Prognostic impact of telomere maintenance gene polymorphisms on hepatocellular carcinoma patients with chronic hepatitis B

Association of deleted in liver cancer-1 gene polymorphism with increased risk of chronicity of disease among Malaysian patients with hepatitis B infection

OBJECTIVE

The aim of this study is to examine the association between genetic variations in deleted in liver cancer 1 (DLC1) gene with progression of the hepatitis B virus (HBV) infection.

METHODS

A total of 623 subjects were included in this study, of whom, 423 were chronic hepatitis B (CHB) patients without liver cirrhosis or hepatocellular carcinoma (HCC), 103 CHB with either liver cirrhosis ± HCC and 97 individuals who had resolved HBV. Two single-nucleotide polymorphisms rs3739298 and rs532841 of DLC1 gene were genotyped using the Sequenom MassARRAY platform.

RESULTS

Our results indicated significant differences between the chronic HBV and resolved HBV groups in genotype and allele frequencies of DLC1-rs3739298 [odds ratio (OR) = 2.23; 95% confidence interval (CI): 1.24-3.99; P = 0.007] and (OR = 1.54; 95% CI: 1.07-2.22; P = 0.021), respectively. Moreover, haplotype analysis revealed significant associations between chronicity of HBV with TG and GA haplotypes (P = 0.041 and P = 0.042), respectively.

CONCLUSION

A significant association exists between the rs3739298 variant and susceptibility to CHB infection.

Genetic variants in telomerase-associated protein 1 are associated with telomere damage in PAH-exposed workers

Telomeres are functional complexes at the ends of linear chromosomes, and telomerase aids in their maintenance and replication. Additionally, accumulating evidence suggests that telomerase-associated protein 1 (TEP1) is a component of the telomerase ribonucleoprotein complex and is responsible for catalyzing the addition of new synthetic telomere sequences to chromosome ends. In our previous study, we found that genetic variants of the TERT gene participated in the regulation of telomere length. Exposure to particulate matter, environmental pollutants, oxidative stress, and pesticides is associated with shortening of telomere length. However, it is unknown whether genetic variants in the TEP1 gene may affect telomere length (TL) in polycyclic aromatic hydrocarbon (PAH)-exposed workers. Therefore, we measured the peripheral leukocyte TL and genotyped the polymorphism loci in the TEP1 gene among 544 PAH-exposed workers and 238 healthy controls. Covariance analysis showed that the individuals carrying TEP1 rs1760903 CC and TEP1 rs1760904 TT had longer TL in the control group (P < 0.05). In the generalized linear model, we found that rs1760903 CC was a protective factor against TL shortening, and PAH exposure could promote telomere shortening (P < 0.05). Thus, this study reinforces the roles of environmental factors and genetic variations in telomere damage, and provides a theoretical foundation for the early detection of susceptible populations and the establishment of occupational standards.

Recipient C7 rs9292795 genotype and the risk of hepatocellular carcinoma recurrence after orthotopic liver transplantation in a Han Chinese population

BACKGROUND

Complement component(C7) gene has been shown to influence the prognosis in Hepatocellular carcinoma (HCC) patients. The association between C7 and HCC recurrence after orthotopic liver transplantation (OLT), however, is still unknown. The purpose of this study was to evaluate whether the donor and recipient C7 gene polymorphisms are related to HCC recurrence after OLT in the Han Chinese population.

METHODS

A total of 73 consecutive patients with HCC who had undergone OLT, both donors and recipients, were involved in this research. A single nucleotide polymorphism of C7, rs9292795, was genotyped using Sequenom MassARRAY in the cohort. The expression of C7 and the association between C7 gene polymorphisms and HCC recurrence following OLT were analyzed by bioinformatics and statistical analysis, respectively.

