Identification and characterization of TM4SF1+ tumor self-seeded cells.

Tumor self-seeding is a process whereby circulating tumor cells (CTCs) recolonize the primary tumor, which promotes tumor growth, angiogenesis, and invasion. However, the detailed nature and functions of tumor self-seeded cells (TSCs) have not been well defined due to challenges in tracking and isolating TSCs. Here, we report an accurate animal model using photoconvertible tagging to recapitulate the spontaneous process of tumor self-seeding and identify TSCs as a subpopulation of primary tumor cells with enhanced invasiveness and survival. We demonstrate transmembrane-4-L-six-family-1 (TM4SF1) as a marker of TSCs, which promotes migration, invasion, and anchorage-independent survival in cancer cells. By analyzing single-cell RNA sequencing datasets, we identify a potential TSC population with a metastatic profile in patients with cancer, which is detectable in early-stage disease and expands during cancer progression. In summary, we establish a framework to study TSCs and identify emerging cell targets with diagnostic, prognostic, or therapeutic potential in cancers.

A salivary biomarker panel to detect liver cirrhosis.

Limited access to diagnostic tests for liver fibrosis remains one of the main reasons for late diagnosis, especially in rural and remote communities. Saliva diagnostics is accessible with excellent patient compliance. The aim of this study was to develop a saliva-based diagnostic tool for liver fibrosis/cirrhosis. Salivary concentrations of hyaluronic acid (HA), tissue inhibitor of metalloproteinase-1 (TIMP-1), and α-2-macroglobulin (A2MG) were significantly increased (p < 0.05) in patients with liver fibrosis/cirrhosis. By combining these biomarkers, we developed the Saliva Liver Fibrosis (SALF) score, which identified patients with liver cirrhosis with an area under the receiver operating characteristic curve (AUROC) of 0.970 and 0.920 in a discovery and validation cohorts, respectively. The SALF score had a performance that was similar to that of the current Fibrosis-4 (AUROC:0.740) and Hepascore (AUROC:0.979). We demonstrated the clinical utility of saliva to diagnose liver fibrosis/cirrhosis with a potential to improve the screening for cirrhosis in asymptomatic populations.

The impact of posttraumatic stress disorder on upper gastrointestinal investigations in Australian Defence Force veterans: a retrospective review.

Veterans with posttraumatic stress disorder (PTSD) commonly exhibit associated gastrointestinal (GI) symptoms. We compared upper GI endoscopy and abdominal ultrasound rates in veterans with and without PTSD. Veterans with PTSD were 77-81% more likely to undergo these procedures than those without PTSD. PTSD symptomatology influences GI investigation rate and more emphasis on clinician and patient education is recommended regarding stress-related gut symptoms.

Post-traumatic stress disorder is associated with a higher rate of polypectomy independent of an increased frequency of colonoscopy in Australian veterans: a retrospective review.

BACKGROUND: Post-traumatic stress disorder (PTSD) is associated with extensive physical comorbidities, including lower gastrointestinal symptoms. Diagnostic uncertainty and poor therapeutic responses may result in more frequent colonoscopies than clinically necessary. Polypectomy is standard practice when polyps are identified, and if PTSD is a risk factor for polyp formation, one would expect a higher rate of polyp detection and removal in veterans with PTSD than those without PTSD. AIM: To determine the association between PTSD and the rate of colonoscopy and polypectomy in Australian veterans. METHODS: Diagnostic and therapeutic colonoscopy rates in Australian male Veterans aged ≥50 years were examined by reviewing case records of veterans who accessed Department of Veterans' Affairs funded health services between 1 January 2013 and 31 December 2018. RESULTS: A total of 138 471 veterans was included, of whom 28 018 had a diagnosis of PTSD; 56.4% were aged ≥65 years. Twenty-one percent of the entire cohort underwent at least one colonoscopy during the study period. Increased rates of diagnostic colonoscopy and polypectomy were associated with the presence of PTSD across all age brackets. The effect was empirically large as veterans with PTSD experience colonoscopy rates 76-81% greater than those without PTSD. Similarly, veterans with PTSD experienced polypectomy rates 76-81% greater than veterans without PTSD, and this increase persisted when controlling for the increased number of diagnostic colonoscopies they undergo. CONCLUSION: The presence of PTSD has a marked impact on colonoscopy rates in Australian veterans. The increased polypectomy rate independent of increased colonoscopy rate suggests that PTSD is a risk factor for colonic polyp formation.

