Micro RNA expression profiles as adjunctive data to assess the risk of hepatocellular carcinoma recurrence after liver transplantation

A Hypoxia-Related miRNA-mRNA Signature for Predicting the Response and Prognosis of Transcatheter Arterial Chemoembolization in Hepatocellular Carcinoma

Purpose

Transcatheter arterial chemoembolization (TACE) is commonly used in the treatment of hepatocellular carcinoma (HCC). However, not all patients respond to this treatment. TACE typically leads to hypoxia in the tumor microenvironment. Therefore, we aimed to construct a prognostic model based on hypoxia-related differentially expressed microRNA (miRNAs) in hepatocellular carcinoma (HCC) and to investigate the potential target mRNAs for predicting TACE response.

Methods

The hypoxia-related miRNAs (HRMs) were identified in liver cancer cells, then global test was performed to further select the miRNAs which were associated with recurrence and vascular invasion. A prognostic model was constructed based on multivariate Cox regression analysis; qRT-PCR analysis was used to validate the differentially expressed miRNAs in HCC cell lines under hypoxic condition. We further identified the putative target genes of the miRNAs and investigate the relationship between the target genes and TACE response, immune cells infiltration.

Results

We established a HRMs prognostic model for HCC patients, containing two miRNAs (miR-638, miR-501-5p), the patients with high-HRMs score showed worse survival in discovery and validation cohort; qRT-PCR analysis confirmed that these two miRNAs are up-regulated in hepatoma cells under hypoxic condition. Furthermore, four putative target genes of these two miRNAs were identified (ADH1B, CTH, FTCD, RCL1), which were significantly associated with TACE response, immune score, immunosuppressive immune cells infiltration, PDCD1 and CTLA4.

Conclusion

The HCC-HRMs signature may be utilized as a promising prognostic factor and may have implications for guiding TACE and immune therapy.

Molecular Clues for Prediction of Hepatocellular Carcinoma Recurrence After Liver Transplantation

Recurrence after liver transplantation (LT) for hepatocellular carcinoma (HCC) is one of the commonest causes of cancer-related mortality. Thus, advances in the HCC molecular features have paid researchers great attention to identifying the different risk factors that could aid in liver cancer initiation and progression for earlier prediction of post-operative HCC recurrence risk. Our review has focused on the possible molecular onco-drivers' for HCC recurrence post-LT that may represent diagnostic/prognostic tools and scoring models for the proper selection of LT candidates with HCC.

Prediction models of hepatocellular carcinoma recurrence after liver transplantation: A comprehensive review

Liver transplantation (LT) is one of the most effective treatments for hepatocellular carcinoma (HCC). Although LT eliminates HCC and greatly reduces recurrence, some patients experience recurrence after LT. Criteria and models for screening patients with a high probability of HCC recurrence after LT, starting with the Milan criteria, have been published. These models have changed over time, but a standard has not been established. We summarized HCC prediction models after LT by focusing on the application of radiologic, serologic, and pathologic factors and recent trends. This review will look at studies that are based on living donor LT and deceased donor LT, as well as studies that downstaging procedures have been performed preoperatively. This ultimately aims to help make decisions for evaluating the HCC state and selecting candidates for LT according to the circumstances of each transplantation center.

Risk Score Based on Two microRNAs as a Prognostic Marker of Hepatocellular Carcinoma and the Corresponding Competitive Endogenous RNA Network

Purpose

Liver transplantation (LT) currently yields the best outcomes for hepatocellular carcinoma (HCC). However, tumor recurrence still occurs in some patients. Identifying markers that predict HCC recurrence after LT is an unmet medical need.

Methods

In this study, differential expression analysis was used to identify differentially expressed microRNAs (DEmiRs) between HCC and liver tissues in the The Cancer Genome Atlas database and in data from patients with recurrent or non-recurrent HCC in the GSE64989 dataset. The expression profiles of the overlap DEmiRs were used to construct an miRNA-based risk score to predict prognosis using Cox regression analysis. The target genes of the miRNAs of interest were predicted, and they were analyzed for functional enrichment. Furthermore, we used the miRNAs of interest to construct a competitive endogenous RNA (ceRNA) network of long non-coding RNAs (lncRNAs), miRs and mRNAs.

Results

Four up-regulated and three down-regulated miRNAs in HCC and recurrent HCC after LT were considered as candidate miRs. MiR-3200-3p and miR-3690 were selected to construct the miR-based risk score, which was found to be associated with poor overall survival and progression-free survival. Furthermore, it proved to be an independent prognostic factor after adjusting for other clinicopathological factors. The corresponding ceRNA networks of these two miRs that we constructed may help to understand their regulatory mechanisms in HCC.

Conclusion

We propose a risk score based on miR-3200-3p and miR-3690 that may be useful as a prognostic marker to predict HCC recurrence after LT. We generated a ceRNA network involving these miRNAs, which may help reveal their regulatory roles in HCC.

Living Donor Liver Transplantation: The Optimal Curative Treatment for Hepatocellular Carcinoma Even Beyond Milan Criteria

Introduction:

Liver transplantation offers the most reasonable expectation for curative treatment for hepatocellular carcinoma. Living-donor liver transplantation represents a treatment option, even in patients with extended Milan criteria. This study aimed to evaluate the outcomes of hepatocellular carcinoma patients, particularly those extended Milan criteria.

Materials and Patients:

All HCC patients who received liver transplant for HCC were included in this retrospective study. Clinical characteristics including perioperative data and survival data (graft and patient) were extracted from records. Univariate and multivariate analyses was performed to identify significant prognostic factors for survival, postoperative complications and recurrence.

Results:

Two-hundred and two patients were included. The median age was 54.8 years (IQR 53-61). Fifty-one patients (25.3%) underwent deceased donors liver transplantation and 151 patients (74.7%) underwent living donor liver transplantation. Perioperative mortality rate was 5.9% (12 patients). Recurrent disease occurred in 43 patients (21.2%). The overall 1-year and 5-year survival rates were 90.7% and 75.6%, respectively. Significant differences between patients beyond Milan criteria compared to those within Milan criteria were not found. Alpha-fetoprotein level >300 ng/mL, vascular invasion, and bilobar tumor lesions were independent negative prognostic factors for survival.

