High frequency of telomerase reverse-transcriptase promoter somatic mutations in hepatocellular carcinoma and preneoplastic lesions

Hepatitis B Virus-Associated Hepatocellular Carcinoma

Hepatitis B virus (HBV) is DNA-based virus, member of the Hepadnaviridae family, which can cause liver disease and increased risk of hepatocellular carcinoma (HCC) in infected individuals, replicating within the hepatocytes and interacting with several cellular proteins. Chronic hepatitis B can progressively lead to liver cirrhosis, which is an independent risk factor for HCC. Complications as liver decompensation or HCC impact the survival of HBV patients and concurrent HDV infection worsens the disease. The available data provide evidence that HBV infection is associated with the risk of developing HCC with or without an underlying liver cirrhosis, due to various direct and indirect mechanisms promoting hepatocarcinogenesis. The molecular profile of HBV-HCC is extensively and continuously under study, and it is the result of altered molecular pathways, which modify the microenvironment and lead to DNA damage. HBV produces the protein HBx, which has a central role in the oncogenetic process. Furthermore, the molecular profile of HBV-HCC was recently discerned from that of HDV-HCC, despite the obligatory dependence of HDV on HBV. Proper management of the underlying HBV-related liver disease is fundamental, including HCC surveillance, viral suppression, and application of adequate predictive models. When HBV-HCC occurs, liver function and HCC characteristics guide the physician among treatment strategies but always considering the viral etiology in the treatment choice.

An Update to Hallmarks of Cancer

In the last decade, there has been remarkable progress in research toward understanding and refining the hallmarks of cancer. In this review, we propose a new hallmark - "pro-survival autophagy." The importance of pro-survival autophagy is well established in tumorigenesis, as it is related to multiple steps in cancer progression and vital for some cancers. Autophagy is a potential anti-cancer therapeutic target. For this reason, autophagy is a good candidate as a new hallmark of cancer. We describe two enabling characteristics that play a major role in enabling cells to acquire the hallmarks of cancer - "tumor-promoting microenvironment and macroenvironment" and "cancer epigenetics, genome instability and mutation." We also discuss the recent updates, therapeutic and prognostic implications of the eight hallmarks of cancer described by Hanahan et al. in 2011. Understanding these hallmarks and enabling characteristics is key not only to developing new ways to treat cancer efficiently but also to exploring options to overcome cancer resistance to treatment.

Hepatocellular Carcinoma: The Role of MicroRNAs

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths worldwide. HCC is diagnosed in its advanced stage when limited treatment options are available. Substantial morphologic, genetic and epigenetic heterogeneity has been reported in HCC, which poses a challenge for the development of a targeted therapy. In this review, we discuss the role and involvement of several microRNAs (miRs) in the heterogeneity and metastasis of hepatocellular carcinoma with a special emphasis on their possible role as a diagnostic and prognostic tool in the risk prediction, early detection, and treatment of hepatocellular carcinoma.

Molecular pathogenesis and systemic therapies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) remains one of the most prevalent and deadliest cancers. The poor outcome associated with HCC is dramatically changing due to the advent of effective systemic therapies. Here we discuss the molecular pathogenesis of HCC, molecular classes and determinants of heterogeneity. In addition, effective single-agent and combination systemic therapies involving immunotherapies as standard of care are analyzed. Finally, we propose a flowchart of sequential therapies, explore mechanisms of resistance and address the need for predictive biomarkers.

Serum TERT C228T is an important predictor of non-viral liver cancer with fatty liver disease

Background

Molecular therapies and precision medicine are expected to be developed for liver cancer based on the diagnosis of DNA somatic alterations. However, it remains unclear whether TERT promoter mutation (TERT C228T) in serum cfDNA is useful for the diagnosis of liver cancer with non-viral fatty liver disease (FLD).

Methods

This retrospective cohort study examined 258 Japanese patients who had a confirmed diagnosis of primary liver cancer. We investigated the factors associated with TERT C228T and abnormal levels of liver cancer-specific tumor markers (AFP and PIVKAII) in serum samples.

Results

Multivariate analysis identified the etiology of FLD, vascular invasion, and non-cirrhosis as determinants of TERT C228T-positive liver cancer. Rates of positive TERT C228T in FLD were significantly higher than those of HBV and HCV. Conversely, rates of abnormal AFP in FLD were significantly lower than those of HBV and HCV. Viral suppression of HBV/HCV and alcohol intake did not affect TERT C228T, but AFP was significantly reduced by viral suppression. The rates of positive TERT C228T were significantly lower in HCV patients with viral clearance than those of FLD patients.

Conclusion

Our results highlight the importance of serum TERT C228T for the detection of non-viral FLD-related liver cancer. TERT C228T is a tumor marker that might not be influenced by inflammation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12072-022-10313-y.

Cell Differentiation Trajectory in Liver Cirrhosis Predicts Hepatocellular Carcinoma Prognosis and Reveals Potential Biomarkers for Progression of Liver Cirrhosis to Hepatocellular Carcinoma

Most hepatocellular carcinoma (HCC) patients occur on a background of liver cirrhosis, the molecular mechanisms of liver cirrhosis and its progression to HCC remain to be fully elucidated. Single cell differentiation trajectory analysis has been used in cell classification and tumor molecular typing, which correlated with disease progression and patient prognosis. Here we use cell differentiation trajectory analysis to investigate the relevance of liver cirrhosis and HCC. Single-cell RNA sequencing (scRNA-seq) data of liver cirrhosis and bulk RNA-seq and clinical data of HCC were downloaded from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) for analysis. HCC samples were divided into three subtypes, based on differentiation-related genes (DRGs) of liver cirrhosis, each with a different expression profile and overall survival (OS). A two- DRGs (CD34 and RAMP3) based prognostic risk scoring (RS) signature was established which could differentiate OS between high-risk and low-risk groups. And expression levels of CD34 and RAMP3 were predominantly high in endothelial cells. By integrating the RS and clinicopathological features, a nomogram was constructed and can accurately predicted the 1-year, 3-years, and 5-years OS. In conclusion, cell differentiation trajectory of liver cirrhosis can predict the prognosis of HCC, and provides new perspectives on the mechanisms of progression of liver cirrhosis to HCC.

Prognostic Value of Circulating Tumour DNA in Asian Patients with Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis

BACKGROUND

Circulating tumour DNA (ctDNA) is a noninvasive method of detecting tumours, and its prognostic significance in hepatocellular carcinoma (HCC) patients is controversial. We conducted a systematic review of published research data to evaluate the prognostic value of ctDNA in HCC patients.

METHODS

The PubMed, Embase, Web of Science, Cochrane Library, and Scopus databases were searched to identify eligible studies reporting disease-free survival (DFS) and overall survival (OS) stratified by ctDNA prior to January 2022. We evaluated the quality and design of these studies. The hazard ratio (HR) was used to combine the survivorship curve and univariate and multivariate results of the included studies.

RESULTS

In total, 8 articles were included, encompassing 577 HCC patients. The results of survival curve analysis showed that ctDNA was related to poor OS and DFS, and the effect sizes were HR = 2.44, 95% CI (1.42, 4.20), P=0.001; HR = 2.63, 95% CI (1.96, 3.53), P < 0.001. The univariate analysis results showed that ctDNA was related to poor OS (HR = 4.48, 95% CI (1.17, 13.70), P=0.003). The combined results of multivariate analysis showed that ctDNA was related to a shorter risk of OS (HR = 3.74, 95% CI (1.45, 9.65), P=0.006). The univariate and multivariate descriptive analysis results showed that ctDNA was related to shorter DFS, and the effect sizes were HR = 3.28, 95% CI (1.23, 11.30), P=0.011; HR = 3.01, 95% CI (1.11, 10.5), P < 0.001.

