Genetic profiling of intrahepatic cholangiocarcinoma

Predictive and prognostic molecular markers for cholangiocarcinoma in Han Chinese population

Cholangiocarcinoma (CCA) is the most common malignant heterogeneous polygenetic carcinoma with a high incidence in Asia. Most patients would die within 1 year after diagnosis and the 5 year survival rate is less than 10-20% worldwide. Single nucleotide polymorphisms (SNPs) in genes regulate telomere maintenance, mitosis, and inflammation, and may help predict individual susceptibility to certain drugs, environmental factor, and risks to particular diseases. The gene-gene interaction and the regulation of SNPs have not been assessed extensively in CCA. According to our previous study, the GRB2-associated-binding protein (Gab1) gene rs3805246 (X(2) =5.015, P=0.025, OR=0.531, 95% CI 0.304-0.928) and epidermal growth factor receptor (EGFR) gene rs2007000 (X(2) =7.934, P=0.005, OR=2.148, 95% CI 1.255-3.675) presented significant difference between CCA patients and controls. This study conducted a population-based analysis using 225 CCA cases (153 biliary tract cancer patients and 72 gall bladder cancer patients) to assess the association between SNPs and progression of CCA patients, including the overall survival and the prognosis analysis. Results showed that an increased susceptibility of BTC was significantly associated with SNP loci distribution frequency in EGFR rs2107000 (X(2) =7.934, P=0.005, OR=2.148, 95% CI 1.255-3.675). Furthermore, multivariate factor regression analysis represented cholelithiasis medical history of BTC patients can be an effective evaluation criteria of BTC susceptibility in early stage. This study also assessed the relationship between these genotypic polymorphisms and clinicopathologic data, including tumor differentiation stage and overall survival. This is the first study identifying that EGFR polymorphisms are associated with BTC and EGFR rs2017000 polymorphisms may be an important survival predictor in BTC patients.

Genetics of Opisthorchis viverrini-related cholangiocarcinoma

PURPOSE OF REVIEW

We review the genetic, epigenetic and transcriptional landscape of liver fluke (Opisthorchis viverrini, Ov)-related cholangiocarcinoma (CCA). Its distinct alterations, as compared with non-Ov-related CCA may help shed light on its underlying molecular mechanisms.

RECENT FINDINGS

Recent whole-exome and targeted sequencing not only confirmed frequent mutations in known CCA-related genes including TP53 (44%), KRAS (16.7%) and SMAD4 (16.7%), but also revealed mutations in novel CCA-related genes associated with chromatin remodeling [BAP1 (2.8%), ARID1A (17.6%), MLL3 (13%) and IDH1/2 (2.8%)], WNT signaling [RNF43 (9.3%) and PEG3 (5.6%)] and KRAS/G protein signaling [GNAS (9.3%) and ROBO2 (9.3%)]. Interestingly, there is a significant difference in the frequency of mutated genes between Ov-related CCA and non-Ov-related CCA, such as p53 and IDH1/2, reflecting the impact of cause on pathogenesis. Altered DNA methylation and transcriptional profiles associated with xenobiotic metabolism and pro-inflammatory responses were also found in Ov-related CCA.

SUMMARY

Liver fluke-induced chronic inflammation plays a crucial role in cholangiocarcinogenesis, resulting in distinct signatures of genetic, epigenetic and transcriptional alterations. These alterations, when contrasted with non-Ov-related CCA, indicate a unique pathogenic process in Ov-related CCA and may have potential clinical implications on diagnostics, therapeutics and prevention.

