Human Telomerase Reverse Transcriptase Gene Promoter Mutation in Serum of Patients with Hepatocellular Carcinoma

Biomarkers for diagnosis and therapeutic options in hepatocellular carcinoma

Liver cancer is a global health challenge, causing a significant social-economic burden. Hepatocellular carcinoma (HCC) is the predominant type of primary liver cancer, which is highly heterogeneous in terms of molecular and cellular signatures. Early-stage or small tumors are typically treated with surgery or ablation. Currently, chemotherapies and immunotherapies are the best treatments for unresectable tumors or advanced HCC. However, drug response and acquired resistance are not predictable with the existing systematic guidelines regarding mutation patterns and molecular biomarkers, resulting in sub-optimal treatment outcomes for many patients with atypical molecular profiles. With advanced technological platforms, valuable information such as tumor genetic alterations, epigenetic data, and tumor microenvironments can be obtained from liquid biopsy. The inter- and intra-tumoral heterogeneity of HCC are illustrated, and these collective data provide solid evidence in the decision-making process of treatment regimens. This article reviews the current understanding of HCC detection methods and aims to update the development of HCC surveillance using liquid biopsy. Recent critical findings on the molecular basis, epigenetic profiles, circulating tumor cells, circulating DNAs, and omics studies are elaborated for HCC diagnosis. Besides, biomarkers related to the choice of therapeutic options are discussed. Some notable recent clinical trials working on targeted therapies are also highlighted. Insights are provided to translate the knowledge into potential biomarkers for detection and diagnosis, prognosis, treatment response, and drug resistance indicators in clinical practice.

Noncoding RNAs and programmed cell death in hepatocellular carcinoma: Significant role of epigenetic modifications in prognosis, chemoresistance, and tumor recurrence rate

Hepatocellular carcinoma (HCC) is the most common type of liver cancer with a high death rate in the world. The molecular mechanisms related to the pathogenesis of HCC have not been precisely defined so far. Hence, this review aimed to address the potential cross-talk between noncoding RNAs (ncRNAs) and programmed cell death in HCC. All related papers in the English language up to June 2023 were collected and screened. The searched keywords in scientific databases, including Scopus, PubMed, and Google Scholar, were HCC, ncRNAs, Epigenetic, Programmed cell death, Autophagy, Apoptosis, Ferroptosis, Chemoresistance, Tumor recurrence, Prognosis, and Prediction. According to the reports, ncRNAs, comprising long ncRNAs, microRNAs, circular RNAs, and small nucleolar RNAs can affect cell proliferation, migration, invasion, and metastasis, as well as cell death-related processes, such as autophagy, ferroptosis, necroptosis, and apoptosis in HCC by regulating cancer-associated genes and signaling pathways, for example, phosphoinositide 3-kinase/Akt, extracellular signal-regulated kinase/MAPK, and Wnt/β-catenin signaling pathways. It seems that ncRNAs, as epigenetic regulators, can be utilized as biomarkers in diagnosis, prognosis, survival and recurrence rates prediction, chemoresistance, and evaluation of therapeutic response in HCC patients. However, more scientific evidence is suggested to be accomplished to confirm these results.

Is Cell-Free DNA Testing in Hepatocellular Carcinoma Ready for Prime Time?

Revamping the current biomarker landscape of hepatocellular carcinoma (HCC) with cell-free DNA (cfDNA) could improve overall outcomes. The use of commercially available cfDNA testing (also known as liquid biopsy) is limited by the low prevalence of targetable mutations and does not have any prognostic or predictive value. Thus, current cfDNA testing cannot be relied upon for perioperative risk stratification (POR), including early detection of recurrence, long-term surveillance, predicting outcomes, and treatment response. Prior evidence on cfDNA mutation profiling (non-specific detection or gene panel testing) suggests that it can be a reliable tool for POR and prognostication, but it still requires significant improvements. cfDNA methylation changes or epigenetic markers have not been explored extensively, but early studies have shown potential for it to be a prognostic biomarker tool. The predictive value of cfDNA (mutations and EM) to assist treatment selection (systemic therapy, immune-checkpoint inhibitor vs. tyrosine kinase inhibitor) and to monitor response to systemic and locoregional therapies should be a future area of focus. We highlighted the unmet needs in the HCC management and the current role of cfDNA testing in HCC in addressing them.

