[Genome-wide Mendelian randomization study of the pathogenic role of gut microbiota in benign biliary tract diseases].

Objective: To investigate the causal relationship between intestinal flora and benign biliary diseases by genome-wide Mendelian randomization. Methods: This is a retrospective observational study. The data from the genome-wide association study of the gut microbiota from 18 340 samples from the MiBioGen consortium were selected as the exposure group,and the data from the genome-wide association study of biliary tract diseases were obtained from the FinnGen consortium R8 as the outcome group. There were 1 491 cases of primary sclerosing cholangitis,32 894 cases of cholelithiasis,3 770 cases of acalculous cholecystitis,and 34 461 cases of cholecystitis. Single nucleotide polymorphisms were screened as instrumental variables,and the Mendelian randomization method was used to infer the causal relationship between exposures and outcomes. The inverse variance weighting method (IVW) was used as the main basis, supplemented by heterogeneity,pleiotropy and sensitivity tests. Results: Coprococcus 2 was associated with a reduced risk of cholelithiasis (IVW OR=0.88,95%CI:0.80 to 0.97,P=0.012) and cholecystitis (IVW OR=0.88,95%CI:0.80 to 0.97,P=0.011). Coprococcus 3 was associated with cholelithiasis (IVW OR=1.15,95%CI:1.02 to 1.30,P=0.019) and acalculous cholecystitis(IVW OR=1.48, 95%CI: 1.08 to 2.04,P=0.016) and cholecystitis (IVW OR=1.17, 95%CI: 1.02 to 1.33, P=0.020). Peptococcus was associated with an increased risk of cholelithiasis (IVW OR=1.08, 95%CI:1.02 to 1.13, P=0.005) and cholecystitis (IVW CI=1.07, 95%CI:1.02 to 1.13,P=0.010). Clostridiumsensustricto 1 was associated with an increased risk of cholelithiasis (IVW OR=1.16,95%CI:1.02 to 1.31, P=0.020) and cholecystitis (IVW OR=1.16, 95%CI:1.03 to 1.30, P=0.015). Eubacterium hallii was associated with an increased risk of primary sclerosing cholangitis (IVW OR=1.43, 95%CI: 1.03 to 1.99, P=0.033). Eubacterium ruminantium (IVW OR=0.87, 95%CI: 0.76 to 1.00, P=0.043) and Methanobrevibacter (IVW OR=0.81, 95%CI: 0.68 to 0.98, P=0.027) were associated with a reduced risk of acalculous cholecystitis. Conclusions: Eight intestinal bacterial genera maybe play pathogenic roles in benign biliary diseases. Eubacterium hallii can increase the risk of primary sclerosing cholangitis. Peptococcus and Clostridiumsensustricto 1 can increase the risk of cholelithiasis and generalized cholecystitis. Coprococcus 3 have multiple correlations with biliary stones and inflammation.

Fine-scale visualizing the hierarchical structure of mouse biliary tree with fluorescence microscopy method.

The liver is a vital organ and the hepatic lobule serves as the most basic structural and functional unit which is mainly assembled with parenchymal cells including hepatocytes and biliary epithelial cells. The continuous tubular arrangement of biliary cells which constitutes the biliary tracts is critical for liver function, however, the biliary tracts are often disrupted in many liver diseases such as cirrhosis and some congenital disorders. Visualization of the biliary tracts in fine-scale and three-dimension will help to understanding the structure basis of these liver diseases. In the present study, we established several biliary tract injury mouse models by diet feeding, surgery or genetic modification. The cytoplasm and nuclei of the parenchymal cells were marked by active uptake of fluorescent dyes Rhodamine B (red) and Hoechst (blue), respectively. After the removal of liver en bloc, the biliary tracts were retrogradely perfused with green fluorescent dye, fluorescein isothiocyanate (FITC). The liver was then observed under confocal microscopy. The fine-scale and three-dimensional (3D) structure of the whole biliary tree, particularly the network of the end-terminal bile canaliculi and neighboring hepatocytes were clearly visualized. The biliary tracts displayed clear distinct characteristics in normal liver and diseased liver models. Taken together, we have developed a simple and repeatable imaging method to visualize the fine-scale and hierarchical architecture of the biliary tracts spreading in the mouse liver.

Integrating next-generation sequencing to endoscopic retrograde cholangiopancreatography (ERCP)-obtained biliary specimens improves the detection and management of patients with malignant bile duct strictures.