Pathogenesis of cholangiocarcinoma: From genetics to signalling pathways

Cholangiocarcinoma (CCA) is a malignant tumour of bile duct epithelial cells with dismal prognosis and rising incidence. Chronic inflammation resulting from liver fluke infection, hepatitis and other inflammatory bowel diseases is a major contributing factor to cholangiocarcinogenesis, likely through accumulation of serial genetic and epigenetic alterations resulting in aberration of oncogenes and tumour suppressors. Recent studies making use of advances in high-throughput genomics have revealed the genetic landscape of CCA, greatly increasing our understanding of its underlying biology. A series of highly recurrent mutations in genes such as TP53, KRAS, SMAD4, BRAF, MLL3, ARID1A, PBRM1 and BAP1, which are known to be involved in cell cycle control, cell signalling pathways and chromatin dynamics, have led to investigations of their roles, through molecular to mouse modelling studies, in cholangiocarcinogenesis. This review focuses on the landscape genetic alterations in CCA and its functional relevance to the formation and progression of CCA.

Patterns of chromosomal copy-number alterations in intrahepatic cholangiocarcinoma

Background

Intrahepatic cholangiocarcinomas (ICC) are relatively rare malignant tumors associated with a poor prognosis. Recent studies using genome-wide sequencing technologies have mainly focused on identifying new driver mutations. There is nevertheless a need to investigate the spectrum of copy number aberrations in order to identify potential target genes in the altered chromosomal regions. The aim of this study was to characterize the patterns of chromosomal copy-number alterations (CNAs) in ICC.

Methods

53 patients having ICC with frozen material were selected. In 47 cases, DNA hybridization has been performed on a genomewide SNP array. A procedure with a segmentation step and a calling step classified genomic regions into copy-number aberration states. We identified the exclusively amplified and deleted recurrent genomic areas. These areas are those showing the highest estimated propensity level for copy loss (resp. copy gain) together with the lowest level for copy gain (resp. copy loss). We investigated ICC clustering. We analyzed the relationships between CNAs and clinico-pathological characteristics.

Results

The overall genomic profile of ICC showed many alterations with higher rates for the deletions. Exclusively deleted genomic areas were 1p, 3p and 14q. The main exclusively amplified genomic areas were 1q, 7p, 7q and 8q. Based on the exclusively deleted/amplified genomic areas, a clustering analysis identified three tumors groups: the first group characterized by copy loss of 1p and copy gain of 7p, the second group characterized by 1p and 3p copy losses without 7p copy gain, the last group characterized mainly by very few CNAs. From univariate analyses, the number of tumors, the size of the largest tumor and the stage were significantly associated with shorter time recurrence. We found no relationship between the number of altered cytobands or tumor groups and time to recurrence.

Conclusion

This study describes the spectrum of chromosomal aberrations across the whole genome. Some of the recurrent exclusive CNAs harbor candidate target genes. Despite the absence of correlation between CNAs and clinico-pathological characteristics, the co-occurence of 7p gain and 1p loss in a subgroup of patients may suggest a differential activation of EGFR and its downstream pathways, which may have a potential effect on targeted therapies.

Liver cancer oncogenomics: opportunities and dilemmas for clinical applications

Primary liver cancers are among the most rapidly evolving malignant tumors worldwide. An underlying chronic inflammatory liver disease, which precedes liver cancer development for several decades and frequently creates a pro-oncogenic microenvironment, impairs progress in therapeutic approaches. Molecular heterogeneity of liver cancer is potentiated by a crosstalk between epithelial tumor and stromal cells that complicate translational efforts to unravel molecular mechanisms of hepatocarcinogenesis with a drugable intend. Next-generation sequencing has greatly advanced our understanding of cancer development. With regards to liver cancer, the unprecedented coverage of next-generation sequencing has created a detailed map of genetic alterations and identified key somatic changes such as CTNNB1 and TP53 as well as several previously unrecognized recurrent disease-causing alterations that could contribute to new therapeutic approaches. Importantly, these investigations indicate that a classical oncogene addiction cannot be assumed for primary liver cancer. Therefore, hepatocarcinogenesis can be considered a paradigm suitable for individualized medicine.