CONCLUSION

The evidence provided by this analysis suggests that ctDNA may be a prognostic biomarker and is negatively correlated with the survival of HCC patients. Mutations in the TERT and SOCS3 promoters in ctDNA are associated with poor prognosis and are expected to become good targets for liquid biopsy and to help select treatment strategies.

Implications of genetic heterogeneity in hepatocellular cancer

Hepatocellular carcinoma (HCC) exhibits a remarkable degree of heterogeneity, not only at an inter-patient level but also between and within tumors in the same patient. The advent of next-generation sequencing (NGS)-based technologies has allowed the creation of high-resolution atlases of HCC. This review outlines recent findings from genomic, epigenomic, transcriptomic, and proteomic sequencing that have yielded valuable insights into the spatial and temporal heterogeneity of HCC. The high heterogeneity of HCC has both clinical and therapeutic implications. The challenges in prospectively validating molecular classifications for HCC either for prognostication or for prediction of therapeutic response are partly due to the immense heterogeneity in HCC. Moreover, the heterogeneity of HCC tumors combined with the lack of commonly mutated, druggable targets severely limits treatment options for HCC. Recently, immune checkpoint inhibitors and combination therapies have shown promise for advanced HCC, while T cell therapies and vaccines are currently being investigated. Yet, immunotherapies show benefit only in a limited subset of patients, making it imperative to decipher tumor heterogeneity in HCC in order to enable optimal patient selection. This review summarizes the cutting-edge research on heterogeneity in HCC and explores the implications of heterogeneity on stratifying patients and developing biomarkers and therapies for HCC.

Predictive biomarkers of response to immune checkpoint inhibitors in hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and fourth leading cause of cancer death. While drug discovery to improve disease survival was historically poor, there is now evidence of significant potential for immune checkpoint inhibitors (ICPIs) in treatment of the disease, and indeed such drug approvals are beginning to emerge.

AREAS COVERED

HCC typically arises in the context of cirrhosis and chronic liver disease (CLD), and HCC exhibits significant biological heterogeneity, in part reflecting the broad range of aetiologies of CLD. Different classes and combinations of ICPI-based therapy exist, but not all patients will respond and predictive biomarkers are not yet available to guide clinician decision making, unlike some other cancer types. In this review, we discuss the emerging biomarkers for ICPI sensitivity in HCC, including tumour genomic features, perturbation of the gut microbiome and systemic inflammatory markers.

EXPERT OPINION

Additional profiling studies are required to appreciate existing trends with clinical outcome and to further drive clinical studies in disease stratification by response. This will only be possible within collaborative and international efforts, especially regarding biopsy collection. A close collaboration between basic scientists and clinicians will be the key to shape the next future of HCC biomarker research.

A clinical and pathological update on hepatocellular carcinoma

It is estimated that more than 1 million individuals will be affected annually by hepatocellular carcinoma (HCC) by 2025. HCC can be broadly grouped into two major molecular subgroups, each of which is characterized by specific morphological and phenotypic features that mirror the genetic background. The use of these tissue biomarkers in the daily practice of pathologists promises to better allocate patients with HCC with adequate treatments. In turn, this will likely boost the attitude of clinicians toward obtaining a pre-treatment biopsy.

Preneoplastic lesions in the liver: Molecular insights and relevance for clinical practice

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) are the most frequent primary liver cancers, accounting for approximately 80% and 15%, respectively. HCC carcinogenesis occurs mostly in cirrhosis and is a complex multi-step process, from precancerous lesions (low-grade and high-grade dysplastic nodules) to progressed HCC. During the different stages of liver carcinogenesis, there is an accumulation of pathological, genetic and epigenetic changes leading to initiation, malignant transformation and finally tumour progression. In contrast, a small subset of HCC occurs in normal liver from the transformation of hepatocellular adenoma (HCA), a benign hepatocellular tumour. The recent molecular classification enables to stratify HCAs according to their risk of complication, in particular malignant transformation, associated with mutations in exon 3 of the catenin beta 1 (CTNNB1) gene. Cholangiocarcinoma (CCA) derives from the multistep malignant transformation of preneoplastic lesions, like biliary intraepithelial neoplasia (BilIN) and intraductal papillary neoplasm of the bile duct (IPNB), for which a pre-operative diagnosis remains difficult. Different genetic alterations are involved in BilIN and IPNB progression, leading to the development of tubular or intestinal adenocarcinoma. The aims of this review are to describe the main clinical and molecular features of preneoplastic lesions leading to the development of HCC and CCA, their implications in clinical practice and the perspectives for future research.

Hepatocellular carcinoma after a sustained virological response by direct-acting antivirals harbors TP53 inactivation

Introduction

The genomic characteristics of hepatocellular carcinoma (HCC) after a sustained virological response (SVR) and its differences according to whether an SVR was achieved by treatment with direct‐acting antivirals (DAA) or interferon (IFN) are still not fully understood.

Methods

Sixty‐nine surgically resected HCCs from patients with hepatitis C virus infection were analyzed by gene expression profiling and whole‐exome sequencing.

Results

Among the 69 HCC patients, 34 HCCs in which an SVR was not achieved at the time of surgery were classified as HCV‐positive, and 35 HCCs in which an SVR was achieved at the time of surgery were classified as HCV‐SVR. According to the HCV treatment, 35 HCV‐SVR HCCs were classified into two groups: eight tumors with DAA (HCV‐SVR‐DAA) and 24 tumors with interferon (HCV‐SVR‐IFN). The frequency of samples with ARID2 mutations was significantly lower in HCV‐SVR than in HCV‐positive tumors (p = 0.048). In contrast, the frequency of samples with PREX2 mutations was significantly higher in HCV‐SVR samples than in HCV‐positive samples (p = 0.048). Among the patients with HCV‐SVR, the frequency of samples with TP53 mutations was significantly higher in HCV‐SVR‐DAA tumors than in HCV‐SVR‐IFN tumors (p = 0.030). TP53 inactivation scores in HCV‐SVR‐DAA tumors were found to be significantly enhanced in comparison to HCV‐SVR‐IFN tumors (p = 0.022). In addition, chromosomal instability and PI3K/AKT/mTOR pathway signatures were enhanced in HCV‐SVR‐DAA tumors. HCV‐SVR‐DAA was significantly associated with portal vein invasion (p = 0.003) in comparison to HCV‐SVR‐IFN.

Conclusion

Our dataset potentially serves as a fundamental resource for the genomic characteristics of HCV‐SVR‐DAA tumors. Our comprehensive genetic profiling by WES revealed significant differences in the mutation rate of several driver genes between HCV‐positive tumors and HCV‐SVR tumors. Furthermore, it was revealed that the frequency of samples with mutations in TP53 was significantly higher in HCV‐SVR‐DAA tumors than in HCV‐SVR‐IFN tumors.

Immune Checkpoint and Telomerase Crosstalk Is Mediated by miRNA-138 in Bladder Cancer

Background

Tumor recurrence and progression in non-muscle invasive bladder cancer (NMIBC), therapy failure, and severe side effects in muscle invasive bladder cancer (MIBC) are the major challenges in the clinical management of bladder cancer (BC). Here, we identify new molecular targetable signatures to improve BC patients’ stratification and the outcome of current immunotherapies.

Material and Methods

In a prospective cohort of 70 BC patients, we assessed the genetic and molecular regulation of TERT in maintaining telomere length in parallel to immune checkpoint and microRNA expression.

Results

TERT was undetectable in healthy bladder tissues but upregulated in invasive BC stages and high tumor grade. Its expression was linked with the combined effect of the C250T mutation and THOR hypermethylation, associated with progressing tumors and maintaining of telomere length. In the same cohort, PD-L1 scored highest in NMIBC, while PD-L2 was upregulated in MIBC. We also show that miR-100-5p and 138-5p were highly expressed in healthy bladder specimens and cell line, while expression decreased in the BC tissues and BC cell lines. In line with the binding prediction for these miRNAs on target genes, miRs 100-5p and 138-5p expression strongly inverse correlated with TERT, PD-L1, and PD-L2 expression, but not PD1.