RESULTS

As shown in database, the expression of C7 was higher in HCC tissues than that in normal tissues, and represented a worse prognosis. We also found that recipient C7 rs9292795 polymorphism, rather than the donor, was significantly associated with HCC recurrence after OLT. Multivariate logistic regression analysis confirmed that TNM stage (P = 0.001), Milan criteria (P = 0.000) and recipient rs9292795 genotype (TT vs AA/AT, P = 0.008) were independent risk factors for HCC recurrence. Furthermore, the recipient carrying AA/AT showed higher recurrence-free survival (RFS) and overall survival (OS) than that carrying TT (P < 0.05). In Cox proportional hazards model, TNM stage, recipient rs9292795 genotype, and Milan criteria were identified as independent factors for RFS and OS (P < 0.05) as well as pre-OLT serum alpha fetoprotein (AFP) level was associated with OS (P < 0.05).

CONCLUSIONS

Recipient C7 rs9292795 gene polymorphism is related to the recurrence of HCC after OLT, which may be a helpful prognostic marker for HCC patients who receive OLT.

Telomere Maintenance Variants and Survival after Colorectal Cancer: Smoking- and Sex-Specific Associations

BACKGROUND

Telomeres play an important role in colorectal cancer prognosis. Variation in telomere maintenance genes may be associated with survival after colorectal cancer diagnosis, but evidence is limited. In addition, possible interactions between telomere maintenance genes and prognostic factors, such as smoking and sex, also remain to be investigated.

METHODS

We conducted gene-wide analyses of colorectal cancer prognosis in 4,896 invasive colorectal cancer cases from the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO); 1,871 common variants within 13 telomere maintenance genes were included. Cox models were fit to estimate associations of these variants individually with overall and colorectal cancer-specific survival. Likelihood ratio tests were used to test for interaction by smoking and sex. P values were adjusted using Bonferroni correction.

RESULTS

The association between minor allele of rs7200950 (ACD) with colorectal cancer-specific survival varied significantly by smoking pack-years (corrected P = 0.049), but no significant trend was observed. By sex, minor alleles for rs2975843 (TERF1), rs75676021 (POT1), and rs74429678 (POT1) were associated with decreased overall and/or colorectal cancer-specific survival in women but not in men.

CONCLUSIONS

Our study reported a gene-wide statistically significant interaction with sex (TERF1, POT1). Although significant interaction by smoking pack-years (ACD) was observed, there was no evidence of a dose response. Validation of these findings in other large studies and further functional annotation on these SNPs are warranted.

IMPACT

Our study found a gene-smoking and gene-sex interaction on survival after colorectal cancer diagnosis, providing new insights into the role of genetic polymorphisms in telomere maintenance on colorectal cancer prognosis.

The role of telomeres and telomerase in cirrhosis and liver cancer

Telomerase is a key enzyme for cell survival that prevents telomere shortening and the subsequent cellular senescence that is observed after many rounds of cell division. In contrast, inactivation of telomerase is observed in most cells of the adult liver. Absence of telomerase activity and shortening of telomeres has been implicated in hepatocyte senescence and the development of cirrhosis, a chronic liver disease that can lead to hepatocellular carcinoma (HCC) development. During hepatocarcinogenesis, telomerase reactivation is required to enable the uncontrolled cell proliferation that leads to malignant transformation and HCC development. Part of the telomerase complex, telomerase reverse transcriptase, is encoded by TERT, and several mechanisms of telomerase reactivation have been described in HCC that include somatic TERT promoter mutations, TERT amplification, TERT translocation and viral insertion into the TERT gene. An understanding of the role of telomeres and telomerase in HCC development is important to develop future targeted therapies and improve survival of this disease. In this Review, the roles of telomeres and telomerase in liver carcinogenesis are discussed, in addition to their potential translation to clinical practice as biomarkers and therapeutic targets.