Conclusion:

Liver transplantation is the preferred treatment for hepatocellular carcinoma and it has demonstrated an excellent potential to cure even in patients with beyond Milan criteria. This study shows that the Milan criteria alone are not sufficient to predict survival after transplantation. The independent parameters for survival prediction are Alpha-Fetoprotein-value and status of vascular invasion.

Role of Molecular Biomarkers in Liver Transplantation for Hepatocellular Carcinoma

Patient selection and organ allocation for liver transplantation (LT) in patients with hepatocellular carcinoma (HCC) relies predominantly on clinical parameters, such as tumor burden (ie, radiological imaging). Patients transplanted within Milan criteria have outstanding outcomes with a 5- and 10-year survival of 70% and 55%, respectively. Tumor recurrence after transplantion is rare in these patients (10%); however, treatment options upon recurrence are generally limited, and outcomes are poor. There are also several studies showing how a subgroup of patients with tumors outside the Milan criteria might achieve comparable outcomes to patients within Milan criteria. In other words, the size and number of tumor nodules does not always reflect tumor biology, which could be better captured using molecular proxies for cancer aggressiveness. Over the last decade, we have significantly improved our understanding of the molecular landscape of early stage HCC. This includes the development of molecular classification, identification of prognostic and mutational signatures, and potential mechanisms of hepatocarcinogenesis. Some molecular markers have already proven useful to predict tumor-related outcomes in HCC patients after LT. Most of these analyses are limited to tissue-derived biomarkers, which limits their implementation in clinical practice because tissue biopsy is not required for HCC diagnosis. Minimally invasive alternative tools, such as liquid biopsy, are being increasingly explored and could help to individualize risk stratification for patients with HCC who will benefit from LT despite being outside the accepted clinical criteria.

MicroRNAs and long non-coding RNAs in liver surgery: Diagnostic and therapeutic merits

BACKGROUND

Hepatectomy and liver transplantation (LT) are the two most commonly performed surgical procedures for various hepatic lesions. microRNA (miRNA) and long non-coding RNA (lncRNA) have been gradually unveiled their roles as either biomarkers for early diagnosis or potentially therapeutic tools to manipulate gene expression in many disease entities. This review aimed to discuss the effects of miRNA or lncRNA in the hepatectomy and LT fields.

DATA SOURCES

We did a literature search from 1990 through January 2018 to summarize the currently available evidence with respect to the effects of miRNA and lncRNA in liver regeneration after partial hepatectomy, as well as their involvement in several key issues related to LT, including ischemia-reperfusion injury, allograft rejection, tolerance, recurrence of original hepatic malignancies, etc. RESULTS: Certain miRNAs and lncRNAs are actively involved in the regulation of various aspects of liver resection and transplantation. During the process of liver regeneration after hepatectomy, the expression of miRNAs and lncRNAs shows dynamic changes.

CONCLUSIONS

It is now clear that miRNAs and lncRNAs orchestrate in various aspects of the pathophysiological process of LT and hepatectomy. Better understanding of the underlying mechanism and future clinical trials may strengthen their positions as either biomarkers or potential therapeutic targets in the management of complications after liver surgery.

Role of MicroRNA in the Diagnosis and Management of Hepatocellular Carcinoma

INTRODUCTION

Hepatocellular Carcinoma (HCC) is one of the most common malignant tumors in the world and comes third in cancer-induced mortality. The need for improved and more specific diagnostic methods that can detect early-stage disease is immense, as it is amenable to curative modalities, while advanced HCC is associated with low survival rates. microRNA (miRNA) expression is deregulated in HCC and this can be implemented both diagnostically and therapeutically.

OBJECTIVE

To provide a concise review on the role of miRNA in diagnosis, prognosis, and treatment of HCC.

METHODS

We conducted a comprehensive review of the PubMed bibliographic database.

RESULTS

Multiple miRNAs are involved in the pathogenesis of HCC. Measurement of the levels of these miRNAs either in tumor tissue or in the blood constitutes a promising diagnostic, as well as prognostic tool. OncomiRs are miRNAs that promote tumorigenesis, thus inhibiting them by administering antagomiRs is a promising treatment option. Moreover, replacement of the depleted miRNAs is another potential therapeutic approach for HCC. Modification of miRNA levels may also regulate sensitivity to chemotherapeutic agents.

CONCLUSION

miRNA play a pivotal role in HCC pathogenesis and once the underlying mechanisms are elucidated, they will become part of everyday clinical practice against HCC.

Multidisciplinary management of recurrent and metastatic hepatocellular carcinoma after resection: an international expert consensus

Hepatocellular carcinoma (HCC) is the sixth-most common cancer and the third leading cause of cancer-related death in the world. However, 40-70% patients eventually suffer from postoperative recurrence within 5 years. HCC recurrence after surgery severely affects prognosis of the patients. Nevertheless, there is an opportunity to improve patients' prognosis if doctors and researchers can recognize the importance of a standardized perioperative management and study it in clinical and pre-clinical settings. Hence, based on our own experience and published studies from other researchers, we develop this consensus regarding multidisciplinary management of locally recurrent and metastatic hepatocellular carcinoma after resection. This consensus consists of the entire course of recurrent hepatocellular carcinoma (RHCC) management, including prediction of recurrence, prevention, diagnosis, treatment and surveillance of RHCC. Consensus recommendations are presented with grades of evidences (Ia, Ib, IIa, IIb, III and IV), and strength of recommendations (A, B, C, D and E). We also develop a decision-making path for RHCC treatment, which can intuitively demonstrate the management for RHCC. It is hoped that we may make some effort to standardize the management of RHCC and ultimately understand how to improve outcomes.

Expansion of the hepatocellular carcinoma Milan criteria in liver transplantation: Future directions

Milan criteria are currently the benchmark related to liver transplantation (LT) for hepatocellular carcinoma. However, several groups have proposed different expanded criteria with acceptable results. In this article, we review the current status of LT beyond the Milan criteria in three different scenarios-expanded criteria with cadaveric LT, downstaging to Milan criteria before LT, and expansion in the context of adult living donor LT. The review focuses on three main questions: what would the impact of the expansion beyond Milan criteria be on the patients on the waiting list; whether the dichotomous criteria (yes/no) currently used are appropriate for LT or continuous survival estimations, such as the one of “Metroticket” and whether it should enter into the clinical practice; and, whether the use of living donor LT in the context of expansion beyond Milan criteria is justified.

