Genomic spectra of biliary tract cancer

Liver Cancer: Molecular Characterization, Clonal Evolution and Cancer Stem Cells

Liver cancer is the second most common cause of cancer-related death. The major forms of primary liver cancer are hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA). Both these tumors develop against a background of cirrhotic liver, non-alcoholic fatty liver disease, chronic liver damage and fibrosis. HCC is a heterogeneous disease which usually develops within liver cirrhosis related to various etiologies: hepatitis B virus (HBV) infection (frequent in Asia and Africa), hepatitis C virus (HCV), chronic alcohol abuse, or metabolic syndrome (frequent in Western countries). In cirrhosis, hepatocarcinogenesis is a multi-step process where pre-cancerous dysplastic macronodules transform progressively into HCC. The patterns of genomic alterations observed in these tumors were recently identified and were instrumental for the identification of potential targeted therapies that could improve patient care. Liver cancer stem cells are a small subset of undifferentiated liver tumor cells, responsible for cancer initiation, metastasis, relapse and chemoresistance, enriched and isolated according to immunophenotypic and functional properties: cell surface proteins (CD133, CD90, CD44, EpCAM, OV-6, CD13, CD24, DLK1, α2δ1, ICAM-1 and CD47); the functional markers corresponding to side population, high aldehyde dehydrogenase (ALDH) activity and autofluorescence. The identification and definition of liver cancer stem cells requires both immunophenotypic and functional properties.

Successful immune checkpoint blockade in a patient with advanced stage microsatellite-unstable biliary tract cancer

Cancers acquire multiple somatic mutations that can lead to the generation of immunogenic mutation-induced neoantigens. These neoantigens can be recognized by the host's immune system. However, continuous stimulation of immune cells against tumor antigens can lead to immune cell exhaustion, which allows uncontrolled outgrowth of tumor cells. Recently, immune checkpoint inhibitors have emerged as a novel approach to overcome immune cell exhaustion and reactivate antitumor immune responses. In particular, antibodies blocking the exhaustion-mediating programmed death receptor (PD-1)/programmed death receptor ligand (PD-L1) pathway have shown clinical efficacy. The effects were particularly pronounced in tumors with DNA mismatch repair (MMR) deficiency and a high mutational load, which typically occur in the colon and endometrium. Here, we report on a 24-yr-old woman diagnosed with extrahepatic cholangiocarcinoma who showed strong and durable response to the immune checkpoint inhibitor pembrolizumab, although treatment was initiated at an advanced stage of disease. The patient's tumor displayed DNA MMR deficiency and microsatellite instability (MSI) but lacked other features commonly discussed as predictors of response toward checkpoint blockade, such as PD-L1 expression or dense infiltration with cytotoxic T cells. Notably, high levels of HLA class I and II antigen expression were detected in the tumor, suggesting a potential causal relation between functionality of the tumor's antigen presentation machinery and the success of immune checkpoint blockade. We suggest determining MSI status in combination with HLA class I and II antigen expression in tumors potentially eligible for immune checkpoint blockade even in the absence of conventional markers predictive for anti-PD-1/PD-L1 therapy and in entities not commonly linked to the MSI phenotype. Further studies are required to determine the value of these markers for predicting the success of immune checkpoint blockade.

Emerging molecular therapeutic targets for cholangiocarcinoma

Cholangiocarcinomas (CCAs) are diverse epithelial tumors arising from the liver or large bile ducts with features of cholangiocyte differentiation. CCAs are classified anatomically into intrahepatic (iCCA), perihilar (pCCA), and distal CCA (dCCA). Each subtype has distinct risk factors, molecular pathogenesis, therapeutic options, and prognosis. CCA is an aggressive malignancy with a poor overall prognosis and median survival of less than 2years in patients with advanced disease. Potentially curative surgical treatment options are limited to the subset of patients with early-stage disease. Presently, the available systemic medical therapies for advanced or metastatic CCA have limited therapeutic efficacy. Molecular alterations define the differences in biological behavior of each CCA subtype. Recent comprehensive genetic analysis has better characterized the genomic and transcriptomic landscape of each CCA subtype. Promising candidates for targeted, personalized therapy have emerged, including potential driver fibroblast growth factor receptor (FGFR) gene fusions and somatic mutations in isocitrate dehydrogenase (IDH)1/2 in iCCA, protein kinase cAMP-activated catalytic subunit alpha (PRKACA) or beta (PRKACB) gene fusions in pCCA, and ELF3 mutations in dCCA/ampullary carcinoma. A precision genomic medicine approach is dependent on an enhanced understanding of driver mutations in each subtype and stratification of patients according to their genetic drivers. We review the current genomic landscape of CCA, the potentially actionable molecular aberrations in each CCA subtype, and the role of immunotherapy in CCA.

Tumoral LINE-1 hypomethylation is associated with poor survival of patients with intrahepatic cholangiocarcinoma

BACKGROUND

DNA methylation changes occurring in cancer cells are featured with both promoter CpG island hypermethylation and diffuse genomic hypomethylation. Long interspersed element-1 (LINE-1) is repeated in an interspersed manner with an estimated 500,000 copies per genome. LINE-1 has its CpG sites of the 5' untranslated region methylated heavily in normal cells and undergoes demethylation in association with cancerization. However, little information is available regarding LINE-1 hypomethylation and its prognostic implication in intrahepatic cholangiocarcinomas.

METHODS

A total of 172 cases of intrahepatic cholangiocarcinomas were analyzed for their methylation levels at four CpG sites of LINE-1 using bisulfite pyrosequencing. We examined the relation between tumoral LINE-1 methylation level and clinicopathological features, including survival.

RESULTS

Tumor differentiation, lymphatic invasion, and T stage were associated with a low average methylation level of LINE-1 at the four CpG sites; LINE-1 methylation level tended to be lower in high-grade differentiation, lymphatic emboli, and higher T stage. LINE-1 hypomethylation was significantly linked with lower cancer-specific survival in patients with intrahepatic cholangiocarcinoma and was found to be an independent prognostic parameter.

CONCLUSIONS

Our findings suggest that tumoral LINE-1 hypomethylation could be a molecular biomarker heralding poor prognosis of patients with intrahepatic cholangiocarcinoma. Our findings need to be validated in further study.

New Horizons for Precision Medicine in Biliary Tract Cancers

Biliary tract cancers (BTC), including cholangiocarcinoma and gallbladder cancer, are poor-prognosis and low-incidence cancers, although the incidence of intrahepatic cholangiocarcinoma is rising. A minority of patients present with resectable disease but relapse rates are high; benefit from adjuvant capecitabine chemotherapy has been demonstrated. Cisplatin/gemcitabine combination chemotherapy has emerged as the reference first-line treatment regimen; there is no standard second-line therapy. Selected patients may be suitable for liver-directed therapy (e.g., radioembolization or external beam radiation), pending confirmation of benefit in randomized studies. Initial trials targeting the epithelial growth factor receptor and angiogenesis pathways have failed to deliver new treatments. Emerging data from next-generation sequencing analyses have identified actionable mutations (e.g., FGFR fusion rearrangements and IDH1 and IDH2 mutations), with several targeted drugs entering clinical development with encouraging results. The role of systemic therapies, including targeted therapies and immunotherapy for BTC, is rapidly evolving and is the subject of this review.Significance: The authors address genetic drivers and molecular biology from a translational perspective, in an intent to offer a clear view of the recent past, present, and future of BTC. The review describes a state-of-the-art update of the current status and future directions of research and therapy in advanced BTC. Cancer Discov; 7(9); 943-62. ©2017 AACR.