Genome-Wide Association Study Identifies a Genetic Prediction Model for Postoperative Survival in Patients with Hepatocellular Carcinoma

BACKGROUND As an important aspect of tumor heterogeneity, genetic variation may influence susceptibility and prognosis in different types of cancer. By exploring the prognostic value of genetic variation, this study aimed to establish a model for predicting postoperative survival and assessing the impact of variation on clinical outcomes in patients with hepatocellular carcinoma (HCC). MATERIAL AND METHODS A genome-wide association study of 367 patients with HCC was conducted to identify single nucleotide polymorphisms (SNPs) associated with prognosis. Identified predictors were further evaluated in 758 patients. Two prognostic models were established using Cox proportional hazards regression and Nomogram strategy, and validated in another 316 patients. The effect of the SNP rs2431 was analyzed in detail. RESULTS A prognostic model including 5 SNPs (rs10893585, rs2431, rs34675408, rs6078460, and rs6766361) was established and exhibited high predictive accuracy for HCC prognosis. The panel combined with tumor node metastasis (TNM) stage resulted in a significantly higher c-index (0.723) than the individual c-index values. Stratified by the Nomogram prediction model, the median overall survival for the low-risk and high-risk groups were 100.1 versus 30.8 months (P<0.001) in the training set and 82.2 versus 22.5 months (P<0.001) in the validation set. A closer examination of rs2431 revealed that it may regulate the expression of FNDC3B by disrupting a microRNA-binding site. CONCLUSIONS This study established prediction models based on genetic factors alone or in combination with TNM stage for postoperative survival in patients with HCC, and identified FNDC3B as a potential therapeutic target for combating HCC metastasis.

Rs2303428 of MSH2 Is Associated with Hepatocellular Carcinoma Prognosis in a Chinese Population

The defects of DNA repair genes may lead to genomic instability and cancer. As an important DNA mismatch repair gene that maintains genomic stability from DNA replication errors, genetic variants of mutS homolog 2 (MSH2) are associated with some cancers. In this study, 1021 hepatocellular carcinoma (HCC) cases and 1021 non-HCC controls from Guangxi were included to explore the association between MSH2 single-nucleotide polymorphisms (SNPs) and HCC. Among the eight MSH2 SNPs, only genotype distribution of rs2303428 was significantly different from HCC and non-HCC patients (p < 0.05). Moreover, CT, TT, and CT/TT genotype of rs2303428 could increase HCC risk [OR (95% CI) = 1.758 (1.195-2.657), 1.846 (1.213-2.896), and 1.823 (1.219-2.763), respectively] and decrease the survival time of HCC patients [codominant, HR (95% CI) = 1.267 (1.046-1.535); dominant, HR (95% CI) = 1.675 (1.162-2.414)]. In addition, rs2303428 was found to interact with HBV infection and family history to increase HCC risk by gene-environment analysis (p < 0.05). Finally, multivariate COX regression analysis showed that rs2303428, tumor number, tumor staging, and metastasis had a significant influence on HCC prognosis. Our results provide MSH2 SNP, rs2303428, as a new prognostic biomarker for HCC patients.

Genetic variants of cell cycle pathway genes predict disease-free survival of hepatocellular carcinoma

Disruption of the cell cycle pathway has previously been related to development of human cancers. However, associations between genetic variants of cell cycle pathway genes and prognosis of hepatocellular carcinoma (HCC) remain largely unknown. In this study, we evaluated the associations between 24 potential functional single nucleotide polymorphisms (SNPs) of 16 main cell cycle pathway genes and disease‐free survival (DFS) of 271 HCC patients who had undergone radical surgery resection. We identified two SNPs, i.e., SMAD3 rs11556090 A>G and RBL2 rs3929G>C, that were independently predictive of DFS in an additive genetic model with false‐positive report probability (FPRP) <0.2. The SMAD3 rs11556090G allele was associated with a poorer DFS, compared with the A allele [hazard ratio (HR) = 1.46, 95% confidential interval (95% CI) = 1.13–1.89, P = 0.004]; while the RBL2 rs3929 C allele was associated with a superior DFS, compared with the G allele (HR = 0.74, 95% CI = 0.57–0.96, P = 0.023). Additionally, patients with an increasing number of unfavorable genotypes (NUGs) of these loci had a significant shorter DFS (P_trend = 0.0001). Further analysis using receiver operating characteristic (ROC) curves showed that the model including the NUGs and known prognostic clinical variables demonstrated a significant improvement in predicting the 1‐year DFS (P = 0.011). Moreover, the RBL2 rs3929 C allele was significantly associated with increased mRNA expression levels of RBL2 in liver tissue (P = 1.8 × 10⁻⁷) and the whole blood (P = 3.9 × 10⁻¹⁴). Our data demonstrated an independent or a joint effect of SMAD3 rs11556090 and RBL2 rs3929 in the cell cycle pathway on DFS of HCC, which need to be validated by large cohort and biological studies.