Conclusion

We identify a loop involving TERT, PD1-ligands, and miR-138-5p in BC, that might represent not only a useful biomarker for improved diagnosis and patients’ stratification but also as a promising axis that might be therapeutically targeted in situ.

Green tea-derived theabrownin induces cellular senescence and apoptosis of hepatocellular carcinoma through p53 signaling activation and bypassed JNK signaling suppression

Background

Theabrownin (TB) is a bioactive component of tea and has been reported to exert effects against many human cancers, but its efficacy and mechanism on hepatocellular carcinoma (HCC) with different p53 genotypes remains unclarified.

Methods

MTT assay, DAPI staining, flow cytometry and SA-β-gal staining were applied to evaluate the effects of TB on HCC cells. Quantitative real time PCR (qPCR) and Western blot (WB) were conducted to explore the molecular mechanism of TB. A xenograft model of zebrafish was established to evaluate the anti-tumor effect of TB.

Results

MTT assays showed that TB significantly inhibited the proliferation of SK-Hep-1, HepG2, and Huh7 cells in a dose-dependent manner, of which SK-Hep-1 was the most sensitive one with the lowest IC50 values. The animal data showed that TB remarkably suppressed SK-Hep-1 tumor growth in xenograft model of zebrafish. The cellular data showed TB's pro-apoptotic and pro-senescent effect on SK-Hep-1 cells. The molecular results revealed the mechanism of TB that p53 signaling pathway (p-ATM, p-ATR, γ-H2AX, p-Chk2, and p-p53) was activated with up-regulation of downstream senescent genes (P16, P21, IL-6 and IL-8) as well as apoptotic genes (Bim, Bax and PUMA) and proteins (Bax, c-Casp9 and c-PARP). The p53-mediated mechanism was verified by using p53-siRNA. Moreover, by using JNK-siRNA, we found JNK as a bypass regulator in TB's mechanism.

Conclusions

To sum up, TB exerted tumor-inhibitory, pro-senescent and pro-apoptotic effects on SK-Hep-1 cells through ATM-Chk2-p53 signaling axis in accompany with JNK bypass regulation. This is the first report on the pro-senescent effect and multi-target (p53 and JNK) mechanism of TB on HCC cells, providing new insights into the underlying mechanisms of TB's anti-HCC efficacy.

Genetic Landscape of Multistep Hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is a major cause of cancer-related death worldwide. Although several targeted therapy agents are available for advanced HCC, their antitumor efficacy remains limited. As the complex genetic landscape of HCC would compromise the antitumor efficacy of targeted therapy, a deeper understanding of the genetic landscape of hepatocarcinogenesis is necessary. Recent comprehensive genetic analyses have revealed the driver genes of HCC, which accumulate during the multistage process of hepatocarcinogenesis, facilitating HCC genetic heterogeneity. In addition, as early genetic changes may represent key therapeutic targets, the genetic landscapes of early HCC and precancerous liver tissues have been characterized in recent years, in parallel with the advancement of next-generation sequencing analysis. In this review article, we first summarize the landscape of the liver cancer genome and its intratumor heterogeneity. We then introduce recent insight on early genetic alterations in hepatocarcinogenesis, especially those in early HCC and noncancerous liver tissues. Finally, we summarize the multistep accumulation of genetic aberrations throughout cancer progression and discuss the future perspective towards the clinical application of this genetic information.

Current Perspectives on the Immunosuppressive Niche and Role of Fibrosis in Hepatocellular Carcinoma and the Development of Antitumor Immunity

Immune checkpoint inhibitors have become the mainstay of treatment for hepatocellular carcinoma (HCC). However, they are ineffective in some cases. Previous studies have reported that genetic alterations in oncogenic pathways such as Wnt/β-catenin are the important triggers in HCC for primary refractoriness. T-cell exhaustion has been reported in various tumors and is likely to play a prominent role in the emergence of HCC due to chronic inflammation and cirrhosis-associated immune dysfunction. Immunosuppressive cells including regulatory T-cells and tumor-associated macrophages infiltrating the tumor are associated with hyperprogressive disease in the early stages of immune checkpoint inhibitor treatment. In addition, stellate cells and tumor-associated fibroblasts create an abundant desmoplastic environment by producing extracellular matrix. This strongly contributes to epithelial to mesenchymal transition via signaling activities including transforming growth factor beta, Wnt/β-catenin, and Hippo pathway. The abundant desmoplastic environment has been demonstrated in pancreatic ductal adenocarcinoma and cholangiocarcinoma to suppress cytotoxic T-cell infiltration, PD-L1 expression, and neoantigen expression, resulting in a highly immunosuppressive niche. It is possible that a similar immunosuppressive environment is created in HCC with advanced fibrosis in the background liver. Although sufficient understanding is required for the establishment of immune therapies of HCC, further investigations are still required in this field.

Direct molecular evidence for both multicentric and monoclonal carcinogenesis followed by transdifferentiation from hepatocellular carcinoma to cholangiocarcinoma in a case of metachronous liver cancer

Frequent recurrence is a major issue in liver cancer and histological heterogeneity frequently occurs in this cancer type. However, it has remained elusive whether such cancers are multicentric or monoclonal. To elucidate the clonal evolution of hepatocellular carcinoma (HCC) recurrence and combined hepatocellular-cholangiocarcinoma (cHCC-CCA) development, the somatic mutation frequency and signatures in a patient with triple occurrence of liver cancer every three years were examined, with samples designated as #1HCC, #2HCC and #3cHCC-CCA, respectively. A total of four tumor regions, including HCC (#3HCC) and intrahepatic CCA (#3iCCA) components of #3cHCC-CCA, and three nontumor regions (#1N, #2N and #3N) were precisely dissected from formalin-fixed paraffin-embedded tissues of each surgical specimen. DNA was extracted and subjected to tumor-specific somatic mutation determination. Of note, five nonsynonymous single-nucleotide variants (SNVs), namely those of KMT2D, TP53, DNMT3A, PKHD1 and TLR4, were identified in #3cHCC-CCA. All five SNVs were detected in both #3HCC and #3iCCA and #2HCC but not in #1HCC. The telomerase reverse transcriptase (TERT) promoter mutation C228T, but not C250T, was observed in all tumors. Digital PCR of C228T also indicated the presence of the TERT promoter mutation C228T in nontumorous liver tissues (#1N, #2N and #3N) at a frequency of 0.11-0.83% compared with normal liver and blood samples. These results suggest the following phylogenetic evolution of three metachronous liver cancers: #1HCC was not related to #2HCC, #3HCC and #3iCCA; both #3HCC and #3iCCA arose from #2HCC. From the above, three novel findings were deduced: i) Both multicentric occurrence and intrahepatic metastasis may be involved in liver cancer in a three-year interval; ii) transdifferentiation from HCC to iCCA is a possible pathogenic mechanism of cHCC-CCA; and iii) a nontumorous, noncirrhotic liver may contain a preneoplastic region with a cancer driver mutation in the TERT promoter.

The Curious Case of the HepG2 Cell Line: 40 Years of Expertise

Liver cancer is the third leading cause of cancer death worldwide. Representing such a dramatic impact on our lives, liver cancer is a significant public health concern. Sustainable and reliable methods for preventing and treating liver cancer require fundamental research on its molecular mechanisms. Cell lines are treated as in vitro equivalents of tumor tissues, making them a must-have for basic research on the nature of cancer. According to recent discoveries, certified cell lines retain most genetic properties of the original tumor and mimic its microenvironment. On the other hand, modern technologies allowing the deepest level of detail in omics landscapes have shown significant differences even between samples of the same cell line due to cross- and mycoplasma infection. This and other observations suggest that, in some cases, cell cultures are not suitable as cancer models, with limited predictive value for the effectiveness of new treatments. HepG2 is a popular hepatic cell line. It is used in a wide range of studies, from the oncogenesis to the cytotoxicity of substances on the liver. In this regard, we set out to collect up-to-date information on the HepG2 cell line to assess whether the level of heterogeneity of the cell line allows in vitro biomedical studies as a model with guaranteed production and quality.