Integrated genomic analysis for prediction of survival for patients with liver cancer using The Cancer Genome Atlas

AIM

To evaluate the prognostic power of different molecular data in liver cancer.

METHODS

Cox regression screen and least absolute shrinkage and selection operator were performed to select significant prognostic variables. Then the concordance index was calculated to evaluate the prognostic power. For the combination data, based on the clinical cox model, molecular features that better fit the model were combined to calculate the concordance index. Prognostic models were built based on the arithmetic summation of the significant variables. Kaplan-Meier survival curve and log-rank test were performed to compare the survival difference. Then a heatmap was constructed and gene set enrichment analysis was performed for pathway analysis.

RESULTS

The mRNA data were the most informative prognostic variables in all kinds of omics data in liver cancer, with the highest concordance index (C-index) of 0.61. For the copy number variation, methylation and miRNA data, the combination of molecular data with clinical data could significantly boost the prediction accuracy of the molecular data alone (P < 0.05). On the other hand, the combination of clinical data with methylation, miRNA and mRNA data could significantly boost the prediction accuracy of the clinical data itself (P < 0.05). Based on the significant prognostic variables, different prognostic models were built. In addition, the heatmap analysis, survival analysis, and gene set enrichment analysis validated the practicability of the prognostic models.

CONCLUSION

In all kinds of omics data in liver cancer, the mRNA data might be the most informative prognostic variable. The combination of clinical data with molecular data might be the future direction for cancer prognosis and prediction.

Role of microRNAs in the main molecular pathways of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver malignant neoplasia. HCC is characterized by a poor prognosis. The need to find new molecular markers for its diagnosis and prognosis has led to a progressive increase in the number of scientific studies on this topic. MicroRNAs (miRNAs) are small non-coding RNA that play a role in almost all main cellular pathways. miRNAs are involved in the regulation of expression of the major tumor-related genes in carcinogenesis, acting as oncogenes or tumor suppressor genes. The aim of this review was to identify papers published in 2017 investigating the role of miRNAs in HCC tumorigenesis. miRNAs were classified according to their role in the main molecular pathways involved in HCC tumorigenesis: (1) mTOR; (2) Wnt; (3) JAK/STAT; (4) apoptosis; and (5) MAPK. The role of miRNAs in prognosis/response prediction was taken into consideration. Bearing in mind that the analysis of miRNAs in serum and other body fluids would be crucial for clinical management, the role of circulating miRNAs in HCC patients was also investigated. The most represented miRNA-regulated pathway in HCC is mTOR, but apoptosis, Wnt, JAK/STAT or MAPK pathways are also influenced by miRNA expression levels. These miRNAs could thus be used in clinical practice as diagnostic, prognostic or therapeutic targets for HCC treatment.

Tissue miRNA 483-3p expression predicts tumor recurrence after surgical resection in histologically advanced hepatocellular carcinomas

The choice of surgical treatment for hepatocellular carcinoma (HCC) depends on several prognostic variables, among which histological features, like microvascular invasion and tumor grade, are well established. This study aims to identify the tissue miRNAs predictive of recurrence after liver resection in "histologically advanced" HCC. We selected 54 patients: 15 retrospective resected patients without recurrence (group A), 19 retrospective resected patients with HCC recurrence (group B), and 20 prospective patients (group C), with 4 recurrence cases. All selected HCC were "histologically advanced" (high Edmondson grade and/or presence of microvascular invasion). A wide spectrum of miRNAs was studied with TaqMan Human microRNA Arrays; qRT-PCR assays were used to validate results on selected miRNAs; immunohistochemistry for IGF2 was applied to study the mechanism of miR-483-3p. As a result, a significant differential expression between group A and B was found for 255 miRNAs. Among them we selected miR-483-3p and miR-548e (P<0.001). As a single variable (group C), HCC with miR-483-3p downregulation (mean fold increase 0.21) had 44.4% of recurrence cases; HCC with miR-483-3p upregulation (mean fold increase 5.94) showed no recurrence cases (P=0.011). At immunohistochemistry (group C), the HCC with loss of cytoplasmic IGF2 expression showed a down-regulation of miR-483-3p (fold increase 0.57). In conclusion, in patients with "histologically advanced" HCC, the analysis of specific tissue miRNAs (particularly miR-483-3p) could help identify the recurrence risk and choose which treatment algorithm to implement (follow-up, resection or transplantation). This could have an important impact on patient survival and transplantation outcome, improving organ allocation.

Over-expression of the miR-483-3p overcomes the miR-145/TP53 pro-apoptotic loop in hepatocellular carcinoma

The miR-145-5p, which induces TP53-dependent apoptosis, is down-regulated in several tumors, including hepatocellular carcinomas (HCCs), but some HCCs show physiological expression of this miR. Here we demonstrate that in HCC cells carrying wild-type TP53 the steady activation of the miR-145 signaling selects clones resistant to apoptosis via up-regulation of the oncogenic miR-483-3p. Expression of the miR-145-5p and of the miR-483-3p correlated negatively in non-neoplastic liver (n=41; ρ=−0.342, P=0.028), but positively in HCCs (n=21; ρ=0.791, P<0.0001), which we hypothesized to be due to impaired glucose metabolism in HCCs versus normal liver. In fact, when liver cancer cells were grown in low glucose, miR-145-5p lowered miR-483-3p expression, allowing apoptosis, whereas when cells were grown in high glucose the levels of miR-483-3p increased, reducing the apoptotic rate. This indicates that depending on glucose availability the miR-145-5p has double effects on the miR-483-3p, either inhibitory or stimulatory. Moreover, resistance to apoptosis in clones overexpressing both miR-145-5p and miR-483-3p was abrogated by silencing the miR-483-3p. Our data highlight a novel mechanism of resistance to apoptosis in liver cancer cells harbouring wild type TP53 and suggest a potential role of miR-145-5p and miR-483-3p as druggable targets in a subset of HCCs.

