference Network on Hepatological Diseases and the European Society of Pathology.

BACKGROUND & AIMS: Diagnostic histological criteria for autoimmune hepatitis (AIH) have not been clearly established. Previously published criteria focused mainly on chronic AIH, in which inflammatory changes mainly occur in portal/periportal regions and may not be applicable to acute presentation of AIH, in which inflammatory changes are typically predominantly lobular in location. International consensus criteria for the diagnosis and assessment of disease severity in both acute and chronic AIH are thus urgently needed. METHODS: Seventeen expert liver pathologists convened at an international workshop and subsequently used a modified Delphi panel approach to establish consensus criteria for the histopathological diagnosis of AIH. RESULTS: The consensus view is that liver biopsy should remain standard for diagnosing AIH. AIH is considered likely, if there is a predominantly portal lymphoplasmacytic hepatitis with more than mild interface activity and/or more than mild lobular hepatitis in the absence of histological features suggestive of another liver disease. AIH is also considered likely if there is predominantly lobular hepatitis with or without centrilobular necroinflammation and at least one of the following features: portal lymphoplasmacytic hepatitis, interface hepatitis or portal-based fibrosis, in the absence of histological features suggestive of another liver disease. Emperipolesis and hepatocellular rosettes are not regarded as being specific for AIH. CONCLUSIONS: The criteria proposed in this consensus statement provide a uniform approach to the histological diagnosis of AIH, which is relevant for patients with an acute as well as a chronic presentation and to more accurately reflect the current understanding of liver pathology in AIH.

Heterogeneity of liver fibrosis in patients with congestive hepatopathy: A biopsy and explant comparison series.

PURPOSE: Patients with end-stage heart failure and concomitant irreversible liver injury may be candidates for combined heart liver transplant (CHLT). Determining appropriate candidates for CHLT is essential given organ scarcity. Transjugular liver biopsy (TJLB) is used to evaluate the severity of parenchymal liver injury in transplant candidates. In patients with congestive hepatopathy (CH), the fibrosis pattern may be heterogenous. METHODS: We reviewed all CHLT cases between 2007 and 2017, as well as lone-heart transplant cases with post-mortem autopsy. Pre-transplant TJLB was compared to explant to assess the performance of biopsy fibrosis staging. RESULTS: 12 patients were included. Median age at time of transplant was 58 and the cohort was predominantly male (75%). Seven (64%) TJLB were predominantly stage 4 fibrosis and 4 (36%) were stage 1. Advanced fibrosis was the dominant pattern in 7 (70%) explants and 5 (50%) explants had heterogenous fibrosis. In 50% of CH cases, there was discordance between the TJLB and explant. In the autopsy cases, the TJLB and autopsy findings differed. CONCLUSIONS: In this series of matched TJLB and explanted livers, we found variable performance of TJLB in predicting the predominant fibrosis stage present in the liver.

Lymphogranuloma venereum (LGV) of the anorectum: evaluation of clinicopathological associations and the utility of a novel RNA in-situ hybridisation stain.

AIMS: Recent studies from multiple global regions have reported a resurgence of lymphogranuloma venereum (LGV) proctitis, which is caused by Chlamydia trachomatis (CT). LGV proctitis is histologically indistinguishable from other forms of sexually transmitted proctitis and is difficult to differentiate from inflammatory bowel disease. While immunohistochemical stains are available for syphilis, there is no commonly available stain for the tissue identification of CT. MATERIALS AND METHODS: From 200 positive CT nucleic acid tests (NAT) from anorectal swabs, we identified 12 patients with biopsies collected from the distal colorectum or anus within 90 days of the positive NAT. We collected basic demographic information and tabulated clinical and histological findings. We examined the performance of a novel RNA in-situ hybridisation (ISH) stain targeting CT 23s rRNA on these 12 cases and 10 controls from the anorectum. RESULTS: All 12 patients were male; nine were HIV+, two had concurrent gonococcal infection, one had concurrent syphilis and one had cytomegalovirus co-infection. The majority of biopsies (11 of 12) showed mild or moderate acute inflammation, had a prominent lymphoplasmacytic infiltrate (eight of 11) and lacked marked crypt distortion (10 of 10). The RNA ISH stain was positive in 10 of 12 cases (sensitivity 83%). One case showed equivocal staining. No controls showed definitive positive staining (specificity 100%). One had equivocal staining. CONCLUSION: Our series showed that anorectal LGV had similar histological findings to those of prior STI proctitis series predominantly comprised of syphilis. The novel RNA ISH stain was sensitive and specific and may show utility in differentiating types of STI proctitis.