New Horizons for Precision Medicine in Biliary Tract Cancers

Biliary tract cancers (BTC), including cholangiocarcinoma and gallbladder cancer, are poor-prognosis and low-incidence cancers, although the incidence of intrahepatic cholangiocarcinoma is rising. A minority of patients present with resectable disease but relapse rates are high; benefit from adjuvant capecitabine chemotherapy has been demonstrated. Cisplatin/gemcitabine combination chemotherapy has emerged as the reference first-line treatment regimen; there is no standard second-line therapy. Selected patients may be suitable for liver-directed therapy (e.g., radioembolization or external beam radiation), pending confirmation of benefit in randomized studies. Initial trials targeting the epithelial growth factor receptor and angiogenesis pathways have failed to deliver new treatments. Emerging data from next-generation sequencing analyses have identified actionable mutations (e.g., FGFR fusion rearrangements and IDH1 and IDH2 mutations), with several targeted drugs entering clinical development with encouraging results. The role of systemic therapies, including targeted therapies and immunotherapy for BTC, is rapidly evolving and is the subject of this review.Significance: The authors address genetic drivers and molecular biology from a translational perspective, in an intent to offer a clear view of the recent past, present, and future of BTC. The review describes a state-of-the-art update of the current status and future directions of research and therapy in advanced BTC. Cancer Discov; 7(9); 943-62. ©2017 AACR.

APOBEC: From mutator to editor

APOBECs (apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like) are a family of cytidine deaminases that prefer single-stranded nucleic acids as substrates. Besides their physiological functions, APOBEC family members have been found to cause hypermutations of cancer genomes, which could be correlated with cancer development and poor prognosis. Recently, APOBEC family members have been combined with the versatile CRISPR/Cas9 system to perform targeted base editing or induce hypermutagenesis. This combination improved the CRISPR/Cas9-mediated gene editing at single-base precision, greatly enhancing its usefulness. Here, we review the physiological functions and structural characteristics of APOBEC family members and their roles as endogenous mutators that contribute to hypermutations during carcinogenesis. We also review the various iterations of the APOBEC-CRISPR/Cas9 gene-editing tools, pointing out their features and limitations as well as the possibilities for future developments.

Genomic Profiling of Biliary Tract Cancers and Implications for Clinical Practice

OPINION STATEMENT

Biliary tract cancers are relatively uncommon, have an aggressive disease course and a dismal clinical outcome. Until recently, there have been very few clinical advances in the management of these patients and gemcitabine-based chemotherapy has been the only widely accepted systemic therapy. The advent of next generation sequencing technologies can potentially change the treatment paradigm of this disease. Targeted therapy directed against actionable mutations and identification of molecular subsets with distinct prognostic significance is now feasible in clinical practice. Mutation profiling has highlighted the genomic differences between the intra, extrahepatic cholangiocarcinoma, and gallbladder cancer. The mutational spectrum of intrahepatic cholangiocarcinoma differs according to geographic location and ethnicity. There is a higher incidence of chromatin modulating gene mutations in Western patients as compared with Asian patients with liver fluke-associated cholangiocarcinoma. KRAS and p53 mutations are associated with an aggressive disease prognosis while FGFR mutations may signify a relatively indolent disease course of intrahepatic cholangiocarcinoma. FGFR and IDH mutations have promising agents in clinical trials at this time. An estimated 15 % of gallbladder cancers have Her2/neu amplification and can be targeted by trastuzumab. On the other hand, an estimated 10-15 % of cholangiocarcinomas have DNA repair mutations and may be candidates for immune therapies with checkpoint inhibitors. The promise of targeted therapies for biliary tract cancers can be fulfilled with well-designed, prospective, and multi-center clinical trials.

Distinct Clinicopathologic and Genetic Features of 2 Histologic Subtypes of Intrahepatic Cholangiocarcinoma

Previous studies have identified 2 clinically significant morphologic subtypes of intrahepatic cholangiocarcinoma (ICC) on the basis of anatomic location and/or histologic appearances. Recognizing that these classification schemes are not always applicable practically, this study aimed to establish a novel classification system based on mucin productivity and immunophenotype and to determine the rationale of this classification by examining the clinicopathologic and genetic characteristics of the 2 subtypes defined by this method. We retrospectively investigated 102 consecutive ICC cases and classified them on the basis of mucin productivity and immunophenotype (S100P, N-cadherin, and NCAM). We found that 42 and 56 cases were classified as type 1 and type 2 ICCs, respectively, and only 4 cases were of indeterminate type. Type 1 ICC, generally characterized by mucin production and diffuse immunoreactivity to S100P, arose less frequently in chronic liver diseases and showed higher levels of serum CEA and CA 19-9 than did type 2 ICC, which generally showed little mucin production and exhibited immunoreactivity to N-cadherin and/or NCAM. Type 1 ICC was characterized by several pathologic features, including higher frequencies of perineural invasion and lymph node metastasis. Although the log-rank test demonstrated that type 1 ICC had significantly worse survival, the multivariate Cox regression analysis showed no prognostic significance of this histologic subtype. Genetic analyses revealed that KRAS mutation was significantly more frequent in type 1 ICC, whereas IDH mutation and FGFR2 translocation were restricted to type 2 ICC. In conclusion, the present classification of ICC based on mucin productivity and immunophenotype identified 2 subtypes with clinicopathologic significance.

Common Molecular Subtypes Among Asian Hepatocellular Carcinoma and Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) and hepatocellular carcinoma (HCC) are clinically disparate primary liver cancers with etiological and biological heterogeneity. We identified common molecular subtypes linked to similar prognosis among 199 Thai ICC and HCC patients through systems integration of genomics, transcriptomics, and metabolomics. While ICC and HCC share recurrently mutated genes, including TP53, ARID1A, and ARID2, mitotic checkpoint anomalies distinguish the C1 subtype with key drivers PLK1 and ECT2, whereas the C2 subtype is linked to obesity, T cell infiltration, and bile acid metabolism. These molecular subtypes are found in 582 Asian, but less so in 265 Caucasian patients. Thus, Asian ICC and HCC, while clinically treated as separate entities, share common molecular subtypes with similar actionable drivers to improve precision therapy.

Dichotomy in intrahepatic cholangiocarcinomas based on histologic similarities to hilar cholangiocarcinomas

Intrahepatic cholangiocarcinomas were classified into two types based on their microscopic appearance. Tumors with histologic similarities to hilar cholangiocarcinomas (predominantly ductal adenocarcinomas with minor tubular components, if present, restricted to the invasive front) were defined as the perihilar type, whereas the others were classified as peripheral cholangiocarcinomas. Among the 47 cases examined in the present study, 26 (55%) were classified as the perihilar type, whereas 21 (45%) were the peripheral type. The perihilar type had higher pT stages and more frequently showed a periductal-infiltrating gross appearance and microscopic perineural infiltration than peripheral cholangiocarcinomas. The presence of low-grade biliary intraepithelial neoplasia in the adjacent bile ducts was only found in perihilar cholangiocarcinomas (6/21, 29%). The immunophenotype also differed between the two types with MUC5AC and MUC6 being more commonly expressed in the perihilar type. One-third of perihilar cholangiocarcinomas lacked the expression of SMAD4, suggesting SMAD4 mutations, whereas the loss of BAP1 expression and IDH1 mutations were almost restricted to the peripheral type (35 and 15%, respectively). Patients with perihilar cholangiocarcinoma had worse overall survival than those with peripheral cancer (P=0.027). A multivariate analysis identified the histologic classification as an independent prognostic factor (P=0.005, HR=3.638). Comparisons between intrahepatic and hilar cholangiocarcinomas also revealed that the molecular features and prognosis of perihilar cholangiocarcinomas were very similar to those of hilar cholangiocarcinomas. In conclusion, this histology-based classification scheme of intrahepatic cholangiocarcinomas will be useful and clinically relevant because it represents different underlying molecular features and has an independent prognostic value.

Whole-Genome and Epigenomic Landscapes of Etiologically Distinct Subtypes of Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a hepatobiliary malignancy exhibiting high incidence in countries with endemic liver-fluke infection. We analyzed 489 CCAs from 10 countries, combining whole-genome (71 cases), targeted/exome, copy-number, gene expression, and DNA methylation information. Integrative clustering defined 4 CCA clusters-fluke-positive CCAs (clusters 1/2) are enriched in ERBB2 amplifications and TP53 mutations; conversely, fluke-negative CCAs (clusters 3/4) exhibit high copy-number alterations and PD-1/PD-L2 expression, or epigenetic mutations (IDH1/2, BAP1) and FGFR/PRKA-related gene rearrangements. Whole-genome analysis highlighted FGFR2 3' untranslated region deletion as a mechanism of FGFR2 upregulation. Integration of noncoding promoter mutations with protein-DNA binding profiles demonstrates pervasive modulation of H3K27me3-associated sites in CCA. Clusters 1 and 4 exhibit distinct DNA hypermethylation patterns targeting either CpG islands or shores-mutation signature and subclonality analysis suggests that these reflect different mutational pathways. Our results exemplify how genetics, epigenetics, and environmental carcinogens can interplay across different geographies to generate distinct molecular subtypes of cancer.Significance: Integrated whole-genome and epigenomic analysis of CCA on an international scale identifies new CCA driver genes, noncoding promoter mutations, and structural variants. CCA molecular landscapes differ radically by etiology, underscoring how distinct cancer subtypes in the same organ may arise through different extrinsic and intrinsic carcinogenic processes. Cancer Discov; 7(10); 1116-35. ©2017 AACR.This article is highlighted in the In This Issue feature, p. 1047.