OBJECTIVE: Despite improvements in imaging, serum CA19-9 and pathological evaluation, differentiating between benign and malignant bile duct strictures remains a diagnostic conundrum. Recent developments in next-generation sequencing (NGS) have opened new opportunities for early detection and management of cancers but, to date, have not been rigorously applied to biliary specimens. DESIGN: We prospectively evaluated a 28-gene NGS panel (BiliSeq) using endoscopic retrograde cholangiopancreatography-obtained biliary specimens from patients with bile duct strictures. The diagnostic performance of serum CA19-9, pathological evaluation and BiliSeq was assessed on 252 patients (57 trainings and 195 validations) with 346 biliary specimens. RESULTS: The sensitivity and specificity of BiliSeq for malignant strictures was 73% and 100%, respectively. In comparison, an elevated serum CA19-9 and pathological evaluation had sensitivities of 76% and 48%, and specificities of 69% and 99%, respectively. The combination of BiliSeq and pathological evaluation increased the sensitivity to 83% and maintained a specificity of 99%. BiliSeq improved the sensitivity of pathological evaluation for malignancy from 35% to 77% for biliary brushings and from 52% to 83% for biliary biopsies. Among patients with primary sclerosing cholangitis (PSC), BiliSeq had an 83% sensitivity as compared with pathological evaluation with an 8% sensitivity. Therapeutically relevant genomic alterations were identified in 20 (8%) patients. Two patients with ERBB2-amplified cholangiocarcinoma received a trastuzumab-based regimen and had measurable clinicoradiographic response. CONCLUSIONS: The combination of BiliSeq and pathological evaluation of biliary specimens increased the detection of malignant strictures, particularly in patients with PSC. Additionally, BiliSeq identified alterations that may stratify patients for specific anticancer therapies.

A novel pathogenic variant of ATP-binding cassette subfamily B member 4 causing gallstones in a young adult.

The low phospholipid-associated cholelithiasis (LPAC) syndrome was reported in European adults with cholelithiasis and a mutation of the ATP-binding cassette subfamily B member 4 (ABCB4). The ABCB4 encodes multidrug resistance 3, which is a phospholipid translocator. Reduced phospholipid transport can lead to the formation of biliary cholesterol stones. Here, we describe a 31-year-old Japanese man diagnosed with recurrent biliary colic. Although he recovered quickly after endoscopic treatment for the most recent presentation, he had a family history of similar problems. His mother had required endoscopic treatment for choledocholithiasis and his maternal aunt had died at age 29 years because of liver failure (etiology unknown). We, therefore, performed genetic analysis, which revealed a heterozygous ABCB4C717S. LPAC syndrome was diagnosed and the patient has received ursodeoxycholic acid for 2 years with no recurrence. The same variant was identified in the patient's mother, who was subsequently found to have a left intrahepatic calculus requiring left-sided lobectomy. She has received ursodeoxycholic acid for 1 year with no recurrence. ABCB4C717S is a novel pathogenic variant, and this is the first patient diagnosed with LPAC syndrome in Japan. We should consider LPAC syndrome in young adults with recurrent cholesterol gallstones to ensure early therapy.

Biliary Tract Disease in Girls and Young Women With Rett Syndrome.

OBJECTIVE: We reviewed medical records and conducted a nationwide survey to characterize the clinical features and determine the prevalence of biliary tract disease in girls and women with Rett syndrome (RTT). METHODS: Sixty-two individuals with RTT and biliary tract disease were identified from the membership of Rett Syndrome Organization and patient files of the principal investigator. Medical records of 46 individuals were reviewed for presenting features, diagnostic tests, and treatment outcomes of biliary tract disease. We designed a questionnaire that probed the frequency of risk factors and treatment outcomes of biliary tract disease in RTT. The questionnaire was completed by 271 parents whose daughters met the clinical criteria for RTT and/or had MECP2 mutations and participated in the Natural History of Rett Syndrome Study. RESULTS: Presenting symptoms identified by record review included abdominal pain (94%), irritability (88%), weight loss (64%), and vomiting (52%). Biliary dyskinesia, cholecystitis, and cholelithiasis were identified in 90%, 77%, and 70%, respectively, by cholescintigraphy, surgical pathology, and abdominal ultrasound. The prevalence of biliary tract disease was 4.4% (n = 12) in the RTT cohort. Risk factors included older age (P < 0.001) and a positive family history (P < 0.01). Diagnoses included cholecystitis (n = 5), biliary dyskinesia (n = 6), and cholelithiasis (n = 7). Ten individuals underwent surgery; 7 had resolution of symptoms after surgical intervention. CONCLUSIONS: Biliary tract disease is not unique to RTT, but may be under-recognized because of the cognitive impairment of affected individuals. Early diagnostic evaluation and intervention may improve the health and quality of life of individuals affected with RTT and biliary tract disease.

