Targeting tumor microenvironment for cholangiocarcinoma: Opportunities for precision medicine

Systemic treatments (e.g., chemotherapy and targeted therapies) have limited efficacy for patients with locally advanced – unresectable – and metastatic cholangiocarcinoma (CCA), with an overall survival of less than a year. Tumor microenvironment (TME) represents the ecosystem surrounding the tumor which comprises immune cells, fibroblasts, endothelial cells, and a wide range of soluble factors. CCA TME is characterized by an abundant desmoplastic stroma, exhibits a high heterogeneity and it plays a central role in cancer onset and progression. There is growing evidence suggesting that it is possible to target TME in association with other treatment modalities, such as cytotoxic chemotherapy or targeted therapies, paving the way to possible combination strategies with a synergistic effect. Herein, we describe the components of CCA TME – such as cancer-associated fibroblasts and other cells of pivotal importance - with their most relevant interactions, focusing on the preclinical rationale for the development of effective anticancer treatments.     

Reappraisal of the Therapeutic Role of Celecoxib in Cholangiocarcinoma

Cholangiocarcinoma (CCA), a lethal disease, affects many thousands worldwide yearly. Surgical resection provides the best chance for a cure; however, only one-third of CCA patients present with a resectable tumour at the time of diagnosis. Currently, no effective chemotherapy is available for advanced CCA. Cyclooxygenase-2 (COX-2) is a potential oncogene expressing in human CCA tissues and represents a candidate target for treatment; however, COX-2 inhibitors increase the risk of negative cardiovascular events as application for chemoprevention aim. Here, we re-evaluated the effectiveness and safety of celecoxib, one widely used COX-2 inhibitor, in treating CCA. We demonstrated that celecoxib exhibited an anti-proliferative effect on CGCCA cells via cell cycle arrest at G2 phase and apoptosis induction. Treatment for 5 weeks high dose celecoxib (160 mg/kg) significantly repressed thioacetamide-induced CCA tumour growth in rats as monitored by animal positron emission tomography through apoptosis induction. No obviously observable side effects were noted during the therapeutic period. As retrospectively reviewing 78 intrahepatic mass-forming CCA patients, their survival was strongly and negatively associated with a positive resection margin and high COX-2 expression. Based on our result, we concluded that short-term high dose celecoxib may be a promising therapeutic regimen for CCA. Yet its clinical application still needs more studies to prove its safety.     

Functions of FGFR2 corrupted by translocations in intrahepatic cholangiocarcinoma

Cholangiocarcinoma, originating from the biliary duct, represents a subset of liver cancer. With about 8000 new cases of cholangiocarcinoma diagnosed annually in the U.S., these fall into three categories: intrahepatic, peri-hilar, and extrahepatic cholangiocarcinoma. Arising from the epithelium of the bile duct, intrahepatic cholangiocarcinoma (ICC) is a universally fatal malignancy with very few treatment options. The poor prognosis and lack of molecular targeted therapies highlights ICC as a critical unmet medical need. With advances in sequencing technology, numerous chromosomal translocations have been discovered as drivers in cancer initiation and progression. Particularly in ICC, chromosomal translocations involving Fibroblast Growth Factor Receptor 2 (FGFR2) have been frequently identified, resulting in the creation of oncogenic fusion proteins. At the N-terminus, these fusion proteins share a nearly-identical FGFR2 moiety retaining an intact kinase domain and, at the C-terminus, a dimerization/oligomerization domain provided by different partner genes, including: Periphilin 1 (PPHLN1), Bicaudal family RNA binding protein 1 (BICC1), Adenosylhomocysteinase Like 1 (AHCYL1), and Transforming Acidic Coiled-Coil Containing Protein 3 (TACC3). A number of pre-clinical and clinical trials have shown the effectiveness of FGFR inhibitors in treating FGFR2 fusion-positive ICC patients. However, the efficacy of these inhibitors may be short-lived due to acquired resistance. In this review, we provide an overview of FGFR2 fusions, comparing their structures and mechanism of dimerization, examining the importance of FGFR2 as a partner gene, as well as highlighting the significance of alternative splicing of FGFR2 in these fusion proteins. In addition, we discuss various therapeutic options and their associated potencies in targeting these translocation-induced ICCs.     