Integrative Genomic Analysis of Cholangiocarcinoma Identifies Distinct IDH-Mutant Molecular Profiles

Cholangiocarcinoma (CCA) is an aggressive malignancy of the bile ducts, with poor prognosis and limited treatment options. Here, we describe the integrated analysis of somatic mutations, RNA expression, copy number, and DNA methylation by The Cancer Genome Atlas, of a set of predominantly intrahepatic CCA cases, and propose a molecular classification scheme. We identified an IDH -mutant enriched subtype with distinct molecular features including low expression of chromatin modifiers, elevated expression of mitochondrial genes, and increased mitochondrial DNA copy number. Leveraging the multi-platform data, we observed that ARID1A exhibited DNA hypermethylation and decreased expression in the IDH -mutant subtype. More broadly, we found that IDH mutations are associated with an expanded histological spectrum of liver tumors with molecular features that stratify with CCA. Our studies reveal insights into the molecular pathogenesis and heterogeneity of cholangiocarcinoma and provide classification information of potential therapeutic significance.

K-Ras mutation and amplification status is predictive of resistance and high basal pAKT is predictive of sensitivity to everolimus in biliary tract cancer cell lines

Advanced biliary tract cancer (BTC) has a poor prognosis and limited treatment options. The PI3K/Akt/mTOR signalling pathway is hyperactivated in a subset of BTCs, and clinical activity of the mTOR inhibitor everolimus has been observed in some patients with BTC. The goal of this study was to identify biomarkers predictive of everolimus response. Twenty BTC cell lines were assessed for everolimus sensitivity with a spectrum of growth inhibitory responses observed. Molecular biomarkers of sensitivity and resistance were identified by interrogation of the activation status of the Ras/MAPK and PI3K/Akt/mTOR pathways. K-Ras mutations and/or amplifications were identified in 45% of cell lines and were associated with resistance to everolimus. Activating mutations in PIK3CA or loss of PTEN was not predictive of everolimus response; however, high basal levels of pAKT were associated with sensitivity, independent of Ras/MAPK pathway activation status. Notably, everolimus inhibited mTOR signalling to a similar extent in sensitive and resistant cell lines, suggesting that relative dependence on the mTOR pathway rather than the magnitude of pathway inhibition determines everolimus response. Consistent with the known limitations of rapalogs, everolimus induced feedback-mediated activation of AKT in BTC cell lines, which could be overcome by cotreatment with an AKT inhibitor or ATP-competitive mTORC1/mTORC2 inhibitors. However, both approaches failed to induce greater apoptosis compared to everolimus, and mTORC1/mTORC2 kinase inhibitors induced compensatory activation of pERK, identifying an inherent limitation of these agents in BTC cell lines. These findings suggest that future trials of everolimus in BTC would benefit from preselecting patients based on their K-Ras and PI3K/mTOR pathway activation status. The study also identifies strategies for enhancing inhibition of the PI3K/mTOR pathway in BTC cell lines.

Gallbladder cancer epidemiology, pathogenesis and molecular genetics: Recent update

Gallbladder cancer is a malignancy of biliary tract which is infrequent in developed countries but common in some specific geographical regions of developing countries. Late diagnosis and deprived prognosis are major problems for treatment of gallbladder carcinoma. The dramatic associations of this orphan cancer with various genetic and environmental factors are responsible for its poorly defined pathogenesis. An understanding to the relationship between epidemiology, molecular genetics and pathogenesis of gallbladder cancer can add new insights to its undetermined pathophysiology. Present review article provides a recent update regarding epidemiology, pathogenesis, and molecular genetics of gallbladder cancer. We systematically reviewed published literature on gallbladder cancer from online search engine PubMed (http://www.ncbi.nlm.nih.gov/pubmed). Various keywords used for retrieval of articles were Gallbladder, cancer Epidemiology, molecular genetics and bullion operators like AND, OR, NOT. Cross references were manually searched from various online search engines (http://www.ncbi.nlm.nih.gov/pubmed,https://scholar.google.co.in/, http://www.medline.com/home.jsp). Most of the articles published from 1982 to 2015 in peer reviewed journals have been included in this review.

Prognostic factors in patients with advanced biliary tract cancer treated with first-line gemcitabine plus cisplatin: retrospective analysis of 740 patients

PURPOSE

Biliary tract cancer (BTC) is a heterogeneous group of diseases comprising intrahepatic and extrahepatic cholangiocarcinoma and gallbladder cancer. Although gemcitabine plus cisplatin (GEMCIS) was established as the standard first-line chemotherapy based on the ABC-02 trial, more data are needed to define the clinical course of BTC and its prognostic factors with the standard GEMCIS treatment.

METHODS

Between April 2010 and June 2016, 740 patients with histologically documented cholangiocarcinoma and gallbladder cancer were treated with first-line GEMCIS in Asan Medical Center, Seoul, Korea.

RESULTS

In 389 patients with measurable disease (53%), the objective response rate was 13% (n = 50) and there was no significant difference between primary tumor sites (p = 0.45). With a median follow-up duration of 27.3 months (95% CI 24.2-30.5), the median PFS and OS were 5.2 months (95% CI 4.7-5.6) and 10.4 months (95% CI 9.6-11.2), respectively. In multivariate analysis, male gender (female versus male, hazard ratio [HR] 0.83), baseline CA 19-9 level (elevated versus normal, HR 1.31), initially metastatic disease (versus locally advanced disease, HR 1.92), poor performance status (2 versus 0-1, HR 1.45), and measurable disease by RECIST criteria (versus non-measurable, HR 1.40) were significantly associated with a poorer OS (all p < 0.05).

CONCLUSIONS

Our retrospective analysis of a large number of patients in a real-world setting found comparable efficacy outcomes to the ABC-02 trial. The prognostic factors identified here may help to predict clinical outcomes and design future clinical trials for advanced BTC.

Current biologics for treatment of biliary tract cancers

Biliary tract cancers (BTC) is a group of malignancies that arise from the epithelial cells of the biliary tree. These cancers are typically classified by anatomic site of origin: intrahepatic cholangiocarcinoma (IHCC) and extrahepatic cholangiocarcinoma (EHCC), and gallbladder cancer (GBC). To date, complete surgical resection remains the mainstay of treatment especially for earlier stage disease. Unfortunately, most patients present with advanced or metastatic disease, when systemic chemotherapy is the only treatment option. Due to the paucity of effective treatments, BTCs have a dismal prognosis. There is a tremendous need to better understand the disease biology, discover new therapies, and improve clinical outcomes for this challenging disease. Next-generation sequencing has produced a more accurate and detailed picture of the molecular signatures in BTCs. The three BTC histologic subtypes are, in fact, quite molecularly distinct. IHCC commonly contain FGFR2 fusions and IDH 1 and 2 mutations, whereas EHCC and GBC tend to carry mutations in EGFR, HER2, and MAPK pathway. In light of this emerging knowledge, clinical trials have become more biomarker-driven, which allows capturing of subsets of patients that are most likely to respond to certain therapies. Many new and promising targeted therapeutics are currently in the pipeline. Here we review the genetic landscape of BTCs while focusing on new molecular targets and targeted therapeutics currently being investigated in biomarker-driven clinical trials.