Dilemma of elevated CA 19-9 in biliary pathology.

Carbohydrate antigen 19-9 (CA 19-9) is a tumor marker which has been extensively evaluated and widely utilized primarily in diagnosing and prognosticating pancreaticobiliary malignancies. Levels may be significantly influenced and elevated in cases of benign biliary conditions however, especially in obstructive jaundice, thereby posing difficulty in distinguishing between benign and malignant cholestasis. A myriad of studies have focused on elucidating proper use and interpretation of CA 19-9 in pancreatic cancer as well as in the setting of cholestasis. These studies have demonstrated that many factors influence CA 19-9 values and various methods for interpreting CA 19-9 in obstructive jaundice have been proposed. With improvements in diagnostic imaging, advancements in endoscopic modalities, and likelihood that management will not change based on the results of the test, clinicians should be cautious when ordering CA 19-9 and consider the reasons for measuring the tumor marker.

Ultrasound of congenital and inherited disorders of the pediatric hepatobiliary system, pancreas and spleen.

Ultrasound is often the initial imaging examination performed of the solid organs of the pediatric abdomen. The sonographic appearance of the hepatobiliary system, pancreas and spleen changes with growth and development. This article reviews the normal US appearance of these organs in children and illustrates, through case examples, congenital and inherited conditions that affect them.

From Clinical Standards to Translating Next-Generation Sequencing Research into Patient Care Improvement for Hepatobiliary and Pancreatic Cancers.

Hepatobiliary and pancreatic (HBP) cancers are associated with high cancer-related death rates. Surgery aiming for complete tumor resection (R0) remains the cornerstone of the treatment for HBP cancers. The current progress in the adjuvant treatment is quite slow, with gemcitabine chemotherapy available only for pancreatic ductal adenocarcinoma (PDA). In the advanced and metastatic setting, only two targeted drugs have been approved by the Food & Drug Administration (FDA), which are sorafenib for hepatocellular carcinoma and erlotinib for PDA. It is a pity that multiple Phase III randomized control trials testing the efficacy of targeted agents have negative results. Failure in the development of effective drugs probably reflects the poor understanding of genome-wide alterations and molecular mechanisms orchestrating therapeutic resistance and recurrence. In the post-ENCODE (Encyclopedia of DNA Elements) era, cancer is referred to as a highly heterogeneous and systemic disease of the genome. The unprecedented potential of next-generation sequencing (NGS) technologies to accurately identify genetic and genomic variations has attracted major research and clinical interest. The applications of NGS include targeted NGS with potential clinical implications, while whole-exome and whole-genome sequencing focus on the discovery of both novel cancer driver genes and therapeutic targets. These advances dictate new designs for clinical trials to validate biomarkers and drugs. This review discusses the findings of available NGS studies on HBP cancers and the limitations of genome sequencing analysis to translate genome-based biomarkers and drugs into patient care in the clinic.

Modulation of the Unfolded Protein Response by Tauroursodeoxycholic Acid Counteracts Apoptotic Cell Death and Fibrosis in a Mouse Model for Secondary Biliary Liver Fibrosis.

