Interaction of hepatitis B virus, chemical carcinogen, and genetic susceptibility: multistage hepatocarcinogenesis with multifactorial etiology

Three-dimensional and single-cell sequencing of liver cancer reveals comprehensive host-virus interactions in HBV infection

Backgrounds

Hepatitis B virus (HBV) infection is a major risk factor for chronic liver diseases and liver cancer (mainly hepatocellular carcinoma, HCC), while the underlying mechanisms and host-virus interactions are still largely elusive.

Methods

We applied HiC sequencing to HepG2 (HBV-) and HepG2-2.2.15 (HBV+) cell lines and combined them with public HCC single-cell RNA-seq data, HCC bulk RNA-seq data, and both genomic and epigenomic ChIP-seq data to reveal potential disease mechanisms of HBV infection and host-virus interactions reflected by 3D genome organization.

Results

We found that HBV enhanced overall proximal chromatin interactions (CIs) of liver cells and primarily affected regional CIs on chromosomes 13, 14, 17, and 22. Interestingly, HBV altered the boundaries of many topologically associating domains (TADs), and genes nearby these boundaries showed functional enrichment in cell adhesion which may promote cancer metastasis. Moreover, A/B compartment analysis revealed dramatic changes on chromosomes 9, 13 and 21, with more B compartments (inactive or closed) shifting to A compartments (active or open). The A-to-B regions (closing) harbored enhancers enriched in the regulation of inflammatory responses, whereas B-to-A regions (opening) were enriched for transposable elements (TE). Furthermore, we identified large HBV-induced structural variations (SVs) that disrupted tumor suppressors, NLGN4Y and PROS1. Finally, we examined differentially expressed genes and TEs in single hepatocytes with or without HBV infection, by using single-cell RNA-seq data. Consistent with our HiC sequencing findings, two upregulated genes that promote HBV replication, HNF4A and NR5A2, were located in regions with HBV-enhanced CIs, and five TEs were located in HBV-activated regions. Therefore, HBV may promote liver diseases by affecting the human 3D genome structure.

Conclusion

Our work promotes mechanistic understanding of HBV infection and host-virus interactions related to liver diseases that affect billions of people worldwide. Our findings may also have implications for novel immunotherapeutic strategies targeting HBV infection.

Epidemiology of Virus Infection and Human Cancer

Seven viruses including the Epstein-Barr virus (EBV), hepatitis B virus (HBV), hepatitis C virus (HCV), Kaposi's sarcoma herpes virus (KSHV), human immunodeficiency virus, type-1 (HIV-1), human T cell lymphotrophic virus, type-1 (HTLV-1), and human papillomavirus (HPV) have been classified as Group 1 human carcinogens by the International Agency for Research on Cancer (IARC). The conclusions are based on the findings of epidemiological and mechanistic studies. EBV, HPV, HTLV-1, and KSHV are direct carcinogens; HBV and HCV are indirect carcinogens through chronic inflammation; and HIV-1 is an indirect carcinogen through immune suppression. Some viruses may cause more than one cancer, while some cancers may be caused by more than one virus. However, only a proportion of persons infected by these oncogenic viruses will develop specific cancers. A series of studies have been carried out to assess the viral, host, and environmental cofactors of EBV-associated nasopharyngeal carcinoma, HBV/HCV-associated hepatocellular carcinoma, and HPV-associated cervical carcinoma. Persistent infection, high viral load, and viral genotype are important risk predictors of these virus-caused cancers. Risk calculators incorporating host and viral risk predictors have been developed for the prediction of long-term risk of hepatocellular carcinoma, nasopharyngeal carcinoma and cervical cancer. These risk calculators are useful for the triage and clinical management of infected patients. Both clinical trials and national programs of immunization, antiviral therapy and screening have demonstrated a significant reduction in the incidence of cancers caused by HBV, HCV, and HPV. Future research on gene-gene and gene-environment interactions of oncogenic viruses and the human host using large-scale longitudinal studies with serial measurements of biosignatures are in urgent need.