Impact of microenvironment and stem-like plasticity in cholangiocarcinoma: molecular networks and biological concepts

Clinical complexity, anatomic diversity and molecular heterogeneity of cholangiocarcinoma (CCA) represent a major challenge in the assessment of effective targeted therapies. Molecular and cellular mechanisms underlying the diversity of CCA growth patterns remain a key issue of clinical concern. Crucial questions comprise the nature of the CCA-origin, the initial target for cellular transformation as well as the relationship with the cancer stem cells (CSC) concept. Additionally, since CCA often develops in the context of an inflammatory milieu (cirrhosis and cholangitis), the stromal compartment or tumour microenvironment (TME) likely promotes initiation and progression of this malignancy, contributing to its heterogeneity. This review will emphasize the dynamic interplay between stem-like intrinsic and TME-extrinsic pathways, which may represent novel options for multi-targeted therapies in CCA.

Dramatic response to dabrafenib and trametinib combination in a BRAF V600E-mutated cholangiocarcinoma: implementation of a molecular tumour board and next-generation sequencing for personalized medicine

This is the case of a 47-year-old woman diagnosed with chemotherapy and radiation-refractory BRAF V600E mutant, poorly differentiated intrahepatic cholangiocarcinoma (ICC), with multiple metastatic lesions within the liver, lungs, pleura, and bone, stage IV. Discussion of her malignancy's next-generation sequencing genomic information at a multidisciplinary molecular tumour board took place. The patient was considered a suitable candidate for dual BRAF and MEK inhibition, with the intent to prolong her survival and optimize the quality of life. We report her excellent tolerance and exceptional response to dual therapy with dabrafenib and trametinib, including symptomatic and sustained near-complete radiological improvement. We also briefly review the current knowledge of the genomics of cholangiocarcinoma with a focus on BRAF mutations, and make a point of the importance of the establishment of a molecular tumour board for personalized genomic medicine approaches. To our knowledge, this is the first reported case of the use of personalized genomic information for the successful management of a patient with ICC, and it is also the first description of dual BRAF and MEK targeted therapy in this malignancy, leading to what is considered an exceptional response.

Cholangiocarcinoma: molecular pathways and therapeutic opportunities

Cholangiocarcinoma (CCA) is an aggressive biliary tract malignancy with limited treatment options and low survival rates. Currently, there are no curative medical therapies for CCA. Recent advances have enhanced our understanding of the genetic basis of this disease, and elucidated therapeutically relevant targets. Therapeutic efforts in development are directed at several key pathways due to genetic aberrations including receptor tyrosine kinase pathways, mutant IDH enzymes, the PI3K-AKT-mTOR pathway, and chromatin remodeling networks. A highly desmoplastic, hypovascular stroma is characteristic of CCAs and recent work has highlighted the importance of targeting this pathway via stromal myofibroblast depletion. Future efforts should concentrate on combination therapies with action against the cancer cell and the surrounding tumor stroma. As the mutational landscape of CCA is being illuminated, molecular profiling of patient tumors will enable identification of specific mutations and the opportunity to offer directed, personalized treatment options.

The significance of genetics for cholangiocarcinoma development

Cholangiocarcinoma (CCA) is a rare malignancy of the liver, arising from bile ducts. The incidence is increasing worldwide, but the prognosis has remained dismal and virtually unchanged in the past 30 years. Although several risk factors have been associated with the development of this cancer, none of them are normally identified in most patients. Diagnosis in advanced stages of the disease and limited therapeutic options contribute to poor survival rates. The recent analysis of genetic and epigenetic alterations occurring in CCA has shed new light in the understanding of the molecular mechanisms leading to the malignant transformation of biliary cells. Further studies in this direction may foster new diagnostic, prognostic and therapeutic approaches. This review provides a global overview of recent advances in CCA and describes the most important genetic mutations and epigenetic alterations so far reported in CCA.