The Prognostic Role of SOCS3 and A20 in Human Cholangiocarcinoma

As an antagonist of the JAK/STAT pathway, suppressor of cytokine signaling 3 (SOCS3) plays an integral role in shaping the inflammatory environment, tumorigenesis and disease progression in cholangiocarcinoma (CCA); however, its prognostic significance remains unclear. Although tumor necrosis factor α-induced protein 3 (TNFAIP3, also known as A20) can decrease SOCS3 expression and is involved in the regulation of tumorigenesis in certain malignancies, its role in CCA remains unknown. In this study, we investigated the expression of SOCS3 and A20 in human CCA tissues to assess the prognostic significance of these proteins. The expression of SOCS3 and A20 was initially detected by western blot in 22 cases of freshly frozen CCA tumors with corresponding peritumoral tissues and 22 control normal bile duct tissues. Then, these proteins were investigated in 86 CCA patients by immunohistochemistry (IHC) and were evaluated for their association with clinicopathological parameters in human CCA. The results indicated that SOCS3 expression was significantly lower in CCA tumor tissues than in corresponding peritumoral biliary tissues and normal bile duct tissues. Conversely, A20 was overexpressed in CCA tissues. Thus, an inverse correlation between the expression of SOCS3 and A20 was discovered. Furthermore, patients with low SOCS3 expression or high A20 expression showed a dramatically lower overall survival rate. These proteins were both associated with CCA lymph node metastasis, postoperative recurrence and overall survival rate. However, only A20 showed a significant association with the tumor node metastasis (TNM) stage, while SOCS3 showed a significant association with tumor differentiation. Multivariate Cox analysis revealed that SOCS3 and A20 were independent prognostic indicators for overall survival in CCA. Thus, our study demonstrated that SOCS3 and A20 represent novel prognostic factors for human CCA.     

MicroRNA和自噬参与胆管癌发病机制的研究进展

胆管癌是一种高度转移的恶性肿瘤,包括肝内胆管癌和肝外胆管癌,目前手术被认为是唯一的根治方案。胆管癌在全球的发病率和死亡率不断增加,原因很可能与早期胆管癌没有明显的临床表现,确诊时通常已达晚期阶段,及预后差、极易复发的特点有关。与人类胆管癌相关的microRNAs有很多,调节着胆管肿瘤的发生发展。此外,自噬作为细胞内环境的一种调节机制,也调节肿瘤恶变和癌症进展,在不同情况下治疗性干预,促进或抑制自噬将有利于胆管癌患者。现将microRNA和自噬参与胆管癌发生发展作一综述。     

A novel carbohydrate antigen expression during development of Opisthorchis viverrini- associated cholangiocarcinoma in golden hamster: a potential marker for early diagnosis

Poor prognosis of cholangiocarcinoma (CCA) is primarily due to delayed diagnosis because of the lack of appropriate tumor marker(s) to detect cancer development at an early stage. We have recently established a S121 monoclonal antibody (mAb) which recognizes an unidentified glycan epitope on MUC5AC, designated as CCA-associated carbohydrate antigen (CCA-CA). This antigen is expressed in human CCA cells but not in normal biliary epithelia. Detection of CCA-CA effectively distinguished CCA patients' sera from normal control sera with high specificity and sensitivity. In the present study, we examined a time profile of the expression of CCA-CA by immunohistochemical methods in the liver tissues of Opisthorchis viverrini (Ov)-associated CCA in a hamster model. Hamsters were divided into four groups; non-treated, Ov infected, NDMA (N-nitrosodimethamine) treated and Ov + NDMA treated groups, and animals from each group were euthanized at 1, 3 and 6 months post-treatment. CCA-CA was not detected in normal biliary cells of non-treated hamsters throughout the course of experiment. CCA-CA became detectable in the cytoplasm and apical surface of biliary cells of the NDMA and Ov + NDMA groups at early stage (1 month) of tumor development and increased with tumor progression. In contrast, CCA-CA was detected as nuclear staining at the 1 month post Ov infection and declined thereafter. These results suggest the possibility of CCA-CA as an early marker for CCA.     