The Curious Case of the HepG2 Cell Line: 40 Years of Expertise

Liver cancer is the third leading cause of cancer death worldwide. Representing such a dramatic impact on our lives, liver cancer is a significant public health concern. Sustainable and reliable methods for preventing and treating liver cancer require fundamental research on its molecular mechanisms. Cell lines are treated as in vitro equivalents of tumor tissues, making them a must-have for basic research on the nature of cancer. According to recent discoveries, certified cell lines retain most genetic properties of the original tumor and mimic its microenvironment. On the other hand, modern technologies allowing the deepest level of detail in omics landscapes have shown significant differences even between samples of the same cell line due to cross- and mycoplasma infection. This and other observations suggest that, in some cases, cell cultures are not suitable as cancer models, with limited predictive value for the effectiveness of new treatments. HepG2 is a popular hepatic cell line. It is used in a wide range of studies, from the oncogenesis to the cytotoxicity of substances on the liver. In this regard, we set out to collect up-to-date information on the HepG2 cell line to assess whether the level of heterogeneity of the cell line allows in vitro biomedical studies as a model with guaranteed production and quality.

The Curious Case of the HepG2 Cell Line: 40 Years of Expertise

Liver cancer is the third leading cause of cancer death worldwide. Representing such a dramatic impact on our lives, liver cancer is a significant public health concern. Sustainable and reliable methods for preventing and treating liver cancer require fundamental research on its molecular mechanisms. Cell lines are treated as in vitro equivalents of tumor tissues, making them a must-have for basic research on the nature of cancer. According to recent discoveries, certified cell lines retain most genetic properties of the original tumor and mimic its microenvironment. On the other hand, modern technologies allowing the deepest level of detail in omics landscapes have shown significant differences even between samples of the same cell line due to cross- and mycoplasma infection. This and other observations suggest that, in some cases, cell cultures are not suitable as cancer models, with limited predictive value for the effectiveness of new treatments. HepG2 is a popular hepatic cell line. It is used in a wide range of studies, from the oncogenesis to the cytotoxicity of substances on the liver. In this regard, we set out to collect up-to-date information on the HepG2 cell line to assess whether the level of heterogeneity of the cell line allows in vitro biomedical studies as a model with guaranteed production and quality.

TERT Promoter Mutations Increase Sense and Antisense Transcription from the TERT Promoter

Background: Chief among mechanisms of telomerase reverse transcriptase (TERT) reactivation is the appearance of mutations in the TERT promoter. The two main TERT promoter mutations are C>T transitions located −146C>T and −124C>T upstream from the translational start site. They generate a novel Ets/TCF binding site. Both mutations are mutually exclusive and −124C>T is strikingly overrepresented in most cancers. We investigated whether this mutational bias and mutual exclusion could be due to transcriptional constraints. Methods: We compared sense and antisense transcription of a panel of TERT promoter-luciferase vectors harboring the −124C>T and -146C>T mutations alone or together. lncRNA TAPAS levels were measured by RT-PCR. Results: Both mutations generally increased TERT transcription by 2–4-fold regardless of upstream and downstream regulatory elements. The double mutant increased transcription in an additive fashion, arguing against a direct transcriptional constraint. The −146C>T mutation, alone or in combination with −124C>T, also unleashed antisense transcription. In line with this finding, lncRNA TAPAS was higher in cells with mutated TERT promoter (T98G and U87) than in cells with wild-type promoter, suggesting that lncRNA TAPAS may balance the effect of TERT promoter mutations. Conclusions: −146C>T and −124C>T TERT promoter mutations increase TERT sense and antisense transcription, and the double mutant features higher transcription levels. Increased antisense transcription may contain TERT expression within sustainable levels.

Accumulation of Genetic and Epigenetic Alterations in the Background Liver and Emergence of Hepatocellular Carcinoma in Patients with Non-Alcoholic Fatty Liver Disease

The incidence of hepatocellular carcinoma (HCC) related to non-alcoholic fatty liver disease (NAFLD) is increasing worldwide. We analyzed 16 surgically resected HCC cases in which the background liver was pathologically diagnosed as NAFLD. Specimens with Brunt classification grade 3 or higher were assigned as the fibrotic progression group (n = 8), and those with grade 1 or lower were classified as the non-fibrosis progression group (n = 8). Comprehensive mutational and methylome analysis was performed in cancerous and noncancerous tissues. The target gene mutation analysis with deep sequencing revealed that CTNNB1 and TP53 mutation was observed in 37.5% and TERT promoter mutation was detected in 50% of cancerous samples. Furthermore, somatic mutations in non-cancerous samples were less frequent, but were observed regardless of the progression of fibrosis. Similarly, on cluster analysis of methylome data, status for methylation events involving non-cancerous liver was similar regardless of the progression of fibrosis. It was found that, even in cases of non-progressive fibrosis, accumulation of gene mutations and abnormal methylation within non-cancerous areas were observed. Patients with NAFLD require a rigorous liver cancer surveillance due to the high risk of HCC emergence based on the accumulation of genetic and epigenetic abnormalities, even when fibrosis is not advanced.

Significance of cytoplasmic expression of telomerase reverse transcriptase in patients with hepatocellular carcinoma undergoing liver resection

Telomerase reverse transcriptase (TERT) is reportedly expressed in various types of cancer. However, to the best of our knowledge, the significance of subcellular expression of TERT in hepatocellular carcinoma (HCC) has not been evaluated in detail. The present study evaluated TERT expression in resected HCC tumor tissues using immunohistochemistry. TERT expression was assessed in both the cytoplasm and the nucleus of HCC cells. The associations between TERT expression and clinical characteristics, including expression levels of DNA-dependent protein kinase catalytic unit (DNA-PKcs) and 8-hydroxyganosine (8-OHdG), were investigated. Among the 135 HCCs, TERT expression was positive only in the cytoplasm in 86 tumors (63.7%), was positive only in the nucleus in 3 tumors (2.2%), was positive in both the cytoplasm and the nucleus in 5 tumors (3.7%) and was negative in 41 tumors (30.4%). Similar results were confirmed using another antibody for TERT. Cytoplasmic TERT expression was markedly associated with hepatitis B surface antigen, poor tumor differentiation, and expression levels of DNA-PKcs and 8-OHdG. However, TERT expression in the cytoplasm or in the nucleus was not significantly associated with the overall or recurrence-free survival periods. In conclusion, TERT was mainly expressed in the cytoplasm of HCC tissues. Cytoplasmic TERT expression was closely associated with hepatitis B virus-related HCC and DNA-PKcs expression, as well as oxidative stress.

The tumor suppression theory of aging

Despite continued increases in human life expectancy, the factors determining the rate of human biological aging remain unknown. Without understanding the molecular mechanisms underlying aging, efforts to prevent aging are unlikely to succeed. The tumor suppression theory of aging introduced here proposes somatic mutation as the proximal cause of aging, but postulates that oncogenic transformation and clonal expansion, not functional impairment, are the relevant consequences of somatic mutation. Obesity and caloric restriction accelerate and decelerate aging due to their effect on cell proliferation, during which most mutations arise. Most phenotypes of aging are merely tumor-suppressive mechanisms that evolved to limit malignant growth, the dominant age-related cause of death in early and middle life. Cancer limits life span for most long-lived mammals, a phenomenon known as Peto's paradox. Its conservation across species demonstrates that mutation is a fundamental but hard limit on mammalian longevity. Cell senescence and apoptosis and differentiation induced by oncogenes, telomere shortening or DNA damage evolved as a second line of defense to limit the tumorigenic potential of clonally expanding cells, but accumulating senescent cells, senescence-associated secretory phenotypes and stem cell exhaustion eventually cause tissue dysfunction and the majority, if not most, phenotypes of aging.