Response to transarterial chemoembolization may serve as selection criteria for hepatocellular carcinoma liver transplantation

Aims

This study sought to extend the inclusion criteria for hepatocellular carcinoma (HCC) liver transplantation (LT), particularly addressing the safety and effectiveness of pre-LT transarterial chemoembolization (TACE).

Materials and Methods

Our study included 115 patients with HCC who underwent LT after TACE. The response measured after each TACE session was based on the mRECIST criteria: complete response (CR), partial response (PR), stable disease (SD) or progressive disease (PD). We defined CR and PR patients as responders (64 cases) and SD and PD patients as non-responders (51 cases).

Results

The majority of responders could be identified after the first or second TACE sessions (57 cases, 89.1%). Overall survival rates at 1, 3 and 5 years were 95.3%, 89.1% and 75.0%, respectively, in the responder group, and these rates were much higher than those in the non-responder group (86.3%, 66.7% and 54.9%, P=0.016). In addition, the tumor-free survival rate in the responder group was also higher than in the non-responder group (P=0.009). In the responder group, a statistically improved long-term outcome was observed in patients whose HCC did not satisfy the Milan criteria (P<0.05). Univariate and multivariate Cox analyses showed that achieving CR or PR was the best predictor of survival and tumor-free survival following TACE.

Conclusion

The response to TACE, particularly following the first two sessions, primarily and robustly predicted overall and tumor-free survival in HCC patients, particularly those whose HCC did not satisfy the Milan criteria.

Diagnosis of HCC for patients with cirrhosis using miRNA profiles of the tumor-surrounding tissue - A statistical model based on stepwise penalized logistic regression

The presence of hepatocellular carcinoma (HCC) is a significant complication of cirrhosis because it changes the prognosis and the treatment of the patients. By now, contrast-enhanced CT and MR scans are the most reliable tools for the diagnosis of HCC; however, in some cases, a biopsy of the tumor is necessary for the final diagnosis. The aim of the study was to develop a diagnostic tool using the microRNA (miRNA) profiles of the tissue surrounding the HCC tumor combined with clinical parameters in statistical models. At a transplantation setting, 32 patients with HCC and cirrhosis (B) were compared to 22 patients suffering from cirrhosis only (A). The diagnosis and exclusion of HCC was confirmed following the histopathological examination of the explanted liver. The HCC patients were significantly older than the patients with cirrhosis only (B: 60.6 and A: 49.9, p<0.001) and showed higher levels of ALT (A: 0.76μkat/l, B: 1.02μkat/, p=0.006) and AFP (A: 5.8ng/ml, B: 70.3ng/ml, p<0.001), whereas the bilirubin levels were higher in the cirrhosis only group (p=0.002). Using age (cut-off 50.23years) and AFP (cut-off 4.2ng/ml) thresholds, the levels of expression of miR-1285-3p and miR-943 differentiated between the patients with HCC and cirrhosis from those with cirrhosis only with an accuracy of 96.3%. This is the first report about the use of stepwise penalized logistic regression and decision tree analyses of miRNA expressions in the tumor-surrounding tissue combined with clinical parameters for the diagnosis of HCC.

Hepatocellular carcinoma beyond Milan criteria: Management and transplant selection criteria

Liver transplantation (LT) for hepatocellular carcinoma (HCC) has been established as a standard treatment in selected patients for the last two and a half decades. After initially dismal outcomes, the Milan criteria (MC) (single HCC ≤ 5 cm or up to 3 HCCs ≤ 3 cm) have been adopted worldwide to select HCC patients for LT, however cumulative experience has shown that MC can be too strict. This has led to the development of numerous expanded criteria worldwide. Morphometric expansions on MC as well as various criteria which incorporate biomarkers as surrogates of tumor biology have been described. HCC that presents beyond MC initially can be downstaged with locoregional therapy (LRT). Post-LRT monitoring aims to identify candidates with favorable tumor behavior. Similarly, tumor marker levels as response to LRT has been utilized as surrogate of tumor biology. Molecular signatures of HCC have also been correlated to outcomes; these have yet to be incorporated into HCC-LT selection criteria formally. The ongoing discrepancy between organ demand and supply makes patient selection the most challenging element of organ allocation. Further validation of extended HCC-LT criteria models and pre-LT treatment strategies are required.

Relevance of microRNA-18a and microRNA-199a-5p to hepatocellular carcinoma recurrence after living donor liver transplantation

There are few reports about recurrence-related microRNAs (miRNAs) after liver transplantation (LT) for hepatocellular carcinoma (HCC). The purpose of this study was to identify novel recurrence-related miRNAs after living donor liver transplantation (LDLT) for HCC. First, we performed microarray analyses of samples from a liver with primary HCC, a liver that was noncancerous, and a liver that had recurrence-metastasis from 3 patients with posttransplant recurrence. Then we selected miRNAs with consistently altered expression in both primary HCC and recurrence as potential candidates of recurrence-related miRNAs. Expression of the miRNAs in HCC and noncancerous livers was assessed in 70 HCC patients who underwent LDLT. The target genes regulated by the recurrence-related miRNAs were identified. MicroRNA-18a (miR-18a) expression was increased, and microRNA-199a-5p (miR-199a-5p) expression was decreased in both primary HCC and recurrence. Increased miR-18a expression correlated with high levels of tumor markers, large tumor size, and a high recurrence rate. Decreased miR-199a-5p expression correlated with high levels of tumor markers, portal venous invasion, and a high recurrence rate. In HCC cells, miR-18a regulated the expression of tumor necrosis factor alpha-induced protein 3 (TNFAIP3), and miR-199a-5p regulated the expression of hypoxia-inducible factor 1 alpha (HIF1A), vascular endothelial growth factor A (VEGFA), insulin-like growth factor 1 receptor, and insulin-like growth factor 2. In conclusion, increased miR-18a levels and decreased miR-199a-5p levels are relevant to HCC recurrence after LDLT. MiR-18a and miR-199a-5p could be novel therapeutic targets of recurrent HCC after LDLT. Liver Transplantation 22 665-676 2016 AASLD.

