Common genetic variation and risk of gallbladder cancer in India: a case-control genome-wide association study

Perforated Calculous Cholecystitis and Incidental Squamous Cell Carcinoma of the Gallbladder-A Complex Relationship with a Difficult Management in the Acute Setting

The worldwide prevalence of gallstones (GSs) is estimated to be between 10% and 15% in the general population. Gallbladder carcinoma (GBC) is the most common biliary tract neoplasia, and it is characterized by highly aggressive behavior and poor overall prognosis. Long-standing GSs and chronic inflammatory state represent the most common risk factors for GBC, promoting a carcinogenic microenvironment. Long-standing GSs expose patients to potentially severe surgical and oncological complications. A 71-year-old gentleman, who had never experienced biliary symptoms and had diabetes mellitus (DM), presented with severe peritonitis due to perforated acute calculous cholecystitis. The patient underwent an emergent laparotomic cholecystectomy. Histopathology found a rare pT2b poorly differentiated squamocellular carcinoma of the gallbladder. Although more difficult due to the concomitant inflammatory context, it is critical to identify suspicious lesions during preoperative imaging in patients at high risk of malignancy presenting with complex acute gallbladder pathologies. A review of the literature was conducted to gain a deeper insight into the relationship between long-standing GSs and GBC, evaluating also the difficult diagnosis and management of malignancy in the acute setting. Considering the existing literature, the choice to pursue a prophylactic cholecystectomy may be justifiable in selected asymptomatic GS patients at high risk for GBC.

Mapping the landscape of biliary tract cancer in Europe: challenges and controversies

Biliary tract cancer (BTC) is becoming more common worldwide, with geographic differences in incidence and risk factors. In Europe, BTC may be associated with primary sclerosing cholangitis, lithiasis, and liver cirrhosis, but is more frequently observed as a sporadic disease. BTC increasingly affects patients under 60 years, resulting in a significant social and economic burden. Early diagnosis remains challenging due to vague symptoms in 50% of patients with BTC, and lack of specific biomarkers, resulting in late presentation and poor prognosis. The identification of patients at increased risk and reliable biomarkers require collaborative efforts to make faster progress. This Series paper highlights the disparities in access to diagnostic tools and multidisciplinary care in Europe, particularly in economically disadvantaged regions, while identifying priority areas for improvement. Addressing these inequities requires harmonised guidelines, accelerated pathways to curative treatments, and improved awareness among healthcare professionals and the public. Multidisciplinary teams (MDTs) are crucial for the diagnosis of BTC and for improving patient outcomes, yet inconsistencies exist in their implementation not only between different countries, but also between different centres within a country. Collaboration and standardisation of diagnostic and treatment protocols across Europe are essential to effectively address the management of patients with BTC.

Small-RNA sequencing reveals potential serum biomarkers for gallbladder cancer: Results from a three-stage collaborative study of large European prospective cohorts

Gallbladder cancer (GBC) is an aggressive disease with limited treatment options but high prevention potential. GBC tumours take 10-20 years to develop, a timeframe that holds potential for early detection. MicroRNAs (miRNAs) play a central role in abnormal cell processes, and circulating miRNAs may constitute valuable biomarkers of early disease. We used microarray data to pre-select differentially expressed miRNAs in formalin-fixed paraffin-embedded (FFPE) gallbladder tissue samples (GBC n = 40, normal n = 8). We then applied small-RNA sequencing to screen for miRNA expression differences in serum samples from three European prospective cohorts (n = 37 GBC case-control pairs), and validated the most promising candidates in three independent cohorts (n = 36 GBC case- control pairs). Statistical analyses included robust linear regression, pathway and meta-analysis, and examination of expression correlation between miRNAs and target genes. MiR-4533 and miR-671-5p were overexpressed in GBC tissue and serum samples, and meta-analysis confirmed the overexpression of miR-4533 in GBC serum samples from the prospective cohorts (p-value = 4.1×10-4), especially in individuals of female sex, under 63.5 years, or with a BMI below 26.2 kg/m2. Pathway and correlation analyses revealed that miR-4533 targets SIPA1L2 in the Rap1 signalling pathway, and SIPA1L2 was downregulated in GBC serum samples. Our study highlights the advantage of integrating small-RNA sequencing results from different types of samples and independent datasets, and the need for international research collaborations to identify and validate biomarkers for secondary prevention of rare tumours such as GBC. The function of miR-4533 and its interaction with SIPA1L2 in GBC development need to be further investigated.

Inbreeding and Gallbladder Cancer Risk: Homozygosity Associations Adjusted for Indigenous American Ancestry, BMI, and Genetic Risk of Gallstone Disease

Latin Americans have a rich genetic make-up that translates into heterogeneous fractions of the autosomal genome in runs of homozygosity (FROH) and heterogeneous types and proportions of indigenous American ancestry. While autozygosity has been linked to several human diseases, very little is known about the relationship between inbreeding, genetic ancestry, and cancer risk in Latin Americans. Chile has one of the highest incidences of gallbladder cancer (GBC) in the world, and we investigated the association between inbreeding, GBC, gallstone disease (GSD), and body mass index (BMI) in 4029 genetically admixed Chileans. We calculated individual FROH above 1.5 Mb and weighted polygenic risk scores for GSD, and applied multiple logistic regression to assess the association between homozygosity and GBC risk. We found that homozygosity was due to a heterogeneous mixture of genetic drift and consanguinity in the study population. Although we found no association between homozygosity and overall GBC risk, we detected interactions of FROH with sex, age, and genetic risk of GSD that affected GBC risk. Specifically, the increase in GBC risk per 1% FROH was 19% in men (p-value = 0.002), 30% in those under 60 years of age (p-value = 0.001), and 12% in those with a genetic risk of GSD above the median (p-value = 0.01). The present study highlighted the complex interplay between inbreeding, genetic ancestry, and genetic risk of GSD in the development of GBC. The applied methodology and our findings underscored the importance of considering the population-specific genetic architecture, along with sex- and age-specific effects, when investigating the genetic basis of complex traits in Latin Americans.

What eliminates the chance for cure: a multi-center evaluation on 10-year follow-up of gallbladder cancer after surgical resection

Curative resection stands as the sole potential cure for gallbladder cancer (GBC); nevertheless, a dearth of knowledge persists regarding long-term follow-up data and prognostic factors that hinder achieving a cure post-surgery. A retrospective cohort study was conducted by analyzing pathologically confirmed initial resections for GBC between 2000 and 2013 across three Chinese medical centers. The concept of observed cure refers to a 10-year survival period devoid of any disease recurrence. Employing a semiparametric proportional hazards mixture cure model enabled the identification of clinicopathological factors impeding a cure for GBC post-surgery. In our current study, a total of 331 patients were included, with a follow-up period exceeding a decade. The median overall survival (OS) was recorded at 31.6 months, with 39 patients (11.78%) achieving a 10-year OS, classified as 10-year survivors. Within this subset, 36 patients reached a 10-year relapse-free survival, denoting cure, and yielding an observed cure rate of 10.88%. Notably, factors such as combined surgical resection involving invaded organs, positive lymph node metastasis, and R1 resection (below 1%) were identified as virtually precluding a cure. Additionally, patients with T3-4 stage, hepatic invasion, advanced AJCC stage or poor tumor differentiation exhibited a low likelihood of achieving cure (below 5%). The discovery of these prognostic factors holds significant value in tailoring individualized treatment strategies and enhancing clinical decision-making processes.

Environmental Risk Factors for Gallbladder Cancer: Field-Wide Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Cholelithiasis is the most well-recognized risk factor for gallbladder cancer (GBC), the predominant biliary-tract malignancy; however, credibility on other modifiable exposures remains uncertain. We performed a field-wide systematic review and meta-analysis on environmental factors associated with GBC.

METHODS

We systematically searched Medline/PubMed and Embase up to May 8, 2023, to identify randomized and nonrandomized studies examining environmental factors for GBC. We conducted random-effects meta-analyses focusing on longitudinal studies. Evidence from case-control studies was considered complementary. Evidence credibility was graded by prespecified criteria including the random-effects estimate, 95% confidence interval (CI), P value, statistical heterogeneity, small-study effects, and robustness to unmeasured confounding.

RESULTS

We identified 215 eligible primary studies and performed 350 meta-analyses across 7 domains: lifestyle, reproductive, metabolic, dietary, infections, interventions, and contaminants and occupational exposures. Based on longitudinal evidence, body mass index (relative risk [RR] per 5-unit increase, 1.27; 95% CI, 1.21‒1.33), hip circumference (RR per 5-cm increase, 1.16; 95% CI, 1.11‒1.22), infection of bile ducts (RR, 31.7; 95% CI, 24.8-40.6), high parity (RR, 1.48; 95% CI, 1.30‒1.68), obesity (RR, 1.70; 95% CI, 1.44‒2.01), overweight (RR, 1.28; 95% CI, 1.14‒1.43), waist circumference (RR per 5-cm increase, 1.14; 95% CI, 1.10‒1.18), and waist-to-height ratio (RR per 0.1 increase, 1.49; 95% CI, 1.36‒1.64) were robustly associated with increased GBC risk, whereas high education (RR, 0.63; 95% CI, 0.49‒0.82) was associated with reduced risk (moderate-to-high credibility). Another 39 significant associations showed lower credibility, including different exposure scenarios of tobacco smoking, alcohol consumption, and insufficient physical activity.