Impact of aging on primary liver cancer: epidemiology, pathogenesis and therapeutics

Aging involves progressive physiological and metabolic reprogramming to adapt to gradual deterioration of organs and functions. This includes mechanisms of defense against pre-malignant transformations. Thus, certain tumors are more prone to appear in elderly patients. This is the case of the two most frequent types of primary liver cancer, i.e., hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA). Accordingly, aging hallmarks, such as genomic instability, telomere attrition, epigenetic alterations, altered proteostasis, mitochondrial dysfunction, cellular senescence, exhaustion of stem cell niches, impaired intracellular communication, and deregulated nutrient sensing can play an important role in liver carcinogenesis in the elders. In addition, increased liver fragility determines a worse response to risk factors, which more frequently affect the aged population. This, together with the difficulty to carry out an early detection of HCC and iCCA, accounts for the late diagnosis of these tumors, which usually occurs in patients with approximately 60 and 70 years, respectively. Furthermore, there has been a considerable controversy on what treatment should be used in the management of HCC and iCCA in elderly patients. The consensus reached by numerous studies that have investigated the feasibility and safety of different curative and palliative therapeutic approaches in elders with liver tumors is that advanced age itself is not a contraindication for specific treatments, although the frequent presence of comorbidities in these individuals should be taken into consideration for their management.

Circulating DNA changes are predictive of disease progression after transarterial chemoembolization

Transarterial chemoembolization (TACE) is used to treat patients with unresectable hepatocellular carcinoma (HCC). We evaluated the clinical impact of a-fetoprotein (AFP) and circulating cell-free and tumor DNA (cfDNA and ctDNA) changes around the TACE procedure. Our prospective monocentric study enrolled consecutive patients treated with TACE, with samples collected at baseline (D - 1), Day 2 (D + 2) and 1 month (M + 1) after TACE. cfDNA was quantified by the fluorometric method, and ctDNA was quantified by digital polymerase chain reaction designed for two hotspot TERT mutations. Computerized tomography scans or magnetic resonance imaging were performed at M + 1 every 3 months following TACE and independently reviewed. The objective was to identify thresholds of cfDNA, ctDNA and AFP changes associated with progressive disease (PD) using receiver operating characteristic curves. Thirty-eight patients were included from March 2018 to March 2019. All markers significantly increased from D - 1 to D + 2 (P < .005), and cfDNA and ctDNA significantly decreased from D + 2 to M + 1 (P < .0001). The analysis of changes from D - 1 to M + 1 identified thresholds at +31.4% for cfDNA and 0% for ctDNA that were significantly associated with PD at M + 1 (44.4% [>+31.4%] vs 3.8% [≤+31.4%] and 50.0% [>0%] vs 5.0% [≤0%], respectively). No significant threshold was identified for AFP. Using a score combining cfDNA and ctDNA, the patients were classified into high- or low-risk PD groups at M + 1, with PD rates of 80.0% vs 4.3% (P = .001) and median progression-free survival times of 1.3 vs 10.3 months (P = .002). Our study suggests that cfDNA and ctDNA increases around the TACE procedure and are associated with therapeutic failure.

Molecular classification of hepatocellular carcinoma: prognostic importance and clinical applications

Hepatocellular carcinoma (HCC) is a lethal human malignancy with a very low overall and long-term survival rate. Poor prognostic outcomes are predominantly associated with HCC due to a huge landscape of heterogeneity found in the deadliest disease. However, molecular subtyping of HCC has significantly improved the knowledge of the underlying mechanisms that contribute towards the heterogeneity and progression of the disease. In this review, we have extensively summarized the current information available about molecular classification of HCC. This review can be of great significance for providing the insight information needed for development of novel, efficient and personalized therapeutic options for the treatment of HCC patients globally.

Hepatocellular adenoma in men: A nationwide assessment of pathology and correlation with clinical course

BACKGROUND & AIMS

Hepatocellular adenomas (HCA) rarely occur in males, and if so, are frequently associated with malignant transformation. Guidelines are based on small numbers of patients and advise resection of HCA in male patients, irrespective of size or subtype. This nationwide retrospective cohort study is the largest series of HCA in men correlating (immuno)histopathological and molecular findings with the clinical course.

METHODS

Dutch male patients with available histological slides with a (differential) diagnosis of HCA between 2000 and 2017 were identified through the Dutch Pathology Registry (PALGA). Histopathology and immunohistochemistry according to international guidelines were revised by two expert hepatopathologists. Next generation sequencing (NGS) was performed to confirm hepatocellular carcinoma (HCC) and/or subtype HCA. Final pathological diagnosis was correlated with recurrence, metastasis and death.

RESULTS

A total of 66 patients from 26 centres fulfilling the inclusion criteria with a mean (±SD) age of 45.0 ± 21.6 years were included. The diagnosis was changed after expert revision and NGS in 33 of the 66 patients (50%). After a median follow-up of 9.6 years, tumour-related mortality of patients with accessible clinical data was 1/18 (5.6%) in HCA, 5/14 (35.7%) in uncertain HCA/HCC and 4/9 (44.4%) in the HCC groups (P = .031). Four B-catenin mutated HCA were identified using NGS, which were not yet identified by immunohistochemistry and expert revision.

CONCLUSIONS

Expert revision with relevant immunohistochemistry may help the challenging but prognostically relevant distinction between HCA and well-differentiated HCC in male patients. NGS may be more important to subtype HCA than indicated in present guidelines.

Integrated Genomic Analysis Identifies Driver Genes and Cisplatin-Resistant Progenitor Phenotype in Pediatric Liver Cancer

Pediatric liver cancers (PLC) comprise diverse diseases affecting infants, children, and adolescents. Despite overall good prognosis, PLCs display heterogeneous response to chemotherapy. Integrated genomic analysis of 126 pediatric liver tumors showed a continuum of driver mechanisms associated with patient age, including new targetable oncogenes. In 10% of patients with hepatoblastoma, all before three years old, we identified a mosaic premalignant clonal expansion of cells altered at the 11p15.5 locus. Analysis of spatial and longitudinal heterogeneity revealed an important plasticity between "hepatocytic," "liver progenitor," and "mesenchymal" molecular subgroups of hepatoblastoma. We showed that during chemotherapy, "liver progenitor" cells accumulated massive loads of cisplatin-induced mutations with a specific mutational signature, leading to the development of heavily mutated relapses and metastases. Drug screening in PLC cell lines identified promising targets for cisplatin-resistant progenitor cells, validated in mouse xenograft experiments. These data provide new insights into cisplatin resistance mechanisms in PLC and suggest alternative therapies. SIGNIFICANCE: PLCs are deadly when they resist chemotherapy, with limited alternative treatment options. Using a multiomics approach, we identified PLC driver genes and the cellular phenotype at the origin of cisplatin resistance. We validated new treatments targeting these molecular features in cell lines and xenografts.This article is highlighted in the In This Issue feature, p. 2355.

Hepatocyte organoids and cell transplantation: What the future holds

Historically, primary hepatocytes have been difficult to expand or maintain in vitro. In this review, we will focus on recent advances in establishing hepatocyte organoids and their potential applications in regenerative medicine. First, we provide a background on the renewal of hepatocytes in the homeostatic as well as the injured liver. Next, we describe strategies for establishing primary hepatocyte organoids derived from either adult or fetal liver based on insights from signaling pathways regulating hepatocyte renewal in vivo. The characteristics of these organoids will be described herein. Notably, hepatocyte organoids can adopt either a proliferative or a metabolic state, depending on the culture conditions. Furthermore, the metabolic gene expression profile can be modulated based on the principles that govern liver zonation. Finally, we discuss the suitability of cell replacement therapy to treat different types of liver diseases and the current state of cell transplantation of in vitro-expanded hepatocytes in mouse models. In addition, we provide insights into how the regenerative microenvironment in the injured host liver may facilitate donor hepatocyte repopulation. In summary, transplantation of in vitro-expanded hepatocytes holds great potential for large-scale clinical application to treat liver diseases.