Personalized and precision medicine: integrating genomics into treatment decisions in gastrointestinal malignancies

The advent of next generation sequencing (NGS) technologies has advanced our understanding of the intrinsic biology of different gastrointestinal (GI) tumor types. The use of novel, more efficient sequencing platforms has improved turnaround times of sequencing results. This is providing real time opportunities to put precision medicine to the test. A number of early phase clinical trials are testing targeted therapies in unique molecularly characterized subsets of patients (baskets). While basket studies are gaining momentum, treatment failures serve to remind us that shifting from a histology-driven to a histology-agnostic approach is unlikely to be a failure-free strategy for a number of tumor types as recently learnt from vemurafenib failure in BRAF mutated metastatic colorectal cancer (mCRC). GI malignancies are clinically and molecularly heterogeneous. Unfortunately, development of biomarkers of response to therapy as well as targeted therapies for GI adenocarcinomas has fallen behind compared to other malignancies. Trastuzumab is the only FDA approved targeted therapy for GI adenocarcinomas for which a biomarker of response (HER2 amplifications) is available. In addition, RAS mutations are known to predict lack of response to epidermal growth factor receptor (EGFR) inhibitors in advanced colorectal cancer (CRC) patients. However, NGS has recently revealed that a number of actionable genetic aberrations are present at low prevalence across different GI malignancies. Prospective randomized clinical trials will determine whether matching actionable aberration with targeted therapy will contribute to improve survival in patients with GI malignancies. Here, we review current evidence for targeted therapies in GI malignancies, as well as application and pitfalls of NGS including tissue testing and liquid biopsies.

The potential role of comprehensive genomic profiling to guide targeted therapy for patients with biliary cancer

Remarkable advancements in techniques of genomic profiling and bioinformatics have led to the accumulation of vast amounts of knowledge on the genomic profiles of biliary tract cancer (BTC). Recent largescale molecular profiling studies have not only highlighted genomic differences characterizing tumors of the intrahepatic and extrahepatic bile ducts and gallbladder, but have also revealed differences in genomic profiles pertaining to associated risk factors. Novel genomic alterations such as FGFR2 fusions and IDH1/2 mutations in intrahepatic cholangiocarcinoma (ICC) and ERBB2 alterations in gallbladder cancer (GBCA) are emerging as targeted therapy options capable of advancing precision medicine for the care of these patients. Moreover, variable genomic alterations also appear to impact prognosis and overall disease outcome independent from their therapy selection value. High mutational burden and increased expression of immune checkpoint-related proteins observed in a subset of BTC also show a potential for guidance of immunotherapy. Thus, comprehensive genomic profiling (CGP) is rapidly achieving status as an integral component of precision medicine and is starting to become invaluable in guiding the management of patients with BTC, a rare disease with dismal outcome.

The microbiome and hepatobiliary-pancreatic cancers

The human intestinal microbiome encompasses at least 100 trillion microorganisms that can influence host immunity and disease conditions, including cancer. Hepatobiliary and pancreatic cancers have been associated with poor prognosis owing to their high level of tumor invasiveness, distant metastasis, and resistance to conventional treatment options, such as chemotherapy. Accumulating evidence from animal models suggests that specific microbes and microbial dysbiosis can potentiate hepatobiliary-pancreatic tumor development by damaging DNA, activating oncogenic signaling pathways, and producing tumor-promoting metabolites. Emerging evidence suggests that the gut microbiota may influence not only the efficacy of cancer chemotherapies and novel targeted immunotherapies such as anti-CTLA4 and anti-CD274 therapies but also the occurrence of postoperative complications after hepatobiliary and pancreatic surgery, which have been associated with tumor recurrence and worse patient survival in hepatobiliary-pancreatic cancers. Hence, a better understanding of roles of the gut microbiota in the development and progression of hepatobiliary-pancreatic tumors may open opportunities to develop new prevention and treatment strategies for patients with hepatobiliary-pancreatic cancer through manipulating the gut microbiota by diet, lifestyle, antibiotics, and pro- and prebiotics.

Overall Survival and Clinical Characteristics of BRCA-Associated Cholangiocarcinoma: A Multicenter Retrospective Study

BACKGROUND

Biliary tract malignancies, in particular cholangiocarcinomas (CCA), are rare tumors that carry a poor prognosis. BRCA2 mutation carriers have an increased risk of developing CCA with a reported relative risk of ∼5 according to the Breast Cancer Linkage Consortium. In addition to this risk, there are potential therapeutic implications in those harboring somatic and/or germline (GL) BRCA mutations. Therefore, it is important to define the clinical characteristics of GL/somatic BRCA1/2 variants in CCA patients.

MATERIALS AND METHODS

We performed a multicenter retrospective analysis of CCA patients diagnosed between January 2000 and December 2013 with GL or somatic variants in BRCA1/2 genes detected by GL mutations testing and/or by tumor next generation sequencing. Cases were identified from clinical databases at participating institutions. Data including demographics, clinical history, surgical procedures, and systemic chemotherapy or radiation were extracted from patients' records.

RESULTS

Overall, 18 cases were identified: 5 carriers of GL BRCA1/2 mutations (4 BRCA2; 1 BRCA1) and 13 harboring somatic variations (7 BRCA1; 6 BRCA2). Mean age at diagnosis was 60, SD ± 10 years (range 36-75 years), with male and female prevalence rates of 61.2% and 38.8%, respectively. Stage at diagnosis was I (n = 4), II (n = 3), III (n = 3), and IV (n = 8). Six patients had extrahepatic CCA and the rest intrahepatic CCA. Thirteen patients received platinum-based therapy and four were treated with poly ADP ribose polymerase inhibitors, of whom one experienced sustained disease response with a progression-free survival of 42.6 months. Median overall survival from diagnosis for patients with stage I/II in this study was 40.3 months (95% confidence interval [CI], 6.73-108.15) and with stages III/IV was 25 months (95% CI, 15.23-40.57).

CONCLUSION

BRCA-associated CCA is uncommon. This multicenter retrospective study provides a thorough clinical analysis of a BRCA-associated CCA cohort, which can serve as a benchmark for future development and design of expanded analyses and clinical trials.

IMPLICATIONS FOR PRACTICE

BRCA-associated CCA is uncommon but a very important subtype of hepatic malignancies, due to its rising prevalence. Better clinical characterization of this subtype might allow application of targeted therapy for CCA patients with germline or somatic mutations in BRCA1/2 genes, especially due to previously reported success of such therapies in other BRCA-associated malignancies. Thus this study, first of its kind, provides a basis for future multi-centered analyses in larger cohorts, as well as clinical trials. Additionally, this study emphasizes the importance of both germline and somatic genotyping for all CCA patients.

Biliary epithelial injury-induced regenerative response by IL-33 promotes cholangiocarcinogenesis from peribiliary glands

The carcinogenic mechanism of extrahepatic cholangiocarcinoma (ECC) is unclear, due at least in part to the lack of an appropriate mouse model. Because human studies have reported frequent genetic alterations in the Ras- and TGFβ/SMAD-signaling pathways in ECC, mice with tamoxifen-inducible, duct-cell-specific Kras activation and a TGFβ receptor type 2 (TGFβR2) deletion were first generated by crossing LSL-KrasG12D , Tgfbr2flox/flox , and K19CreERT mice (KT-K19CreERT ). However, KT-K19CreERT mice showed only mild hyperplasia of biliary epithelial cells (BECs) in the extrahepatic bile duct (EHBD) and died within 7 wk, probably a result of lung adenocarcinomas. Next, to analyze the additional effect of E-cadherin loss, KT-K19CreERT mice were crossed with CDH1flox/flox mice (KTC-K19CreERT ). Surprisingly, KTC-K19CreERT mice exhibited a markedly thickened EHBD wall accompanied by a swollen gallbladder within 4 wk after tamoxifen administration. Histologically, invasive periductal infiltrating-type ECC with lymphatic metastasis was observed. Time-course analysis of EHBD revealed that recombined BECs lining the bile duct lumen detached due to E-cadherin loss, whereas recombined cells could survive in the peribiliary glands (PBGs), which are considered a BEC stem-cell niche. Detached dying BECs released high levels of IL-33, as determined by microarray analysis using biliary organoids, and stimulated inflammation and a regenerative response by PBGs, leading eventually to ECC development. Cell lineage tracing suggested PBGs as the cellular origin of ECC. IL-33 cooperated with Kras and TGFβR2 mutations in the development of ECC, and anti-IL-33 treatment suppressed ECC development significantly. Thus, this mouse model provided insight into the carcinogenic mechanisms, cellular origin, and potential therapeutic targets of ECC.