Prognostic value of Notch receptors in postsurgical patients with hepatitis B virus-related hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies and a major cause of cancer involved death worldwide. Prognosis remains poor because of high recurrence rates and lack of effective relapse prevention strategies. Notch pathway plays an important role in tumor progression and metastasis, and it is associated with the prognosis of cancer. A total of 465 hepatitis B virus (HBV)‐related HCC patients who underwent surgery were enrolled. Single nucleotide polymorphisms (SNP) of Notch pathway receptors were genotyped using Sanger DNA sequencing. Kaplan–Meier curves and the Cox proportional hazards regression model were adopted to analyze the association of polymorphisms and mRNA expression with clinical and pathological features, respectively. Four SNPs (rs1043996 in Notch3 and rs422951, rs520692, rs3830041 in Notch4) were significantly associated with overall survival (OS) (P = 0.023, P = 0.042, P = 0.028, and P = 0.001 respectively). Patients carrying the AA genotype in rs1043996 and TT/TC genotypes in rs422951 and rs520692 significantly decreased risks of death, compared to those carrying the AG/GG genotype in rs1043996 and CC genotype in rs422951 and rs520692, respectively. Patients carrying the TT genotype in rs3830041 showed poorer OS, compared with those carrying the TC/CC genotype. A haplotype block (rs422951 was in strong LD with rs520692, r² = 0.843) was identified in Notch4. Notch3 mRNA expression significantly increased in tumor tissue, compared with nontumor normal tissue (P < 0.0001). Moreover, higher expression of Notch3 was associated with poorer OS (HR = 2.11, 95% CI = 1.32–3.37, P = 0.002) and shorter recurrence time of HBV‐related HCC (HR = 1.96, 95% CI = 1.31–2.93, P = 0.001). Our findings collectively indicate that Notch receptors variants (rs1043996 in Notch3 and rs422951, rs520692, rs3830041 in Notch4) are independent predictive targets for OS in HBV‐related HCC patients. Notch3 expression is a potential prognostic biomarker of OS and recurrence‐free survival (RFS) prediction in HBV‐related HCC patients following surgical treatment.

Association between rs2853669 in TERT gene and the risk and prognosis of human cancer: a systematic review and meta-analysis

The polymorphism rs2853669 within the promoter of telomerase reverse transcriptase gene (TERTp) has been debated about its role in cancer risk and prognosis. Additionally, several studies report inconsistent results concerning the modifying effect of rs2853669 on the prognostic value of TERTp mutations in cancer patients. Here, we performed this meta-analysis to comprehensively evaluate the role of rs2853669 in the risk and prognosis of human cancer, and further assess its modifying impact on TERTp mutations in the survival of cancer patients. We systematically searched literature via PubMed, Web of Science, and EMBASE through July 2016, and included 22 eligible studies. The overall analysis (64,119 cases and 78,988 controls) demonstrated that rs2853669 did not increase or decrease the overall cancer risk. Subsequent analyses also did not reveal any association between rs2853669 and overall cancer prognosis. However, we identified a modifying effect of rs2853669 on TERTp mutations in that, among cancer patients with TERTp mutations, only those carrying the TT genotype had a poor survival (Hazard ratio = 1.56, 95% confidence interval = 1.06-2.28); subgroup analyses by cancer type also supported these results. In conclusion, our findings suggest that rs2853669 could be important for assessing the prognostic value of TERTp mutations. Future large studies are required to further validate our results.