Polypharmacy in Australian Veterans with Post-traumatic Stress Disorder upon Admission to a Mental Health Facility: A Retrospective Chart Review.

OBJECTIVE: Polypharmacy increases the risk of adverse drug events and drug-drug interactions, and contributes to falls, hospital admissions, morbidity and mortality. Veterans with post-traumatic stress disorder often have psychological and physical comorbidities, increasing the likelihood of general and psychotropic polypharmacy. This study investigates the prevalence of general and psychotropic polypharmacy in inpatient veterans with post-traumatic stress disorder, and illustrates potential risks associated with polypharmacy in this population. METHODS: Medical records of 219 veterans admitted to a mental health facility for post-traumatic stress disorder management were retrospectively reviewed. Medication lists on admission were extracted and coded according to Anatomical Therapeutic Chemical Classification classes. The prevalence of general (five or more total medications), psychotropic (two or more N-code medications), and sedative (two or more medications with sedating effects) polypharmacy and Drug Burden Index were calculated. Class combinations were reported, and associations between demographic characteristics and polypharmacy were determined. RESULTS: Mean age was 62.5 (± 14.6) years. In addition to post-traumatic stress disorder, 90.9% had a diagnosis of at least one other psychiatric condition, and 96.8% had a diagnosis of at least one non-psychiatric medical condition. The prevalence of general polypharmacy was 76.7%, psychotropic polypharmacy was 79.9% and sedative polypharmacy was 75.3%. Drug Burden Index scores ranged from 0 to 8.2, with 66.2% of participants scoring ≥ 1. CONCLUSIONS: This cohort of inpatient veterans with post-traumatic stress disorder had a high prevalence of general, psychotropic and sedative polypharmacy, and were at high risk for drug-related adverse events. This highlights the importance of increasing awareness of polypharmacy and potentially inappropriate drug combinations, and the need for improved medication review by prescribers.

Efficacy and safety of immune-modulating therapy for primary sclerosing cholangitis: A systematic review and meta-analysis.

Primary sclerosing cholangitis (PSC) is a rare chronic cholestatic liver disease of unclear cause. Until now, there are no effective therapies for patients with PSC. A number of studies have evaluated the effects of immune-modulating therapies on the treatment of PSC. However, clinical benefits of these treatments in PSC patients are controversial and inconclusive. We performed a systematic review and meta-analysis to assess the efficacy and adverse effects of immunomodulators in adult patients with PSC based on prognostic markers (alkaline phosphatase (ALP) and total bilirubin), liver function marker (aspartate aminotransferase (AST)) and adverse event (AE) rates. Twenty-one studies (seven randomized controlled trials (RCT) and fourteen observational studies) involving 737 patients were included in this analysis. Immune-modulating therapies significantly reduced ALP level in PSC patients, but not to normal level. AST level was non-significantly decreased, while no effect was observed on total bilirubin level after treatments in PSC patients. In 16 studies reporting AEs, an average of 16.1% patients had severe AEs, resulting in discontinuation of therapies. Importantly, subgroup analysis further indicated that immune-modulating therapy significantly reduced ALP or AST levels in PSC patients with high baseline levels of ALP (over 420 U/L, > three times the upper limit of normal (ULN)) or AST (over 80 U/L, > two times the ULN), but had no effect in patients with low baseline levels. Compared to other immune-modulating therapies, immunosuppressants had the most significant effect on reducing ALP and AST levels in PSC patients but was associated with the highest incidence of severe AEs of 24.9%. Glucocorticoids showed a positive effect by significantly reducing ALP levels with the minimal AE rate of 6.1%. In conclusion, immune-modulating therapies could improve the prognostic marker of cholestasis (ALP level) in patients with PSC, especially in those of worse liver function. These findings suggest patients with high baseline level of ALP (>420 U/L) and AST (>80 U/L) respond better to immune-modulating therapy compared to those with low level of ALP and AST. Future RCTs would be needed to include different dosing regimens, a longer treatment duration and follow-up period, and patients stratified by liver function to obtain solid conclusion.

CD73 and PD-L1 as Potential Therapeutic Targets in Gallbladder Cancer.