CONCLUSIONS

This study offers a detailed appraisal and mapping of the evidence on modifiable factors for GBC. Further high-quality prospective studies are essential to validate emerging associations and inform preventive strategies in high-incidence areas. (Systematic review registration: CRD42023434673.).

Trends and Patterns of Top Ten Common Cancers in Eastern India from 2014 to 2021: A Retrospective Hospital-based Cancer Registry Data Update

Background

India is a vast and diverse country with existing variations in the frequency and distribution of cancers across its various parts. In regions lacking population-based cancer registries (PBCRs) in a vast country like India, hospital-based cancer registry (HBCR) data become an important source of information on the trends and patterns of a region. To determine the numerical trends of cases of the top ten cancer sites reporting to HBCR of a tertiary care cancer center in Bihar from 2014 to 2021.

Materials and Methods

The details of all histopathologically confirmed cancer cases registered in the HBCR department of radiation oncology, State Cancer Institute, Indira Gandhi Institute of Medical Sciences, Patna, India between January 2014 and December 2021 were included in this retrospective observational study. All these cases were grouped site-wise and listed in descending order of the total number of cases reported in each group. Cross-tabulation with age and sex distribution was done. The frequency distribution of the top ten leading cancers for every consecutive calendar year was plotted in line diagrams for time trend analysis. Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp.). was used for analysis. Annual percent change (APC) was determined for the number of cases of all ten cancer sites using joinpoint regression analysis (Joinpoint Regression Software, Version 4.0.4-May 2013; Statistical Methodology and Applications Branch, Surveillance Research Program of the US National Cancer Institute; Bethesda, MD, USA).

Results

Out of 32,057 total cancer cases registered between Jan 2014 and Dec 2021, 21,848 patients (68.2%) cases constituted the top ten cancers. The top ten cancers among both sexes were cancer gallbladder (n = 4204, 13.1%), head and neck (n = 3395, 10.6%), breast (n = 3392, 10.6%), lung (n = 2069, 6.5%), cervix (n = 2039, 6.4%), hematolymphoid (n = 1930, 6.0%), liver (n = 1572, 4.9%), stomach (n = 1116, 3.5%), ovary (n = 1103, 3.4%), and colon-rectum (n = 1028, 3.2%). Except for cervical and hematolymphoid cancers, the rest all showed a rising trend over consecutive years.

Conclusion

Cancer of the gallbladder continues to be among the most common cancers in the region. Focused research in all aspects of this deadly disease is needed. Strengthening of prevention and screening programs for common cancers and upliftment of the existing infrastructure for diagnosis and treatment of cancer in the region are necessitated.

Lansoprazole (LPZ) reverses multidrug resistance (MDR) in cancer through impeding ATP-binding cassette (ABC) transporter-mediated chemotherapeutic drug efflux and lysosomal sequestration

AIMS

Lansoprazole is one of the many proton pump inhibitors (PPIs) that acts more strongly with ABCB1 and ABCG2. The present study is to investigate the potential of lansoprazole on reversal of ABCB1/G2-mediated MDR in cancer, in vitro and in vivo.

METHODS

Reversal studies and combination evaluation were conducted to determine the synergistic anti-MDR effects on lansoprazole. Lysosomal staining was used to determination of lansoprazole on ABCB1-mediated lysosomal sequestration. Substrate accumulation and efflux assays, ATPase activity, and molecular docking were conducted to evaluate lansoprazole on ABCB1/G2 functions. Western blot and immunofluorescence were used to detect lansoprazole on ABCB1/G2 expression and subcellular localization. MDR nude mice models were established to evaluate the effects of lansoprazole on MDR in vivo.

RESULTS

Lansoprazole attenuated ABCB1/G2-mediated MDR and exhibited synergistic effects with substrate drugs in MDR cells. In vivo experiments demonstrated that lansoprazole attenuated ABCB1/G2-mediated MDR and exhibited synergistic effects that augmented the sensitivity of substrate anticancer drugs in ABCB1/G2-mediated settings without obvious toxicity. Lansoprazole impeded lysosomal sequestration mediated by ABCB1, leading to a substantial increase in intracellular accumulation of substrate drugs. The effects of lansoprazole were not attributable to downregulation or alterations in subcellular localization of ABCB1/G2. Lansoprazole promoted the ATPase activity of ABCB1/G2 and competitively bound to the substrate-binding region of ABCB1/G2.

CONCLUSIONS

These findings present novel therapeutic avenues whereby the combination of lansoprazole and chemotherapeutic agents mitigates MDR mediated by ABCB1/G2 overexpression.

Intestinal microbiota and biliary system diseases

Introduction

The incidence of biliary system diseases has been continuously increasing in the past decade. Biliary system diseases bring a heavy burden to humanity and society. However, the specific etiology and pathogenesis are still unknown. The biliary system, as a bridge between the liver and intestine, plays an indispensable role in maintaining the physiological metabolism of the body. Therefore, prevention and treatment of biliary diseases are crucial. It is worth noting that the microorganisms participate in the lipid metabolism of the bile duct, especially the largest proportion of intestinal bacteria.

Methods

We systematically reviewed the intestinal microbiota in patients with gallstones (GS), non-calculous biliary inflammatory, and biliary tract cancer (BTC). And searched Pubmed, Embase and Web of science for research studies published up to November 2023.

Results

We found that the abundance of Faecalibacterium genus is decreased in GS, primary sclerosing cholangitis (PSC), primary biliary cholangitis (PBC) and BTC. Veillonella, Lactobacillus, Streptococcus and Enterococcus genus were significantly increased in PSC, PBC and BTC. Interestingly, we found that the relative abundance of Clostridium was generally reduced in GS, PBC and BTC. However, Clostridium was generally increased in PSC.

Discussion

The existing research mostly focuses on exploring the mechanisms of bacteria targeting a single disease. Lacking comparison of multiple diseases and changes in bacteria during the disease process. We hope to provide biomarkers forearly diagnosis of biliary system diseases and provide new directions for the mechanism of intestinal microbiota in biliary diseases.

Germline Genetic Associations for Hepatobiliary Cancers

Hepatobiliary cancers (HBCs) include hepatocellular carcinoma, cholangiocarcinoma, and gallbladder carcinoma, which originate from the liver, bile ducts, and gallbladder, respectively. They are responsible for a substantial burden of cancer-related deaths worldwide. Despite knowledge of risk factors and advancements in therapeutics and surgical interventions, the prognosis for most patients with HBC remains bleak. There is evidence from familial aggregation and case-control studies to suggest a familial risk component in HBC susceptibility. Recent progress in genomics research has led to the identification of germline variants including single nucleotide polymorphisms (SNPs) and pathogenic or likely pathogenic (P/LP) variants in cancer-associated genes associated with HBC risk. These findings emerged from genome-wide association studies and next-generation sequencing techniques such as whole-exome sequencing. Patients with other cancer types, including breast, colon, ovarian, prostate, and pancreatic cancer, are recommended by guidelines to undergo germline genetic testing, but similar recommendations are lagging in HBC. This prompts the question of whether multi-gene panel testing should be integrated into clinical guidelines for HBC management. Here, we review the hereditary genetics of HBC, explore studies investigating SNPs and P/LP variants in HBC patients, discuss the clinical implications and potential for personalized treatments and impact on patient's family members, and conclude that additional studies are needed to examine how genetic testing can be applied clinically.

Advances in the structure, mechanism and targeting of chemoresistance-linked ABC transporters

Cancer cells frequently display intrinsic or acquired resistance to chemically diverse anticancer drugs, limiting therapeutic success. Among the main mechanisms of this multidrug resistance is the overexpression of ATP-binding cassette (ABC) transporters that mediate drug efflux, and, specifically, ABCB1, ABCG2 and ABCC1 are known to cause cancer chemoresistance. High-resolution structures, biophysical and in silico studies have led to tremendous progress in understanding the mechanism of drug transport by these ABC transporters, and several promising therapies, including irradiation-based immune and thermal therapies, and nanomedicine have been used to overcome ABC transporter-mediated cancer chemoresistance. In this Review, we highlight the progress achieved in the past 5 years on the three transporters, ABCB1, ABCG2 and ABCC1, that are known to be of clinical importance. We address the molecular basis of their broad substrate specificity gleaned from structural information and discuss novel approaches to block the function of ABC transporters. Furthermore, genetic modification of ABC transporters by CRISPR-Cas9 and approaches to re-engineer amino acid sequences to change the direction of transport from efflux to import are briefly discussed. We suggest that current information regarding the structure, mechanism and regulation of ABC transporters should be used in clinical trials to improve the efficiency of chemotherapeutics for patients with cancer.

Global epidemiological trends and variations in the burden of gallbladder cancer

BACKGROUND

Gallbladder cancer (GBC) is a rare but lethal malignancy with a dismal prognosis. The aim of this study is to analyze the burdens and trends of GBC across the world based on geography, socioeconomic development (based on human development index [HDI]), and gender.