Association of PINX1 but not TEP1 Polymorphisms with Progression to Hepatocellular Carcinoma in Thai Patients with Chronic Hepatitis B Virus Infection

Hepatocellular carcinoma (HCC) is major health problem with high mortality rates, especially in patients with hepatitis B virus (HBV) infection. Telomerase function is one of common mechanisms affecting genome stability and cancer development. Recent studies demonstrated that genetic polymorphisms of telomerase associated genes such as telomerase associated protein 1 (TEP1) rs1713449 and PIN2/TERF1-interacting telomerase inhibitor 1 (PINX1) rs1469557 may be associated with risk of HCC and other cancers. In this study, 325 patients with HCC and 539 non-HCC groups [193 healthy controls, 80 patients with HBV-related liver cirrhosis (LC) and 266 patients with HBV-related chronic hepatitis (CH)] were enrolled to explore genetic polymorphisms of both SNPs using the allelic discrimination method based on MGB probe TaqMan real time PCR. We demonstrated that all genotypes of both genes were in Hardy-Wienberg equilibrium (>0.05). Moreover, there was no significant association between rs1713449 genotypes and HCC risk, HCC progression and overall survival (>0.05). Interestingly, we observed positive association of rs1469557 with risk of HCC when compared with the LC group under dominant (CC versus CT+TT, OR=1.89, 95% CI= 1.06-3.40, P=0.031) and allelic (C versus T alleles, OR=1.75, 95% CI=1.04-2.94, P=0.033) models, respectively. Moreover, overall survival of HCC patients with CC genotype of rs1469557 was significantly higher than non-CC genotype (Log-rank P=0.015). These findings suggest that PINX1 rs1469557 but not TEP1 rs1469557 might play a role in HCC progression in Thai patients with LC and be used as the prognosis marker to predict overall survival in HCC patients.

The TERT promoter SNP rs2853669 decreases E2F1 transcription factor binding and increases mortality and recurrence risks in liver cancer

A common single-nucleotide polymorphism in the telomerase reverse transcriptase (TERT) promoter, rs2853669 influences patient survival rates and the risk of developing cancer. Recently, several lines of evidence suggest that the rs2853669 suppresses TERT promoter mutation-mediated TERT expression levels and cancer mortality as well as recurrence rates. However, no reports are available on the impact of rs2853669 on TERT expression in hepatocellular carcinoma (HCC) and its association with patient survival. Here, we found that HCC-related overall and recurrence-free survival rates were not associated with TERT promoter mutation individually, but rs2853669 and the TERT promoter mutation in combination were associated with poor survival rates. TERT mRNA expression and telomere fluorescence levels were greater in patients with HCC who had both the combination. The combination caused TERT promoter methylation through regulating the binding of DNA methyltransferase 1 and histone deacetylase 1 to the TERT promoter in HCC cell lines. The TERT expression level was significantly higher in HCC tumor with a methylated promoter than in that with an unmethylated promoter. In conclusion, we demonstrate a substantial role for the rs2853669 in HCC with TERT promoter mutation, which suggests that the combination of the rs2853669 and the mutation indicate poor prognoses in liver cancer.

Genetic variants in telomere-maintenance genes are associated with ovarian cancer risk and outcome

Most ovarian cancer patients present at an advanced stage with poor prognosis. Telomeres play a critical role in protecting chromosomes stability. The associations of genetic variants in telomere maintenance genes and ovarian cancer risk and outcome are unclear. We genotyped 137 single nucleotide polymorphisms (SNPs) in telomere-maintenance genes in 417 ovarian cancer cases and 417 matched healthy controls to evaluate their associations with cancer risk, survival and therapeutic response. False discovery rate Q-value was calculated to account for multiple testing. Eleven SNPs from two genes showed nominally significant associations with the risks of ovarian cancer. The most significant SNP was TEP1: rs2228026 with participants carrying at least one variant allele exhibiting a 3.28-fold (95% CI: 1.72-6.29; P < 0.001, Q = 0.028) increased ovarian cancer risk, which remained significant after multiple testing adjusting. There was also suggested evidence for the associations of SNPs with outcome, although none of the associations had a Q < 0.05. Seven SNPs from two genes showed associations with ovarian cancer survival (P < 0.05). The strongest association was found in TNKS gene (rs10093972, hazard ratio = 1.88; 95% CI: 1.20-2.92; P = 0.006, Q = 0.076). Five SNPs from four genes showed suggestive associations with therapeutic response (P < 0.05). In a survival tree analysis, TEP1:rs10143407 was the primary factor contributing to overall survival. Unfavourable genotype analysis showed a cumulative effect of significant SNPs on ovarian cancer risk, survival and therapeutic response. Genetic variations in telomere-maintenance genes may be associated with ovarian cancer risk and outcome.