Applying criteria for hepatocellular neoplasm of uncertain malignant potential reclassifies more than half of hepatocellular adenomas.

OBJECTIVES: Hepatocellular adenoma (HCA) is a benign well-differentiated hepatocellular neoplasm that can be difficult to distinguish from well-differentiated hepatocellular carcinoma (HCC). The term "well-differentiated hepatocellular neoplasm of uncertain malignant potential" (HUMP) has been proposed for neoplasms resembling HCAs, but arising in atypical clinical situations (in females over 50 years old or under 15, in males, with anabolic steroid use, or in some congenital conditions), and/or with atypical pathological features (focal cytological/architectural atypia, ß-catenin activation, or focal reticulin loss) insufficient for an unequivocal diagnosis of HCC. METHODS: This study evaluated HUMP criteria on 42 previously diagnosed HCAs from 33 patients. RESULTS: Twenty-six (62%) masses from 21 patients were classified as HUMPs. Eleven (42%) had focal cytological atypia, and two (8%) had focal architectural atypia. Four (15%) showed focal reticulin loss. Five (19%) showed evidence of ß-catenin activation. Four (12%) HUMP patients were male. CONCLUSIONS: In this series, HUMP did not correlate with an increased rate of synchronous or metachronous HCC compared to HCA. Clinical colleagues may not accept such a high rate of tumors placed in a category of "uncertain malignant potential". Additional study is warranted to refine criteria for designating well-differentiated hepatocellular neoplasms as of uncertain malignant potential.

Hepatic Tm6sf2 overexpression affects cellular ApoB-trafficking, plasma lipid levels, hepatic steatosis and atherosclerosis.

The human transmembrane 6 superfamily member 2 (TM6SF2) gene has been implicated in plasma lipoprotein metabolism, alcoholic and non-alcoholic fatty liver disease and myocardial infarction in multiple genome-wide association studies. To investigate the role of Tm6sf2 in metabolic homeostasis, we generated mice with elevated expression using adeno-associated virus (AAV)-mediated gene delivery. Hepatic overexpression of mouse Tm6sf2 resulted in phenotypes previously observed in Tm6sf2-deficient mice including reduced plasma lipid levels, diminished hepatic triglycerides secretion and increased hepatosteatosis. Furthermore, increased hepatic Tm6sf2 expression protected against the development of atherosclerosis in LDL-receptor/ApoB48-deficient mice. In cultured human hepatocytes, Tm6sf2 overexpression reduced apolipoprotein B secretion and resulted in its accumulation within the endoplasmic reticulum (ER) suggesting impaired ER-to-Golgi trafficking of pre-very low-density lipoprotein (VLDL) particles. Analysis of two metabolic trait-associated coding polymorphisms in the human TM6SF2 gene (rs58542926 and rs187429064) revealed that both variants impact TM6SF2 expression by affecting the rate of protein turnover. These data demonstrate that rs58542926 (E167K) and rs187429064 (L156P) are functional variants and suggest that they influence metabolic traits through altered TM6SF2 protein stability. Taken together, our results indicate that cellular Tm6sf2 level is an important determinant of VLDL metabolism and further implicate TM6SF2 as a causative gene underlying metabolic disease and trait associations at the 19p13.11 locus.

Wilson disease.

Wilson disease (WD) is an inherited disorder of copper metabolism. The resultant defective handling of copper results in toxic effects on the hepatocytes and increased copper in the circulation. Copper accumulates in other organ sites especially the central nervous system. WD occurs worldwide, usually between 5 and 35 years; a wider age range is now recognized. Clinical presentations are diverse and include combinations of hepatic, neurological, ophthalmic and psychiatric manifestations. Biochemical abnormalities such as serum ceruloplasmin and 24-h urinary copper excretion are important for the diagnosis but are not always abnormal in WD. They can overlap with non-WD causes. Patients may present with hepatic or neurological disease or combinations thereof. Approx. 50% of WD patients present with liver disease. Liver presentation is variable: asymptomatic abnormal liver tests, chronic hepatitis picture, cirrhosis, and acute liver failure. Similarly, the histology has several different patterns: mild nonspecific changes, steatosis or steatohepatitis, chronic hepatitis, and acute hepatitis with submassive or massive necrosis. None of these are specific for WD. Aids to the histologic diagnosis include special stains for copper and copper associated protein, and copper concentration in liver tissue. The biopsy is performed in the context of the clinical algorithms for the diagnosis of WD put forth by the clinical hepatology organizations such as the European Association for the Study of Liver Disease and the American Association for the Study of Liver Disease. The discovery of the responsible gene ATP7B has made the molecular diagnosis feasible through genetic testing and sequencing of the gene.