Are Humanized Mouse Models Useful for Basic Research of Hepatocarcinogenesis through Chronic Hepatitis B Virus Infection?

Chronic hepatitis B virus (HBV) infection is a global health problem that can lead to liver dysfunction, including liver cirrhosis and hepatocellular carcinoma (HCC). Current antiviral therapies can control viral replication in patients with chronic HBV infection; however, there is a risk of HCC development. HBV-related proteins may be produced in hepatocytes regardless of antiviral therapies and influence intracellular metabolism and signaling pathways, resulting in liver carcinogenesis. To understand the mechanisms of liver carcinogenesis, the effect of HBV infection in human hepatocytes should be analyzed. HBV infects human hepatocytes through transfer to the sodium taurocholate co-transporting polypeptide (NTCP). Although the NTCP is expressed on the hepatocyte surface in several animals, including mice, HBV infection is limited to human primates. Due to this species-specific liver tropism, suitable animal models for analyzing HBV replication and developing antivirals have been lacking since the discovery of the virus. Recently, a humanized mouse model carrying human hepatocytes in the liver was developed based on several immunodeficient mice; this is useful for analyzing the HBV life cycle, antiviral effects of existing/novel antivirals, and intracellular signaling pathways under HBV infection. Herein, the usefulness of human hepatocyte chimeric mouse models in the analysis of HBV-associated hepatocarcinogenesis is discussed.

An Overview of the Genomic Characterization of Hepatocellular Carcinoma

Tumor classifications based on alterations in the genome, epigenome, or proteome have revealed distinct tumor subgroups that are associated with clinical outcomes. Several landmark studies have demonstrated that such classifications can significantly improve patient outcomes by enabling tailoring of therapy to specific alterations in cancer cells. Since cancer cells accumulate numerous alterations in many cancer-related genes, it is a daunting task to find and confirm important cancer-promoting alterations as therapeutic targets or biomarkers that can predict clinical outcomes such as survival and response to treatments. To aid further advances, we provide here an overview of the current understanding of molecular and genomic subtypes of hepatocellular carcinoma (HCC). System-level integration of data from multiple studies and development of new technical platforms for analyzing patient samples hold great promise for the discovery of new targets for treatment and correlated biomarkers, leading to personalized medicine for treatment of HCC patients.

Calcifying nested stromal-epithelial tumor: a clinicopathologic and molecular genetic study of eight cases highlighting metastatic potential and recurrent CTNNB1 and TERT promoter alterations

Calcifying nested stromal-epithelial tumor (CNSET) is a rare hepatic tumor that occurs in children and young adults. With <40 cases in the literature, the mechanism for tumorigenesis and the biological behavior of CNSET remain uncertain. Here, we studied the clinicopathologic and molecular genetic features of eight CNSETs. Six patients (75%) were female, and the median age at presentation was 22.5 years (range 14-34 years). The median tumor size was 14 cm (range 2.7-18 cm). All tumors had fibrous stroma that contained organoid nests of epithelioid to spindled tumor cells with moderate amounts of palely eosinophilic cytoplasm and ovoid, vesicular nuclei. Five tumors showed calcifications, and one showed lymphovascular invasion. Necrosis was absent in all. Immunohistochemistry demonstrated nuclear β-catenin expression in five of five tested tumors and focal to diffuse nuclear WT-1 positivity in five of seven. Hepatocellular markers (HepPar-1, arginase-1, and albumin in situ hybridization) and neuroendocrine markers (synaptophysin, chromogranin, and INSM1) were uniformly negative. Next-generation sequencing demonstrated CTNNB1 alterations in all seven sequenced tumors. Sanger sequencing demonstrated TERT promoter mutations in all six sequenced tumors. Clinical follow-up was available for seven patients (median duration 4.4 years; range 1.2-6.2 years): four (57%) developed metastatic disease; all four developed lung metastases; and two also had abdominal metastases. All four patients with metastatic disease also had persistent or recurrent liver tumors. Three patients with metastases were alive with disease at the most recent follow-up and one died of disease. The other three patients with available follow-up did not develop metastasis or recurrence. One tumor treated with neoadjuvant chemotherapy showed no response, and another showed 90% tumor fibrosis; the latter patient remained disease-free at 6.2 years of follow-up. Our series demonstrates the presence of TERT promoter mutations and CTNNB1 alterations in all sequenced tumors and suggests that CNSET might perhaps be more aggressive than previously reported.

Proteomic Profiling of Hepatocellular Adenomas Paves the Way to Diagnostic and Prognostic Approaches

BACKGROUND AND AIMS

Through an exploratory proteomic approach based on typical hepatocellular adenomas (HCAs), we previously identified a diagnostic biomarker for a distinctive subtype of HCA with high risk of bleeding, already validated on a multicenter cohort. We hypothesized that the whole protein expression deregulation profile could deliver much more informative data for tumor characterization. Therefore, we pursued our analysis with the characterization of HCA proteomic profiles, evaluating their correspondence with the established genotype/phenotype classification and assessing whether they could provide added diagnosis and prognosis values.

APPROACH AND RESULTS

From a collection of 260 cases, we selected 52 typical cases of all different subgroups on which we built a reference HCA proteomics database. Combining laser microdissection and mass-spectrometry-based proteomic analysis, we compared the relative protein abundances between tumoral (T) and nontumoral (NT) liver tissues from each patient and we defined a specific proteomic profile of each of the HCA subgroups. Next, we built a matching algorithm comparing the proteomic profile extracted from a patient with our reference HCA database. Proteomic profiles allowed HCA classification and made diagnosis possible, even for complex cases with immunohistological or genomic analysis that did not lead to a formal conclusion. Despite a well-established pathomolecular classification, clinical practices have not substantially changed and the HCA management link to the assessment of the malignant transformation risk remains delicate for many surgeons. That is why we also identified and validated a proteomic profile that would directly evaluate malignant transformation risk regardless of HCA subtype.

CONCLUSIONS

This work proposes a proteomic-based machine learning tool, operational on fixed biopsies, that can improve diagnosis and prognosis and therefore patient management for HCAs.

Exploring the Interplay of Telomerase Reverse Transcriptase and β-Catenin in Hepatocellular Carcinoma

Simple Summary

Liver cancer is one of the deadliest human cancers. Two of the most common molecular aberrations in liver cancer are: (1) activating mutations in the gene encoding β-catenin (CTNNB1); and (2) promoter mutations in telomerase reverse transcriptase (TERT). Here, we review recent findings regarding the interplay between TERT and β-catenin in order to better understand their role in liver cancer.

Abstract

Hepatocellular carcinoma (HCC) is one of the deadliest human cancers. Activating mutations in the telomerase reverse transcriptase (TERT) promoter (TERTp) and CTNNB1 gene encoding β-catenin are widespread in HCC (~50% and ~30%, respectively). TERTp mutations are predicted to increase TERT transcription and telomerase activity. This review focuses on exploring the role of TERT and β-catenin in HCC and the current findings regarding their interplay. TERT can have contradictory effects on tumorigenesis via both its canonical and non-canonical functions. As a critical regulator of proliferation and differentiation in progenitor and stem cells, activated β-catenin drives HCC; however, inhibiting endogenous β-catenin can also have pro-tumor effects. Clinical studies revealed a significant concordance between TERTp and CTNNB1 mutations in HCC. In stem cells, TERT acts as a co-factor in β-catenin transcriptional complexes driving the expression of WNT/β-catenin target genes, and β-catenin can bind to the TERTp to drive its transcription. A few studies have examined potential interactions between TERT and β-catenin in HCC in vivo, and their results suggest that the coexpression of these two genes promotes hepatocarcinogenesis. Further studies are required with vertebrate models to better understand how TERT and β-catenin influence hepatocarcinogenesis.