Distinguished prognosis after hepatectomy of HBV-related hepatocellular carcinoma with or without cirrhosis: a long-term follow-up analysis

BACKGROUND

Conflicting results have often been observed for the prognosis of hepatocellular carcinoma (HCC) patients, but few studies have attempted to explore the reasons for the conflicting results. We aimed to distinguish the prognosis of patients with HCC with cirrhosis (HCC-C) and that of patients with HCC without cirrhosis (HCC-NC).

METHODS

Patients with hepatitis B virus (HBV)-associated HCC treated by curative liver resection at a single institution between 1995 and 2013 were retrospectively evaluated. Kaplan-Meier and multivariate analyses were performed to identify risk factors, including tumor-related factors, hypoxia-inducible factor 1α expression, HBV X protein (HBx) expression, and HBx double mutations for overall survival and recurrence-free survival in these patients.

RESULTS

The long-term prognosis of HCC-NC patients is better than that of HCC-C patients. Male sex, poor differentiation, preoperative serum alanine aminotransferase level greater than 80 IU/L, and α-fetoprotein level greater than 400 ng/mL were risk factors for overall survival among HCC-NC patients but not among HCC-C patients, and age greater than 50 years was associated with poor overall survival only in cirrhotic patients. HCC-C patients benefit more from antiviral therapy following curative hepatectomy than do HCC-NC patients. The clinical value of the biomarkers hypoxia-inducible factor 1α, HBx, and HBx double mutations for predicting HCC prognosis was significantly different between these two groups.

CONCLUSIONS

There were differences in tumor-related prognostic factors, effectiveness of the antiviral therapy after hepatectomy, and biomarkers between HCC-C and HCC-NC patients, indicating that subgroup analysis of the prognostic factors may result in better management of HCC and that HCC patients, especially those with liver cirrhosis, should be given antiviral therapy.

Detection of the rs10250202 polymorphism in protection of telomeres 1 gene through introducing a new restriction enzyme site for PCR-RFLP assay

Human protection of telomeres 1 (POT1) gene is a single stranded telomere binding proteins with a critical role in ensuring chromosome stability. There have been variants of POT1 gene, and the polymorphisms of POT1 gene were associated with some diseases. Polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) is a traditional method to detect the single nucleotide polymorphism (SNP), and it can be used to detect the polymorphism of rs10250202. But the restriction enzymes required for the detection of the polymorphism of rs10250202 are expensive. So we designed a novel PCR–RFLP assay for genotyping the POT1 rs10250202 SNP. In the study, a new restriction enzyme cutting site was created by created restriction site PCR (CRS-PCR), and the restriction enzyme BclI for CRS-PCR was cheaper than other enzymes. After detecting Han Chinese workers, Allele frequencies were found to be 51.54 % for allele A and 48.46 % for allele C respectively. The PCR results were confirmed by DNA sequencing. CRS-PCR provides a simple, low-cost, practical, and reproducible method.

TERT promoter mutations and polymorphisms as prognostic factors in primary glioblastoma

Telomerase reverse transcriptase (TERT) activity is up-regulated in several types of tumors including glioblastoma (GBM). In the present study, 128 primary glioblastoma patients were examined for single nucleotide polymorphisms of TERT in blood and in 92 cases for TERT promoter mutations in tumors. TERT promoter mutations were observed in 86% of the tumors and of these, C228T (-124 bp upstream start codon) was detected in 75% and C250T (-146 bp) in 25% of cases. TERT promoter mutations were associated with shorter overall survival (11 vs. 20 months p = 0.002 and 12 vs. 20, p = 0.04 for C228T and C250T, respectively). The minor alleles of rs2736100 and rs10069690 SNP's, located in intron 2 and the promotor regions, respectively, were associated with an increased risk of developing GBM (p = 0.004 and 0.001). GBM patients having both TERT promoter mutations and being homozygous carriers of the rs2853669 C-allele displayed significantly shorter overall survival than those with the wild type allele. The rs2853669 SNP is located in a putative Ets2 binding site in the promoter (-246 bp upstream start codon) close to the C228T and C250T mutation hot spots. Interleukin-6 (IL-6) expression regulated by TERT promoter status and polymorphism, what leads us to think that TERT and IL-6 plays a significant role in GBM, where specific SNPs increase the risk of developing GBM while the rs2853669 SNP and specific mutations in the TERT promoter of the tumor lead to shorter survival.