Gallbladder cancer (GBC) is one of the most common and aggressive biliary tract cancers with a dismal prognosis. Ongoing clinical trials are evaluating a few selected immune checkpoint inhibitors (ICIs) as monotherapy for the treatment of GBC patients. However, only a subset of patients benefits from these treatments. To improve ICI therapy response, molecular mechanisms that confer resistance to immune checkpoint (IC) blockade needs to be explored. Epithelial-to-mesenchymal transition (EMT) program and cancer stem cells (CSCs) have been implicated as key processes that confer ICI treatment resistance. However, in GBC the EMT-CSC-IC axis has not yet been clearly elucidated. This study aims to examine the aberrant expression of ICs associated with CSC and EMT. We successfully enriched CSCs by utilizing a 3-dimensional culture system and established a reversible EMT model with human GBC NOZ cell line. Notably, ICs CD73 and PD-L1 were closely associated with both CSC and EMT phenotypes. Knockdown of CD73 or PD-L1 reduced the proliferative and motile abilities of both adherent monolayers and anchorage-free spheroids. In conclusion, blocking CD73 and PD-L1 offer a promising therapeutic strategy for targeting highly aggressive populations with CSC and EMT phenotype to improve GBC patient prognosis.

Long-term survival and postoperative complications of pre-liver transplantation transarterial chemoembolisation in hepatocellular carcinoma: A systematic review and meta-analysis.

OBJECTIVES: The aim of this meta-analysis was to conduct a contemporary systematic review of high quality non-randomised controlled trials to determine the effect of pre-liver transplantation (LT) transarterial chemoembolisation (TACE) on long-term survival and complications of hepatocellular carcinoma (HCC) patients. BACKGROUND: TACE is used as a neoadjuvant therapy to mitigate waitlist drop-out for patients with HCC awaiting LT. Previous studies have conflicting conclusions on the effect of TACE on long-term survival and complications of HCC patients undergoing LT. METHODS: CINAHL, Cochrane Controlled Register of Trials, Embase, PubMed, and Web of Science were systematically searched. Baseline characteristics included number of patients outside Milan criteria, tumour diameter, MELD score, and time on the waiting list. Primary outcomes included 3- and 5-year overall and disease-free survival. Secondary outcomes included tumour recurrence, 30-day postoperative mortality, and hepatic artery and biliary complications. RESULTS: Twenty-one high-quality NRCTs representing 8242 patients were included. Tumour diameter was significantly larger in TACE patients (3.49 cm vs 3.15 cm, P = 0.02) and time on the waiting list was significantly longer in TACE patients (4.87 months vs 3.46 months, P = 0.05), while MELD score was significantly higher in non-TACE patients (10.81 vs 12.35, P = 0.005). All primary and secondary outcomes displayed non-significant differences. CONCLUSION: Patients treated with TACE had similar survival and postoperative outcomes to non-TACE patients, however, they had worse prognostic features compared to non-TACE patients. These findings strongly support the current US and European clinical practice guidelines that neoadjuvant TACE can be used for patients with longer expected waiting list times (specifically >6 months). Randomised controlled trials would be needed to increase the quality of evidence.

Dual Targeting of Sorafenib-Resistant HCC-Derived Cancer Stem Cells.

Sorafenib, an oral multi-tyrosine kinase inhibitor, has been the first-line therapy for the treatment of patients with advanced HCC, providing a survival benefit of only three months in approximately 30% of patients. Cancer stem cells (CSCs) are a rare tumour subpopulation with self-renewal and differentiation capabilities, and have been implicated in tumour growth, recurrence and drug resistance. The process of epithelial-to-mesenchymal transition (EMT) contributes to the generation and maintenance of the CSC population, resulting in immune evasion and therapy resistance in several cancers, including HCC. The aim of this study is to target the chemoresistant CSC population in HCC by assessing the effectiveness of a combination treatment approach with Sorafenib, an EMT inhibitor and an immune checkpoint inhibitor (ICI). A stem-cell-conditioned serum-free medium was utilised to enrich the CSC population from the human HCC cell lines Hep3B, PLC/PRF/5 and HepG2. The anchorage independent spheres were characterised for CSC features. The human HCC-derived spheres were assessed for EMT status and expression of immune checkpoint molecules. The effect of combination treatment with SB431542, an EMT inhibitor, and siRNA-mediated knockdown of programmed cell death protein ligand-1 (PD-L1) or CD73 along with Sorafenib on human HCC-derived CSCs was examined with cell viability and apoptosis assays. The three-dimensional spheres enriched from human HCC cell lines demonstrated CSC-like features. The human HCC-derived CSCs also exhibited the EMT phenotype along with the upregulation of immune checkpoint molecules. The combined treatment with SB431542 and siRNA-mediated PD-L1 or CD73 knockdown effectively enhanced the cytotoxicity of Sorafenib against the CSC population compared to Sorafenib alone, as evidenced by the reduced size and proliferation of spheres. Furthermore, the combination treatment of Sorafenib with SB431542 and PD-L1 or CD73 siRNA resulted in an increased proportion of an apoptotic population, as evidenced by flow cytometry analysis. In conclusion, the combined targeting of EMT and immune checkpoint molecules with Sorafenib can effectively target the CSC tumour subpopulation.