Cadherin-11 Is a Cell Surface Marker Up-Regulated in Activated Pancreatic Stellate Cells and Is Involved in Pancreatic Cancer Cell Migration.

Chronic pancreatitis is a prominent risk factor for the development of pancreatic ductal adenocarcinoma. In both conditions, the activation of myofibroblast-like pancreatic stellate cells (PSCs) plays a predominant role in the formation of desmoplastic reaction through the synthesis of connective tissue and extracellular matrix, inducing local pancreatic fibrosis and an inflammatory response. Yet the signaling events involved in chronic pancreatitis and pancreatic cancer progression and metastasis remain poorly defined. Cadherin-11 (Cad-11, also known as OB cadherin or CDH11) is a cell-to-cell adhesion molecule implicated in many biological functions, including tissue morphogenesis and architecture, extracellular matrix-mediated tissue remodeling, cytoskeletal organization, epithelial-to-mesenchymal transition, and cellular migration. In this study, we show that, in human chronic pancreatitis and pancreatic cancer tissues, Cad-11 expression was significantly increased in PSCs and pancreatic cancer cells. In particular, an increased expression of Cad-11 can be detected on the plasma membrane of activated PSCs isolated from chronic pancreatitis tissues and in pancreatic cancer cells metastasized to the liver. Moreover, knockdown of Cad-11 in cancer cells reduced pancreatic cancer cell migration. Taken together, our data underline the potential role of Cad-11 in PSC activation and pancreatic cancer metastasis.

Comparison of endoscopic ultrasound guided fine needle aspiration and PET/CT in preoperative diagnosis of pancreatic adenocarcinoma.

BACKGROUND: Endoscopic ultrasound guided fine needle aspiration (EUS-FNA) is the procedure of choice to investigate and sample pancreatic masses for the preoperative diagnosis of pancreatic ductal adenocarcinoma (PDAC). The role of 18fluoro-deoxyglucose positron emission tomography/computed tomography (PET/CT) in PDAC is debated. This study evaluates the role of EUS-FNA as compared to PET/CT in the preoperative evaluation of PDAC. METHODS: Preoperative evaluation by PET/CT and EUS-FNA was performed on 25 patients with pancreatic solid lesions, who underwent a subsequent Whipple procedure or partial pancreatic resection. RESULTS: This series included 19 PDACs and 6 non-PDACs including 1 metastatic breast ductal adenocarcinoma, 2 low grade neuroendocrine tumors, 2 chronic pancreatitis and 1 gastrointestinal tumor abutting the pancreas. EUS-FNA correctly diagnosed 18 of 19 PDACs, 1 metastatic breast ductal adenocarcinoma and all 5 of the other non-PDAC cases. One case of well differentiated PDAC was negative on EUS-FNA. PET/CT provided excellent size and was positive in 14 of 19 PDACs and the metastatic breast ductal adenocarcinoma. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy for EUS-FNA in diagnosis of selected pancreatic tumors were 91%, 100%, 100%, 50% and 92%, respectively, while they were 65%, 100%, 100%, 20% and 68% for PET/CT, respectively. CONCLUSIONS: Compared to PET/CT, EUS-FNA has a higher sensitivity and accuracy for preoperative diagnosis of PDAC. However, PET/CT provides excellent size, volume and stage information. A combination of both PET/CT and EUS will better help guide diagnosis and treatment of pancreatic adenocarcinoma.

The State of the Art in Colorectal Cancer Molecular Biomarker Testing.

The number of molecular biomarkers to inform treatment decisions in patients with metastatic colorectal cancer (mCRC) continues to expand and with it the methodologies that can be employed to evaluate these biomarkers. Beyond standard diagnostic and prognostic biomarkers, such as those used for Lynch syndrome, mutations in KRAS exon 2 are well established as predictive for lack of response to the antiepidermal growth factor receptor therapies panitumumab and cetuximab. Recent studies have extended these findings by demonstrating that mutations in KRAS exons 3 and 4 and in NRAS exons 2, 3, and 4 (with all KRAS and NRAS mutations collectively referred to as RAS) are also predictive for treatment outcomes among patients with mCRC receiving panitumumab and cetuximab in combination with chemotherapy or as monotherapy. Consequently, evaluation of these additional loci has been incorporated into current clinical guidelines, and pathologists will need to develop testing procedures and algorithms to reliably and rapidly evaluate RAS status. With the increased number of mutations that must be examined to evaluate the status of RAS and other emerging biomarkers, next-generation sequencing technologies are likely to become increasingly important in mCRC testing. This review describes new considerations for pathologists that have arisen as a consequence of the incorporation of additional biomarker testing into clinical practice for mCRC.