Essential role of polymorphism of Gab1, EGFR, and EGF for the susceptibility of biliary tract cancer

Cholangiocarcinoma is a malignant neoplasm arising from the epithelial cells lining the biliary ducts and its occurrence can be anatomically classified as within the liver (intrahepatic) or outside the liver (extrahepatic). Extrahepatic cholangiocarcinoma, which can be called as biliary tract cancer (BTC), is the most common form of this malignancy, and its etiology is still unclear. In this study, we tried to elucidate the complicated association between receptor tyrosine kinase (RTK) gene polymorphisms and susceptibility of BTC by analyzing frequency distribution of genotypes and alleles of GRB2-associated-binding protein 1 (Gab1), endothelial growth factor receptor (EGFR), and endothelial growth factor (EGF) and identified potential risk of BTC for people carrying specific genotype of Gab1 and EGFR. Two hundred twenty-five and 300 patients with BTC and cholelithiasis (gallstone (GS)), respectively, and 300 controls matched by age, sex, and ethnicity with patients were recruited from Shengjing Hospital of China Medical University from January 2008 to July 2011 with informed consents. Genomic DNA of BTC group was extracted and purified from formalin-fixed, paraffin-embedded tumor tissue sections using QiAamp DNA FFPE Tissue kit. For GS group and controls, DNA was extracted from peripheral blood leukocytes using genomic DNA extraction kit from Aid Lab. Target genes of RTK family were identified from National Center of Biotechnology Information (NCBI) SNP database and Japanese Single Nucleotide Polymorphisms (JSNP) database. Frequency distribution of genotypes and alleles was analyzed using HapMap Project database. All of the statistical analysis was conducted with SPSS 13.0 software. Eight loci were identified for Gab1 (4), EGFR (3), and EGF (1) as the target single-nucleotide polymorphisms (SNPs) for the association of gene polymorphisms and BTC. A/A genotype and A allele of rs3805246 in Gab1 and G/G genotype and G allele of rs2017000 in EGFR were significantly higher in BTC group than in GS group or controls. After controlling for BMI, age, gender, and smoking habit, patients with "A/A + G/A" had 2.154 times odds to have BTC; as for patients with "A/A" only, they still had 1.976 times odds to have BTC. In the rs2017000 of EGFR, patients with "G/G + G/A" had 1.772 times odds to have BTC, and patients with "G/G" only had 1.530 times odds to have BTC. Furthermore, patients with A/A in rs3805246 and G/G in rs2017000 simultaneously had 1.620 times chance to have BTC than people with other genotypes. This study explored the independent potential effect of EGFR signaling transduction pathway and its downstream element Gab1 and the gene-gene interaction on the disease mechanism of BTC in the perspective of genetics and molecular epidemiology.

Molecular pathogenesis of intrahepatic cholangiocarcinoma

Cholangiocarcinoma (CCA) is an orphan cancer of the hepatobiliary tract, the incidence of which has increased in the past decade. The molecular pathogenesis of this treatment-refractory disease is poorly understood. Desmoplasia is a key causal feature of CCA; however, a majority of tumors develop with no apparent etiological background. The impact of the stromal compartment on tumor progression as well as resistance to therapy is in vogue, and the epithelial-stromal crosstalk may present a target for novel treatment strategies. As such, the complexity of tumor cellularity and the molecular mechanisms underlying the diversity of growth patterns of this malignancy remain a clinical concern. It is crucial to advance our present understanding of the molecular pathogenesis of CCA to improve current clinical strategies and patient outcome. This will facilitate the delineation of patient subsets and individualization for precision therapies. Many questions persevere as to the evolutionary process and cellular origin of the initial transforming event, the context of intratumoral plasticity and the causal driver action. Next-generation sequencing has begun to underline the persistent alterations, which may be the trigger of acquired drug resistance, and the cause of metastasis and disease recurrence. A complex issue that remains is to account for the heterogeneous pool of "backseat" aberrations, which in chromosomal proximity to the causative variant are likely to influence, for example, drug response. This review explores the recent advances in defining the molecular pathways implicated in the development of this devastating disease and, which present putative clinical strategies.