Serologic and molecular biomarkers for recurrence of hepatocellular carcinoma after liver transplantation: A systematic review and meta-analysis

INTRODUCTION

Recurrence after liver transplantation (LT) for hepatocellular carcinoma (HCC) is a major cause of mortality. Knowledge on biomarkers may contribute to better surveillance based on the patients' risk of recurrence. Reviewing the literature, we aimed to identify serological and molecular biomarkers for recurrence of hepatocellular carcinoma after liver transplantation.

METHODS

A literature search was performed in the databases PubMed and Scopus to identify observational studies evaluating serological or molecular biomarkers for recurrence of HCC after LT using adjusted analysis to correct for confounding.

RESULTS

Of 502 records, 69 mainly retrospective studies were included with a total of 15,213 patients. Of these, 41 studies were suitable for meta-analyses, which showed that the serum markers pre-transplant α-fetoprotein (AFP) (hazard ratio (HR) 2.69 [2.08-3.47]), pre-transplant des-gamma-carboxy prothrombin (DCP) (HR 5.99 [3.27-10.98]), and allelic imbalance in microsatellites in DNA of tumor tissue (HR 13.49 [3.17-57.30]) were related to recurrence.

CONCLUSIONS

AFP, DCP and allelic imbalance in microsatellites may be used to predict recurrence. Together with other modalities, biomarkers may be used in future transplantation criteria to optimize selection of suitable patients.

A microRNA biomarker of hepatocellular carcinoma recurrence following liver transplantation accounting for within-patient heterogeneity

Background

Liver cancer, of which hepatocellular carcinoma (HCC) is by far the most common type, is the second most deadly cancer (746,000 deaths in 2012). Currently, the only curative treatment for HCC is surgery to remove the malignancy (resection) or to remove the entire diseased liver followed by transplantation of healthy liver tissue. Given the shortage of healthy livers, it is crucial to provide transplants to patients that have the best chance of long-term survival. Currently, transplantation is determined via the Milan criteria—patients within Milan (single tumor < 5 cm or 2–3 tumors < 3 cm with no extrahepatic spread nor intrahepatic vascular invasion) are typically eligible for transplantation. However, combining microRNA expression profiling with the Milan criteria can improve prediction of recurrence.

HCC often presents with multiple distinct tumor foci arising from local spread of a primary tumor or from the oncogenic predisposition of the diseased liver. Substantial genomic heterogeneity between tumor foci within a single patient has been reported; therefore, biomarker development must account for the possibility of highly heterogeneous genomic profiles from the same individual.

Methods

MicroRNA profiling was performed on 180 HCC tumor samples from 89 patients who underwent liver transplantation at the University of Rochester Medical Center. The primary outcome was recurrence-free survival time, and patients were observed for 3 years post-transplantation.

Results

MicroRNA expression profiles were used to develop a biomarker that distinguishes HCC patients at greater risk of recurrence post-transplantation. Unsupervised clustering uncovered two distinct subgroups with vast differences in standard transplantation selection criteria and recurrence-free survival times. These subgroups were subsequently used to identify microRNAs strongly associated with HCC recurrence. Our results show that reduced expression of five specific microRNAs is significantly associated with HCC recurrence post-transplantation.

Conclusions

MicroRNA profiling of distinct tumor foci, coupled with methods that address within-subject tumor heterogeneity, has the potential to significantly improve prediction of HCC recurrence post-transplantation. The development of a clinically applicable HCC biomarker would inform treatment options for patients and contribute to liver transplant selection criteria for practitioners.

Electronic supplementary material

The online version of this article (doi:10.1186/s12920-016-0179-4) contains supplementary material, which is available to authorized users.

Particulate Air Pollution Exposure and Expression of Viral and Human MicroRNAs in Blood: The Beijing Truck Driver Air Pollution Study

BACKGROUND

MicroRNAs (miRNAs) are post-transcriptional gene suppressors and potential mediators of environmental effects. In addition to human miRNAs, viral miRNAs expressed from latent viral sequences are detectable in human cells.

OBJECTIVE

In a highly exposed population in Beijing, China, we evaluated the associations of particulate air pollution exposure on blood miRNA profiles.

METHODS

The Beijing Truck Driver Air Pollution Study (BTDAS) included 60 truck drivers and 60 office workers. We investigated associations of short-term air pollution exposure, using measures of personal PM2.5 (particulate matter ≤ 2.5 μm) and elemental carbon (EC), and ambient PM10 (≤ 10 μm), with blood NanoString nCounter miRNA profiles at two exams separated by 1-2 weeks.

RESULTS

No miRNA was significantly associated with personal PM2.5 at a false discovery rate (FDR) of 20%. Short-term ambient PM10 was associated with the expression of 12 miRNAs in office workers only (FDR < 20%). Short-term EC was associated with differential expression of 46 human and 7 viral miRNAs, the latter including 3 and 4 viral miRNAs in office workers and truck drivers, respectively. EC-associated miRNAs differed between office workers and truck drivers with significant effect modification by occupational group. Functional interaction network analysis suggested enriched cellular proliferation/differentiation pathways in truck drivers and proinflammation pathways in office workers.

CONCLUSIONS

Short-term EC exposure was associated with the expression of human and viral miRNAs that may influence immune responses and other biological pathways. Associations between EC exposure and viral miRNA expression suggest that latent viral miRNAs are potential mediators of air pollution-associated health effects. PM2.5/PM10 exposures showed no consistent relationships with miRNA expression.

A possible role of microRNAs as predictive markers for the recurrence of hepatocellular carcinoma after liver transplantation

With favourable 5-year survival rates up to 75%, liver transplantation (LT) is the treatment of choice for hepatocellular carcinoma (HCC). Nonetheless, tumour recurrence after LT remains a challenge. The aim of this retrospective study was to develop a predictive score for tumour recurrence after LT by combining clinical parameters with HCC biomarkers (microRNA). A microRNA (miRNA) microarray analysis was used to compare miRNA expression patterns in tissue samples of 40 patients with and without HCC recurrence after LT. In a screening cohort (n = 18), the miRNA analysis identified significant differences in the expression of 13 miRNAs in patients with tumour recurrence. Using the most significant miRNAs in this screening cohort, we could develop a predictive score, which combined the expression levels of miR-214, miR-3187 and the Milan criteria, and we could define low- and high-risk groups for tumour recurrence and death. The above score was evaluated in a second and independent cohort (n = 22). In contrast to the Milan criteria alone, this score was significantly associated with tumour recurrence. Our analysis indicated that the use of a specific miRNA expression pattern in combination with a limited tumour burden as defined by the Milan criteria may lead to a more accurate prediction of tumour recurrence.