METHODS

GLOBOCAN 2020 database was used to extract data (2020-2040) relating to the incidence and mortality of GBC across the world.

RESULTS

Asia had the highest burden of GBC with India and China contributing to majority of the absolute burden. The burden of GBC by age standardized rate was highest in Latin America (Bolivia and Chile) and Southeast Asia (Bangladesh and Nepal). Medium HDI countries had a higher mortality rate compared to very high HDI countries. Females had a higher predilection for GBC across different regions and socioeconomic groups. GBC burden is expected to significantly increase across the world by 2040 with variable trends across different regions, age groups, and genders.

CONCLUSION

The global burden of GBC will significantly increase over the next two decades with marked regional and demographic variations. The results of this study will empower national and global health leaders to develop policies to address the increasing burden of this lethal malignancy.

Ultrasound Surveillance of Small, Incidentally Detected Gallbladder Polyps: Projected Benefits by Sex, Age, and Comorbidity Level

OBJECTIVE

Incidentally detected gallbladder polyps are commonly encountered when performing upper abdominal ultrasound. Our purpose was to estimate the life expectancy (LE) benefit of ultrasound-based gallbladder surveillance in patients with small (6-7 to <10 mm), incidentally detected gallbladder polyps, accounting for patient sex, age, and comorbidity level.

METHODS

We developed a decision-analytic Markov model to evaluate hypothetical cohorts of women and men with small gallbladder polyps, with varying age (66-80 years) and comorbidity level (none, mild, moderate, severe). Drawing from current evidence, in the base case, we assumed no increased risk of gallbladder cancer in patients with small gallbladder polyps. To estimate maximal possible LE gains from surveillance, we assumed perfect cancer control consequent to 5 years of surveillance. We varied key assumptions including cancer risk and test performance characteristics in sensitivity analysis.

RESULTS

Projected LE gains from surveillance were <3 days across most cohorts and scenarios evaluated. For 66- and 80-year-olds with no comorbidities, LE gains were 1.46 and 1.45 days, respectively, for women, and 0.67 and 0.75 days for men. With 10 years of surveillance, LE gains increased to 2.94 days for 66-year-old women with no comorbidities (men: 1.35 days). If we assumed a 10% increase in gallbladder cancer risk among individuals with polyps, LE gains increased slightly to 1.60 days for 66-year-old women with no comorbidities (men: 0.74 days). Results were sensitive to test performance and surgical mortality.

DISCUSSION

Even under unrealistic, optimistic assumptions of cancer control, ultrasound surveillance of incidentally detected small gallbladder polyps provided limited benefit.

Molecular aspects of ABCB1 and ABCG2 in Gallbladder cancer and its clinical relevance

The function of ABC transporters in the body is manifold; such as maintenance of homeostasis, effect on multi-drug resistance and their role in tumor initiation & progression. Evidence pointing towards the direct or indirect role of ABC transporter genes in particular; ABCB1 and ABCG2 in cancer genesis is increasing. However, their role in gallbladder cancer is unexplored. Therefore, we investigated the methylation status and expression pattern of ABCB1 and ABCG2in gallbladder carcinogenesis. The methylation and expression study of ABCB1/MDR1 and ABCG2/BCRP was performed in tumour and normal fresh tissue samples collected from 61 histopathologically diagnosed gallbladder cancer patients. The methylation status was analysed by Methylation-Specific PCR and expression was determined by Real-Time PCR and Immunohistochemistry. Hypomethylation of ABCB1 and ABCG2 was found in 44 (72.13%) and 48 (78.6%) cases, respectively. ABCB1 hypomethylation pattern showed association with female patients (p = 0.040) and GradeII tumors (p = 0.036) while, ABCG2 hypomethylation was more frequent in early tumors (T1-T2). The mRNA expression ofABCB1 and ABCG2 was up-regulated in 33 (54.10%) and 41 (67.21%) patients with fold change of 4.7 and 5.5, respectively. The mRNA expression of both genes showed association with Grade II tumours and the increased fold change of ABCG2 was higher in (T1-T2) depth of invasion (p = 0.02) and Stage I-II disease (p = 0.08). The protein expression on IHC was strongly positive for ABCB1/MDR1and ABCG2/BCRP in 32 (52.46%) and 45 (73.77%) patients, respectively. The protein expression in ABCG2 showed association with patients age > 50 years (p = 0.04) and GradeII differentiation (p = 0.07). Interestingly, the hypomethylation of both the genes showed significant correlation with increased expression. ABCB1/MDR1 and ABCG2/BCRP hypomethylation and overexpression could have a potential role in gallbladder cancer tumorigenesis especially in early stages. The epigenetic change might be a plausible factor for altered gene expression of ABCB1 and ABCG2 in gallbladder cancer.

Molecular and Clinical Links between Drug-Induced Cholestasis and Familial Intrahepatic Cholestasis

Idiosyncratic Drug-Induced Liver Injury (iDILI) represents an actual health challenge, accounting for more than 40% of hepatitis cases in adults over 50 years and more than 50% of acute fulminant hepatic failure cases. In addition, approximately 30% of iDILI are cholestatic (drug-induced cholestasis (DIC)). The liver's metabolism and clearance of lipophilic drugs depend on their emission into the bile. Therefore, many medications cause cholestasis through their interaction with hepatic transporters. The main canalicular efflux transport proteins include: 1. the bile salt export pump (BSEP) protein (ABCB11); 2. the multidrug resistance protein-2 (MRP2, ABCC2) regulating the bile salts' independent flow by excretion of glutathione; 3. the multidrug resistance-1 protein (MDR1, ABCB1) that transports organic cations; 4. the multidrug resistance-3 protein (MDR3, ABCB4). Two of the most known proteins involved in bile acids' (BAs) metabolism and transport are BSEP and MDR3. BSEP inhibition by drugs leads to reduced BAs' secretion and their retention within hepatocytes, exiting in cholestasis, while mutations in the ABCB4 gene expose the biliary epithelium to the injurious detergent actions of BAs, thus increasing susceptibility to DIC. Herein, we review the leading molecular pathways behind the DIC, the links with the other clinical forms of familial intrahepatic cholestasis, and, finally, the main cholestasis-inducing drugs.

RNA sequencing revealed the multi-stage transcriptome transformations during the development of gallbladder cancer associated with chronic inflammation

Gallbladder cancer (GBC) is a highly malignant tumor with extremely poor prognosis. Previous studies have suggested that the carcinogenesis and progression of GBC is a multi-stage and multi-step process, but most of them focused on the genome changes. And a few studies just compared the transcriptome differences between tumor tissues and adjacent noncancerous tissues. The transcriptome changes, relating to every stage of GBC evolution, have rarely been studied. We selected three cases of normal gallbladder, four cases of gallbladder with chronic inflammation induced by gallstones, five cases of early GBC, and five cases of advanced GBC, using next-generation RNA sequencing to reveal the changes in mRNAs and lncRNAs expression during the evolution of GBC. In-depth analysis of the sequencing data indicated that transcriptome changes from normal gallbladder to gallbladder with chronic inflammation were distinctly related to inflammation, lipid metabolism, and sex hormone metabolism; transcriptome changes from gallbladder with chronic inflammation to early GBC were distinctly related to immune activities and connection between cells; and the transcriptome changes from early GBC to advanced GBC were distinctly related to transmembrane transport of substances and migration of cells. Expression profiles of mRNAs and lncRNAs change significantly during the evolution of GBC, in which lipid-based metabolic abnormalities play an important promotive role, inflammation and immune activities play a key role, and membrane proteins are very highlighted molecular changes.

A common variant in the hepatobiliary phospholipid transporter ABCB4 modulates liver injury in PBC but not in PSC: prospective analysis in 867 patients

BACKGROUND

The ATP-binding cassette subfamily B member 4 (ABCB4) gene encodes the hepatic phospholipid transporter. Variants in the ABCB4 gene are associated with various cholestatic phenotypes, some of which progress to liver fibrosis and cirrhosis. The aim of our study was to investigate the role of the cholestasis-associated variant ABCB4 c.711A > T (p.I237I, rs2109505) in patients with primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC).

RESULTS

Two cohorts of Polish patients took part in this study. The Szczecin cohort comprised 196 patients with PBC (174 females, 38% with cirrhosis) and 135 patients with PSC (39 females, 39% with cirrhosis). The Warsaw cohort consisted of 260 patients with PBC (241 females, 44% with cirrhosis) and 276 patients with PSC (97 females, 33% with cirrhosis). Two control cohorts-150 healthy blood donors and 318 patients without liver disease, were recruited in Szczecin and in Warsaw, respectively. The ABCB4 c.711A > T polymorphism was genotyped using TaqMan assay. In both PBC cohorts, carriers of the risk variant presented more frequently with cirrhosis (Szczecin: OR = 1.841, P = 0.025; Warsaw: OR = 1.528, P = 0.039). The risk allele was associated with increased serum AST, GGT and ALP (all P < 0.05) at inclusion. During the follow-up, patients in both cohorts significantly improved their laboratory results, independently of their ABCB4 c.711A > T genotype (P > 0.05). During 8 ± 4 years follow-up, a total of 22 patients in the Szczecin PBC group developed cirrhosis, and this risk was higher among carriers of the risk variant (OR = 5.65, P = 0.04). In contrast to PBC, we did not detect any association of ABCB4 c.711A > T with a liver phenotype in PSC cohorts.