A genetic variant in the promoter region of miR-877 is associated with an increased risk of hepatocellular carcinoma

INTRODUCTION

Genome wide association study has identified chromosome 6p21.33 as a risk locus of hepatocellular carcinoma (HCC). MiR-877 is located on this region, functioning as a tumor suppressor. The aim of this study was to investigate the association between rs1264440 in the promoter of miR-877 and HCC risk.

MATERIALS AND METHODS

A total of 352 HCC patients and 359 age, gender, ethnicity and living area matched controls were enrolled in this study. The rs1264440 was genotyped using the TaqMan allelic discrimination assay. MiR-877 expression in HCC tissues was examined using quantitative PCR.

RESULTS

After Adjustment for age, sex, smoking status, drinking status and HBsAg status, this study showed a significant association between the rs1264440 and HCC risk. Subjects with the rs1264440 TT genotype and T allele showed a 2.20- and 1.44-fold increased risk to develop HCC, respectively (TT vs. CC: 95% CI, 1.18-4.11, P=0.01;T vs. C: 95% CI, 1.07-1.94, P=0.02). The increased risk was also observed in smokers and nondrinkers subgroup. The rs1264440 TT carriers had lower levels of miR-877.

CONCLUSION

The rs1264440 in the promoter region of miR-877 may regulate miR-877 expression and serve as an independent biomarker for the risk of HCC.

Interleukin IL-1B gene polymorphism in Tunisian patients with chronic hepatitis B infection: Association with replication levels

Approaches based on association studies have proven useful in identifying genetic predictors for many diseases, including susceptibility to chronic hepatitis B. In this study we were interested by the IL-1B genetic variants that have been involved in the immune response and we analyzed their role in the susceptibility to develop chronic hepatitis B in the Tunisian population. IL-1B is a potent proinflammatory cytokine that plays an important role in inflammation of the liver. Polymorphic gene IL-1 (-511, +3954) was analyzed in a total of 476 individuals: 236 patients with chronic hepatitis B from different cities of Tunisia recruited in Pasteur Institute between January 2017 and December 2018 and 240 controls. Genomic DNA was obtained using the standard salting-out method and genotyping was performed by polymerase chain reaction (PCR)-restriction fragment length polymorphism. For -511C>T polymorphism a significant association was found between patients and controls when comparing the genotypic (P = 0.007; χ²  = 9.74 and odds ratio [OR] = 0.60; confidence interval [CI] = 0.41-0.89) and allelic (P = 0.001; χ²  = 10.60) frequencies. When the viral load was taken into account a highly significant difference was found (P = 9 × 10^-4 ; χ²  = 10.89). For +3954C>T polymorphism a significant association was found between patients and controls when comparing genotypic (P = 0.0058; χ²  = 7.60 and OR = 1.67; CI = 1.14-2.46) and allelic (P = 0.0029; χ²  = 8.81) frequencies. T allele can be used as a strong marker for hepatitis B virus disease for both polymorphisms.

Interaction analysis of miR-1275/IGF2BP1/IGF2BP3 with the susceptibility to hepatocellular carcinoma

Aim: The aim of this study was to investigate the association of miR-1275 rs16759, IGF2BP1 rs11079850 and IGF2BP3 rs34414305 with hepatocellular carcinoma (HCC) risk. Materials & methods: Genotyping of the rs16759 and rs11079850 was performed using a Taqman assay and genotyping of the rs34414305 was performed using PCR. Relative expression of miR-1275, IGF2BP1 and IGF2BP3 was examined using quantitative PCR. Results: Comparison of the rs16759GG, CG/GG and CC genotype showed an increased risk of HCC. When comparing G with C allele, a significantly increased risk of HCC was also found. The rs16759, rs11079850 and rs34414305 had combined the interactive effects on the carcinogenesis of HCC. Moreover, the rs34414305 Del/ATT-Del/Del carriers displayed lower levels of IGF2BP3. Conclusion: The rs16759, rs11079850 and rs34414305 may singly and interactively contribute to carcinogenesis of HCC.