Evaluation of Immune Profiles and MicroRNA Expression Profiles in Peripheral Blood Mononuclear Cells of Long-Term Stable Liver Transplant Recipients and Recipients With Acute Rejection Episodes

OBJECTIVE

This study aimed to document the difference of immunophenotypes in peripheral blood mononuclear cells (PBMCs) between long-term stable liver transplant recipients and recipients with acute rejection. We also sought to identify whether there is any correlation between microRNA (miRNA) expression profile and the differential immunoprofile in these 2 groups to establish a specific miRNA biomarker to identify potential liver transplant recipients.

METHODS

PBMCs were isolated from 53 stable liver transplant recipients (STA group) and 15 liver transplant recipients with repeated biopsy-proven rejection episodes admitted to our hospital. Immunoprofiles were analyzed by means of flow cytometry. Analysis of miRNA expression in the PBMCs was performed by means of real-time polymerase chain reaction.

RESULTS

The immune profiling analysis showed increased frequency of peripheral natural killer cells and regulatory T cells in stable liver transplant recipients compared with the acute rejection recipients and healthy volunteers (P < .05). There was no significant difference in the immune cell levels (CD19(+) B cells, CD4(+) T cells, and CD8(+) T cells) in PBMCs among the transplant recipient groups and healthy control subjects. Three miRNAs, miR-18b, miR-340, and miR-106b, were up-regulated in the PBMCs of the STA recipients compared with recipients with acute rejection.

CONCLUSIONS

These results suggest that miR-18b, miR-340, and miR-106b, which regulate the expression of specific immunophenotypes, can be used as potential biomarkers to identify long-term stable liver transplant recipients from recipients with acute rejection.

MicroRNAs: Emerging Novel Clinical Biomarkers for Hepatocellular Carcinomas

The discovery of small non-coding RNAs known as microRNAs has refined our view of the complexity of gene expression regulation. In hepatocellular carcinoma (HCC), the fifth most frequent cancer and the third leading cause of cancer death worldwide, dysregulation of microRNAs has been implicated in all aspects of hepatocarcinogenesis. In addition, alterations of microRNA expression have also been reported in non-cancerous liver diseases including chronic hepatitis and liver cirrhosis. MicroRNAs have been proposed as clinically useful diagnostic biomarkers to differentiate HCC from different liver pathologies and healthy controls. Unique patterns of microRNA expression have also been implicated as biomarkers for prognosis as well as to predict and monitor therapeutic responses in HCC. Since dysregulation has been detected in various specimens including primary liver cancer tissues, serum, plasma, and urine, microRNAs represent novel non-invasive markers for HCC screening and predicting therapeutic responses. However, despite a significant number of studies, a consensus on which microRNA panels, sample types, and methodologies for microRNA expression analysis have to be used has not yet been established. This review focuses on potential values, benefits, and limitations of microRNAs as new clinical markers for diagnosis, prognosis, prediction, and therapeutic monitoring in HCC.

MicroRNA-494 is a master epigenetic regulator of multiple invasion-suppressor microRNAs by targeting ten eleven translocation 1 in invasive human hepatocellular carcinoma tumors

Vascular invasion provides a direct route for tumor metastasis. The degree to which microRNA (miRNA) expression plays a role in tumor vascular invasion is unclear. Here, we report that miR-494 is up-regulated in human hepatocellular carcinoma (HCC) tumors with vascular invasion and can promote HCC cell invasiveness by gene inactivation of multiple invasion-suppressor miRNAs. Our results show that ten eleven translocation (TET) methylcytosine dioxygenase, predominantly TET1 in HCC cells, is a direct target of miR-494. The reduced 5'-hydroxymethylcytosine levels observed in the proximal cytosine-phosphate-guanine (CpG) regions of multiple invasion-suppressor miRNA genes are strongly associated with their transcriptional repression upon miR-494 overexpression, whereas enforced DNA demethylation can abolish the repression. Furthermore, TET1 knockdown shows a similar effect as miR-494 overexpression. Conversely, miR-494 inhibition or enforced TET1 expression is able to restore invasion-suppressor miRNAs and inhibit miR-494-mediated HCC cell invasion.

CONCLUSIONS

miR-494 can trigger gene silencing of multiple invasion-suppressor miRNAs by inhibiting genomic DNA demethylation by direct targeting of TET1, thereby leading to tumor vascular invasion.

Current issues on genomic heterogeneity in hepatocellular carcinoma and its implication in clinical practice

Hepatocellular carcinoma (HCC) is a highly heterogeneous disease leading to a major diversity. Since staging systems are used in patient care, molecular and histopathological features remain to be incorporated in management algorithms. HCC, as other malignant solid tumors, exhibit a complex genetic diversity and genomic instability, driving tumorigenesis. The recent development of deep sequencing techniques has revealed different subgroups of tumors defined by specific patterns of genomic alterations that are related to clinical and histopathological diversity in HCC. Additionally, several genomic defects identified in HCC will be used in the future to develop clinical trial design for tumorized treatment.