CONCLUSIONS

The frequent pro-cholestatic variant ABCB4 c.711A > T modulates liver injury in PBC, but not in PSC. In particular, carriers of the major allele are at increased risk of progressive liver scarring.

Gallbladder cancer

Gallbladder cancer (GBC) is the most common cancer of the biliary tract, characterized by a very poor prognosis when diagnosed at advanced stages owing to its aggressive behaviour and limited therapeutic options. Early detection at a curable stage remains challenging because patients rarely exhibit symptoms; indeed, most GBCs are discovered incidentally following cholecystectomy for symptomatic gallbladder stones. Long-standing chronic inflammation is an important driver of GBC, regardless of the lithiasic or non-lithiasic origin. Advances in omics technologies have provided a deeper understanding of GBC pathogenesis, uncovering mechanisms associated with inflammation-driven tumour initiation and progression. Surgical resection is the only treatment with curative intent for GBC but very few cases are suitable for resection and most adjuvant therapy has a very low response rate. Several unmet clinical needs require to be addressed to improve GBC management, including discovery and validation of reliable biomarkers for screening, therapy selection and prognosis. Standardization of preneoplastic and neoplastic lesion nomenclature, as well as surgical specimen processing and sampling, now provides reproducible and comparable research data that provide a basis for identifying and implementing early detection strategies and improving drug discovery. Advances in the understanding of next-generation sequencing, multidisciplinary care for GBC, neoadjuvant and adjuvant strategies, and novel systemic therapies including chemotherapy and immunotherapies are gradually changing the treatment paradigm and prognosis of this recalcitrant cancer.

The human ATP-binding cassette (ABC) transporter superfamily

The ATP-binding cassette (ABC) transporter superfamily comprises membrane proteins that efflux various substrates across extra- and intracellular membranes. Mutations in ABC genes cause 21 human disorders or phenotypes with Mendelian inheritance, including cystic fibrosis, adrenoleukodystrophy, retinal degeneration, cholesterol, and bile transport defects. To provide tools to study the function of human ABC transporters we compiled data from multiple genomics databases. We analyzed ABC gene conservation within human populations and across vertebrates and surveyed phenotypes of ABC gene mutations in mice. Most mouse ABC gene disruption mutations have a phenotype that mimics human disease, indicating they are applicable models. Interestingly, several ABCA family genes, whose human function is unknown, have cholesterol level phenotypes in the mouse. Genome-wide association studies confirm and extend ABC traits and suggest several new functions to investigate. Whole-exome sequencing of tumors from diverse cancer types demonstrates that mutations in ABC genes are not common in cancer, but specific genes are overexpressed in select tumor types. Finally, an analysis of the frequency of loss-of-function mutations demonstrates that many human ABC genes are essential with a low level of variants, while others have a higher level of genetic diversity.

Management of Incidentally Detected Gallbladder Polyps: Society of Radiologists in Ultrasound Consensus Conference Recommendations

Gallbladder polyps (also known as polypoid lesions of the gallbladder) are a common incidental finding. The vast majority of gallbladder polyps smaller than 10 mm are not true neoplastic polyps but are benign cholesterol polyps with no inherent risk of malignancy. In addition, recent studies have shown that the overall risk of gallbladder cancer is not increased in patients with small gallbladder polyps, calling into question the rationale for frequent and prolonged follow-up of these common lesions. In 2021, a Society of Radiologists in Ultrasound, or SRU, consensus conference was convened to provide recommendations for the management of incidentally detected gallbladder polyps at US. See also the editorial by Sidhu and Rafailidis in this issue.

Reproductive factors and gall-bladder cancer, and the effect of common genetic variants on these associations: a case-control study in India

BACKGROUND

In India, as elsewhere, the incidence of gall-bladder cancer (GBC) is substantially higher in women than in men. Yet, the relevance of reproductive factors to GBC remains poorly understood.

METHODS

We used logistic regression adjusted for age, education and area to examine associations between reproductive factors and GBC risk, using 790 cases of histologically confirmed GBC and group-matched 1726 visitor controls. We tested the interaction of these associations by genetic variants known to increase the risk of GBC.

RESULTS

Parity was strongly positively associated with GBC risk: each additional pregnancy was associated with an ∼25% higher risk {odds ratio [OR] 1.26 [95% confidence interval (95% CI) 1.17-1.37]}. After controlling for parity, GBC risk was weakly positively associated with later age of menarche [postmenopausal women, OR 1.11 (95% CI 1.00-1.22) per year], earlier menopause [OR 1.03 (95% CI 1.00-1.06) per year] and shorter reproductive lifespan [OR 1.04 (95% CI 1.01-1.07) per year], but there was little evidence of an association with breastfeeding duration or years since last pregnancy. Risk alleles of single-nucleotide polymorphisms in the ABCB4 and ABCB1 genetic regions had a multiplicative effect on the association with parity, but did not interact with other reproductive factors.

CONCLUSIONS

We observed higher GBC risk with higher parity and shorter reproductive lifespan, suggesting an important role for reproductive and hormonal factors.

Acetylation stabilizes stathmin1 and promotes its activity contributing to gallbladder cancer metastasis

Gallbladder cancer is the most common biliary tract malignant tumor with highly metastatic characters and poor prognosis. However, the underlying mechanism remains unclear. Stathmin1 is ubiquitous phosphoprotein, regulating microtubule stabilization. We identified the acetylation of stahtmin1 at lysine 9 (K9) in gallbladder cancer. K9 acetylation of stathmin1 was reversely regulated by the acetyltransferase PCAF and the deacetylases sirt2. K9 acetylation of stathmin1 inhibited the combining of stathmin1 to E3 ubiquitin ligase RLIM, thereby inhibiting its ubiquitination degradation. Moreover, K9 acetylation also promoted the activity of stahtmin1 interacting and destabilizing microtubule through the inhibition of stathmin1 phosphorylation. K9 acetylated stathmin1 significantly promoted gallbladder cancer cell migration and invasion viability in vitro and lung metastasis in vivo, and indicated poor prognosis of nude mice. IHC assay suggested the positive correlation of high levels of K9 acetylation and stathmin1 expression in gallbladder cancer. Our study revealed that K9 acetylation up-regulated stathmin1 protein stability and microtubule-destabilizing activity to promoted gallbladder cancer metastasis, which provides a potential target for gallbladder cancer therapy.

Risk factors associated with gall bladder cancer in high incidence areas in India: a systematic review protocol

INTRODUCTION

Gall bladder cancer (GBC) is a lethal form of malignancy of the gastrointestinal tract with a unique geographical distribution. Cases are aggregated in the river basins of Ganga-Brahmaputra, in the north, east and north-east India, collectively termed as the 'high-risk' zone for GBC. Although some studies report high prevalence of typhoid infection linking with high burden of GBC in these regions, there is no systematic review of the factors associated with GBC in the high incidence areas. To address this gap, we are conducting a systematic review to identify and organise the factors associated with GBC in the high-risk zone of India.

METHODS AND ANALYSIS

A systematic review of all observational studies that report a quantitative relationship between at least one risk factor for GBC among adults (>18 years) in the high-risk zone in India will be conducted. The databases PubMed-MEDLINE, CINAHL, EMBASE, Web of Science, Scopus, OpenGrey and Google Scholar published in English and after 1990 will be searched. This review will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations. The primary outcome is GBC. If data permit, meta-analysis will be performed. Two independent reviewers will independently screen the articles, extract the data and assess the methodological quality of the studies.

ETHICS AND DISSEMINATION

As this will be a systematic review without human participants' involvement, there will be no requirement for ethics approval. Findings will be disseminated widely through peer-reviewed publication and media, for example, conferences and symposia.

PROSPERO REGISTRATION NUMBER

CRD42021256673.

Environmental and Lifestyle Risk Factors in the Carcinogenesis of Gallbladder Cancer

Gallbladder cancer (GBC) is an aggressive neoplasm that in an early stage is generally asymptomatic and, in most cases, is diagnosed in advanced stages with a very low life expectancy because there is no curative treatment. Therefore, understanding the early carcinogenic mechanisms of this pathology is crucial to proposing preventive strategies for this cancer. The main risk factor is the presence of gallstones, which are associated with some environmental factors such as a sedentary lifestyle and a high-fat diet. Other risk factors such as autoimmune disorders and bacterial, parasitic and fungal infections have also been described. All these factors can generate a long-term inflammatory state characterized by the persistent activation of the immune system, the frequent release of pro-inflammatory cytokines, and the constant production of reactive oxygen species that result in a chronic damage/repair cycle, subsequently inducing the loss of the normal architecture of the gallbladder mucosa that leads to the development of GBC. This review addresses how the different risk factors could promote a chronic inflammatory state essential to the development of gallbladder carcinogenesis, which will make it possible to define some strategies such as anti-inflammatory drugs or public health proposals in the prevention of GBC.