Hepatocellular carcinoma surveillance: An evidence-based approach

Hepatocellular carcinoma (HCC) makes up 75%-85% of all primary liver cancers and is the fourth most common cause of cancer related death worldwide. Chronic liver disease is the most significant risk factor for HCC with 80%-90% of new cases occurring in the background of cirrhosis. Studies have shown that early diagnosis of HCC through surveillance programs improve prognosis and availability of curative therapies. All patients with cirrhosis and high-risk hepatitis B patients are at risk for HCC and should undergo surveillance. The recommended surveillance modality is abdominal ultrasound (US) given that it is cost effective and noninvasive with good sensitivity. However, US is limited in obese patients and those with non-alcoholic fatty liver disease (NAFLD). With the current obesity epidemic and rise in the prevalence of NAFLD, abdominal computed tomography or magnetic resonance imaging may be indicated as the primary screening modality in these patients. The addition of alpha-fetoprotein to a surveillance regimen is thought to improve the sensitivity of HCC detection. Further investigation of serum biomarkers is needed. Semiannual screening is the suggested surveillance interval. Surveillance for HCC is underutilized and low adherence disproportionately affects certain demographics such as non-Caucasian race and low socioeconomic status.

An indel polymorphism in the 3' untranslated region of JAK1 confers risk for hepatocellular carcinoma possibly by regulating JAK1 transcriptional activity in a Chinese population

The purpose of the present study was to assess whether the rs112395617 polymorphism located in the Janus kinase 1 (JAK1) 3' untranslated region (3' UTR) was associated with the risk of hepatocellular carcinoma (HCC), and to explore the potential mechanism of action. Genomic DNA was extracted from peripheral blood of 290 patients with HCC and 320 controls. A polymerase chain reaction-polyacrylamide gel electrophoresis assay was used to genotype the rs112395617 polymorphism. Quantitative (q)PCR was used to detect the genotype-phenotype association between HCC tissues and different genotypes. Vectors containing the insertion (ins)/ins or deletion (del)/del genotype of the rs112395617 polymorphism were constructed, and the luciferase assay was used to detect the JAK1 transcriptional activity affected by the rs112395617 polymorphism. It was identified that, when compared with the ins/ins genotype, the del/del and del/ins genotypes of rs112395617 were significantly associated with a decreased risk of HCC. The qPCR results demonstrated that the JAK1 mRNA expression level with ins/ins and ins/del genotypes was increased by 3.36 and 1.75-fold compared with the del/del genotype in human HCC tissue samples. In addition, the 'AATT' insertion allele of rs112395617 disrupted the binding site for microRNA (miR)-431-5p, thereby increasing JAK1 transcription in vitro. These data suggest that the rs112395617 polymorphism may contribute to HCC susceptibility, in full or at least partially through an effect on JAK1 transcriptional activity by disrupting its binding with miR-431-5p.

Genetic variants in IL-33/ST2 pathway with the susceptibility to hepatocellular carcinoma in a Chinese population