Identification of recurrence-related serum microRNAs in hepatocellular carcinoma following hepatectomy

Hepatocellular carcinoma (HCC) is one of the most deadly tumors. Prognosis of patients with HCC is generally poor due to the high recurrence rate. In the present study, TaqMan Real-time PCR microRNA Array was used to identify differentially expressed miRNAs from 10 tumor tissue samples (5 from recurrence group vs. 5 from non-recurrence group) and the matched serum samples. Four differentially expressed miRNAs (miR-486–5p, miR-422a, miR-125b and miR-139–5p) were further quantified in 20 tumor tissues and 116 HCC patients' serum before they received hepatectomy. Univariate analysis revealed that miR-486–5p, miR-422a and miR-125b were significantly associated with patients' relapse free survival (RFS). Multivariate analysis demonstrated that miR-486–5p, AFP and microvascular invasion (MVI) were the independent prognostic factors associated with RFS in this cohort (p = 0.000, 0.043, 0.000, respectively). Besides, the expression levels of miR-486–5p were positively correlated in tumor tissues and the paired serum samples, so was miR-422a. The probability of the prognostic accuracy of miR-486–5p in predicting postoperative recurrence of HCC within the first year was 76.79% (65.38% specificity and 81.58% sensitivity), which was almost equal to the classifier established by combination of AFP and MVI (75.98% probability, 63.13% specificity and 85.90% sensitivity). Furthermore, the combination of AFP, MVI and miR-486–5p yielded a ROC curve area of 88.02% (69.20% specificity and 92.10% sensitivity). Our study was the first to identify that serum miR-486–5p could be used to stratify the patients with higher recurrence risk before hepatic resection and potentially guide more effective surveillance strategies for them.

Multidisciplinary perspective of hepatocellular carcinoma: A Pacific Northwest experience

Hepatocellular carcinoma (HCC) is the most rapidly increasing type of cancer in the United States. HCC is a highly malignant cancer, accounting for at least 14000 deaths in the United States annually, and it ranks third as a cause of cancer mortality in men. One major difficulty is that most patients with HCC are diagnosed when the disease is already at an advanced stage, and the cancer cannot be surgically removed. Furthermore, because almost all patients have cirrhosis, neither chemotherapy nor major resections are well tolerated. Clearly there is need of a multidisciplinary approach for the management of HCC. For example, there is a need for better understanding of the fundamental etiologic mechanisms that are involved in hepatocarcinogenesis, which could lead to the development of successful preventive and therapeutic modalities. It is also essential to define the cellular and molecular bases for malignant transformation of hepatocytes. Such knowledge would: (1) greatly facilitate the identification of patients at risk; (2) prompt efforts to decrease risk factors; and (3) improve surveillance and early diagnosis through diagnostic imaging modalities. Possible benefits extend also to the clinical management of this disease. Because there are many factors involved in pathogenesis of HCC, this paper reviews a multidisciplinary perspective of recent advances in basic and clinical understanding of HCC that include: molecular hepatocarcinogenesis, non-invasive diagnostics modalities, diagnostic pathology, surgical modality, transplantation, local therapy and oncological/target therapeutics.

A Seven-microRNA Expression Signature Predicts Survival in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fifth common cancer. The differential expression of microRNAs (miRNAs) has been associated with the prognosis of various cancers. However, limited information is available regarding genome-wide miRNA expression profiles in HCC to generate a tumor-specific miRNA signature of prognostic values. In this study, the miRNA profiles in 327 HCC patients, including 327 tumor and 43 adjacent non-tumor tissues, from The Cancer Genome Atlas (TCGA) Liver hepatocellular carcinoma (LIHC) were analyzed. The associations of the differentially expressed miRNAs with patient survival and other clinical characteristics were examined with t-test and Cox proportional regression model. Finally, a tumor-specific miRNA signature was generated and examined with Kaplan-Meier survival, univariate\multivariate Cox regression analyses and KEGG pathway analysis. Results showed that a total of 207 miRNAs were found differentially expressed between tumor and adjacent non-tumor HCC tissues. 78 of them were also discriminatively expressed with gender, race, tumor grade and AJCC tumor stage. Seven miRNAs were significantly associated with survival (P value <0.001). Among the seven significant miRNAs, six (hsa-mir-326, hsa-mir-3677, hsa-mir-511-1, hsa-mir-511-2, hsa-mir-9-1, and hsa-mir-9-2) were negatively associated with overall survival (OS), while the remaining one (hsa-mir-30d) was positively correlated. A tumor-specific 7-miRNAs signature was generated and validated as an independent prognostic predictor. Collectively, we have identified and validated an independent prognostic model based on the expression of seven miRNAs, which can be used to assess patients' survival. Additional work is needed to translate our model into clinical practice.

Identification of a bona fide microRNA biomarker in serum exosomes that predicts hepatocellular carcinoma recurrence after liver transplantation

Background

Predictive biomarkers for the recurrence of hepatocellular carcinoma (HCC) have great benefit in the selection of treatment options, including liver transplantation (LT), for HCC. The purpose of this study was to identify specific microRNAs (miRs) in exosomes from the serum of patients with recurrent HCC and to validate these molecules as novel biomarkers for HCC recurrence.

Methods

We employed microarray-based expression profiling of miRs derived from exosomes in the serum of HCC patients to identify a biomarker that distinguishes between patients with and without HCC recurrence after LT. This was followed by the validation in a separate cohort of 59 HCC patients who underwent living related LT. The functions and potential gene targets of the recurrence-specific miRs were analysed using a database, clinical samples and HCC cell lines.

Results

We found that miR-718 showed significantly different expression in the serum exosomes of HCC cases with recurrence after LT compared with those without recurrence. Decreased expression of miR-718 was associated with HCC tumour aggressiveness in the validated cohort series. We identified HOXB8 as a potential target gene of miR-718, and its upregulation was associated with poor prognosis.

Conclusion

Circulating miRs in serum exosomes have potential as novel biomarkers for predicting HCC recurrence.

Specific miRNA expression profiles of non-tumor liver tissue predict a risk for recurrence of hepatocellular carcinoma

AIM

It is reasonable to investigate non-tumor liver tissues to predict a risk for development of hepatocellular carcinoma (HCC). A molecular analysis of chronically damaged liver tissues may identify specific miRNA expression profiles associated with a risk for multicentric (MC) HCC.

METHODS

Twenty HCC patients, who underwent a curative hepatectomy were classified into two groups: a non-MC group (no MC recurrence in more than 3 years, n = 10) and an MC group (MC recurrence within 3 years after hepatectomy, n = 10). An miRNA microarray (955 probes) was used to compare the miRNA expression patterns of the non-cancerous liver tissues between the two groups. This study identified the differentially expressed miRNA related to MC recurrence in the liver remnant.