Thymidine phosphorylase promotes angiogenesis and tumour growth in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver cancer, and thymidine phosphorylase (TP) is a regulator of angiogenesis. To investigate the biological activities of TP in ICC, we established human cholangiocarcinoma RBE cell lines overexpressing TP or silencing TP. Overexpression of TP enhanced viability, suppressed apoptosis and increased tube formation in human umbilical vein endothelial cells, while downregulation of TP reversed these effects. Moreover, an orthotopic xenograft mouse model of ICC was built to further explore TP's function in ICC in vivo. Histological analysis using H&E, TUNEL and Ki67 staining showed that TP promoted tumour growth and inhibited cell apoptosis. Immunostaining for CD31 revealed an elevation in microvessel density in the presence of TP. Besides, upregulation of TP increased the expression of vascular endothelial growth factor, basic fibroblast growth factor, interleukin-8 and tumour necrosis factor alpha. In contrast, TP knockdown inhibited tumour growth, suppressed microvessel formation and decreased the expression of angiogenesis-related proteins. Therefore, we suggest that TP promotes angiogenesis and tumour growth in ICC, which can be a potent therapeutic target for ICC treatment.     

Beclin 1 Deficiency Correlated with Lymph Node Metastasis,Predicts a Distinct Outcome in Intrahepatic and Extrahepatic Cholangiocarcinoma

Autophagy can be tumor suppressive as well as promotive in regulation of tumorigenesis and disease progression. Accordingly, the prognostic significance of autophagy key regulator Beclin 1 was varied among different tumors. Here, we detected the clinicopathological and prognostic effect of Beclin 1 in the subtypes of intrahepatic cholangiocarcinoma (ICC) and extrahepatic cholangiocarcinoma (ECC). Beclin 1 expression level was detected by immunohistochemistry staining in 106 ICC and 74 ECC patients. We found that Beclin 1 was lowly expressed in 126 (70%) cholangiocarcinoma patients, consist of 72 ICC and 54 ECC. Moreover, the cholangiocarcinoma patients with lymph node metastasis (N1) had a lower Beclin 1 level than that of N0 subgroup (P=0.012). However, we did not detect any correlations between Beclin 1 and other clinicopathological features, including tumor subtypes, vascular invasion, HBV infection, liver cirrhosis, cholecystolithiasis and TNM stage. Survival analysis showed that, compared with the high expression subset, Beclin 1 low expression was correlated with a poorer 3-year progression-free survival (PFS, 69.1% VS 46.8%, P=041) for cholangiocarcinoma. Importantly, our stratified univariate and multivariate analysis confirmed that Beclin 1 lowly expressed ICC had an inferior PFS as well as overall survival than ECC, particularly than that of Beclin 1 highly expressed ECC patients. Thus, our study demonstrated that Beclin 1low expression, correlated with lymph node metastasis, and might be a negative prognostic biomarker for cholangiocarcinoma. Combined Beclin 1 level with the anatomical location might lead to refined prognosis for the subtypes of ICC and ECC.     

LncRNA-MEG3 inhibits cell proliferation and invasion by modulating Bmi1/RNF2 in cholangiocarcinoma

Cholangiocarcinoma (CCA) is a mortal cancer with gradually increasing incidences all over the world, whereas effective diagnosis and treatment for this disease are still lacking. As a classical long noncoding RNA (lncRNA), maternally expressed gene 3 (MEG3) has been reported to exhibit pivotal regulatory roles in the occurrence and development of various digestive system tumors. Nevertheless, the clinical relevance and biological function of MEG3 in CCA remain largely unclear. In this study, MEG3 expression was significantly downregulated in both CCA tissues and cells in comparison with that in nontumor controls, respectively, and this downexpression was prominently associated with advanced TNM stage, lymph node invasion, and poor survival. Moreover, decreased MEG3 was an independent forecaster of poor prognosis for CCA patients. Functionally, MEG3 overexpression inhibited CCA growth in vitro and in vivo. Enhanced MEG3 also suppressed migration and invasion of CCLP-1 and QBC939 cells by reversing epithelial-mesenchymal transition (EMT) process. On the contrary, the proliferation, metastasis, and EMT were facilitated via knocking down MEG3. In addition, the expression of B lymphoma Mo-MLV insertion region 1 (Bmi1) and RING finger protein 2 was impacted by gain or loss of MEG3, furthermore, the malignant processes induced by MEG3 knockdown were rescued by means of silencing Bmi1. These data suggested that MEG3 caused tumor suppressive effects partly through mediating polycomb repressive complex 1. Our findings elucidate that MEG3 exerts critical functions in CCA development and likely acts as a promising tumor indicator or intervention target for CCA.     