The role of endoplasmic reticulum stress and the unfolded protein response (UPR) in cholestatic liver disease and fibrosis is not fully unraveled. Tauroursodeoxycholic acid (TUDCA), a hydrophilic bile acid, has been shown to reduce endoplasmic reticulum (ER) stress and counteract apoptosis in different pathologies. We aimed to investigate the therapeutic potential of TUDCA in experimental secondary biliary liver fibrosis in mice, induced by common bile duct ligation. The kinetics of the hepatic UPR and apoptosis during the development of biliary fibrosis was studied by measuring markers at six different timepoints post-surgery by qPCR and Western blot. Next, we investigated the therapeutic potential of TUDCA, 10 mg/kg/day in drinking water, on liver damage (AST/ALT levels) and fibrosis (Sirius red-staining), in both a preventive and therapeutic setting. Common bile duct ligation resulted in the increased protein expression of CCAAT/enhancer-binding protein homologous protein (CHOP) at all timepoints, along with upregulation of pro-apoptotic caspase 3 and 12, tumor necrosis factor receptor superfamily, member 1A (TNFRsf1a) and Fas-Associated protein with Death Domain (FADD) expression. Treatment with TUDCA led to a significant reduction of liver fibrosis, accompanied by a slight reduction of liver damage, decreased hepatic protein expression of CHOP and reduced gene and protein expression of pro-apoptotic markers. These data indicate that TUDCA exerts a beneficial effect on liver fibrosis in a model of cholestatic liver disease, and suggest that this effect might, at least in part, be attributed to decreased hepatic UPR signaling and apoptotic cell death.

Human leucocyte antigens B*08, DRB1*03 and DRB1*13 are significantly associated with autoimmune liver and biliary diseases in Finnish children.

AIM: The human leucocyte antigen (HLA) allele and haplotype frequencies of the Finnish population are unique because of the restricted and homogenous gene population. There are no published data on HLA genotype associations in paediatric autoimmune liver diseases in Scandinavia. This study characterised the HLA genotypes of children with autoimmune liver or biliary disease in Finland. METHODS: The study cohort comprised 19 paediatric patients (13 female) aged three years to 15 years treated for autoimmune liver or biliary disease at the Children's Hospital, Helsinki University Hospital, between 2000 and 2011, and followed up for four years and three months to 14.6 years. We genotyped HLA-B and HLA-DRB1 in the children, and the HLA antigen frequencies were compared with 19 807 records from the Finnish Bone Marrow Donor Registry. RESULTS: All paediatric patients with autoimmune liver or biliary disease had either autoimmune HLA haplotype B*08;DRB1*03 or DRB1*13. These were significantly more common among patients with autoimmune hepatitis, primary sclerosing cholangitis and autoimmune hepatitis/primary sclerosing cholangitis overlap syndrome than the Finnish control population. HLA RB1*04 was not found in the study cohort. CONCLUSION: Our study found that B*08, DRB1*03 and DRB1*13 were significantly associated with autoimmune liver and biliary diseases in Finnish paediatric patients.

MicroRNAs and benign biliary tract diseases.

Cholangiocytes, the epithelial cells lining the biliary tree, represent only a small portion of the total liver cell population (3-5%), but they are responsible for the secretion of up to 40% of total daily bile volume. In addition, cholangiocytes are the target of a diverse group of liver diseases affecting the biliary tract, the cholangiopathies; for most of these conditions, the pathological mechanisms are unclear. MicroRNAs (miRNAs) are small, noncoding RNAs that posttranscriptionally regulate gene expression. Thus, it is not surprising that altered miRNA profiles underlie the dysregulation of several proteins involved in the pathobiology of the cholangiopathies, as well as showing promise as diagnostic and prognostic tools. Here the authors review recent work relevant to the role of miRNAs in the etiopathogenesis of several of the cholangiopathies (i.e., fibroinflammatory cholangiopathies and polycystic liver diseases), discuss their value as prognostic and diagnostic tools, and provide suggestions for further research.

Cellular senescence in biliary pathology. Special emphasis on expression of a polycomb group protein EZH2 and a senescent marker p16INK4a in bile ductular tumors and lesions.

A subgroup of intrahepatic cholangiocarcinoma and combined hepatocellular- cholangiocarcinoma contain a component of cholangiolocellular carcinoma, which is composed of small bile ductular cells. Ductular reaction, a reactive lesion at the portal tract interface comprising increased bile ductules, is frequently seen in chronic advanced liver diseases. Bile duct adenoma, a benign tumor/tumorous lesion is also composed of bile ductular cells. Differential diagnosis among these bile ductular tumors/lesions is sometimes difficult. Given overexpression of a polycomb group protein EZH2 in intrahepatic cholangiocarcinoma and high expression of senescence-associated p16INK4a in ductular reactions, we plan to apply immunostaining for EZH2 and p16INK4a for differential diagnosis of these bile ductular tumors/lesions. The expression of EZH2 was seen in all cases of cholangiolocellular carcinomas, while it was not observed in bile duct adenomas or ductular reactions. In contrast, the expression of p16INK4a was seen in most bile duct adenomas and all ductular reactions, whereas it was barely seen in cholangiolocellular carcinomas. A borderline between cholangiolocellular carcinoma and the surrounding ductular reaction was clearly highlighted by the reverse expression pattern of EZH2 and p16INK4a. In conclusion, immunostaining for EZH2 and p16INK4a may be useful for differential diagnosis for bile ductular tumors/lesions.