MicroRNA-21 regulates the invasion and metastasis in cholangiocarcinoma and may be a potential biomarker for cancer prognosis

BACKGROUND

MicroRNAs are noncoding RNA molecules that posttranscriptionally regulate gene expression. The aim of this study was to determine the role of microRNA-21 in cholangiocarcinomas and its relationship to cholangiocarcinoma RBE cell capacity for invasion and metastasis.

METHODS

MicroRNA-21 expression was investigated in 41 cases of cholangiocarcinoma samples by in situ hybridization and real-time PCR. Influence on cholangiocarcinoma cell line invasion and metastasis was analyzed with microRNA-21 transfected cells. In addition, regulation of reversion-inducing-cysteine-rich protein with kazal motifs (RECK) by microRNA-21 was elucidated to identify mechanisms.

RESULTS

In situ hybridization and real-time quantitative PCR results for patients with lymph node metastasis or perineural invasion showed significantly high expression of microRNA-21 (P<0.05). There was a dramatic decrease in cholangiocarcinoma cell line invasion and metastasis ability after microRNA-21 knockdown (P<0.05). However, overexpression significantly increased invasion and metastasis (P<0.05). Real-time PCR and Western-blot analysis showed that microRNA-21 could potentially inhibit RECK expression in RBE cells. Survival analysis showed that patients with higher expression levels of microRNA-21 more often had a poor prognosis (P<0.05).

CONCLUSIONS

MicroRNA-21 may play an important role in cholangiocarcinoma invasion and metastasis, suggesting that MicroRNA-21 should be further evaluated as a biomarker for predicting cholangiocarcinoma prognosis.

Genomic profiling of intrahepatic cholangiocarcinoma: refining prognosis and identifying therapeutic targets

BACKGROUND

The molecular alterations that drive tumorigenesis in intrahepatic cholangiocarcinoma (ICC) remain poorly defined. We sought to determine the incidence and prognostic significance of mutations associated with ICC among patients undergoing surgical resection.

METHODS

Multiplexed mutational profiling was performed using nucleic acids that were extracted from 200 resected ICC tumor specimens from 7 centers. The frequency of mutations was ascertained and the effect on outcome was determined.

RESULTS

The majority of patients (61.5 %) had no genetic mutation identified. Among the 77 patients (38.5 %) with a genetic mutation, only a small number of gene mutations were identified with a frequency of >5 %: IDH1 (15.5 %) and KRAS (8.6 %). Other genetic mutations were identified in very low frequency: BRAF (4.9 %), IDH2 (4.5 %), PIK3CA (4.3 %), NRAS (3.1 %), TP53 (2.5 %), MAP2K1 (1.9 %), CTNNB1 (0.6 %), and PTEN (0.6 %). Among patients with an IDH1-mutant tumor, approximately 7 % were associated with a concurrent PIK3CA gene mutation or a mutation in MAP2K1 (4 %). No concurrent mutations in IDH1 and KRAS were noted. Compared with ICC tumors that had no identified mutation, IDH1-mutant tumors were more often bilateral (odds ratio 2.75), while KRAS-mutant tumors were more likely to be associated with R1 margin (odds ratio 6.51) (both P < 0.05). Although clinicopathological features such as tumor number and nodal status were associated with survival, no specific mutation was associated with prognosis.

CONCLUSIONS

Most somatic mutations in resected ICC tissue are found at low frequency, supporting a need for broad-based mutational profiling in these patients. IDH1 and KRAS were the most common mutations noted. Although certain mutations were associated with ICC clinicopathological features, mutational status did not seemingly affect long-term prognosis.