Relationship between long non-coding RNAs and liver-related diseases and injuries

Long non-coding RNAs (lncRNAs) are a class of non-coding RNAs>200 bp in length. In recent years, it was discovered that lncRNAs play an important role in many physiological processes, such as transcription activation, transcriptional interference, X chromosome silencing, genomic imprinting and chromatin modification, transport and so on. More and more studies show alterations of lncRNA expression in primary liver cancer, hepatitis and other liver diseases. This paper reviews the relationship between long non-coding RNAs and liver-related diseases and injuries.

Significance of genetic variants in DLC1 and their association with hepatocellular carcinoma

DLC1 has been shown to be downregulated or absent in hepatocellular carcinoma (HCC) and is associated with tumorigenesis and development. However, only a small number of studies have focused on genetic variations of DLC1. The present study performed exon sequencing for the DLC1 gene in HCC tissue samples from 105 patients to identify functional genetic variation of DLC1 and its association with HCC susceptibility, clinicopathological features and prognosis. A novel missense mutation and four non-synonymous single nucleotide polymorphisms (SNPs; rs3816748, rs11203495, rs3816747 and rs532841) were identified. A significant correlation of rs3816747 polymorphisms with HCC susceptibility was identified. Compared to individuals with the GG genotype of rs3816747, those with the GA (odds ratio (OR)=0.486; P=0.037) or GA+AA genotype (OR=0.51; P=0.039) were associated with a significantly decreased HCC risk. Furthermore, patients with the GC+CC genotype of rs3816748, the TC+CC genotype of rs11203495 or the GA+AA genotype of rs3816747 had small-sized tumors compared with those carrying the wild-type genotype. No significant association of DLC1 SNPs with the patients' prognosis was found. These results indicated that genetic variations in the DLC1 gene may confer a risk for HCC.

Short telomere length in peripheral blood leukocyte predicts poor prognosis and indicates an immunosuppressive phenotype in gastric cancer patients

Compelling evidences indicate that relative telomere length (RTL) in peripheral blood leukocytes (PBLs) can predict the clinical outcome of several cancers. However, to date, the prognostic value of leukocyte RTL in gastric cancer (GC) patients has not been explored. In this study, relative telomere length (RTL) in peripheral blood leukocytes (PBLs) was measured using a real-time PCR-based method in a total of 693 GC patients receiving surgical resection. The prognostic value of leukocyte RTL was first explored in the training set (112 patients) using Kaplan-Meier and Cox proportional hazards regression analyses. Then an independent cohort of 581 patients was used as a validation set. To explore potential mechanism, we detected the immunophenotypes of peripheral blood mononuclear cells and plasma concentrations of several cytokines in GC patients. Patients with short RTL showed significantly worse overall survival (OS) and relapse-free survival (RFS) than those with long RTL in all patient sets. Furthermore, leukocyte RTL and TNM stage exhibited a notable joint effect in prognosis prediction. Integration of TNM stage and leukocyte RTL significantly improved the prognosis prediction efficacy for GC. In addition, we found that patients with short RTL had a higher CD4(+) T cell percentage in PBMCs, CD19(+)IL-10(+) Breg percentage in B cells and plasma IL-10 concentration, indicating an enhanced immunosuppressive status with short leukocyte RTL. In conclusion, our study for the first time demonstrates that leukocyte RTL is an independent prognostic marker complementing TNM stage and associated with an immunosuppressive phenotype in the peripheral blood lymphocytes in GC patients.