Genetics of Hepatocellular Carcinoma: From Tumor to Circulating DNA

Hepatocellular carcinoma (HCC) accounts for 90% of primary hepatic malignancies and is one of the major causes of cancer-related death. Over the last 15 years, the molecular landscape of HCC has been deciphered, with the identification of the main driver genes of liver carcinogenesis that belong to six major biological pathways, such as telomere maintenance, Wnt/b-catenin, P53/cell cycle regulation, oxidative stress, epigenetic modifiers, AKT/mTOR and MAP kinase. The combination of genetic and transcriptomic data composed various HCC subclasses strongly related to risk factors, pathological features and prognosis. However, translation into clinical practice is not achieved, mainly because the most frequently mutated genes are undruggable. Moreover, the results derived from the analysis of a single tissue sample may not adequately catch the intra- and intertumor heterogeneity. The analysis of circulating tumor DNA (ctDNA) is broadly developed in other types of cancer for early diagnosis, prognosis and monitoring under systemic treatment in order to identify primary and secondary mechanisms of resistance. The aim of this review is to describe recent data about the HCC molecular landscape and to discuss how ctDNA could be used in the future for HCC detection and management.

Applications of molecular barcode sequencing for the detection of low-frequency variants in circulating tumour DNA from hepatocellular carcinoma

PURPOSE

Liquid biopsy has emerged as a promising tool for minimally invasive and accurate detection of various malignancies. We aimed to apply molecular barcode sequencing to circulating tumour DNA (ctDNA) from liquid biopsies of hepatocellular carcinoma (HCC).

STUDY DESIGN

Patients with HCC or benign liver disease were enrolled between 2017 and 2018. Matched tissue and serum samples were obtained from these patients. Plasma cell-free DNA was extracted and subjected to targeted sequencing with ultra-high coverage and molecular barcoding.

RESULTS

The study included 143 patients: 102 with HCC, 7 with benign liver tumours and 34 with chronic liver disease. No tier 1/2 or oncogenic mutations were detected in patients with benign liver disease. Among the HCC patients, 49 (48%) had tier 1/2 mutations in at least one gene; detection rates were higher in advanced stages (75%) than in early stages (26%-33%). TERT was the most frequently mutated gene (30%), followed by TP53 (16%), CTNNB1 (14%), ARID2 (5%), ARID1A (4%), NFE2L2 (4%), AXIN1 (3%) and KRAS (1%). Survival among patients with TP53 mutations was significantly worse (p = 0.007) than among patients without these mutations, whereas CTNNB1 and TERT mutations did not affect survival. ctDNA testing combined with α-fetoprotein and prothrombin induced by vitamin K absence-II analyses improved HCC detection, even in early stages.

CONCLUSIONS

ctDNA detection using molecular barcoding technology offers dynamic and personalized information concerning tumour biology, such information can guide clinical diagnosis and management. This detection also has the potential as a minimally invasive approach for prognostic stratification and post-therapeutic monitoring.

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.

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.

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.

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.