Intrahepatic cholangiocarcinoma: current management and emerging therapies

Intrahepatic cholangiocarcinoma (iCCA) is a malignancy with an increasing incidence and a high-case fatality. While surgery offers the best hope at long-term survival, only one-third of tumors are amenable to surgical resection at the time of the diagnosis. Unfortunately, conventional chemotherapy offers limited survival benefit in the management of unresectable or metastatic disease. Recent advances in understanding the molecular pathogenesis of iCCA and the use of next-generation sequencing techniques have provided a chance to identify 'target-able' molecular aberrations. These novel molecular therapies offer the promise to personalize therapy for patients with iCCA and, in turn, improve the outcomes of patients. Area covered: We herein review the current management options for iCCA with a focus on defining both established and emerging therapies. Expert commentary: Surgical resection remains as an only hope for cure in iCCA patients. However, frequently the diagnosis is delayed till advanced stages when surgery cannot be offered; signifying the urge for specific diagnostic tumor biomarkers and targeted therapies. New advances in genomic profiling have contributed to a better understanding of the landscape of molecular alterations in iCCA and offer hope for the development of novel diagnostic biomarkers and targeted therapies.

PD-L1 and PD-1 expression correlate with prognosis in extrahepatic cholangiocarcinoma

The present study aimed to investigate the clinicopathological significance of programmed cell death ligand-1 (PD-L1) and programmed cell death protein 1 (PD-1) expression in extrahepatic cholangiocarcinoma (ECC). PD-L1 and PD-1 expression was detected by immunohistochemical methods in 70 ECC formalin-fixed, paraffin-embedded tissue specimens and 50 para-carcinoma tissue specimens. The associations of PD-L1 and PD-1 expression with clinicopathological characteristics and prognosis of ECC patients were explored. Positive rates of PD-L1 and PD-1 expression were increased in ECC tissues compared with those in the corresponding para-carcinoma tissues. Besides, the expression of PD-L1 was correlated with the expression of PD-1 (P<0.05). Statistical analysis revealed that the expression of PD-L1 and PD-1 in ECC tissues exhibited no correlation with patient age, sex or histological grade, but was significantly correlated with tumor-node-metastasis (TNM) stage and lymphatic metastasis. Univariate analysis demonstrated that PD-L1 expression, PD-1 expression, TNM stage and lymphatic metastasis were significantly associated with the survival time of patients. Further multivariate analysis revealed the PD-L1 expression was an independent prognostic factor of patients with ECC. These preliminary results suggested that PD-L1 or PD-1 immunodetection may be a valuable prognostic marker for ECC patients, and that PD-L1 immunodetection may be used as an independent factor to evaluate the prognosis of ECC patients.

Molecular profiling of intrahepatic cholangiocarcinoma: the search for new therapeutic targets

Intrahepatic cholangiocarcinoma (iCCA) is the second most frequent primary tumor of the liver and a highly lethal disease. Therapeutic options for advanced iCCA are limited and ineffective due to the largely incomplete understanding of the molecular pathogenesis of this deadly tumor. Areas covered: The present review article outlines the main studies and resulting discoveries on the molecular profiling of iCCA, with a special emphasis on the different techniques used for this purpose, the diagnostic and prognostic markers identified, as well as the genes and pathways that could be potentially targeted with innovative therapies. Expert commentary: Molecular profiling has led to the identification of distinct iCCA subtypes, characterized by peculiar genetic alterations and transcriptomic features. Targeted therapies against some of the identified genes are ongoing and hold great promise to improve the prognosis of iCCA patients.

Long term responders to palliative chemotherapy for advanced biliary tract cancer

BACKGROUND

Patients with advanced biliary tract cancer (BTC) are often treated with palliative chemotherapy (PC). Standard PC since 2010 is a cisplatin/gemcitabine doublet, with median overall survival (OS) of 11.7 months from the ABC-02 trial. Prior to this, our institutional standard was gemcitabine and fluoropyrimidine. The ABC-02 study used 8 cycles of PC as standard with treatment stopped even in the absence of disease progression, but some patients may benefit from continuing PC longer than 8 cycles.

METHODS

Patients treated with at least 2 cycles of PC for advanced BTC in Princess Margaret Cancer Centre between 1987 and 2015 were included, and divided into 2 groups for analysis-long-term responders (LTR) who received 9 or more cycles, and controls (2-8 cycles). Data was collected on demographics, clinicopathological features, PC regimen, toxicities, and survival. The primary outcome measure was OS, with secondary analyses including progression-free survival (PFS) and toxicity rates between groups.

RESULTS

A total of 382 patients were identified, 123 who met the criteria for LTR and 259 who were included as controls. The baseline demographic and clinical characteristics were similar, although more patients in the control group had gallbladder cancer or extrahepatic cholangiocarcinoma than LTR (P=0.024), and more patients in the LTR group were treated with combination chemotherapy regimens (93% vs. 82% in controls, P=0.003). The LTR patients had significantly longer PFS (median 13.3 vs. 4.1 months, P<0.001) and longer OS than controls (median 22.1 vs. 9.2 months, P<0.001). In LTR patients, 15% had a break from chemotherapy of 3 months or more and restarted the same regimen. The LTR patients reported higher rates of nausea, cutaneous and hematologic toxicity, but also more frequently went on to receive second-line chemotherapy (47% vs. 33%, P=0.007). In multivariable analysis of OS, LTR, good performance status and intrahepatic site of cancer were associated with better survival.

CONCLUSIONS

From this institutional dataset, a significant proportion of patients continued chemotherapy past 8 cycles, and appeared to derive benefit from longer duration of treatment. Toxicity rates were higher in this group, but manageable as evidenced by second-line treatment rates. Discontinuation of chemotherapy for reasons other than toxicity or progression may result in loss of disease control and impact survival in this population; these data suggest the use of continued chemotherapy to disease progression in patients with advanced BTC is a favorable option.

New molecular and immunotherapeutic approaches in biliary cancer

Biliary tract carcinoma is a collective term for a group of rare gastrointestinal cancers. This overview outlines the key pathways and specialised therapeutics in biliary cancer and the emerging role of immunotherapy by highlighting the rationale and selected examples of studies in each area.

Systematic evaluation of immune regulation and modulation

Cancer immunotherapies are showing promising clinical results in a variety of malignancies. Monitoring the immune as well as the tumor response following these therapies has led to significant advancements in the field. Moreover, the identification and assessment of both predictive and prognostic biomarkers has become a key component to advancing these therapies. Thus, it is critical to develop systematic approaches to monitor the immune response and to interpret the data obtained from these assays. In order to address these issues and make recommendations to the field, the Society for Immunotherapy of Cancer reconvened the Immune Biomarkers Task Force. As a part of this Task Force, Working Group 3 (WG3) consisting of multidisciplinary experts from industry, academia, and government focused on the systematic assessment of immune regulation and modulation. In this review, the tumor microenvironment, microbiome, bone marrow, and adoptively transferred T cells will be used as examples to discuss the type and timing of sample collection. In addition, potential types of measurements, assays, and analyses will be discussed for each sample. Specifically, these recommendations will focus on the unique collection and assay requirements for the analysis of various samples as well as the high-throughput assays to evaluate potential biomarkers.

Integrative Genomic Analysis of Cholangiocarcinoma Identifies Distinct IDH-Mutant Molecular Profiles

Cholangiocarcinoma (CCA) is an aggressive malignancy of the bile ducts, with poor prognosis and limited treatment options. Here, we describe the integrated analysis of somatic mutations, RNA expression, copy number, and DNA methylation by The Cancer Genome Atlas of a set of predominantly intrahepatic CCA cases and propose a molecular classification scheme. We identified an IDH mutant-enriched subtype with distinct molecular features including low expression of chromatin modifiers, elevated expression of mitochondrial genes, and increased mitochondrial DNA copy number. Leveraging the multi-platform data, we observed that ARID1A exhibited DNA hypermethylation and decreased expression in the IDH mutant subtype. More broadly, we found that IDH mutations are associated with an expanded histological spectrum of liver tumors with molecular features that stratify with CCA. Our studies reveal insights into the molecular pathogenesis and heterogeneity of cholangiocarcinoma and provide classification information of potential therapeutic significance.