Hypoxia after transarterial chemoembolization may trigger a progenitor cell phenotype in hepatocellular carcinoma.

AIMS: To test the hypothesis that the hypoxia marker carbonic anhydrase IX (CAIX), and the cholangiocytic/progenitor markers cytokeratin (CK) 19 and epithelial cell adhesion molecule (EpCAM), may be expressed in areas of hypoxia in hepatocellular carcinoma (HCC) after transarterial chemoembolization (TACE). METHODS AND RESULTS: Immunohistochemistry for CAIX, CK19 and EpCAM (BerEP4) was performed in 57 HCCs, including 40 residual/recurrent tumours adjacent to the TACE treatment site and 17 untreated tumours from the same 40 patients. CAIX was exxpressed in 19 of 40 residual/recurrent HCCs and in two of 17 untreated HCCs. The rate of CAIX immunoreactivity in the treated tumours was significantly higher than that in the non-treated tumours (47.5% versus 11.8%, P = 0.015). CK19 and EpCAM were expressed in six of 19 and in seven of 19 CAIX-positive TACE-treated HCCs, respectively, but were not expressed in CAIX-negative tumours or untreated tumours. There were significant associations between CK19 and CAIX immunoreactivity, and between EpCAM and CAIX immunoreactivity (P = 0.007 and P = 0.003, respectively). Double staining of CAIX and CK19 showed co-localization of both proteins in five of six cases. Three of seven EpCAM-positive tumours were also positive for CK19. CONCLUSIONS: Hypoxia may trigger the expression of proteins that are normally associated with cholangiocytic/progenitor cell differentiation, suggesting that TACE paradoxically causes an aggressive tumour phenotype.

Identification of driver genes in hepatocellular carcinoma by exome sequencing.

UNLABELLED: Genetic alterations in specific driver genes lead to disruption of cellular pathways and are critical events in the instigation and progression of hepatocellular carcinoma (HCC). As a prerequisite for individualized cancer treatment, we sought to characterize the landscape of recurrent somatic mutations in HCC. We performed whole-exome sequencing on 87 HCCs and matched normal adjacent tissues to an average coverage of 59×. The overall mutation rate was roughly two mutations per Mb, with a median of 45 nonsynonymous mutations that altered the amino acid sequence (range, 2-381). We found recurrent mutations in several genes with high transcript levels: TP53 (18%); CTNNB1 (10%); KEAP1 (8%); C16orf62 (8%); MLL4 (7%); and RAC2 (5%). Significantly affected gene families include the nucleotide-binding domain and leucine-rich repeat-containing family, calcium channel subunits, and histone methyltransferases. In particular, the MLL family of methyltransferases for histone H3 lysine 4 were mutated in 20% of tumors. CONCLUSION: The NFE2L2-KEAP1 and MLL pathways are recurrently mutated in multiple cohorts of HCC.

Arginase-1 is More Specific Than Hepatocyte Paraffin 1 for Differentiating Hepatocellular Carcinomas With Cytoplasmic Clearing from Nonhepatocellular Clear Cell Tumors in Liver Biopsies.

Arginase-1 (Arg1) and hepatocyte paraffin antigen 1 (HepPar1) are specific and sensitive markers of hepatocellular differentiation. HepPar1 is a granular cytoplasmic immunostain that may be negative in hepatocellular carcinoma (HCC) with cytoplasmic clearing. Arg1 shows uniform cytoplasmic positivity and frequent nuclear positivity. This study was undertaken to determine the staining pattern of Arg1 in HCC with cytoplasmic clearing and compare its use to HepPar1. Fifteen resected HCCs with cytoplasmic clearing and 31 biopsies of clear cell liver tumors (14 HCCs and 17 nonhepatocellular tumors) were identified. Resections were stained with Arg1 to characterize the pattern, intensity, and extent of Arg1 positivity. Biopsies were stained with Arg1 (n=31) and HepPar1 (n=28). In all, 13/15 resected and 11/14 biopsied HCCs with cytoplasmic clearing showed nuclear positivity for Arg1. Both Arg1 and HepPar1 stained significantly more HCCs than nonhepatocellular tumors (13/14 and 11/12, respectively, with P <0.0001 and P =0.0018, respectively). However, HepPar1 stained significantly more nonhepatocellular tumors (5/12) than Arg1 (0/17, P =0.0445). Arg1 frequently displayed nuclear positivity, and interobserver agreement was better for Arg1 ( K =0.93 vs. 0.79). Overall, Arg1 is more specific than HepPar1 for differentiating HCC with cytoplasmic clearing from nonhepatocellular clear cell tumors in the liver. Its staining characteristics, including nuclear positivity, make it easier to interpret in combination with morphology, improving interobserver variability, and it stains significantly fewer mimics than HepPar1.