Stellate cells and the development of liver cancer: therapeutic potential of targeting the stroma

Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) are the most common types of primary tumors in the liver. Although major advances have been made in understanding the cellular and molecular mechanisms underlying liver carcinogenesis, HCC and ICC are still deadly cancers worldwide waiting for innovative therapeutic options. Growing evidence from the literature highlight the critical role of the tumor cell microenvironment in the pathogenesis of cancer diseases. Thus, targeting the microenvironment, particularly the crosstalk between tumor cells and stromal cells, has emerged as a promising therapeutic strategy. This strategy would be particularly relevant for liver cancers which frequently develop in a setting of chronic inflammation and microenvironment remodeling associated with hepatic fibrosis and cirrhosis, such processes in which hepatic stellate cells (HSC) greatly contribute. This review brings a genomic point of view on the alterations of the cellular microenvironment in liver cancers, particularly the stromal tissue within tumor nodules, emphasizing the importance of the crosstalk between tumor cells and stromal cells, notably activated HSC, in tumor onset and progression. Furthermore, potential therapeutic modalities of targeting the stroma and HSC are discussed.

Mutations of isocitrate dehydrogenase 1 and 2 in intrahepatic cholangiocarcinoma

PURPOSE OF REVIEW

Exome sequencing studies have recently expanded the genetic characterization of intrahepatic cholangiocarcinomas. Among a number of novel genes, isocitrate dehydrogenase (IDH) is recurrently mutated in intrahepatic cholangiocarcinomas. We review the effects of these mutations on several biochemical pathways, as well as potential changes to downstream signaling pathways.

RECENT FINDINGS

Hotspot mutations in IDH isoforms 1 or 2 occur in approximately 15% of intrahepatic cholangiocarcinomas. These mutations result in elevated levels of an oncometabolite, 2-hydroxyglutarate, which is associated with higher DNA CpG methylation and altered histone methylation that accompany a block in cellular differentiation. Exploratory studies have suggested additional phenotypes associated with IDH1/2 mutations.

SUMMARY

Tumors with IDH1 or IDH2 mutations may represent a distinct subtype of cholangiocarcinomas. Further studies are required to elucidate the exact role that mutant IDH1/2 and 2-hydroxyglutarate play in tumorigenesis, and what are the best strategies to target these tumor types.

New routes to targeted therapy of intrahepatic cholangiocarcinomas revealed by next-generation sequencing

BACKGROUND

Intrahepatic cholangiocarcinoma (ICC) is a subtype of primary liver cancer that is rarely curable by surgery and is rapidly increasing in incidence. Relapsed ICC has a poor prognosis, and current systemic nontargeted therapies are commonly extrapolated from those used in other gastrointestinal malignancies. We hypothesized that genomic profiling of clinical ICC samples would identify genomic alterations that are linked to targeted therapies and that could facilitate a personalized approach to therapy.

METHODS

DNA sequencing of hybridization-captured libraries was performed for 3,320 exons of 182 cancer-related genes and 36 introns of 14 genes frequently rearranged in cancer. Sample DNA was isolated from 40 μm of 28 formalin-fixed paraffin-embedded ICC specimens and sequenced to high coverage.

RESULTS

The most commonly observed alterations were within ARID1A (36%), IDH1/2 (36%), and TP53 (36%) as well as amplification of MCL1 (21%). Twenty cases (71%) harbored at least one potentially actionable alteration, including FGFR2 (14%), KRAS (11%), PTEN (11%), CDKN2A (7%), CDK6 (7%), ERBB3 (7%), MET (7%), NRAS (7%), BRCA1 (4%), BRCA2 (4%), NF1 (4%), PIK3CA (4%), PTCH1 (4%), and TSC1 (4%). Four (14%) of the ICC cases featured novel gene fusions involving the tyrosine kinases FGFR2 and NTRK1 (FGFR2-KIAA1598, FGFR2-BICC1, FGFR2-TACC3, and RABGAP1L-NTRK1).