Immune checkpoint molecules are regulated by transforming growth factor (TGF)-ß1-induced epithelial-to-mesenchymal transition in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer with a high mortality rate. Epithelial-to-mesenchymal transition (EMT) confers cancer cells with immune evasive ability by modulating the expression of immune checkpoints in many cancers. Thus, the aim of our study is to examine the interplay between EMT and immune checkpoint molecules in HCC. A reversible EMT model was utilised with transforming growth factor (TGF)-ß1 as an EMT inducer for HCC cell lines Hep3B and PLC/PRF/5. HCC cells were treated with TGF-ß1 for 72 h and the EMT status and immune checkpoint expression were examined. In addition, the migratory ability of HCC cells were examined using wound healing and transwell migration assays in the reversible EMT model. siRNA-mediated knockdown of immune checkpoint molecule, B7-H3, was further utilised to validate the association between TGF-ß1-mediated EMT and immune checkpoint expression in HCC. In addition, a web-based platform, SurvExpress, was utilised to evaluate the association between expression of TGF-ß1 in combination with immune checkpoint molecules and overall survival in HCC patients. We observed induction of EMT upon treatment of HCC cells with TGF-ß1 revealed by reduced expression of epithelial markers along with increased expression of mesenchymal markers. Withdrawal of TGF-ß1 reversed the process of EMT with elevated expression of epithelial markers and reduced expression of mesenchymal markers. TGF-ß1 treatment elevated the migratory potential of HCC cells which was reversed following reversal assay. Notably, during TGF-ß1-induced EMT, there was upregulation of immune checkpoint molecules PD-L1 and B7-H3. However, the reversal of EMT decreased the expression of PD-L1 and B7-H3. In addition, TGF-ß1 driven EMT was reversed following knockdown of B7-H3 in both HCC cells further validating the interplay between TGF-ß1-mediated EMT and immune checkpoint expression in HCC. Furthermore, the coordinate expression of TGF-ß1 with PD-L1 (p=0.01487) and B7-H3 (p=0.009687) was correlated with poor overall survival in 422 HCC patients. Our study has demonstrated a close association between TGF-ß1-mediated EMT and regulation of immune checkpoints in HCC.

Prognostic Role of Immune Checkpoint Regulators in Cholangiocarcinoma: A Pilot Study.

Cholangiocarcinoma (CCA) is a hepatobiliary malignancy associated with steadily increasing incidence and poor prognosis. Ongoing clinical trials are assessing the effectiveness and safety of a few immune checkpoint inhibitors (ICIs) in CCA patients. However, these ICI treatments as monotherapies may be effective for a proportion of patients with CCA. The prevalence and distribution of other immune checkpoints (ICs) in CCA remain unclear. In this pilot study, we screened databases of CCA patients for the expression of 19 ICs and assessed the prognostic significance of these ICs in CCA patients. Notably, expression of immune modulator IDO1 and PD-L1 were linked with poor overall survival, while FASLG and NT5E were related to both worse overall survival and progression-free survival. We also identified immune modulators IDO1, FASLG, CD80, HAVCR2, NT5E, CTLA-4, LGALS9, VTCN1 and TNFRSF14 that synergized with PD-L1 and correlated with worse patient outcomes. In vitro studies revealed that the expression of ICs was closely linked with aggressive CCA subpopulations, such as cancer stem cells and cells undergoing TGF-ß and TNF-α-mediated epithelial-to-mesenchymal transition. These findings suggest that the aforementioned IC molecules may serve as potential prognostic biomarkers and drug targets in CCA patients, leading to lasting and durable treatment outcomes.

Combined Inhibition of TGF-ß1-Induced EMT and PD-L1 Silencing Re-Sensitizes Hepatocellular Carcinoma to Sorafenib Treatment.