5-Hydroxymethylcytosine (5-hmC) loss is a marker of malignancy in biliary neoplasms.

OBJECTIVES: Adenocarcinomas of the biliary tract frequently present diagnostic challenges because of their histologic overlap with benign and preinvasive lesions. The molecular profiles of biliary adenocarcinomas vary by anatomical location. Variations in IDH1/2, common in intrahepatic cholangiocarcinoma, can lead to defective production of 5-hydroxymethylcytosine (5-hmC). Limited ancillary studies are available for biliary adenocarcinomas, and loss of 5-hmC staining could serve as a helpful ancillary diagnostic tool for biliary tract malignancies. METHODS: We evaluated 93 cases-20 benign biliary lesions, 15 preinvasive biliary neoplasms, 46 invasive biliary carcinomas, and 12 pancreatic adenocarcinomas-for 5-hmC staining. Preoperative biopsies from 16 cases of biliary carcinoma were also stained. Sixteen nonneoplastic/reactive bile duct biopsies served as controls. RESULTS: Loss of 5-hmC was seen in 41 of 46 (89.1%) biliary malignancies vs 0 of 20 benign tumors (P < .001), for a sensitivity and specificity of 89.1% and 100%, respectively. Intrahepatic cholangiocarcinoma showed loss of 5-hmC in 11 of 13 (84.6%) cases, similar to the 30 of 33 (90.9%) cases in other biliary adenocarcinomas (P = .61). Similarly, 5-hmC loss was more frequent in distal bile duct adenocarcinomas than in pancreatic ductal adenocarcinomas, at 15 of 17 (88.2%) vs 4 of 12 (33.3%), respectively (P = .0045). There was no difference in the frequency of 5-hmC loss in patients that received neoadjuvant therapy vs those who did not (90.9% vs 88.6%, P > .99). 5-hmC immunohistochemistry in preoperative biopsies was concordant with the resection specimen in 81.3% (13/16) of cases. CONCLUSIONS: Loss of 5-hmC is not unique to intrahepatic cholangiocarcinoma among biliary carcinomas, but is a useful diagnostic marker differentiating malignancies of the biliary tree from benign mimics.

Hepatic cell-type specific gene expression better predicts HCV treatment outcome than IL28B genotype.

BACKGROUND & AIMS: Cell-type specific expression patterns of hepatic interferon-stimulated genes (ISGs) and single nucleotide polymorphisms (SNPs) near the IL28B gene are associated with response to interferon-based therapy in patients with chronic hepatitis C virus (HCV) infection. It is not known how the IL28B genotype influences the ISG expression pattern and which is a better predictor of treatment response. METHODS: Patients at the Toronto Western Hospital Liver Centre with known outcome to interferon-based treatment for HCV infection were evaluated. Analysis included hepatic gene expression profile using complementary DNA microarrays, genotype at the IL28B SNP rs12979860, and immunostaining for human myxovirus A protein 1 (MxA) in hepatocytes and macrophages. RESULTS: The level of ISG immunostaining in hepatic macrophages correlated inversely with that of hepatocytes and was strongly associated with treatment outcome. Gene expression profiles and the IL28B genotype were associated with treatment response, but only absence of MxA staining in macrophages accurately predicted nonresponse to treatment. The positive predictive value (PPV) of the IL28B genotype was 94% and the negative predictive value (NPV) was 51% (n = 209). For messenger RNA expression, the PPV was 94% and the NPV was 54% (n = 65). For detection of MxA in macrophages, the PPV was 60% and the NPV was 98% (n = 110). Of 53 patients with undetectable macrophage MxA staining, only one had a sustained virologic response. IL28B genotype was strongly associated with cell-type specific staining for MxA. There was a stepwise increase in macrophage staining and decrease in hepatocyte staining from the TT (lack of response) to CC SNP (associated with response) in IL28B. By logistic regression, after controlling for the presence of macrophage MxA staining, the IL28B genotype was no longer associated with treatment response. CONCLUSIONS: The cell-type-specific expression pattern of ISGs varies among patients with different IL28B genotypes and is a strong predictor of response to interferon-based treatment.