CONCLUSION

Two thirds of patients in this study harbored genomic alterations that are associated with targeted therapies and that have the potential to personalize therapy selection for to individual patients.

Genomic and transcriptional alterations of cholangiocarcinoma

Cholangiocarcinoma (CCA) is one of the representative cancers refractory to any therapeutic approach. The incidence of CCA is highest in the northeastern part of Thailand, where chronic inflammation caused by liver fluke (Opisthorchis viverrini: Ov) infection is a major etiologic factor. The incidence of CCA is also increasing in other countries, including Japan. Here, we overview the genetic and transcriptional alterations of CCA with and without association with Ov infection. CCA with Ov shows enhanced expression of the genes involved in xenobiotic metabolism and chronic inflammatory responses, including cytokine signaling, whereas CCA without Ov shows enhanced expression of growth factor signaling, such as HER2. Exome and the following prevalence sequencing identified mutations of the BAP1, ARID1A, IDH1 and IDH2 genes in CCA, in addition to the high incidence of known mutations in the TP53, KRAS2 SMAD4, and CDKN2A genes, suggesting the role of chromatin modulators in CCA pathogenesis. CCA with Ov shows significantly higher incidence of the TP53 gene mutation, whereas CCA without Ov showed significantly more frequent mutations of the BAP1, IDH1 and IDH2 genes. However, CCAs with Ov and without Ov share a similar mutation spectrum dominated by C : G > T : A transitions mainly at CpG dinucleotides, suggesting that CCA shares etiologic factors with pancreatic ductal carcinoma but not with hepatocellular carcinoma. Comprehensive analyses of the genetic and transcriptional alterations of CCA with and without Ov infection would provide useful information for the prevention, early diagnosis, and treatment of CCA.

New insights into the molecular pathogenesis of intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma is an aggressive malignancy and is one of the most devastating cancers of the gastrointestinal tract. The molecular mechanisms contributing to the pathogenesis of these cancers are not well understood. The recognition and distinction of these cancers from other tumors such as perihilar or extrahepatic distal cholangiocarcinoma and hepatocellular carcinoma are important in defining the pathogenesis. New insights into molecular mechanisms contributing to disease pathogenesis are emerging from recent epidemiological, genome-wide profiling and laboratory based studies. These have contributed to an improved understanding of risk factors, genetic mutations and pathophysiological mechanisms that are associated with these tumors. The contribution of well-established risk factors such as biliary tract inflammation and key signaling pathways involved in intrahepatic cholangiocarcinoma are being further defined. These new insights have several important implications for both molecular diagnosis and therapy of these cancers.

A perspective on molecular therapy in cholangiocarcinoma: present status and future directions

Cholangiocarcinoma (CCA) is an orphan cancer with limited understanding of its genetic and genomic pathogenesis. Typically, it is highly treatment-refractory and patient outcome is dismal. Currently, there are no approved therapeutics for CCA and surgical resection remains the only option with curative intent. Clinical trials are currently being performed in a mixed cohort of biliary tract cancers that includes intrahepatic CCA, extrahepatic/perihilar CCA, distal extrahepatic CCA, gallbladder carcinoma and, in rare cases, even pancreatic cancers. Today, clinical trials fail primarily because they are underpowered mixed cohorts and designed without intent to enrich for markers to optimize success for targeted therapy. This review aims to emphasize current clinical attempts for targeted therapy of CCA, as well as highlight promising new candidate pathways revealed by translational genomics.

Molecular pathogenesis of cholangiocarcinoma

It has become increasingly apparent of late that inflammation plays an integral role in a spectrum of malignancies including cholangiocarcinoma (CCA). Primary sclerosing cholangitis with chronic inflammation is the most common risk factor for CCA in the Western world. Recent work has highlighted that inflammatory pathways are essential in carcinogenesis and tissue invasion and migration. Inflammation advances carcinogenesis by induction of DNA damage, evasion of apoptosis, promotion of cell proliferation, and neoangiogenesis. CCA is characterized by the presence of a desmoplastic stroma consisting of cancer-associated fibroblasts, tumor-associated macrophages, and tumor-infiltrating lymphocytes. This rich inflammatory milieu is vital to the cancer ecosystem, and targeting its components represents an attractive therapeutic option.