Multidisciplinary management of intrahepatic cholangiocarcinoma: Current approaches

Intrahepatic cholangiocarcinoma (ICC) is a common primary hepatic tumor. However, its outcomes are usually worse than those of hepatocellular carcinoma owing to its non-specific presentation and detection at an advanced stage. The most widely used serum marker, carbohydrate antigen 19-9, is non-specific. Furthermore, imaging studies rarely identify any pathognomonic features. Surgery is the only treatment option that offers a chance of long-term survival. However, the resectability rate is low owing to the high frequencies of intrahepatic metastases, peritoneal carcinomatosis, or extrahepatic metastases. Surgical treatment should be tailored according to the macroscopic classification of ICC (e.g. mass-forming, periductal infiltrating, and intraductal growth types) because it reflects the tumor's dissemination pattern. Although lymph node metastasis is a negative prognostic factor, the importance and extent of lymph node dissection is still controversial. To improve patient survival, liver transplantation is considered in some patients with unresectable ICC, especially in those with an insufficient remnant liver volume. Minimally invasive procedures, including laparoscopic and robotic liver resection, have been tested and achieved comparable outcomes to conventional surgery in preliminary studies. No randomized trials have confirmed the efficacy of adjuvant chemotherapy in ICC, and several trials have evaluated molecular-targeted agents as monotherapy or in combination with cytotoxic chemotherapy. Multidisciplinary approaches are necessary to improve the outcomes of ICC.

Liver Cancer Cell of Origin, Molecular Class, and Effects on Patient Prognosis

Primary liver cancer is the second leading cause of cancer-related death worldwide and therefore a major public health challenge. We review hypotheses of the cell of origin of liver tumorigenesis and clarify the classes of liver cancer based on molecular features and how they affect patient prognosis. Primary liver cancer comprises hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (iCCA), and other rare tumors, notably fibrolamellar carcinoma and hepatoblastoma. The molecular and clinical features of HCC versus iCCA are distinct, but these conditions have overlapping risk factors and pathways of oncogenesis. A better understanding of the cell types originating liver cancer can aid in exploring molecular mechanisms of carcinogenesis and therapeutic options. Molecular studies have identified adult hepatocytes as the cell of origin. These cells have been proposed to transform directly into HCC cells (via a sequence of genetic alterations), to dedifferentiate into hepatocyte precursor cells (which then become HCC cells that express progenitor cell markers), or to transdifferentiate into biliary-like cells (which give rise to iCCA). Alternatively, progenitor cells also give rise to HCCs and iCCAs with markers of progenitor cells. Advances in genome profiling and next-generation sequencing have led to the classification of HCCs based on molecular features and assigned them to categories such as proliferation-progenitor, proliferation-transforming growth factor β, and Wnt-catenin β1. iCCAs have been assigned to categories of proliferation and inflammation. Overall, proliferation subclasses are associated with a more aggressive phenotype and poor outcome of patients, although more specific signatures have refined our prognostic abilities. Analyses of genetic alterations have identified those that might be targeted therapeutically, such as fusions in the FGFR2 gene and mutations in genes encoding isocitrate dehydrogenases (in approximately 60% of iCCAs) or amplifications at 11q13 and 6p21 (in approximately 15% of HCCs). Further studies of these alterations are needed before they can be used as biomarkers in clinical decision making.

Intratumoral heterogeneity of intrahepatic cholangiocarcinoma

No personalized therapy regimens could demonstrate a benefit in survival of intrahepatic cholangiocarcinoma (iCCA). Since genetic heterogeneity might influence single biopsy based targeted therapy or the outcome of clinical trials, aim of the present study was to investigate intratumoral heterogeneity of iCCA by whole exome sequencing. Therefore, samples from tumor center and tumor periphery of large iCCA lesions as well as a control from healthy liver tissue were obtained from four patients and whole exome sequencing was performed. Mutations that occurred only in the tumor center or periphery were defined as private, whereas mutations present in both samples were regarded as common. A mean of 3 non-synonymous private mutations (range 0-14) per sample compared to 33,3 common mutations per sample (range 24-41) was identified. Mean percentage of non-synonymous private mutations per sample was 12% (range 0-58). In all samples of patient 1-3 as well as the central sample of patient 4 ≤ 10% private mutations were found, whereas 58% of private mutations were identified in the peripheral sample of patient 4. In this sample a private mutation in the DNA mismatch repair protein MSH6 could be identified most likely causing the high amount of private mutations. No substantial intratumoral heterogeneity was found in copy number variation analysis. In conclusion, iCCA show a small but distinct intratumoral heterogeneity. Somatic mutations in mismatch repair proteins might contribute significantly to increased spatial tumor burden and thereby may influence clinical management.

Targeting Angiogenesis in Biliary Tract Cancers: An Open Option

Biliary tract cancers (BTCs) are characterized by a bad prognosis and the armamentarium of drugs for their treatment is very poor. Although the inflammatory status of biliary tract represents the first step in the cancerogenesis, the microenvironment also plays a key role in the pathogenesis of BTCs, promoting tumor angiogenesis, invasion and metastasis. Several molecules, such as vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF), are involved in the angiogenesis process and their expression on tumor samples has been explored as prognostic marker in both cholangiocarcinoma and gallbladder cancer. Recent studies evaluated the genomic landscape of BTCs and evidenced that aberrations in several genes enrolled in the pro-angiogenic signaling, such as FGF receptor-2 (FGFR-2), are characteristic of BTCs. New drugs targeting the signaling pathways involved in angiogenesis have been tested in preclinical studies both in vitro and in vivo with promising results. Moreover, several clinical studies tested monoclonal antibodies against VEGF and tyrosine kinase inhibitors targeting the VEGF and the MEK/ERK pathways. Herein, we evaluate both the pathogenic mechanisms of BTCs focused on angiogenesis and the preclinical and clinical data available regarding the use of new anti-angiogenic drugs in these malignancies.

The PD-1/PD-L1 axis may be aberrantly activated in occupational cholangiocarcinoma

An outbreak of cholangiocarcinoma in a printing company was reported in Japan, and these cases were regarded as an occupational disease (occupational cholangiocarcinoma). This study examined the expression status of programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) in occupational cholangiocarcinoma. Immunostaining of PD-1, PD-L1, CD3, CD8, and CD163 was performed using tissue sections of occupational cholangiocarcinoma (n = 10), and the results were compared with those of control cases consisting of intrahepatic (n = 23) and extrahepatic (n = 45) cholangiocarcinoma. Carcinoma cells expressed PD-L1 in all cases of occupational cholangiocarcinoma, whereas the detection of PD-L1 expression in cholangiocarcinoma cells was limited to a low number of cases (less than 10%) in the control subjects. In cases of occupational cholangiocarcinoma, occasional PD-L1 expression was also noted in precancerous/preinvasive lesions such as biliary intraepithelial neoplasia and intraductal papillary neoplasm of the bile duct. Additionally, tumor-associated macrophages and tumor-infiltrating T cells expressed PD-L1 and PD-1, respectively. The number of PD-L1-positive mononuclear cells, PD-1-positive lymphocytes, and CD8-positive lymphocytes infiltrating within the tumor was significantly higher in occupational cholangiocarcinoma compared with that in control cases. These results indicate that immune escape via the PD-1/PD-L1 axis may be occurring in occupational cholangiocarcinoma.

Intrahepatic cholangiocarcinoma frequently shows loss of BAP1 and PBRM1 expression, and demonstrates specific clinicopathological and genetic characteristics with BAP1 loss

AIMS

BAP1 and PBRM1 expression loss has been observed in multiple cancers, including intrahepatic cholangiocarcinoma (ICC). We investigated BAP1 and PBRM1 expression in ICC using immunohistochemistry, and analysed its association with clinicopathological and genetic features, including two histological subtypes.