Hepatocellular carcinoma (HCC) is the most common type of primary hepatic malignancy. HCC is one of the leading causes of cancer deaths worldwide. The oral multi-tyrosine kinase inhibitor Sorafenib is the standard first-line therapy in patients with advanced unresectable HCC. Despite the significant survival benefit in HCC patients post treatment with Sorafenib, many patients had progressive disease as a result of acquiring drug resistance. Circumventing resistance to Sorafenib by exploring and targeting possible molecular mechanisms and pathways is an area of active investigation worldwide. Epithelial-to-mesenchymal transition (EMT) is a cellular process allowing epithelial cells to assume mesenchymal traits. HCC tumour cells undergo EMT to become immune evasive and develop resistance to Sorafenib treatment. Immune checkpoint molecules control immune escape in many tumours, including HCC. The aim of this study is to investigate whether combined inhibition of EMT and immune checkpoints can re-sensitise HCC to Sorafenib treatment. Post treatment with Sorafenib, HCC cells PLC/PRF/5 and Hep3B were monitored for induction of EMT and immune checkpoint molecules using quantitative reverse transcriptase (qRT)- PCR, western blot, immunofluorescence, and motility assays. The effect of combination treatment with SB431542, a specific inhibitor of the transforming growth factor (TGF)-ß receptor kinase, and siRNA mediated knockdown of programmed cell death protein ligand-1 (PD-L1) on Sorafenib resistance was examined using a cell viability assay. We found that three days of Sorafenib treatment activated EMT with overexpression of TGF-ß1 in both HCC cell lines. Following Sorafenib exposure, increase in the expression of PD-L1 and other immune checkpoints was observed. SB431542 blocked the TGF-ß1-mediated EMT in HCC cells and also repressed PD-L1 expression. Likewise, knockdown of PD-L1 inhibited EMT. Moreover, the sensitivity of HCC cells to Sorafenib was enhanced by combining a blockade of EMT with SB431542 and knockdown of PD-L1 expression. Sorafenib-induced motility was attenuated with the combined treatment of SB431542 and PD-L1 knockdown. Our findings indicate that treatment with Sorafenib induces EMT and expression of immune checkpoint molecules, which contributes to Sorafenib resistance in HCC cells. Thus, the combination treatment strategy of inhibiting EMT and immune checkpoint molecules can re-sensitise HCC cells to Sorafenib.

Liver organoid as a 3D in vitro model for drug validation and toxicity assessment.

The past decade has seen many advancements in the development of three-dimensional (3D) in vitro models in pharmaceutical sciences and industry. Specifically, organoids present a self-organising, self-renewing and more physiologically relevant model than conventional two-dimensional (2D) cell cultures. Liver organoids have been developed from a variety of cell sources, including stem cells, cell lines and primary cells. They have potential for modelling patient-specific disease and establishing personalised therapeutic approaches. Additionally, liver organoids have been used to test drug efficacy and toxicity. Herein we summarise cell sources for generating liver organoids, the advantages and limitations of each cell type, as well as the application of the organoids in modelling liver diseases. We focus on the use of liver organoids as tools for drug validation and toxicity assessment.

Iron depletion attenuates steatosis in a mouse model of non-alcoholic fatty liver disease: Role of iron-dependent pathways.

BACKGROUND & AIMS: Iron has been proposed as influencing the progression of liver disease in subjects with non-alcoholic fatty liver disease (NAFLD). We have previously shown that, in the Hfe-/- mouse model of hemochromatosis, feeding of a high-calorie diet (HCD) leads to increased liver injury. In this study we investigated whether the feeding of an iron deficient/HCD to Hfe-/- mice influenced the development of NAFLD. METHODS: Liver histology was assessed in Hfe-/- mice fed a standard iron-containing or iron-deficient diet plus or minus a HCD. Hepatic iron concentration, serum transferrin saturation and free fatty acid were measured. Expression of genes implicated in iron regulation and fatty liver disease was determined by quantitative real-time PCR (qRT-PCR). RESULTS: Standard iron/HCD-fed mice developed severe steatosis whereas NAS score was reduced in mice fed iron-deficient HCD. Mice fed iron-deficient HCD had lower liver weights, lower transferrin saturation and decreased ferroportin and hepcidin gene expression than HCD-fed mice. Serum non-esterified fatty acids were increased in iron-deficient HCD-fed mice compared with standard iron HCD. Expression analysis indicated that genes involved in fatty-acid binding and mTOR pathways were regulated by iron depletion. CONCLUSIONS: Our results indicate that decreasing iron intake attenuates the development of steatosis resulting from a high calorie diet. These results also suggest that human studies of agents that modify iron balance in patients with NAFLD should be revisited.