Chemoresistance and chemosensitization in cholangiocarcinoma

One of the main difficulties in the management of patients with advanced cholangiocarcinoma (CCA) is their poor response to available chemotherapy. This is the result of powerful mechanisms of chemoresistance (MOC) of quite diverse nature that usually act synergistically. The problem is often worsened by altered MOC gene expression in response to pharmacological treatment. Since CCA includes a heterogeneous group of cancers their genetic signature coding for MOC genes is also diverse; however, several shared traits have been defined. Some of these characteristics are shared with other types of liver cancer, namely hepatocellular carcinoma and hepatoblastoma. An important goal in modern oncologic pharmacology is to develop novel strategies to overcome CCA chemoresistance either by increasing drug specificity, such as in targeted therapies aimed to inhibit receptors with tyrosine kinase activity, or to increase the amounts of active agents inside CCA cells by enhancing drug uptake or reducing efflux through export pumps. This article is part of a Special Issue entitled: Cholangiocytes in Health and Diseaseedited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.     

Prognostic significance of Beclin 1 in intrahepatic cholangiocellular carcinoma

Autophagy enables cells to recycle long-lived proteins or damaged organelles. Beclin 1 plays important roles in autophagy, differentiation, apoptosis and the development and progression of cancer, but the expression of Beclin 1 and its possible role in primary intrahepatic cholangiocarcinoma (ICC) has not been reported yet. This study aimed to investigate Beclin 1 expression and its prognostic significance in ICC. First, we assessed the expression levels of Becn1 by real-time PCR in 50 ICC samples and found Becn1 mRNA expression was markedly increased in 78% (39 of 50) samples compared with normal bile duct epithelium. Beclin 1 protein expression in 108 tumor specimens from patients diagnosed with ICC was examined by immunohistochemistry and the correlation between Beclin 1 expression and clinicopathological factors were investigated. Immunopositivity for Beclin 1 was found in 72.2% (78 of 108) samples and low Beclin 1 expression was significantly associated with lymph node metastasis. The correlation between Beclin 1 expression and metastasis was validated in 46 ICC samples with lymph node metastasis. In survival analysis, low Beclin 1 expression was associated with worse overall survival (OS; p = 0.025) and disease-free survival (DFS; p = 0.027). In multivariate analysis, Beclin 1 expression, intrahepatic metastasis, lymph node metastasis and tumor size were found to be independent prognostic factors of OS. Thus, our results suggested the expression of Beclin 1 was correlated with progression and metastasis of ICC and it might serve as a novel prognostic marker for patients with ICC.     

Macrophage-capping protein as a tissue biomarker for prediction of response to gemcitabine treatment and prognosis in cholangiocarcinoma

Cholangiocarcinoma is one of the deadliest malignancies worldwide. Recent studies reported that treatment with gemcitabine was effective in prolonging survival. However, as the treatment only benefited a limited subset of patients, selection of patients before treatment is required. To discover biomarkers predictive of the response to gemcitabine treatment in cholangiocarcinoma, we examined the proteome of three types of material resource; ten cell lines, nine xenografts and nine surgically resected primary tumors from patients who exhibited different response to gemcitabine treatment. Two-dimensional difference gel electrophoresis generated quantitative protein expression profiles including 3571 protein spots. We detected 172 protein spots with significant correlation with response to gemcitabine treatment. All proteins corresponding to these 172 protein spots were identified by mass spectrometry. We found that the macrophage-capping protein (CapG) was associated with response to gemcitabin treatment in all three types of material source. Immunohistochemical validation in an additional set of 196 cholangiocarcinoma cases revealed that CapG expression was associated with lymphatic invasion status and overall survival. Multivariate analysis showed that CapG protein expression was an independent prognostic factor for overall survival. In conclusion, CapG was identified as a novel candidate biomarker to predict response to gemcitabine treatment and survival in cholangiocarcinoma.     