The wide phenotypic and genetic spectrum of ABCB4 gene deficiency: A case series

BACKGROUND

ABCB4-gene mutations are responsible for several cholestatic diseases with a heterogeneous clinical spectrum.

AIMS

To analyse phenotype/genotype relationships in ABCB4-mutations.

METHODS

Retrospective characterization of adult patients with ABCB4-variations diagnosed between 2015 and 2020. Genotype-phenotype correlations were analysed and compared with previously reported data.

RESULTS

Twenty patients from 12 families were included. Thirteen patients presented recurrent elevated liver tests, eight fulfilled Low-Phospholipid-Associated-Cholelithiasis syndrome criteria, five had Intrahepatic Cholestasis of Pregnancy and three patients developed Drug-Induced-Liver-Injury. ABCB4 screening identified eight different mutations. Five patients were homozygotes to the variant c.504T > C. Ten patients had one mutation in heterozygote-state and five patients had two mutations in compound-heterozygosity. Portal fibrosis occurred in two patients. One of these patients presented progressive fibrosis and progression of cholestasis despite ursodeoxycholic-acid treatment, this patient also harbours a ABCB11 polymorphism.

CONCLUSION

Although, phenotype-genotype relationships have not been clearly defined, an early diagnosis of ABCB4-variants may have an important role in management decisions and patient outcomes. To our knowledge, we describe a not previously reported deletion (c.1181delT) in ABCB4. The c.504T > C polymorphism, although a silent mutation at the protein level, seems to be associated to different cholestatic diseases. The role of other genes variants, namely ABCB11, as co-factor for progression, needs to be clarified.

PARP1 rs1136410 (A/G) polymorphism is associated with early age of onset of gallbladder cancer

OBJECTIVES

Evaluation of the association of PARP1 rs1136410 (A/G) polymorphism with gallbladder cancer susceptibility and its prognosis in the Indian population of eastern Uttar Pradesh and western Bihar.

METHODS

PARP1 rs1136410 was genotyped by PCR-RFLP and its association with the prognosis of gallbladder cancer patients were analyzed using Kaplan-Meier plot and log-rank tests.

RESULTS

Our results demonstrate that minor allele G is more frequent in gallbladder cancer patients than controls. The frequencies of minor allele G and GG genotype are significantly associated with increased risk of gallbladder cancer. Our data suggest that the minor allele G and homozygous genotype GG are significant predisposing factors for the early age of onset of gallbladder cancer. Similarly, women patients having AG and GG genotypes demonstrate an increased risk of gallbladder cancer. The risk group genotypes (AG + GG) are significantly more frequent in patients with thick gallbladder wall, with jaundice and with the presence of lymph node than in patients with normal gallbladder wall thickness, without jaundice and absence of lymph node involvement. Survival analysis data suggest that patients with risk group genotype (AG + GG) presenting jaundice have shorter overall survival.

CONCLUSION

Our study suggests that the minor allele G of PARP1 rs1136410 (A/G) is a predisposing factor for gallbladder carcinogenesis and is significantly associated with early onset of the disease. Interestingly, the minor allele G is significantly more frequent in the patients with jaundice, lymph node metastasis and gallbladder wall thickness.

FGF19 and FGFR4 promotes the progression of gallbladder carcinoma in an autocrine pathway dependent on GPBAR1-cAMP-EGR1 axis

Treatment options for gallbladder carcinoma (GBC) are limited and GBC prognosis remains poor. There is no well-accepted targeted therapy to date, so effective biomarkers of GBC are urgently needed. Here we investigated the expression and correlations of fibroblast growth factor receptors (FGFR1-4) and 18 fibroblast growth factors (FGFs) in two independent patient cohorts and evaluated their prognostic significance. Consequently, we demonstrated that both FGF19 and FGFR4 were unfavorable prognostic biomarkers, and their co-expression was a more sensitive predictor. By analyzing the correlations between all 18 FGFs and FGFR4, we showed that FGF19 expression was significantly associated with FGFR4 and promoted GBC progression via stimulating FGFR4. With experiments using GBC cells, GPBAR1-/- mice models, and human subjects, we demonstrated that elevated bile acids (BAs) could increase the transcription and expression of FGF19 and FGFR4 by activating GPBAR1-cAMP-EGR1 pathway. FGF19 secreted from GBC cells promoted GBC progression by stimulating FGFR4 and downstream ERK in an autocrine manner with bile as a potential carrier. Patients with GBC had significantly higher FGF19 in serum and bile, compared to patients with cholelithiasis. BLU9931 inhibited FGFR4 and attenuated its oncogenic effects in GBC cell line. In conclusion, upregulation of BAs elevated co-expression of FGF19 and FGFR4 by activating GPBAR1-cAMP-EGR1 pathway. Co-expression of FGF19 and FGFR4 was a sensitive and unfavorable prognostic marker. GBC cells secreted FGF19 and facilitated progression by activating FGFR4 with bile as a potential carrier in an autocrine pathway.

Trends in gallbladder cancer incidence in the high- and low-risk regions of India

Background: Gallbladder cancer (GBC), a common cancer surrounding the Gangetic belt of India, accounts for 80%–90% of biliary tract cancers. GBC incidence shows striking geographical variation in India. Materials and Methods: We used the data from the National Cancer Registry Programme for the year 2001–2014 to study the time trends of GBC in the high- and low-risk geographical regions of India. Annual percentage change (APC) in age-adjusted incidence rates was computed by log-linear regression model. Results: Among females, a statistically significant increase in trend was observed in Cachar (APC: 7.0, P = 0.02), Delhi (APC: 4.0, P = 0.04), and Kamrup (APC: 4.3, P = 0.02) marked under high-risk region and in Bengaluru (APC: 5.7, P = 0.04) and Pune (APC: 3.4, P = 0.04) marked under low-risk region. Among males, increasing but statistically nonsignificant trends were observed in Cachar, Dibrugarh, Kamrup, Nagpur, and Sikkim, whereas decreasing trends were observed in Bengaluru, Barshi, Bhopal, and Kolkata. Aurangabad showed a statistically significant decrease in trend (APC: −14.5, P < 0.001) among males. Conclusion: The time trend and pattern of GBC have striking differences within the country as well as in state. Further large-scale region-wise studies are needed to find the risk factors of GBC.

Epigenome-Wide Analysis of Methylation Changes in the Sequence of Gallstone Disease, Dysplasia, and Gallbladder Cancer

BACKGROUND AND AIMS

Gallbladder cancer (GBC) is a highly aggressive malignancy of the biliary tract. Most cases of GBC are diagnosed in low-income and middle-income countries, and research into this disease has long been limited. In this study we therefore investigate the epigenetic changes along the model of GBC carcinogenesis represented by the sequence gallstone disease → dysplasia → GBC in Chile, the country with the highest incidence of GBC worldwide.

APPROACH AND RESULTS

To perform epigenome-wide methylation profiling, genomic DNA extracted from sections of formalin-fixed, paraffin-embedded gallbladder tissue was analyzed using Illumina Infinium MethylationEPIC BeadChips. Preprocessed, quality-controlled data from 82 samples (gallstones n = 32, low-grade dysplasia n = 13, high-grade dysplasia n = 9, GBC n = 28) were available to identify differentially methylated markers, regions, and pathways as well as changes in copy number variations (CNVs). The number and magnitude of epigenetic changes increased with disease development and predominantly involved the hypermethylation of cytosine-guanine dinucleotide islands and gene promoter regions. The methylation of genes implicated in Wnt signaling, Hedgehog signaling, and tumor suppression increased with tumor grade. CNVs also increased with GBC development and affected cyclin-dependent kinase inhibitor 2A, MDM2 proto-oncogene, tumor protein P53, and cyclin D1 genes. Gains in the targetable Erb-B2 receptor tyrosine kinase 2 gene were detected in 14% of GBC samples.

CONCLUSIONS

Our results indicate that GBC carcinogenesis comprises three main methylation stages: early (gallstone disease and low-grade dysplasia), intermediate (high-grade dysplasia), and late (GBC). The identified gradual changes in methylation and CNVs may help to enhance our understanding of the mechanisms underlying this aggressive disease and eventually lead to improved treatment and early diagnosis of GBC.

Molecular Oncology of Gall Bladder Cancer

Gall bladder carcinoma (GBC) is a worldwide problem, with a higher incidence in areas of the world where cholelithiasis is common. As GBC is usually diagnosed in an advanced stage, the mortality is high. An understanding of the molecular pathways of carcinogenesis and the mutations involved in the development and progression of GBC could be useful in early diagnosis. Understanding molecular markers of prognosis as well as predictors of outcome could also potentially benefit patients undergoing treatment. New therapies targeting major molecular pathways and immunotherapy are exciting novel therapeutic options. This review focuses on the current understanding of the molecular oncology of GBC.

Serum microRNAs as Biomarkers for the Noninvasive Early Diagnosis of Biliary Tract Cancer

Background

Biliary tract cancers (BTCs) are aggressive malignancies with difficult early diagnosis and poor prognosis. Studies have shown that microRNAs (miRNAs) are expected to be biomarkers of the disease, which indicates that we can diagnose cancers according to the miRNAs that have significant changes. The aim of this study was to explore miRNA biomarkers of BTCs.