METHODS AND RESULTS

Whole-section slides of 108 consecutive primary ICC cases were immunostained against BAP1 and PBRM1. Complete loss of BAP1 and PBRM1 was observed in 21 (19.4%) and 25 (23.1%) cases, respectively, and partial loss was identified in four (3.7%) and nine (8.4%) cases. In all cases, normal bile ducts were strongly and diffusely positive for both BAP1 and PBRM1. ICC with BAP1 loss showed lower serum CA19-9 levels, less perineural invasion, rare mucin production, weaker immunoreactivity against S-100P and stronger immunoreactivity against N-cadherin and NCAM. IDH mutations were identified more frequently in ICCs with BAP1 loss. All ICC with BAP1 loss corresponded to small-duct type ICC. Multivariate Cox regression analysis showed that BAP1 loss was an independent prognostic factor for both overall and recurrence-free survival (P < 0.05). Conversely, PBRM1 loss was found in both small-duct type and large-duct type ICC, and was not associated significantly with any specific characteristics, including prognosis.

CONCLUSION

BAP1 and PBRM1 loss is seen frequently in ICC. ICC with BAP1 loss shares features of small-duct type ICC.

Efficacy of fluoropyrimidine-based chemotherapy in patients with advanced biliary tract cancer after failure of gemcitabine plus cisplatin: retrospective analysis of 321 patients

Background:

We aimed to assess the efficacy of second-line fluoropyrimidine-based chemotherapy in patients with advanced biliary tract cancer (BTC) after failure of gemcitabine plus cisplatin (GEMCIS).

Methods:

We retrospectively examined patients with histologically documented advanced BTC who received first-line GEMCIS between December 2010 and June 2015. Among 748 patients treated with first-line GEMCIS, 321 (43%) subsequently received fluoropyrimidine-based second-line systemic chemotherapy.

Results:

Fluoropyrimidine monotherapy and fluoropyrimidine–platinum combination were used in 255 and 66 patients, respectively. In patients with measurable disease, the overall response rate (ORR) was 3% and disease control rate was 47%. After a median follow-up of 27.6 months (range, 0.9–70.4 months), the median progression-free survival (PFS) and overall survival (OS) were 1.9 months (95% confidence interval (CI), 1.6–2.2) and 6.5 months (95% CI, 5.9–7.0), respectively. The ORR was significantly higher in patients who received fluoropyrimidine–platinum combination compared with those who received fluoropyrimidine alone (8 vs 1%, P=0.009), although the PFS (P=0.43) and OS (P=0.88) did not significantly differ between these groups.

Conclusions:

Fluoropyrimidine-based chemotherapy was modestly effective as a second-line chemotherapy for advanced BTC patients after failure of GEMCIS. Fluoropyrimidine–platinum combination therapy was not associated with improved survival outcomes, as compared with fluoropyrimidine monotherapy.

The Role of Cancer-Associated Fibroblasts and Fibrosis in Liver Cancer

Liver cancer is the second leading cause of cancer mortality worldwide, causing more than 700,000 deaths annually. Because of the wide landscape of genomic alterations and limited therapeutic success of targeting tumor cells, a recent focus has been on better understanding and possibly targeting the microenvironment in which liver tumors develop. A unique feature of liver cancer is its close association with liver fibrosis. More than 80% of hepatocellular carcinomas (HCCs) develop in fibrotic or cirrhotic livers, suggesting an important role of liver fibrosis in the premalignant environment (PME) of the liver. Cholangiocarcinoma (CCA), in contrast, is characterized by a strong desmoplasia that typically occurs in response to the tumor, suggesting a key role of cancer-associated fibroblasts (CAFs) and fibrosis in its tumor microenvironment (TME). Here, we discuss the functional contributions of myofibroblasts, CAFs, and fibrosis to the development of HCC and CCA in the hepatic PME and TME, focusing on myofibroblast- and extracellular matrix-associated growth factors, fibrosis-associated immunosuppressive pathways, as well as mechanosensitive signaling cascades that are activated by increased tissue stiffness. Better understanding of the role of myofibroblasts in HCC and CCA development and progression may provide the basis to target these cells for tumor prevention or therapy.

Soluble programmed death-ligand 1 (sPDL1) and neutrophil-to-lymphocyte ratio (NLR) predicts survival in advanced biliary tract cancer patients treated with palliative chemotherapy

Programmed death-ligand 1 (PD-L1) expression in tumor tissue is under investigation as a candidate biomarker in immuno-oncology dug development. The soluble form of PD-L1 (sPDL1) is suggested to have immunosuppressive activity. In this study, we measured the serum level of sPDL1 and evaluated its prognostic implication in biliary tract cancer (BTC). Blood was collected from 158 advanced BTC patients (68 intrahepatic cholangiocarcinoma, 56 gallbladder cancer, 22 extrahepatic cholangiocarcinoma and 12 ampulla of vater cancer) before initiation of palliative chemotherapy. Serum sPDL1 was measured using an enzyme-linked immunosorbent assay. Clinical data included neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and systemic immune-inflammation index (SII, neutrophil × platelet/lymphocyte). The patients were assigned to two cohorts (training and validation cohort) using a simple random sampling method to validate the cut-off value of each marker. Validation was performed using a twofold cross-validation method. Overall survival (OS) of all patients was 9.07 months (95% CI: 8.20-11.33). Median sPDL1 was 1.20 ng/mL (range 0.03-7.28, mean 1.50, SD 1.22). Median NLR, PLR and SII were 2.60, 142.85 and 584.93, respectively. Patients with high sPDL1 (≥0.94 ng/mL) showed worse OS than patients with low sPDL1 (7.93 vs. 14.10 months, HR 1.891 (1.35-2.65), p<0.001). In multivariate analysis, high sPDL1 and NLR were independent poor prognostic factors. In conclusion, serum sPDL1 can be measured and has significant role on the prognosis of advanced BTC patients treated with palliative chemotherapy.

A phase 1 study combining the HER3 antibody seribantumab (MM-121) and cetuximab with and without irinotecan

Background HER3/EGFR heterodimers have been implicated as a mode of resistance to EGFR-directed therapies. Methods This Phase 1 trial assessed the tolerability, maximum tolerated dose (MTD) and pharmacokinetic (PK) properties of the HER-3 antibody seribantumab in combination with cetuximab (Part I) or cetuximab and irinotecan (Part II) in patients with EGFR-dependent cancers. In Part I, escalating doses of seribantumab and cetuximab were administered. In Part II of the trial, escalating doses of seribantumab/cetuximab were combined with irinotecan 180 mg/m2 administered every two weeks. Results 34 patients were enrolled in Part I (seribantumab/cetuximab) and 14 patients were enrolled in Part II (seribantumab/cetuximab/irinotecan). Common toxicities of seribantumab/cetuximab included acneiform rash, diarrhea, stomatitis, and paronychia. The MTD of Part I was seribantumab 40 mg/kg bolus, then 20 mg/kg weekly combined with cetuximab 400 mg/m2 bolus, then 250 mg/m2 IV weekly. Common toxicities reported in the seribantumab/cetuximab/irinotecan combination were similar to the Part I portion. However, toxicities were more frequent and severe with the triplet combination. There was one treatment-related death in Part II secondary to Grade 4 neutropenia and grade 3 diarrhea. Other dose-limiting toxicities in Part II were Grade 3 mucositis and Grade 3 diarrhea. A cholangiocarcinoma patient, previously untreated with EGFR-directed therapy, had a confirmed partial response (PR). One colorectal cancer patient, previously treated with EGFR-directed therapy, had an unconfirmed PR. Conclusions Seribantumab/cetuximab was well tolerated and patients experienced toxicities typical to EGFR inhibition. Unlike the seribantumab/cetuximab doublet, seribantumab/cetuximab/irinotecan was difficult to tolerate in this heavily pretreated population. There was limited efficacy of the combination therapy.