Epigenetic regulation in the carcinogenesis of cholangiocarcinoma

Cholangiocarcinoma (CCA) is a malignancy arising from the epithelial cells lining the biliary tract. Despite the existence of variation in incidence and etiology worldwide, its incidence is increasing globally in the past few decades. Surgery is the only curative treatment option for a minority of patients presented with early disease; while moderate effective chemotherapy remains the standard care for patients with locally advanced or metastatic diseases. In this article, we briefly review the molecular alterations that have been described in CCAs focusing on the role of epigenetic modification, including promoter methylation inactivation, histone modification and microRNA, in the carcinogenesis and progression of CCAs. This article is part of a Directed Issue entitled: Epigenetics dynamics in development and disease.     

Prognostic significance of Beclin 1 in intrahepatic cholangiocellular carcinoma

Autophagy enables cells to recycle long-lived proteins or damaged organelles. Beclin 1 plays important roles in autophagy, differentiation, apoptosis and the development and progression of cancer, but the expression of Beclin 1 and its possible role in primary intrahepatic cholangiocarcinoma (ICC) has not been reported yet. This study aimed to investigate Beclin 1 expression and its prognostic significance in ICC. First, we assessed the expression levels of Becn1 by real-time PCR in 50 ICC samples and found Becn1 mRNA expression was markedly increased in 78% (39 of 50) samples compared with normal bile duct epithelium. Beclin 1 protein expression in 108 tumor specimens from patients diagnosed with ICC was examined by immunohistochemistry and the correlation between Beclin 1 expression and clinicopathological factors were investigated. Immunopositivity for Beclin 1 was found in 72.2% (78 of 108) samples and low Beclin 1 expression was significantly associated with lymph node metastasis. The correlation between Beclin 1 expression and metastasis was validated in 46 ICC samples with lymph node metastasis. In survival analysis, low Beclin 1 expression was associated with worse overall survival (OS; p = 0.025) and disease-free survival (DFS; p = 0.027). In multivariate analysis, Beclin 1 expression, intrahepatic metastasis, lymph node metastasis and tumor size were found to be independent prognostic factors of OS. Thus, our results suggested the expression of Beclin 1 was correlated with progression and metastasis of ICC and it might serve as a novel prognostic marker for patients with ICC.     

MicroRNA‐551b‐3p inhibits tumour growth of human cholangiocarcinoma by targeting Cyclin D1

MicroRNAs (miRNAs) are powerful regulators in the tumorigenesis of cholangiocarcinoma (CCA). Previous studies report that miR‐551b‐3p acts as an oncogenic factor in ovarian cancer, but plays a tumour suppressive role in gastric cancer. However, the expression pattern and potential function of miR‐551b‐3p were still unclear in CCA. Therefore, this study aimed to explore the expression of miR‐551b‐3p and its role as well as molecular mechanism in CCA. Analysis of TCGA dataset suggested that miR‐551b‐3p was under‐expressed in CCA tissues compared to normal bile duct tissues. Furthermore, our data confirmed the decreased levels of miR‐551b‐3p in CCA samples and cell lines. Interestingly, TCGA data suggested that low miR‐551b‐3p level indicated reduced overall survival of CCA patients. Gain‐ and loss‐of‐function experiments found that miR‐551b‐3p inhibited the proliferation, G1‐S phase transition and induced apoptosis of CCA cells. In vivo experiments revealed that ectopic expression of miR‐551b‐3p inhibited tumour growth of CCA in mice. Further investigation demonstrated that miR‐551b‐3p directly bond to the 3′‐UTR of Cyclin D1 (CCND1) mRNA and negatively regulated the abundance of CCND1 in CCA cells. An inverse correlation between miR‐551b‐3p expression and the level of CCND1 mRNA was detected in CCA tissues from TCGA dataset. Notably, CCND1 knockdown showed similar effects to miR‐551b‐3p overexpression in HuCCT‐1 cells. CCND1 restoration rescued miR‐551b‐3p‐induced inhibition of proliferation, G1 phase arrest and apoptosis in HuCCT‐1 cells. In summary, miR‐551b‐3p inhibits the expression of CCND1 to suppress CCA cell proliferation and induce apoptosis, which may provide a theoretical basis for improving CCA treatment.     