Methods

A total of 163 samples were collected and divided into the control group, the benign group and the malignant group. High-throughput low-density chips were used to screen miRNAs with significant changes. Then, the preliminary screening test and the verification test were performed by quantitative real time PCR (qRT-PCR). Finally, the level of miRNAs in serum exosomes was measured.

Results

MiR-10a, miR-21, miR-135b, miR-221, and miR-214 were upregulated in the BTCs group compared to the control group. The change in the miR-221 level was statistically significant when the malignant group was compared with the benign group (P<0.01). Meanwhile, miR-135b and miR-214 were enriched in serum exosomes.

Conclusion

Five miRNAs in the serum were found to be significantly upregulated in patients with BTCs. Among them, miR-221 can serve as an early diagnostic marker for BTCs patients. MiR-10a, miR-21, miR-135b and miR-214 can be used as biomarkers for the diagnosis of biliary diseases.

Genetic association of MMP14 promoter variants and their functional significance in gallbladder cancer pathogenesis

Gallbladder cancer (GBC) is relatively rare but shows high frequency in certain geographical regions and ethnic groups, which include Northern and Eastern states of India. Previous studies in India have indicated the possible role of genetic predisposition in GBC pathogenesis. Although matrix metalloproteinase-14 (MMP14) is known modulator of tumour microenvironment and tumorigenesis and TCGA data also suggests its upregulation yet, its role in genetic predisposition for GBC is completely unknown. We explored MMP14 promoter genetic variants as risk factors and their implication in expression modulation and the pathogenesis of GBC. We genotyped all single nucleotide polymorphisms of MMP14 promoter by Sanger's sequencing in approximately 300 GBC and 300 control study subjects of Indian ethnicity and, in 26 GBC tissue samples. Protein expression of MMP14 in GBC tissue samples was checked by immunohistochemistry. In vitro luciferase reporter assay was carried out to elucidate role of promoter genetic variants on expression levels in two different cell lines. MMP14 promoter variants, rs1003349 (p value = 0.0008) and rs1004030 (p value = 0.0001) were significantly associated with GBC. Luciferase reporter assay showed high expression for risk alleles of both the SNPs. Genotype-phenotype correlation for rs1003349 and rs1004030, in patient sample, confirmed that risk allele carriers had higher expression levels of MMP14; moreover, the correlation pattern matched with genetic association models. Overall, this study unravels the association of MMP14 promoter SNPs with GBC which contribute to pathogenesis by increasing its expression.

A novel compound heterozygous mutation in ABCB4 gene in a pedigree with progressive familial intrahepatic cholestasis 3: a case report

Progressive familial intrahepatic cholestasis (PFIC) includes a group of genetic autosomal recessive disorders that predominantly affects young children and results in early-onset progressive liver damage. Variations in ABCB4 have been shown to cause PFIC3. However, the association between ABCB4 genotype and clinical manifestations remains unclear. We investigated the clinical manifestations and genetic features of a Chinese Han pedigree with PFIC3. A 15-year-old boy, with high-serum gamma-glutamyl transferase (γ-GT) cholestatic cirrhosis, was diagnosed with PIFC3. After ursodeoxycholic acid (UDCA) treatment, the boy stayed in a relatively stable state with mild itching, and elevated γ-GT exhibited a remarkable decrease. Genetic testing identified a novel compound heterozygous mutation L842P/V1051A in ABCB4, which was inherited from his mother and father, respectively. Several predictive software suggested that these two mutations are pathogenic. Interestingly, the same compound heterozygous mutation was also found in his two sisters, one of whom had a history of intrahepatic cholestasis of pregnancy (ICP) and the other had asymptomatic gallstones. Therefore, this novel compound heterozygous mutation L842P/V1051A caused a continuum of ABCB4-related diseases including ICP, cholelithiasis and PFIC3 in our pedigree. The inconsistency between genotypes and phenotypes may be influenced by other factors. Genetic testing will be useful for diagnosis and genetic counseling.

ABCB4 variants in adult patients with cholestatic disease are frequent and underdiagnosed

BACKGROUND

Heterozygous ABCB4 variants are not routinely tested in adults with cholestasis because of their supposed rarity and high costs.

METHODS

Nineteen adult patients presenting with unexplained cholestasis, and/or recurrent gallstones were included; genotyping was not done in five due to lack of health insurance approval.

RESULTS

heterozygous ABCB4 variants were identified in seven patients, followed by cascade testing of 12 family members: one patient underwent liver transplantation at age 40 for end-stage liver disease; one had compensated cirrhosis; all symptomatic adults had gallstones, including four with low phospholipid-associated cholelithiasis; four had intrahepatic cholestasis of pregnancy; all children and one 54-year old female were asymptomatic. Genotype: Families A and C: c.2211G>A (p.Ala737=) combined with c.959C>T (p.Ser320Phe) in one subject; Family B: c.1130T>C (p.Ile377Thr); Family D: large deletion removing ABCB4 exons 1-4 plus ABCB1, RUNDC3B, SLC25A40, DBF4, ADAM22 exons 1-3; Family E: c.1565T>C (p.Phe522Ser) ; Family F: c.1356+2T>C combined with c.217C>G (p.Leu73Val). All patients responded to ursodeoxycholic acid.

CONCLUSIONS

We found ABCB4 variants in half of the adults with unexplained cholestasis and/or recurrent gallstones presenting at our center, suggesting that this condition is underdiagnosed and undertreated, with serious consequences not only for the patients and their families, but also in terms of healthcare costs.

ABCB4 disease: Many faces of one gene deficiency

ATP-binding cassette (ABC) subfamily B member 4 (ABCB4), also known as multidrug resistance protein 3 (MDR3), encoded by ABCB4, is involved in biliary phospholipid secretion, protecting hepatobiliary system from deleterious detergent and lithogenic properties of the bile. ABCB4 mutations altering canalicular ABCB4 protein function and expression may have variable clinical presentation and predispose to several human liver diseases. Well-established phenotypes of ABCB4 deficit are: progressive familial intrahepatic cholestasis type 3, gallbladder disease 1 (syn. low phospholipid associated cholelithiasis syndrome), high ɣ-glutamyl transferase intrahepatic cholestasis of pregnancy, chronic cholangiopathy, and adult biliary fibrosis/cirrhosis. Moreover, ABCB4 aberrations may be involved in some cases of drug induced cholestasis, transient neonatal cholestasis, and parenteral nutrition-associated liver disease. Recently, genome-wide association studies have documented occurrence of malignant tumours, predominantly hepatobiliary malignancies, in patients with ABCB4/MDR3 deficit. The patient's age at the time of the first presentation of cholestatic disease, as well as the severity of liver disorder and response to treatment are related to the ABCB4 allelic status. Mutational analysis of ABCB4 in patients and their families should be considered in all individuals with cholestasis of unknown aetiology, regardless of age and/or time of onset of the first symptoms.

The Role of Gallstones in Gallbladder Cancer in India: A Mendelian Randomization Study

BACKGROUND

Past history of gallstones is associated with increased risk of gallbladder cancer in observational studies. We conducted complementary observational and Mendelian randomization (MR) analyses to determine whether history of gallstones is causally related to development of gallbladder cancer in an Indian population.

METHODS

To investigate associations between history of gallstones and gallbladder cancer, we used questionnaire and imaging data from a gallbladder cancer case-control study conducted at Tata Memorial Hospital, Mumbai, Maharashtra, India (cases = 1,170; controls = 2,525). We then used 26 genetic variants identified in a genome-wide association study of 27,174 gallstone cases and 736,838 controls of European ancestry in an MR approach to assess causality. The association of these genetic variants with both gallstones and gallbladder cancer was examined in the gallbladder cancer case-control study. Various complementary MR approaches were used to evaluate the robustness of our results in the presence of pleiotropy and heterogeneity, and to consider the suitability of the selected SNPs as genetic instruments for gallstones in an Indian population.

RESULTS

We found a strong observational association between gallstones and gallbladder cancer using self-reported history of gallstones [OR = 4.5; 95% confidence interval (CI) = 3.5-5.8] and with objective measures of gallstone presence using imaging techniques (OR = 2.0; 95% CI = 1.5-2.7). We found consistent causal estimates across all MR techniques, with ORs for gallbladder cancer in the range of 1.3-1.6.

CONCLUSIONS

Our findings indicate a causal relationship between history of gallstones and increased risk of gallbladder cancer, albeit of a smaller magnitude than those found in observational analysis.

IMPACT

Our findings emphasize the importance of gallstone treatment for preventing gallbladder cancer in high-risk individuals.