Inhibition of MLKL Attenuates Necroptotic Cell Death in a Murine Cell Model of Ischaemia Injury.

BACKGROUND: Steatosis in donor livers poses a major risk of organ dysfunction due to their susceptibility to ischaemia-reperfusion (I/R) injury during transplant. Necroptosis, a novel form of programmed cell death, is orchestrated by receptor-interacting protein kinase 1 (RIPK1), receptor-interacting protein kinase 3 (RIPK3) and mixed-lineage kinase domain-like pseudokinase (MLKL), has been implicated in I/R injury. Here we investigated the mechanisms of cell death pathways in an in vitro model of hepato-steatotic ischaemia. METHODS: Free fatty acid (FFA) treated alpha mouse liver 12 (AML-12) cells were incubated in oxygen-glucose-deprivation (OGD) conditions as seen during ischaemia. RESULTS: We found that OGD triggered upregulation of insoluble fraction of RIPK3 and MLKL in FFA + OGD cells compared to FFA control cells. We report that intervention with small interfering (si) MLKL and siRIPK3 significantly attenuated cell death in FFA + OGD cells. Absence of activated CASPASE8 and cleaved-CASPASE3, no change in the expression of CASPASE1 and prostaglandin-endoperoxide synthase 2 (Ptgs2) in FFA + OGD treated cells compared to FFA control cells indicated that apoptosis, pyroptosis and ferroptosis, respectively, are unlikely to be active in this model. CONCLUSION: Our findings indicate that RIPK3-MLKL dependent necroptosis contributed to cell death in our in vitro model. Both MLKL and RIPK3 are promising therapeutic targets to inhibit necroptosis during ischaemic injury in fatty liver.

Australian recommendations for the management of hepatocellular carcinoma: a consensus statement.

INTRODUCTION: Hepatocellular carcinoma (HCC) is a leading cause of cancer deaths both globally and in Australia. Surveillance for HCC in at-risk populations allows diagnosis at an early stage, when potentially curable. However, most Australians diagnosed with HCC die of the cancer or of liver disease. In the changing landscape of HCC management, unique challenges may lead to clinical practice variation. As a result, there is a need to identify best practice management of HCC in an Australian context. This consensus statement has been developed for health professionals involved in the care of adult patients with HCC in Australia. It is applicable to specialists, general medical practitioners, nurses, health coordinators and hospital administrators. METHODS AND RECOMMENDATIONS: This statement has been developed by specialists in hepatology, radiology, surgery, oncology, palliative care, and primary care, including medical practitioners and nurses. The statement addresses four main areas relevant to HCC management: epidemiology and incidence, diagnosis, treatment, and patient management. A modified Delphi process was used to reach consensus on 31 recommendations. Principal recommendations include the adoption of surveillance strategies, use of multidisciplinary meetings, diagnosis, treatment options and patient management. CHANGES IN MANAGEMENT AS A RESULT OF THIS STATEMENT: This consensus statement will simplify HCC patient management and reduce clinical variation. Ultimately, this should result in better outcomes for patients with HCC.

The use of minimally invasive biomarkers for the diagnosis and prognosis of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a common cause of cancer-related deaths worldwide. Despite advances in systemic therapies, patient survival remains low due to late diagnosis and frequent underlying liver diseases. HCC diagnosis generally relies on imaging and liver tissue biopsy. Liver biopsy presents limitations because it is invasive, potentially risky for patients and it frequently misrepresents tumour heterogeneity. Recently, liquid biopsy has emerged as a way to monitor cancer progression in a non-invasive manner. Tumours shed content into the bloodstream, such as circulating tumour cells (CTCs), circulating nucleic acids, extracellular vesicles and proteins, that can be isolated from biological fluids of patients with HCC. These biomarkers provide knowledge regarding the genetic landscape of tumours and might be used for diagnostic or prognostic purposes. In this review, we summarize recent literature on circulating biomarkers for HCC, namely CTCs, circulating tumour DNA (ctDNA), RNA, extracellular vesicles and proteins, and their clinical relevance in HCC.