Pathogenesis, diagnosis, and management of cholangiocarcinoma

Cholangiocarcinomas (CCAs) are hepatobiliary cancers with features of cholangiocyte differentiation; they can be classified anatomically as intrahepatic CCA (iCCA), perihilar CCA (pCCA), or distal CCA. These subtypes differ not only in their anatomic location, but in epidemiology, origin, etiology, pathogenesis, and treatment. The incidence and mortality of iCCA has been increasing over the past 3 decades, and only a low percentage of patients survive until 5 years after diagnosis. Geographic variations in the incidence of CCA are related to variations in risk factors. Changes in oncogene and inflammatory signaling pathways, as well as genetic and epigenetic alterations and chromosome aberrations, have been shown to contribute to the development of CCA. Furthermore, CCAs are surrounded by a dense stroma that contains many cancer-associated fibroblasts, which promotes their progression. We have gained a better understanding of the imaging characteristics of iCCAs and have developed advanced cytologic techniques to detect pCCAs. Patients with iCCAs usually are treated surgically, whereas liver transplantation after neoadjuvant chemoradiation is an option for a subset of patients with pCCAs. We review recent developments in our understanding of the epidemiology and pathogenesis of CCA, along with advances in classification, diagnosis, and treatment.

Multidisciplinary approaches to intrahepatic cholangiocarcinoma

After hepatocellular carcinoma, intrahepatic cholangiocarcinoma (ICC) is the second most common primary hepatic malignancy. The etiology of ICC in most patients is not known, but its incidence is on the rise worldwide. There are 3 morphologic subtypes of ICC that can be characterized on cross-sectional imaging, mass forming, periductal infiltrating, and intraductal growth; and the radiographic characteristics of ICC may vary based on the subtype. Complete surgical resection remains the only potentially curative option for patients with ICC. Routine lymphadenectomy at the time of surgical resection should be strongly considered, because lymph node status provides important prognostic information. After surgery, the 5-year survival rate for ICC remains poor at only 25% to 35% in most series. Although numerous clinical trials have been conducted using a variety of chemotherapy regimens to treat ICC, systemic options for ICC remain limited. Doublet gemcitabine and cisplatin therapy is currently considered the standard-of-care first-line therapy for patients with advanced disease. Because ICC is typically confined to the liver and systemic chemotherapy traditionally has had only limited efficacy, there has been increasing interest in locoregional therapy. Although locoregional therapy may include intra-arterial therapies, stereotactic radiotherapy, hepatic artery pump therapy, or ablation, most data are limited. The purpose of this article was to provide a multidisciplinary appraisal of the current therapeutic approaches to ICC.

Curcumin and liver disease

Liver diseases pose a major medical problem worldwide and a wide variety of herbs have been studied for the management of liver-related diseases. In this respect, curcumin has long been used in traditional medicine, and in recent years it has been the object of increasing research interest. In combating liver diseases, it seems clear that curcumin exerts a hypolipidic effect, which prevents the fatty acid accumulation in the hepatocytes that may result from metabolic imbalances, and which may cause nonalcoholic steatohepatitis. Another crucial protective activity of curcumin, not only in the context of chronic liver diseases but also regarding carcinogenesis and other age-related processes, is its potent antioxidant activity, which affects multiple processes and signaling pathways. The effects of curcumin on NF-κβ are crucial to our understanding of the potent hepatoprotective role of this herb-derived micronutrient. Because curcumin is a micronutrient that is closely related to cellular redox balance, its properties and activity give rise to a series of molecular reactions that in every case and biological situation affect the mitochondria.