Clinical Application of TERT Promoter Mutations in Urothelial Carcinoma

Urothelial carcinoma (UC) is a common urological malignancy with a high rate of disease recurrence. Telomerase activity, a hallmark of cancer characterized by overcoming the replicative senescence, is upregulated in over 90% of patients with UC. Somatic mutations in the promoter region of telomerase reverse transcriptase (TERT) are frequently detected in UC, and drive telomerase activity. Recent studies have demonstrated a strong association between TERT promoter mutation and tumorigenesis of UC. Also, TERT promoter mutation has great potential for diagnosis, as well as prognosis in UC treatment, and this is also applicable for the liquid biopsy techniques. In this review, we discuss the progress in these areas and highlight the challenges, clinical potential, and future direction for developing UC treatment methods.

Clinical Significance of Telomerase Reverse-Transcriptase Promoter Mutations in Hepatocellular Carcinoma

Simple Summary

Activating mutations in the promoter region of TERT (TERTp) gene are frequently observed in low- and high-grade dysplastic nodules and defined as early events in hepatocellular carcinoma development. This study shows that the nucleotide change G>A at position −124 in the TERTp region is very common in hepatocellular carcinoma. The concordance rate between droplet digital PCR (ddPCR) (63.6%) and Sanger sequencing (52.1%) detection methods is good (83.5%). HCC patients carrying the TERTp mutation had lower levels of the tumour biomarker Ca19-9 but showed reduced survival. The presence of TERTp mutations may represent a prognostic signature in liver cancer.

Abstract

Telomerase reactivation during hepatocarcinogenesis is recurrently caused by two point mutations occurring most frequently at the nucleotide −124 (95%) and occasionally at the nucleotide −146 (<5%) upstream of the TERT translational start site in hepatocellular carcinoma (HCC). In this study, we designed a droplet digital PCR (ddPCR) assay to detect TERT promoter (TERTp) nucleotide change G>A at position −124 and to quantify the mutant allele frequency (MAF) in 121 primary liver cancers, including 114 HCC along with 23 autologous cirrhotic tissues, five cholangiocarcinoma (CC), and two hepato-cholangiocarcinoma (HCC-CC). All cases were evaluated for tumour markers such as α-fetoprotein (AFP), carbohydrate antigen 19-9 (CA19-9), and carcinoembryonic antigen (CEA). We compared the sensitivity of ddPCR and Sanger sequencing and investigated the prognostic relevance of TERTp mutations. The TERTp G>A transition was identified in 63.6% and 52.1% of HCC samples by ddPCR and Sanger sequencing, respectively. One out of 23 (4.3%) peri-tumour tissues tested positive only by ddPCR. One out of five CC (20%) and none of the HCC-CC were found concordantly mutated by the two methods. The TERTp MAF ranged from 2% to 66%, and the large majority (85.5%) of mutated samples showed a value above 20%. A statistically significant correlation was found between TERTp mutation and tumour size (p = 0.048), while an inverse correlation was observed with CA19-9 levels (p = 0.0105). Moreover, HCC patients with TERTp −124A had reduced survival. In conclusion, the single nucleotide variation G>A at position −124 in TERTp, detected either by ddPCR or by Sanger sequencing, showed a remarkable high frequency in HCC. Such mutation is associated with lower levels of CA19-9 and reduced survival in HCC patients suggesting that the TERTp status may represent a distinct signature of liver cancer subgroups.

Somatic Mutations in Circulating Cell-Free DNA and Risk for Hepatocellular Carcinoma in Hispanics

Hispanics are disproportionally affected by liver fibrosis and hepatocellular carcinoma (HCC). Advanced liver fibrosis is a major risk factor for HCC development. We aimed at identifying somatic mutations in plasma cell-free DNA (cfDNA) of Hispanics with HCC and Hispanics with advanced liver fibrosis but no HCC. Targeted sequencing of over 262 cancer-associated genes identified nonsynonymous mutations in 22 of the 27 HCC patients. Mutations were detected in known HCC-associated genes (e.g., CTNNB1, TP53, NFE2L2, and ARID1A). No difference in cfDNA concentrations was observed between patients with mutations and those without detectable mutations. HCC patients with higher cfDNA concentrations or higher number of mutations had a shorter overall survival (p < 0.001 and p = 0.045). Nonsynonymous mutations were also identified in 17 of the 51 subjects with advanced liver fibrosis. KMT2C was the most commonly mutated gene. Nine genes were mutated in both subjects with advanced fibrosis and HCC patients. Again, no significant difference in cfDNA concentrations was observed between subjects with mutations and those without detectable mutations. Furthermore, higher cfDNA concentrations and higher number of mutations correlated with a death outcome in subjects with advanced fibrosis. In conclusion, cfDNA features are promising non-invasive markers for HCC risk prediction and overall survival.

Telomerase: a key player in the pathogenesis of non-alcoholic fatty liver disease?

Introduction: Telomerase is a basic nuclear protein reverse transcriptase, which plays a key role in maintaining telomere stability, genome integrity, long-term cell activity, and potential continued proliferation.Area covered: This narrative review discusses key research advances involving telomerase in the development and progression of nonalcoholic fatty liver disease (NAFLD). The review evaluates 9a) whether the assessment of telomerase can be used as a noninvasive diagnostic tool; and (b) whether modification of telomerase function might be a useful potential therapeutic target for treatment of NAFLD. Furthermore, the relationship between telomerase and other chronic metabolic diseases is evaluated.Expert opinion: Several experimental and preclinical studies have suggested that telomerase plays an important role in the development of NAFLD. However, further mechanistic studies are needed to prove a causal relationship and to better elucidate whether the measurement of telomerase has utility as a diagnostic tool or whether pharmacological manipulation of telomerase has therapeutic potential in NAFLD treatment.

Identification and monitoring of mutations in circulating cell-free tumor DNA in hepatocellular carcinoma treated with lenvatinib

Background

There has been a recent surge in interest in predicting biological effects associated with genomic alterations in order to implement personalized cancer treatment strategies. However, no reports have yet evaluated the utility of profiling blood-based circulating tumor DNA (ctDNA) in hepatocellular carcinoma (HCC) patients treated with lenvatinib (LEN).

Method

We retrospectively performed ctDNA next-generation sequencing (NGS) analysis in 24 patients with advanced HCC at baseline and 4 weeks after initiation of LEN. Association of the changes in variant allele frequencies (VAFs) during treatment and clinical outcome were evaluated.

Results

In total, 131 single nucleotide variants, 17 indels, and 23 copy number variations were detected as somatic alterations in 28, 6, and 12 genes, respectively in 23 of 24 patients. The most frequently altered genes were TP53 (54%), CTNNB1 (42%), TERT (42%), ATM (25%), and ARID1A (13%). The reduction in the mean frequency of variants (VAF_mean) following 4 weeks of LEN treatment was associated with longer progression-free survival. The specificity and sensitivity of the reduction of VAF_mean for predicting partial response were 0.67 and 1.0, respectively, which were higher than those of serum α-fetoprotein level (0.10 and 0.93, respectively). No association between the mutation status at baseline and the effectiveness of LEN was observed.

Conclusion

Our study demonstrated that somatic alterations could be detected in the majority of advanced HCC patients by ctDNA profiling and that ctDNA-kinetics during LEN treatment was a useful marker of disease progression. These results suggest that ctDNA profiling is a promising method that provides valuable information in clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02016-3.