Heap of stones: an unusual cause for biliary colic and elevated liver function tests.

A 40-year old woman presented with symptomatic intrahepatic gallstones in one liver segment only four years after cholecystectomy for cholelithiasis. Multiple small, yellow and round calculi were completely removed from the intrahepatic bile ducts via ERCP. The young age of the patient, recurrence of gallstones after cholecystectomy and intrahepatic gallstones suggested a subtype of the low-phospholipid associated cholelithiasis syndrome, a monogenic form of cholesterol cholelithiasis due to variations of the ABCB4 gene that encodes the canalicular phospholipid transporter MDR3.

MicroRNAs in biliary diseases.

Cholangiopathies are a group of diseases primarily or secondarily affecting bile duct cells, and result in cholangiocyte proliferation, regression, and/or transformation. Their etiopathogenesis may be associated with a broad variety of causes of different nature, which includes genetic, neoplastic, immune-associated, infectious, vascular, and drug-induced alterations, or being idiopathic. miRNAs, small non-coding endogenous RNAs that post-transcriptionally regulate gene expression, have been associated with pathophysiological processes in different organs and cell types, and are postulated as potential targets for diagnosis and therapy. In the current manuscript, knowledge regarding the role of miRNAs in the development and/or progression of cholangiopathies has been reviewed and the most relevant findings in this promising field of hepatology have been highlighted.

Detection of IGF2BP3, HOXB7, and NEK2 mRNA expression in brush cytology specimens as a new diagnostic tool in patients with biliary strictures.

INTRODUCTION: It is a challenging task to distinguish between benign and malignant lesions in patients with biliary strictures. Here we analyze whether determination of target gene mRNA levels in intraductal brush cytology specimens may be used to improve the diagnosis of bile duct carcinoma. MATERIALS AND METHODS: Brush cytology specimens from 119 patients with biliary strictures (malignant: n = 72; benign: n = 47) were analyzed in a retrospective cohort study. mRNA of IGF-II mRNA-binding protein 3 (IGF2BP3), homeobox B7 (HOXB7), Forkhead box M1 (FOXM1), kinesin family member 2C (KIF2C) and serine/threonine kinase NEK2 was determined by semi-quantitative RT-PCR using the ΔCt method. RESULTS: IGF2BP3 (p<0.0001), HOXB7 (p<0.0001), and NEK2 (p<0.0001) mRNA expression levels were significantly increased in patients with cholangiocarcinoma or pancreatic cancer. Median ΔCt values differed by 3.5 cycles (IGF2BP3), 2.8 cycles (HOXB7) and 1.3 cycles (NEK2) corresponding to 11-fold, 7-fold and 2.5-fold increased mRNA levels in malignant versus benign samples. Sensitivity to detect biliary cancer was 76.4% for IGF2BP3 (80.9% specificity); 72.2% for HOXB7 (78.7% specificity) and 65.3% for NEK2 (72.3% specificity), whereas routine cytology reached only 43.1% sensitivity (85.4% specificity). Diagnostic precision was further improved, when all three molecular markers were assessed in combination (77.8% sensitivity, 87.2% specificity) and achieved 87.5% sensitivity and 87.2% specificity when molecular markers were combined with routine cytology. CONCLUSIONS: Our data suggest that measuring IGF2BP3, HOXB7 and NEK2 mRNA levels by RT-PCR in addition to cytology has the potential to improve detection of malignant biliary disorders from brush cytology specimens.

Liver specific deletion of CYLDexon7/8 induces severe biliary damage, fibrosis and increases hepatocarcinogenesis in mice.