Significance of TERT Genetic Alterations and Telomere Length in Hepatocellular Carcinoma

Simple Summary

Telomerase reverse transcriptase (TERT) mutations are the most frequent genetic alterations in hepatocellular carcinoma (HCC). However, integrative analysis studies of TERT-telomere signaling during hepatocarcinogenesis are lacking. In this study, we investigated the clinicopathological association and prognostic value of TERT gene alterations and telomere length in HCC patients undergoing hepatectomy as well as transarterial chemotherapy (TACE). We found that there are eight key TERT-interacting genes and higher TERT expression and longer telomere length in HCC. We also found TERT-telomeric signals related to correlation with tumor differentiation and stage progression. TERT promoter mutations were an independent predictor of worse overall survival after hepatectomy, while TERT expression independently predicted worse time to progression after TACE. Telomere length was also associated with survival in TACE-treated patients. These findings suggest that TERT-telomere signals might be useful biomarkers for HCC, but the prognostic values may differ with tumor characteristics and treatment.

Abstract

Telomerase reverse transcriptase (TERT) mutations are reportedly the most frequent somatic genetic alterations in hepatocellular carcinoma (HCC). An integrative analysis of TERT-telomere signaling during hepatocarcinogenesis is lacking. This study aimed to investigate the clinicopathological association and prognostic value of TERT gene alterations and telomere length in HCC patients undergoing hepatectomy as well as transarterial chemotherapy (TACE). TERT promoter mutation, expression, and telomere length were analyzed by Sanger sequencing and real-time PCR in 305 tissue samples. Protein–protein interaction (PPI) analysis was performed to identify a set of genes that physically interact with TERT. The PPI analysis identified eight key TERT-interacting genes, namely CCT5, TUBA1B, mTOR, RPS6KB1, AKT1, WHAZ, YWHAQ, and TERT. Among these, TERT was the most strongly differentially expressed gene. TERT promoter mutations were more frequent, TERT expression was significantly higher, and telomere length was longer in tumors versus non-tumors. TERT promoter mutations were most frequent in HCV-related HCCs and less frequent in HBV-related HCCs. TERT promoter mutations were associated with higher TERT levels and longer telomere length and were an independent predictor of worse overall survival after hepatectomy. TERT expression was positively correlated with tumor differentiation and stage progression, and independently predicted shorter time to progression after TACE. The TERT-telomere network may have a crucial role in the development and progression of HCC. TERT-telomere abnormalities might serve as useful biomarkers for HCC, but the prognostic values may differ with tumor characteristics and treatment.

TERT Promoter Mutation in Serum Cell-Free DNA Is a Diagnostic Marker of Primary Hepatocellular Carcinoma in Patients with Nonalcoholic Fatty Liver Disease

INTRODUCTION

It remains unclear whether TERT promoter mutation (TERT C228T) in serum cell-free DNA (cfDNA) is useful for the diagnosis of hepatocellular carcinoma (HCC) in patients with nonalcoholic fatty liver disease (NAFLD).

METHODS

In this retrospective study, we analyzed the relationships between TERT C228T in serum cfDNA and levels of AFP and PIVKAII in 57 Japanese patients with histopathologically confirmed NAFLD background, consisting of 36 patients with HCC and 21 without HCC. We also examined the liver-related survival rate and HCC recurrence rate after the initial treatment for HCC. TERT C228T was detected using a highly sensitive method based on wild-type blocking PCR (detection limit in excess of 0.7% mutant-type DNA).

RESULTS

In all of the 57 patients, multivariate analysis identified TERT C228T positive as significant determinant of primary HCC. In the 36 patients with HCC, the percentage of patients positive for TERT C228T was 63.9%. The percentage of patients positive for TERT C228T with normal AFP and PIVKAII was 35.3%. The positive predictive value and specificity for prediction of BCLC stage 0 or A were both high. In 6 patients, TERT C228T was repeatedly negative during follow-up but became positive at the time of HCC diagnosis. Four patients who underwent HCC surgical resection had well-differentiated solitary HCC measuring <30 mm, and all were TERT C228T positive with normal AFP and PIVKAII. TERT C228T status had no influence on the cumulative liver-related survival rate and HCC recurrence rate.

CONCLUSIONS

Our results highlight the superiority of TERT C228T in serum cfDNA compared with AFP and PIVKAII in the early diagnosis of primary HCC in NAFLD patients.