A phase I trial investigating pulsatile erlotinib in combination with gemcitabine and oxaliplatin in advanced biliary tract cancers

Advanced biliary tract cancers (ABTC) are among the deadliest malignancies with limited treatment options after progression on standard-of-care chemotherapy, which includes gemcitabine (GEM) and oxaliplatin (OX). The epidermal growth factor receptor inhibitor erlotinib has been explored in ABTC with modest efficacy. Erlotinib given continuously may antagonize the action of chemotherapy against cycling tumor cells, but pulsatile dosing of erlotinib with chemotherapy may improve efficacy. The purpose of this study was to assess the safety of pulsatile erlotinib with GEMOX. This was a single-institution phase Ib study that enrolled adult patients with unresectable or metastatic biliary tract, pancreas, duodenal, or ampullary carcinomas that have not received any prior treatment for their disease. Dose escalation followed a standard 3 + 3 design, and dose-limiting toxicities (DLTs) were any treatment-related, first course non-hematologic grade ≥ 3 toxicity, except nausea/vomiting, or grade 4 hematologic toxicity. A dose expansion cohort in ABTC was treated at the MTD. Twenty-eight patients were enrolled and 4 dose levels were explored. The MTD was erlotinib 150 mg + GEM 800 mg/m² + OX 85 mg/m². DLTs were diarrhea and anemia. Most frequent toxicities were nausea (78 %), fatigue (71 %), neuropathy (68 %), and diarrhea (61 %), predominantly grade 1–2. In the ABTC patients, the objective response and disease control rates were 29 % and 94 %, respectively, and median overall survival was 18 months. Erlotinib plus GEMOX was well tolerated. Encouraging anti-tumor activity was seen as evidenced by a high disease control rate and longer median OS than standard chemotherapy in the patients with ABTC.

Mutational landscape of combined hepatocellular carcinoma and cholangiocarcinoma, and its clinicopathological significance

AIMS

Combined hepatocellular carcinoma and cholangiocarcinoma (cHC-CC), which generally has a poor prognosis, comprises hepatocellular carcinoma (HCC), cholangiocarcinoma (CC), and diverse components with intermediate features between HCC and CC. Histological subtypes with stem cell (SC) features (the SC subtype) have different clinicopathological significance in cHC-CC. The mutational status may reflect the clinicopathological subgroup of cHC-CC together with the histological subtype.

METHODS AND RESULTS

We examined the mutational statuses of KRAS, IDH1 or IDH2 (IDH1/2), ARID1A, the TERT promoter, and TP53, and their relationships with clinicopathological features in 53 patients with cHC-CC. Background liver diseases were hepatitis B (n = 9), hepatitis C (n = 22), alcoholic liver disease (n = 5), non-alcoholic fatty liver disease (NAFLD) (n = 8), and unknown (n = 9). Mutations in KRAS, IDH1/2, ARID1A, the TERT promoter and TP53 were detected in four (7.5%), six (11.8%) seven (13.2%), 16 (31.3%), and 24 patients (45.3%), respectively. KRAS mutations correlated with higher histological diversity scores and a higher M-factor (P < 0.05). ARID1A mutations correlated with alcoholic liver disease, smaller tumour size, a lower grade of coexistent HCC, and α-fetoprotein (AFP) positivity, and were associated with cholangiolocellular carcinoma subtype predominance (P < 0.05). TERT promoter mutations correlated with hepatitis B, an intermediate subtype-predominant histology, higher clinical stage, and a higher N-factor (P < 0.05), and were associated with gender (female-predominant) and previous therapy. TP53 mutations correlated with AFP positivity (P < 0.05).

CONCLUSIONS

The results of the mutational analysis revealed that cHC-CC has diverse types of mutations, and also that mutations in the TERT promoter and ARID1A may reflect aetiological impact, different histological subtypes, histogenesis, and tumour aggressiveness. These results suggest the potential efficacy of molecular-based subclassification of cHC-CC.

Aberrant activation of Notch signaling in extrahepatic cholangiocarcinoma: clinicopathological features and therapeutic potential for cancer stem cell-like properties

BACKGROUND

Little is known about the roles of Notch signaling in cholangiocarcinoma (CC). The expression of hairy and enhancer of split 1 (Hes-1) has not been investigated yet in resected specimens of CC. Notch signaling has been reported to be related to cancer stem cell (CSC) like properties in some malignancies. Our aim is to investigate the participation of Notch signaling in resected specimens of extrahepatic CC (EHCC) and to evaluate the efficacy of CC cells with CSC-like properties by Notch signaling blockade.

METHODS

First, the expression of Notch1, 2, 3, 4 and Hes-1 was examined by immunohistochemistry in 132 resected EHCC specimens. The clinicopathological characteristics in the expression of Notch receptors and Hes-1 were investigated. Second, GSI IX, which is a γ-secretase-inhibitor, was used for Notch signaling blockade in the following experiment. Alterations of the subpopulation of CD24⁺CD44⁺ cells, which are surface markers of CSCs in EHCC, after exposure with GSI IX, gemcitabine (GEM), and the combination of GSI IX plus GEM were assessed by flow cytometry using the human CC cell lines, RBE, HuCCT1 and TFK-1. Also, anchorage-independent growth and mice tumorigenicity in the cells recovered by regular culture media after GSI IX exposure were assessed.

RESULTS

Notch1, 2, 3, 4 and Hes-1 in the resected EHCC specimens were expressed in 50.0, 56.1, 42.4, 6.1, and 81.8 % of the total cohort, respectively. Notch1 and 3 expressions were associated with poorer histological differentiation (P = 0.008 and 0.053). The patients with the expression of at least any one of Notch1-3 receptors, who were in 80.3 % of the total, exhibited poorer survival (P = 0.050). Similarly, the expression of Hes-1 tended to show poor survival (P = 0.093). In all of the examined CC cell lines, GSI IX treatment significantly diminished the subpopulation of CD24⁺CD44⁺ cells. Although GEM monotherapy relatively increased the subpopulation of CD24⁺CD44⁺ cells in all lines, GSI IX plus GEM attenuated it. Anchorage-independent growth and mice tumorigenicity were inhibited in GSI IX-pretreated cells in RBE and TFK-1 (P < 0.05).

CONCLUSION

Aberrant Notch signaling is involved with EHCC. Inhibition of Notch signaling is a novel therapeutic strategy for targeting cells with CSC-like properties.

The case for immune-based approaches in biliary tract carcinoma

Biliary tract cancers (BTC) comprise a group of uncommon malignancies in which the standard therapies are minimally effective and evolve slowly. Like the majority of gastrointestinal cancers, with some notable exceptions, the impact of immune-based approaches has yet to be seen. However, the etiological background of BTC-overlapping in almost every known causative or associated factor with inflammation-provides a strong clue that these approaches may have an impact in this group of diseases. This review covers what we currently know about the role of the immune system in the etiology of BTC, highlighting differences by subtype, and pointing to the therapeutic opportunities currently entering the clinic or about to do so. (Hepatology 2016;64:1785-1791).

Establishment of various biliary tract carcinoma cell lines and xenograft models for appropriate preclinical studies

We recently reported several driver genes of biliary tract carcinoma (BTC) that are known to play important roles in oncogenesis and disease progression. Although the need for developing novel therapeutic strategies is increasing, there are very few BTC cell lines and xenograft models currently available for conducting preclinical studies. Using a total of 88 surgical BTC specimens and 536 immunodeficient mice, 28 xenograft models and 13 new BTC cell lines, including subtypes, were established. Some of our cell lines were found to be resistant to gemcitabine, which is currently the first choice of treatment, thereby allowing highly practical preclinical studies to be conducted. Using the aforementioned cell lines and xenograft models and a clinical pathological database of patients undergoing BTC resection, we can establish a preclinical study system and appropriate parameters for drug efficacy studies to explore new biomarkers for practical applications in the future studies.

Mutational signatures in esophageal adenocarcinoma define etiologically distinct subgroups with therapeutic relevance

Esophageal adenocarcinoma (EAC) has a poor outcome, and targeted therapy trials have thus far been disappointing owing to a lack of robust stratification methods. Whole-genome sequencing (WGS) analysis of 129 cases demonstrated that this is a heterogeneous cancer dominated by copy number alterations with frequent large-scale rearrangements. Co-amplification of receptor tyrosine kinases (RTKs) and/or downstream mitogenic activation is almost ubiquitous; thus tailored combination RTK inhibitor (RTKi) therapy might be required, as we demonstrate in vitro. However, mutational signatures showed three distinct molecular subtypes with potential therapeutic relevance, which we verified in an independent cohort (n = 87): (i) enrichment for BRCA signature with prevalent defects in the homologous recombination pathway; (ii) dominant T>G mutational pattern associated with a high mutational load and neoantigen burden; and (iii) C>A/T mutational pattern with evidence of an aging imprint. These subtypes could be ascertained using a clinically applicable sequencing strategy (low coverage) as a basis for therapy selection.