Downregulation of LAT1 expression suppresses cholangiocarcinoma cell invasion and migration

Currently, there is no effective treatment for cholangiocarcinoma (CCA), which is the most prevalent in the northeastern part of Thailand. A new molecular target for the treatment of CCA is, therefore, urgently needed. Although L-type amino acid transporter 1 (LAT1) is highly expressed in CCA cells, its role in malignant phenotypes of CCA cells remains unclear. This study aimed to investigate the impact of LAT1 on proliferation, migration, and invasion of KKU-M213 cells, the CCA cells derived from Thai patients with intrahepatic cholangiocarcinoma. Results showed that KKU-M213 cells expressed all LAT isoforms (LAT1, LAT2, LAT3 and LAT4). The expressions of LAT1 and its associated protein 4F2hc were highest whereas those of LAT2 and LAT4 were extremely low. Treatment with 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH) reduced l-leucine uptake concomitant with an inhibition of cell motility and, to a lesser extent, on cell proliferation. It also induced a time dependent up-regulation of LAT1 and 4F2hc expressions. Similarly, cell migration and invasion, but not proliferation, were reduced in LAT1 knockdown KKU-M213 cells. In addition, silencing of LAT1 inhibited the expressions of 4F2hc mRNA and protein whereas the expression of microRNA-7, the 4F2hc down-regulator, was increased. Furthermore, the phosphorylation levels of ERK1/2 and p70S6K were reduced after LAT1 knockdown. Collectively, these results suggest that suppression of cell invasion and migration in LAT1 knockdown KKU-M213 cells may be partly mediated through the inhibition of the 4F2hc-signaling pathway by the up-regulation of microRNA-7. Based on this finding, LAT1 may be a potential therapeutic target for treating CCA.     

Aldolase A Enhances Intrahepatic Cholangiocarcinoma Proliferation and Invasion through Promoting Glycolysis

Energy metabolism reprogramming has been implicated in tumorigenesis and development. Key metabolism enzyme Aldolase A (ALDOA) has been shown to be highly expressed and involved in various kinds of cancers including hepatocellular carcinoma. In this study, we found that ALDOA was highly expressed in clinical intrahepatic cholangiocarcinoma (ICC) tissues, and its high expression was negatively correlated with overall survival (OS) and recurrence-free survival (RFS) in ICC patients. Knockdown of ALDOA expression significantly inhibited the proliferation and migration of ICC both in vitro and in vivo, while highly-expressed ALDOA in ICC cells promoted the proliferation and migration of ICC cells. By applying ALDOA inhibitor and metabolic mass spectrometry tests, we demonstrated that ALDOA modulated the biological characteristics and metabolic level of ICC cells depending on its enzymatic activity. In summary, ALDOA promotes ICC proliferation and migration by enhancing ICC cells glycolysis. Blocking enzymatic activity of ALDOA provides a strategy to inhibit ICC.     

Pharmacologic IL-6Rα inhibition in cholangiocarcinoma promotes cancer cell growth and survival

Biliary tract cancer (BTC) represents a malignant tumor of the biliary tract including cholangiocarcinoma (CCA) and the carcinoma of the gallbladder (GBC) with a 5-year survival rate between 5 and 18% due to late diagnosis and rapid disease progression. Chronic inflammation is one of the main risk factors for CCA and GBC in particular. IL-6, as a mediator of inflammation, can act through a membrane-bound receptor alpha-chain (mIL-6R, “IL-6 classic signaling”) or via soluble forms (sIL-6R, “IL-6 trans-signaling”). However, little is known about the impact on cellular responses of IL-6 trans-signaling on BTC. We analyzed primary tumors as whole sections and as tissue microarrays, and also searched The Cancer Genome Atlas database. Compared to non-neoplastic, non-inflamed gallbladder tissue, IL-6Rα was downregulated in GBC, and this correlated with the patients' overall survival. Furthermore, different CCA cell lines and compounds for activation (IL-6 and Hyper-IL-6) or inhibition (Tocilizumab and sgp130Fc) of IL-6 classic signaling and trans-signaling were used to determine their effects on cellular processes between the two modes of IL-6 signaling. Inhibition of IL-6 trans-signaling by sgp130Fc reduced CCA cell line viability and apoptosis, whereas migration and proliferation were increased. We conclude that IL-6Rα expression is a good prognostic marker for GBC, and that the blocking of IL-6 trans-signaling and activation of IL-6 classic signaling have tumor promoting activity. These findings warrant the exclusion of patients with GBC or other malignancies associated with bile metabolism from IL-6R inhibitor therapy.