RESULTS

No differences were observed between the two groups in the liver function tests and pathological variables including both tumor factors and non-tumor liver tissues. The investigation selected 20 differentially expressed miRNA related to MC recurrence. Eighteen miRNA were downregulated, while two miRNA were upregulated in the MC group. A hierarchical clustering analysis identified a cluster that may be associated with risk of the MC recurrence of HCC. The MC recurrence-related miRNA included let-7d*, miR-328 and miR18a*, which potentially regulate K-ras gene expression. A significant inverse correlation between the miR-18a* expression and the K-ras mRNA expression was confirmed by quantitative reverse transcription polymerase chain reaction.

CONCLUSION

Specific miRNA expression signatures in non-cancerous liver tissue may help to predict the risk for de novo development of HCC.

Living donor liver transplantation for patients with hepatocellular carcinoma

BACKGROUND

Liver transplantation has become an established treatment for cirrhotic patients with hepatocellular carcinoma (HCC), and the Milan criteria are now widely accepted and applied as an indication for deceased donor liver transplantation (DDLT) in Western countries. In contrast, however, due to the severe organ shortage, living donor liver transplantation (LDLT) is mainstream in Japan and in other Asian countries.

SUMMARY

Unlike DDLT, LDLT is not limited by the restrictions imposed by the nationwide allocation system, and the indication for LDLT in patients with HCC often depends on institutional or case-by-case considerations, balancing the burden on the donor, the operative risk, and the overall survival benefit for the recipient. Accumulating data from a nationwide survey as well as individual center experience indicate that extending the Milan criteria is warranted.

KEY MESSAGES

While the promotion of DDLT should be intensified in Japan and other Asian countries, LDLT will continue to be a mainstay for the treatment of HCC in cirrhotic patients.

Regulation of microRNAs and their role in liver development, regeneration and disease

Since their discovery more than a decade ago microRNAs have been demonstrated to have profound effects on almost every aspect of biology. Numerous studies in recent years have shown that microRNAs have important roles in development and in the etiology and progression of disease. This review is focused on microRNAs and the roles they play in liver development, regeneration and liver disease; particularly chronic liver diseases such as alcoholic liver disease, non-alcoholic fatty liver disease, non-alcoholic steatohepatitis, viral hepatitis and primary liver cancer. The key microRNAs identified in liver development and chronic liver disease will be discussed together with, where possible, the target messenger RNAs that these microRNAs regulate to profoundly alter these processes. This article is part of a Directed Issue entitled: The Non-coding RNA Revolution.

Differential expression of microRNAs in the non-permissive schistosome host Microtus fortis under schistosome infection

The reed vole Microtus fortis is the only mammal known in China in which the growth, development and maturation of schistosomes (Schistosoma japonicum) is prevented. It might be that the anti-schistosomiasis mechanisms of M. fortis associate with microRNA-mediated gene expression, given that the latter has been found to be involved in gene regulation in eukaryotes. In the present study, the difference between pathological changes in tissues of M. fortis and of mice (Mus musculus) post-schistosome infection were observed by using hematoxylin-eosin staining. In addition, microarray technique was applied to identify differentially expressed miRNAs in the same tissues before and post-infection to analyze the potential roles of miRNAs in schistosome infection in these two different types of host. Histological analyses showed that S. japonicum infection in M. fortis resulted in a more intensive inflammatory response and pathological change than in mice. The microarray analysis revealed that 162 miRNAs were expressed in both species, with 12 in liver, 32 in spleen and 34 in lung being differentially expressed in M. fortis. The functions of the differentially expressed miRNAs were mainly revolved in nutrient metabolism, immune regulation, etc. Further analysis revealed that important signaling pathways were triggered after infection by S. japonicum in M. fortis but not in the mice. These results provide new insights into the general mechanisms of regulation in the non-permissive schistosome host M. fortis that exploits potential miRNA regulatory networks. Such information will help improve current understanding of schistosome development and host-parasite interactions.

Modulation of immune responses following solid organ transplantation by microRNA

Organ transplantation, an accepted treatment for end stage organ failure, is often complicated by allograft rejection and disease recurrence. In this review we will discuss the potential role of microRNAs in allograft immunity especially leading to rejection of the transplanted organ. microRNAs (miRNAs), originally identified in C. elegans, are short non-coding 21-24 nucleotide sequences that bind to its complementary sequences in functional messenger RNAs and inhibits post-translational processes through RNA duplex formation resulting in gene silencing (Lau et al., 2001). Gene specific translational silencing by miRNAs regulates pathways for immune responses such as development of innate immunity, inflammation, T-cell and B-cell differentiation and signaling that are implicated in various stages of allograft rejection. miRNAs also play a role in development of post-transplant complicacies like fibrosis, cirrhosis, carcinogenesis often leading to graft loss and poor patient outcome. Recent advancements in the methods for detecting and quantifying miRNA in tissue biopsies, as well as in serum and urine samples, has led to identification of specific miRNA signatures in patients with allograft rejection and have been utilized to predict allograft status and survival. Therefore, miRNAs play a significant role in post-transplant events including allograft rejection, disease recurrence and tumor development impacting patient outcome.

Recurrent hepatocellular carcinoma after liver transplantation - an emerging clinical challenge

In western countries, hepatocellular carcinoma (HCC) is a major reason for orthotopic liver transplantation (OLT) with estimated recurrence rates between 15% and 20%. This selective literature review addresses follow-up care after OLT in HCC and current treatment options. Recurrence prediction is based on pathological tumor stage, vascular invasion, serum alfafetoprotein levels, and histological differentiation, but further advances are expected by molecular profiling techniques. Lower levels of immunosuppressive agents are associated with a lower risk for HCC recurrence. Retrospective studies indicate that mammalian target of rapamycin (mTOR) inhibitors as immunosuppression reduce the risk of HCC recurrence. However, prospective studies supporting this potential advantage of mTOR inhibitors are still lacking, and higher rejection rates were reported for sirolimus after OLT in HCC. Prognosis is poor in recurrent HCC, a longer interval between OLT and recurrence and feasibility of surgical resection are associated with improved survival. Systemic treatment with sorafenib is the current standard of care in patients with advanced-stage HCC not suitable for locoregional therapy. After OLT, combination of an mTOR inhibitor with sorafenib is feasible and frequently used in clinical practice. As safety and efficacy data are still limited, close clinical monitoring is mandatory.