Current and New Biomarkers for Early Detection, Prognostic Stratification, and Management of Gallbladder Cancer Patients

Gallbladder cancer (GBC) is an aggressive disease that shows evident geographic variation and is characterized by a poor prognosis, mainly due to the late diagnosis and ineffective treatment. Genetic variants associated with GBC susceptibility, including polymorphisms within the toll-like receptors TLR2 and TLR4, the cytochrome P450 1A1 (CYP1A1), and the ATP-binding cassette (ABC) transporter ABCG8 genes, represent promising biomarkers for the stratification of patients at higher risk of GBC; thus, showing potential to prioritize cholecystectomy, particularly considering that early diagnosis is difficult due to the absence of specific signs and symptoms. Similarly, our better understanding of the gallbladder carcinogenic processes has led to identify several cellular and molecular events that may influence patient management, including HER2 aberrations, high tumor mutational burden, microsatellite instability, among others. Despite these reports on interesting and promising markers for risk assessment, diagnosis, and prognosis; there is an unmet need for reliable and validated biomarkers that can improve the management of GBC patients and support clinical decision-making. This review article examines the most potentially significant biomarkers of susceptibility, diagnosis, prognosis, and therapy selection for GBC patients, highlighting the need to find and validate existing and new molecular biomarkers to improve patient outcomes.

Biliary Tract Cancers: Molecular Heterogeneity and New Treatment Options

Most patients with biliary tract cancer (BTC) are diagnosed with advanced disease, relapse rates are high in those undergoing surgery and prognosis remains poor, while the incidence is increasing. Treatment options are limited, and chemotherapy is still the standard of care in both adjuvant and advanced disease setting. In recent years, different subtypes of BTC have been defined depending on the anatomical location and genetic and/or epigenetic aberrations. Especially for intrahepatic cholangiocarcinoma (iCCA) novel therapeutic targets have been identified, including fibroblast growth factor receptor 2 gene fusions and isocitrate dehydrogenase 1 and 2 mutations, with molecularly targeted agents having shown evidence of activity in this subgroup of patients. Additionally, other pathways are being evaluated in both iCCA and other subtypes of BTC, alongside targeting of the immune microenvironment. The growing knowledge of BTC biology and molecular heterogeneity has paved the way for the development of new therapeutic approaches that will completely change the treatment paradigm for this disease in the near future. This review provides an overview of the molecular heterogeneity of BTC and summarizes new targets and emerging therapies in development. We also discuss resistance mechanisms, open issues, and future perspectives in the management of BTC.

Mustard oil consumption, cooking method, diet and gallbladder cancer risk in high- and low-risk regions of India

The current study aimed to investigate the role of cooking with mustard oil and other dietary factors in relation to gallbladder cancer (GBC) in high- and low-incidence regions of India. A case-control study was conducted including 1,170 histologically confirmed cases and 2,525 group-matched visitor controls from the largest cancer hospital in India. Dietary data were collected through a food frequency questionnaire. For oil consumption, we enquired about monthly consumption of 11 different types of cooking oil per family and the number of individuals usually sharing the meal to estimate per-individual consumption of oil. Information about method of cooking was also requested. Odds ratios (ORs) and 95% confidence intervals (CIs) quantifying the association of GBC risk consumption of different types of oil, method of cooking, and dietary food items, were estimated using logistic regression models, after adjusting for potential confounders. High consumption of mustard oil was associated with GBC risk in both high- and low-risk regions (OR = 1.33, 95% CI = 0.99-1.78; OR = 3.01, 95% CI = 1.66-5.45), respectively. An increased risk of GBC was observed with deep frying of fresh fish in mustard oil (OR = 1.57, 95% CI = 0.99-2.47, p-value = 0.052). A protective association was observed with consumption of leafy vegetables, fruits, onion and garlic. No association was observed between consumption of meat, spicy food, turmeric, pulses or with any other oil as a cooking medium. The effect of high consumption of mustard oil on GBC risk, if confirmed, has implications for the primary prevention of GBC, via a reduced consumption.

Gallbladder and extrahepatic bile duct cancers in the Americas: Incidence and mortality patterns and trends

Trends in gallbladder cancer incidence and mortality in populations across the Americas can provide insight into shifting epidemiologic patterns and the current and potential impact of preventative and curative programs. Estimates of gallbladder and extrahepatic bile duct cancer incidence and mortality for the year 2018 were extracted from International Agency for Research on Cancer (IARC) GLOBOCAN database for 185 countries. Recorded registry-based incidence from 13 countries was extracted from IARCs Cancer Incidence in Five Continents series and corresponding national deaths from the WHO mortality database. Among females, the highest estimated incidence for gallbladder and extrahepatic bile duct cancer in the Americas were found in Bolivia (21.0 per 100,000), Chile (11.7) and Peru (6.0). In the US, the highest incidence rates were observed among Hispanics (1.8). In the Chilean population, gallbladder cancer rates declined in both females and males between 1998 and 2012. Rates dropped slightly in Canada, Costa Rica, US Whites and Hispanics in Los Angeles. Gallbladder cancer mortality rates also decreased across the studied countries, although rising trends were observed in Colombia and Canada after 2010. Countries within Southern and Central America tended to have a higher proportion of unspecified biliary tract cancers. In public health terms, the decline in gallbladder cancer incidence and mortality rates is encouraging. However, the slight increase in mortality rates during recent years in Colombia and Canada warrant further attention. Higher proportions of unspecified biliary tract cancers (with correspondingly higher mortality rates) suggest more rigorous pathology procedures may be needed after surgery.

Critical Analysis of Genome-Wide Association Studies: Triple Negative Breast Cancer Quae Exempli Causa

Genome-wide association studies (GWAS) are useful in assessing and analyzing either differences or variations in DNA sequences across the human genome to detect genetic risk factors of diseases prevalent within a target population under study. The ultimate goal of GWAS is to predict either disease risk or disease progression by identifying genetic risk factors. These risk factors will define the biological basis of disease susceptibility for the purposes of developing innovative, preventative, and therapeutic strategies. As single nucleotide polymorphisms (SNPs) are often used in GWAS, their relevance for triple negative breast cancer (TNBC) will be assessed in this review. Furthermore, as there are different levels and patterns of linkage disequilibrium (LD) present within different human subpopulations, a plausible strategy to evaluate known SNPs associated with incidence of breast cancer in ethnically different patient cohorts will be presented and discussed. Additionally, a description of GWAS for TNBC will be presented, involving various identified SNPs correlated with miRNA sites to determine their efficacies on either prognosis or progression of TNBC in patients. Although GWAS have identified multiple common breast cancer susceptibility variants that individually would result in minor risks, it is their combined effects that would likely result in major risks. Thus, one approach to quantify synergistic effects of such common variants is to utilize polygenic risk scores. Therefore, studies utilizing predictive risk scores (PRSs) based on known breast cancer susceptibility SNPs will be evaluated. Such PRSs are potentially useful in improving stratification for screening, particularly when combining family history, other risk factors, and risk prediction models. In conclusion, although interpretation of the results from GWAS remains a challenge, the use of SNPs associated with TNBC may elucidate and better contextualize these studies.

ABCB1/4 gallbladder cancer risk variants identified in India also show strong effects in Chileans

BACKGROUND

The first large-scale genome-wide association study of gallbladder cancer (GBC) recently identified and validated three susceptibility variants in the ABCB1 and ABCB4 genes for individuals of Indian descent. We investigated whether these variants were also associated with GBC risk in Chileans, who show the highest incidence of GBC worldwide, and in Europeans with a low GBC incidence.

METHODS

This population-based study analysed genotype data from retrospective Chilean case-control (255 cases, 2042 controls) and prospective European cohort (108 cases, 181 controls) samples consistently with the original publication.

RESULTS

Our results confirmed the reported associations for Chileans with similar risk effects. Particularly strong associations (per-allele odds ratios close to 2) were observed for Chileans with high Native American (=Mapuche) ancestry. No associations were noticed for Europeans, but the statistical power was low.

CONCLUSION

Taking full advantage of genetic and ethnic differences in GBC risk may improve the efficiency of current prevention programs.

Survival benefits of simple versus extended cholecystectomy and lymphadenectomy for patients with T1b gallbladder cancer: An analysis of the surveillance, epidemiology, and end results database (2004 to 2013)

Although guidelines recommend extended surgical resection, radical resection and lymphadenectomy for patients with tumor stage (T)1b gallbladder cancer, these procedures are substantially underutilized. This population‐based, retrospective cohort study aimed to evaluate treatment patterns and outcomes of 401 patients using the US Surveillance, Epidemiology, and End Results (SEER) database from 2004 to 2013. Results showed that median overall survival (OS) was 69 months for lymphadenectomy patients and 37 months for those without lymphadenectomy. Lymphadenectomy also tended to prolong cancer‐specific survival (CSS), although the differences were not statistically significant. OS and CSS were similar for patients who received simple cholecystectomy and extended surgical resection. Cox proportional hazards regression models revealed survival advantages in patients with stage T1bN0 gallbladder cancer compared to those with stage T1bN1, and patients who received simple cholecystectomy plus lymphadenectomy compared to those who did not receive lymph node dissection. In further analyses, patients undergoing simple cholecystectomy who had five or more lymph nodes excised had better OS and CSS than those without lymph node dissection. In conclusion, survival advantages are shown for patients with T1b gallbladder cancer undergoing surgeries with lymphadenectomy. Future studies with longer follow‐up and control of potential confounders are highly warranted.