Hepatocellular Carcinomas: Towards a pathomolecular approach

Molecular analysis of primary liver malignancies has provided a refinement of the pathological diagnosis of this entity and the identification of an increasing number of tumor subtypes of hepatocellular proliferation, either malignant (hepatocellular carcinomas) or benign (hepatocellular adenomas). Besides the diagnosis, a combined pathomolecular approach can also provide further insights into patient prognosis, and help select patients who can benefit from targeted therapies. Hepatocellular carcinomas define a heterogeneous group of malignant hepatocellular proliferation at various levels: macroscopic, histological and molecular. While most carcinomas occur in patients with chronic liver diseases and advanced fibrosis in the background liver, some arise from the malignant transformation of a pre-existing hepatocellular adenoma. TERT promoter mutations are the most frequent genomic alterations observed in the process of malignancy, and they occur early in the process of liver carcinogenesis. Overall, a more active biopsy strategy should be considered a key step in the management of patients with HCC.

Hepatocellular carcinoma: a clinical and pathological overview

HCC incidence rates have been rising in the past 3 decades and by 2025 > 1 million individuals will be affected annually. High-throughput sequencing technologies led to the identification of several molecular HCC subclasses that can be broadly grouped into 2 major subgroups, each characterized by specific morphological and phenotypical features. It is likely that this increasing knowledge and a more appropriate characterization of HCC at the pathological level will impact HCC patient management.

Influence of Human Telomerase Reverse Transcriptase Mutation on the Aggressiveness and Recurrence in Meningiomas

Background: Over 200 human telomerase reverse transcriptase (hTERT) polymorphism combinations have been implicated in the development of cancer. This study aimed to evaluate hTERT mutations in meningioma tissue and its association with meningioma.

Material and Methods: A total of 90 patients who underwent surgery between 2006 and 2015 and were histopathologically diagnosed with meningioma (WHO 2016) were included.

Results: Among the 90 participants included herein, 50 (55.5%) and 40 (44.5%) were female and male, respectively, with an average age of 56.2 ± 14 years. Mean Ki-67 values were 10.56% (SD 12.41, range 0-60), while the mean follow-up duration was 39.1 months (SD 26.3). Low- and high-grade patients had a mean Ki-67 score of 4.31% (SD 3.58, range 0-16) and 19.92% (SD 14.91, range 2-60) (p = 0.0001). Our results showed a moderate positive correlation between Ki-67 score and the presence of hTERT mutation (Pearson correlation test, r = 0.5161; p = 0.0001). Patients with an hTERT mutation > 30% had significantly higher risk for reoperation than those with lower levels of mutation (p = 0.016, chi square test). None of the patients requiring reoperation had an hTERT mutation < 10%. Moreover, high-grade patients had a 7.2 times higher risk of reoperation than those with an hTERT mutation > 30%.

Conclusion: The presence of hTERT mutation, in addition to high Ki-67, indicated a more aggressive meningioma disease course and potentially increased risk of recurrence.

The Endless Sources of Hepatocellular Carcinoma Heterogeneity

Hepatocellular carcinoma (HCC) represents a global health problem. The incidence keeps increasing and current therapeutic options confer limited benefits to the patients. Tumor heterogeneity plays a central role in this context, limiting the availability of predictive biomarkers and complicating the criteria used to choose the most suitable therapeutic option. HCC heterogeneity occurs at different levels: within the population (inter-patient heterogeneity) and within tumors from the same patient (intra-patient and intra-tumor heterogeneity). Experts in the field have made many efforts to classify the patients based on clinicopathological characteristics and molecular signatures; however, there is still much work ahead to be able to integrate the extra-tumor heterogeneity that emerges from the complexity of the tumor microenvironment, which plays a critical role in the pathogenesis of the disease and therapy responses. In this review, we summarize tumor intrinsic and extrinsic sources of heterogeneity of the most common etiologies of HCC and summarize the most recent discoveries regarding the evolutionary trajectory of liver cancer cells and the influence of tumor-extrinsic factors such as the microbiome and the host immune system. We further highlight the potential of novel high-throughput methodologies to contribute to a better understanding of this devastating disease and to the improvement of the clinical management of patients.

Recurrent HBV Integration Targets as Potential Drivers in Hepatocellular Carcinoma

Chronic hepatitis B virus (HBV) infection is the major etiology of hepatocellular carcinoma (HCC), frequently with HBV integrating into the host genome. HBV integration, found in 85% of HBV-associated HCC (HBV–HCC) tissue samples, has been suggested to be oncogenic. Here, we investigated the potential of HBV–HCC driver identification via the characterization of recurrently targeted genes (RTGs). A total of 18,596 HBV integration sites from our in-house study and others were analyzed. RTGs were identified by applying three criteria: at least two HCC subjects, reported by at least two studies, and the number of reporting studies. A total of 396 RTGs were identified. Among the 28 most frequent RTGs, defined as affected in at least 10 HCC patients, 23 (82%) were associated with carcinogenesis and 5 (18%) had no known function. Available breakpoint positions from the three most frequent RTGs, TERT, MLL4/KMT2B, and PLEKHG4B, were analyzed. Mutual exclusivity of TERT promoter mutation and HBV integration into TERT was observed. We present an RTG consensus through comprehensive analysis to enable the potential identification and discovery of HCC drivers for drug development and disease management.

Genomic landscape of hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is a global health issue and the fourth leading cause of cancer deaths worldwide. Large-scale HCC genome sequencing analyses have identified core drivers (TERT, TP53, and CTNNB1/AXIN1) as initial molecular events, and other low-frequent drivers that include therapeutically targetable ones. The recent genetic analysis uncovered a distinctive driver gene landscape in precancerous lesions, arguing a discontinuous process at early HCC development. In advanced tumors, intra-tumoral heterogeneity through clonal evolution processes is common, and it displays clear geographic segregation genetically and epigenetically. Diverse epidemiological risk factors for HCC mirrors heterogeneous mutational processes among patient cohorts with distinctive ethnicity, environmental exposures, and lifestyles. The genetic information of individual tumors has been utilized for optimizing treatments, early diagnosis, and monitoring recurrence. It will expand the opportunity for screening high-risk populations, thereby preventing hepatocarcinogenesis in the near future.

Post-treatment cell-free DNA as a predictive biomarker in molecular-targeted therapy of hepatocellular carcinoma

BACKGROUND

Liquid biopsies, particularly those involving circulating tumor DNA (ctDNA), are rapidly emerging as a non-invasive alternative to tumor biopsies. However, clinical applications of ctDNA analysis in hepatocellular carcinoma (HCC) have not been fully elucidated.

METHODS

We measured the amount of plasma-derived cell-free DNA (cfDNA) in HCC patients before (n = 100) and a few days after treatment (n = 87), including radiofrequency ablation, transarterial chemoembolization, and molecular-targeted agents (MTAs), and prospectively analyzed their associations with clinical parameters and prognosis. TERT promoter mutations in cfDNA were analyzed using droplet digital PCR. Furthermore, we performed a comprehensive mutational analysis of post-treatment cfDNA via targeted ultra-deep sequencing (22,000× coverage) in a panel of 275 cancer-related genes in selected patients.

RESULTS

Plasma cfDNA levels increased significantly according to HCC clinical stage, and a high cfDNA level was independently associated with a poor prognosis. TERT promoter mutations were detected in 45% of all cases but were not associated with any clinical characteristics. cfDNA levels increased significantly a few days after treatment, and a greater increase in post-treatment cfDNA levels was associated with a greater therapeutic response to MTAs. The detection rate of TERT mutations increased to 57% using post-treatment cfDNA, suggesting that the ctDNA was enriched. Targeted ultra-deep sequencing using post-treatment cfDNA after administering lenvatinib successfully detected various gene mutations and obtained promising results in lenvatinib-responsive cases.

CONCLUSIONS

Post-treatment cfDNA analysis may facilitate the construction of biomarkers for predicting MTA treatment effects.