BACKGROUND & AIMS: CYLD is a tumor suppressor gene that is mutated in familial cylindromatosis, an autosomal dominant predisposition to tumors of skin appendages. Reduced CYLD expression has been observed in other tumor entities, including hepatocellular carcinoma. In the present study, we analyzed the role of CYLD in liver homeostasis and hepatocarcinogenesis in vivo. METHODS: Mice with liver-specific deletion of CYLDexon7/8 (CYLD(FF)xAlbCre) were generated. Liver tissues were histologically analyzed and oval cell activation was investigated. Hepatocarcinogenesis was induced by diethylnitrosamine/phenobarbital (DEN/PB). Microarray expression profiling of livers was performed in untreated as well as DEN/PB-treated mice. NF-κB signaling was assessed by ELISA, quantitative real-time PCR, and Western blotting. RESULTS: CYLD(FF)xAlbCre hepatocytes and cholangiocytes did not express full-length CYLD (FL-CYLD) protein but showed increased expression of the naturally occurring short-CYLD splice variant (s-CYLD). CYLD(FF)xAlbCre mice exhibited a prominent biliary phenotype with ductular reaction and biliary-type fibrosis. In addition, CYLD(FF)xAlbCre mice showed a significantly increased sensitivity towards DEN/PB-induced hepatocarcinogenesis. Moreover, we could observe the development of cholangiocellular carcinoma, in line with enhanced oval cell activity. NF-κB-signaling was increased in livers of CYLD(FF)xAlbCre mice and likely contributed to the inflammatory and fibrotic response. CONCLUSIONS: The deletion of exon7/8 of the CYLD gene activates oval cells, leads to a biliary phenotype, and increases the susceptibility towards carcinogenesis in the liver. Thus, our study presents a novel model of biliary damage and liver fibrosis, followed by cancer development.

Prognostic relevance of circulating CK19 mRNA in advanced malignant biliary tract diseases.

AIM: To determine the role of circulating tumor cells (CTCs) in prediction of the overall survival of patients with advanced malignant biliary tract obstruction. METHODS: We investigated the prognostic value of CTCs by examining two markers, cytokeratin (CK) 19 and human telomerase reverse transcriptase (hTERT) mRNA, in 40 patients diagnosed with advanced malignant biliary tract diseases. Quantitative real-time reverse transcription polymerase chain reaction was used to detect CK19 and hTERT mRNA in the peripheral blood of these patients. Overall survival was analyzed using the Kaplan-Meier method and Cox regression modeling. RESULTS: Positive CK19 and hTERT mRNA expression was detected in 45% and 60%, respectively, of the 40 patients. Univariable analysis indicated that positive CK19 mRNA expression was significantly associated with worse overall survival (P = 0.009). Multivariable analysis determined that positive CK19 mRNA expression, patient's age and serum bilirubin were each independently associated with overall survival. CONCLUSION: CK19 mRNA expression levels in peripheral blood appear to provide a valuable marker to predict the overall survival of patients with advanced malignant biliary tract obstruction.

Genetic factors in the pathogenesis of cholangiocarcinoma.

BACKGROUND: Cholangiocarcinoma (CC) is increasing in incidence, but its pathogenesis remains poorly understood. Chronic inflammation of the bile duct and cholestasis are major risk factors, but most cases in the West are sporadic. Genetic polymorphisms in biliary transporter proteins have been implicated in benign biliary disease and, in the case of progressive familial cholestasis, have been associated with childhood onset of CC. In the current study, five biologically plausible candidate genes were investigated: ABCB11 (BSEP), ABCB4 (MDR3), ABCC2 (MRP2), ATP8B1 (FIC1) and NR1H4 (FXR). METHODS: DNA was collected from 172 Caucasian individuals with confirmed CC. A control cohort of healthy Caucasians was formed. Seventy-three SNPs were selected using the HapMap database to capture genetic variation around the five candidate loci. Genotyping was undertaken with a competitive PCR-based system. Confirmation of Hardy-Weinberg equilibrium and Cochran-Armitage trend testing were performed using PLINK. Haplotype frequencies were compared using haplo.stats. RESULTS: All 73 SNPs were in Hardy-Weinberg equilibrium. Four SNPs in ABCB11 were associated with altered susceptibility to CC, including the V444A polymorphism, but these associations did not retain statistical significance after Bonferroni correction for multiple testing. Haplotype analysis of the genotyped SNPs in ATP8B1 identified significant differences in frequencies between cases and controls (global p value of 0.005). CONCLUSION: Haplotypes in ATP8B1 demonstrated a significant difference between CC and control groups. There was a trend towards significant association of V444A with CC. Given the biological plausibility of polymorphisms in ABCB11 and ATP8B1 as risk modifiers for CC, further study in a validation cohort is required.