GWAS in cancer: progress and challenges

The genome-wide association study (GWAS) is an effective method to detect single-nucleotide polymorphisms (SNPs) of multiple individual genes based on linkage disequilibrium (LD). GWAS examines genotypes and distinguishing gene characteristics that are exhibited in diseases. In the past few decades, more and more literature has reported the results of applying GWAS to study tumors. Although many pleiotropic loci associated with complex phenotypes have been identified by GWAS, the biological functions of many genetic variation loci remain unclear, and the genetic mechanisms of most complex phenotypes cannot be systematically explained. In this article, we will review the new findings of several tumor types, and categorize the new sites and mechanisms that have recently been discovered. We linked the mechanisms of action of various tumors and searched for links to related gene expression pathways. We found that susceptible sites can be divided into hub genes and peripheral genes; the two interact to link gene expression in a variety of diseases.

Structure of the human lipid exporter ABCB4 in a lipid environment

ABCB4 is an ATP-binding cassette transporter that extrudes phosphatidylcholine into the bile canaliculi of the liver. Its dysfunction or inhibition by drugs can cause severe, chronic liver disease or drug-induced liver injury. We determined the cryo-EM structure of nanodisc-reconstituted human ABCB4 trapped in an ATP-bound state at a resolution of 3.2 Å. The nucleotide binding domains form a closed conformation containing two bound ATP molecules, but only one of the ATPase sites contains bound Mg²⁺. The transmembrane domains adopt a collapsed conformation at the level of the lipid bilayer, but we observed a large, hydrophilic and fully occluded cavity at the level of the cytoplasmic membrane boundary, with no ligand bound. This indicates a state following substrate release but prior to ATP hydrolysis. Our results rationalize disease-causing mutations in human ABCB4 and suggest an 'alternating access' mechanism of lipid extrusion, distinct from the 'credit card swipe' model of other lipid transporters.

Somatic genetic aberrations in gallbladder cancer: comparison between Chinese and US patients

Background

Gallbladder cancer (GBC) is often diagnosed at an advanced stage with limited therapeutic options and poor prognosis. The five-year survival rate of this cancer when diagnosed at an advanced stage is below 5%, and the median survival time is less than a year with standard gemcitabine-based chemotherapy. Survival benefit with second-line treatment is unknown. Thus, there is an urgent need for novel treatment strategies and targeted therapy based on next generation sequencing (NGS) may be of value.

Methods

Comprehensive genomic profiling (CGP) was performed with NGS panel on paraffin-embedded tumors from a cohort of 108 Chinese and 107 US GBC patients. Clinical data were collected using an IRB approved protocol from a single-center in US and from China.

Results

In Chinese and US GBC cohorts, an average of 6.4 vs. 3.8 genomic alterations (GAs) were identified per patient. The most frequent alterations were TP53 (69.4%), CDKN2A/B (26%), ERBB2 (18.5%), PIK3CA (17%) and CCNE1 (13%) in Chinese cohort, TP53 (57.9%), CDKN2A/B (25%), SMAD4 (17%), ARID1A (14%), PIK3CA (14%) and ERBB2 (13.1%) in US patients. NFE2L2 mutations were present in 6.5% of Chinese patients and not observed in the US cohort. Interestingly, ERBB2 genetic aberrations were significantly associated with better pathological tumor differentiation and tended to co-occurrence with CDKN2A/B mutations in both the Chinese and US GBC cases. Out of the top 9 dysregulated genetic pathways in cancer, Chinese patients harbored more frequent mutations in ERBB genes (30.6% vs. 19.0%, P=0.04). High frequency of PI3K/mTOR pathway variations was observed in both Chinese (37%) and US cohort (33%) (P=0.5). Additionally, both Chinese and US GBC patients exhibited a relatively high tumor mutational burden (TMB) (17.6% and 17.0%, respectively). In the Chinese cohort, a significant association was seen between direct repair gene alterations and TMB ≥10 muts/Mb (P=0.004).

Conclusions

In our study, over 83% Chinese and 68% US GBC patients had actionable alterations that could potentially guide and influence personalized treatment options. The identification of high TMB, ERBB2, CDKN2A/B, PI3K/mTOR pathway and DNA repair mutations indicated that both Chinese and US GBC patients may benefit from targeted or immune checkpoint inhibitors.

Molecular pathogenesis of gallbladder cancer: An update

Gallbladder carcinoma (GBC) is the most aggressive gastrointestinal malignancy throughout the world, with wide geographical variance. It is the subtype of biliary tract malignancy that has the poorest prognosis and lower survival among all biliary tract malignancies. Various factors are associated with GBC pathogenesis such as environmental, microbial, metabolic and molecular. Chronic inflammation of gallbladder due to presence of gallstone or microbial infection (eg. Salmonella or H. pylori) results in sustained production of inflammatory mediators in the tissue microenvironment, which can cause genomic changes linked to carcinogenesis. Genetic alterations are one of the major factors, associated with aggressiveness and prognosis. Researches have been done to explore suitable biomarker for early diagnosis and identify altered molecular pathways to develop appropriate biomarkers for early diagnosis, therapy and predicting prognosis. Different agents for targeted therapy against actionable mutations of molecules like EGFR, VEGF, mTOR, HER2, PDL-1, PD-1, MET, PI3K, N-cadherin, VEGFR, MEK1 and MEK2 are being tried. Despite these advancements, there is dismal improvement in the survival of GBC patients. Genetic aberrations other than actionable mutations and epigenetic modification including aberrant expressions of micro-RNAs, are also being studied both as diagnostic biomarker and therapeutic targets. Complex pathogenesis of GBC still needs to be unfolded. In this review we focus on the molecular pathogenesis of GBC elucidated till date along with future directions that can be explored to achieve better management of GBC patients.

Genomic ERBB2/ERBB3 mutations promote PD-L1-mediated immune escape in gallbladder cancer: a whole-exome sequencing analysis

OBJECTIVES

Patients with gallbladder carcinoma (GBC) lack effective treatment methods largely due to the inadequacy of both molecular characterisation and potential therapeutic targets. We previously uncovered a spectrum of genomic alterations and identified recurrent mutations in the ErbB pathway in GBC. Here, we aimed to study recurrent mutations of genes and pathways in a larger cohort of patients with GBC and investigate the potential mechanisms and clinical significance of these mutations.

DESIGN

We performed whole-exome sequencing (WES) in 157 patients with GBC. Functional experiments were applied in GBC cell lines to explore the oncogenic roles of ERBB2/ERBB3 hotspot mutations, their correlation with PD-L1 expression and the underlying mechanisms. ERBB inhibitors and a PD-L1 blocker were used to evaluate the anticancer activities in co-culture systems in vitro and in vivo.

RESULTS

WES identified ERBB2 and ERBB3 mutations at a frequency of 7%-8% in the expanded cohort, and patients with ERBB2/ERBB3 mutations exhibited poorer prognoses. A set of in vitro and in vivo experiments revealed increased proliferation/migration on ERBB2/ERBB3 mutation. Ectopic expression of ERBB2/ERBB3 mutants upregulated PD-L1 expression in GBC cells, effectively suppressed normal T-cell-mediated cytotoxicity in vitro through activation of the PI3K/Akt signalling pathway and contributed to the growth and progression of GBC in vivo. Treatment with an ERBB2/ERBB3 inhibitor or a PD-L1 monoclonal antibody reversed these immunosuppressive effects, and combined therapy revealed promising therapeutic activities.

CONCLUSIONS

ERBB2/ERBB3 mutations may serve as useful biomarkers in identifying patients who are sensitive to ERBB2/ERBB3 inhibitors and PD-L1 monoclonal antibody treatment.

TRIAL REGISTRATION NUMBER

NCT02442414;Pre-results.

Unexpected Gallbladder Cancer during or after Laparoscopic Cholecystectomy: Risk Factors and Experience of Diagnosis and Treatment of 22 Cases

This study aims to provide some experience in diagnosis and treatment of unexpected gallbladder cancer (UGBC) and find the major risk factors. Retrospective data were collected and analyzed on 22 patients who were diagnosed with UGBC during or after laparoscopic cholecystectomy from January 2013 to January 2018 at our hospital. Average age of the patients was (60.2 ± 12.8) years (range, 42–83 years). Among them, there were 6 men and 16 women. Gallbladder stones, atrophic gallbladder, uneven thickened wall of the gallbladder, and choledocholithiasis were found to be the major risk factors. Eight patients (36.4%) were diagnosed intraoperatively. Seven cases (31.8%) were at the T1 stage; of these, three were treated with laparoscopic cholecystectomy; two were converted to cholecystectomy; and two underwent cholecystectomy, lymph node dissection, and liver resection. Eight (36.4%) T2 patients, five (22.7%) T3 patients, and one T4 patient had radical cholecystectomy. Partial cholecystectomy and cholecystotomy were carried out in another T4 patient. T1 patients did not receive chemotherapy or radiotherapy. Eleven had chemotherapy and four received chemoradiotherapy. The follow-up period ranged from six months to five years. The one-year survival rate for T1 to T4 patients was 100 per cent, 75 per cent, 40 per cent, and 0 per cent, respectively. A high index of clinical suspicion of UGBC is needed if one patient suffered from both gallbladder stones and choledocholithiasis with atrophic gallbladder or uneven thickened wall of the gallbladder preoperatively. To avoid more UGBC and reoperation, imaging examinations combined with tumor marker tests and intraoperative histopathologic examination are highly recommended.