Interleukin (IL)-33/ST2 pathway plays a pivotal role in tumorigenesis through influencing cancer stemness, tumor growth, metastasis, angiogenesis, and accumulation of regulatory T cells in tumor microenvironments. The aim of this study was to investigate the association of IL-33 rs7025417 and ST2 rs3821204 with the risk of hepatocellular carcinoma (HCC). Genotyping of IL-33 rs7025417 and ST2 rs3821204 was carried out using a Taqman assay. IL-33 and ST2 mRNA was examined using real-time PCR and plasma IL-33 and sST2 levels were measured using enzyme-linked immunosorbent assay. The ST2 rs3821204 CC genotype was associated with a significantly increased risk of HCC (CC vs. GG: adjusted OR = 2.29, 95% CI, 1.39-3.78; dominant model: adjusted OR = 1.58, 95% CI, 1.12-2.23; recessive model: adjusted OR = 1.88, 95% CI, 1.21-2.93; C vs. G: adjusted OR = 1.53, 95% CI, 1.20-1.95). Gene-environment interaction analysis showed that the risk effect of rs3821204 CG/CC genotypes was more evident in smokers (adjusted OR = 1.70, 95% CI, 1.13-2.55) and drinkers (adjusted OR = 1.57, 95% CI, 1.04-2.37). The increased risk was also observed in combined analysis. Moreover, HCC patients with ST2 rs3821204 CC genotype had higher levels of mRNA and protein expression (P < 0.05). These findings suggest that ST2 rs3821204 CC genotype may contribute to hepatocarcinogenesis by enhancing ST2 production at the transcriptional and translational level.

The prognostic impacts of TEA domain (TEAD) transcription factor polymorphisms in Chinese hepatocellular carcinoma patients

TEA domain (TEAD) transcription factors play an important role in hepatocellular carcinoma (HCC) development and progression by regulating the expression of a number of genes. However, the association of their genetic variations with HCC prognosis remains elusive. Seven potentially functional single nucleotide polymorphisms in TEAD1-4 (rs2304733, rs10831923, rs12104362, rs3745305, rs11756089, rs2076173, rs7135838) were genotyped from 331 hepatitis B virus positive HCC patients using the Sequenom MassARRAY iPLEX platform. The TEAD3 rs2076173 C allele and rs11756089 T allele were identified as protective alleles as they were significantly associated with longer median overall survival time (MST). The T allele of rs2076173 was significantly associated with HCC survival independent of age, gender, smoking and drinking status, BCLC stage, and chemotherapy or TACE status (HR = 0.73, 95% CI = 0.56-0.93, P = 0.012). This protective effect was more prominent for patients who were non-drinkers (P for multiplicative interaction = 0.002). Patients had more than one of these protective alleles had significant longer MST of 19.25 months than those had none (MST=12.85 months, adjusted HR = 0.56, 95% CI = 0.33-0.95, P=0.030), especially for those non-drinkers (adjusted HR = 0.48, 95% CI = 0.32-0.74, P = 0.001). These findings suggested that rs2076173 and rs11756089 in TEAD3 gene could serve as genetic markers for favorable survival in the Chinese HCC patients.

BRIP1 coding variants are associated with a high risk of hepatocellular carcinoma occurrence in patients with HCV- or HBV-related liver disease

The molecular mechanisms of hepatocellular carcinoma (HCC) carcinogenesis are still not fully understood. DNA repair defects may influence HCC risk. The aim of the study was to look for potential genetic variants of DNA repair genes associated with HCC risk among patients with alcohol- or viral-induced liver disease. We performed four case-control studies on 2,006 European- (Derivation#1 and #2 studies) and African-ancestry (Validation#1 and #2 studies) patients originating from several cohorts in order to assess the association between genetic variants on DNA repair genes and HCC risk using a custom array encompassing 94 genes. In the Derivation#1 study, the BRIP1 locus reached array-wide significance (Chi-squared SV-Perm, P=5.00×10-4) among the 253 haplotype blocks tested for their association with HCC risk, in patients with viral cirrhosis but not among those with alcoholic cirrhosis. The BRIP1 haplotype block included three exonic variants (rs4986763, rs4986764, rs4986765). The BRIP1 'AAA' haplotype was significantly associated with an increased HCC risk [odds ratio (OR), 2.01 (1.19-3.39); false discovery rate (FDR)-P=1.31×10-2]. In the Derivation#2 study, results were confirmed for the BRIP1 'GGG' haplotype [OR, 0.53 (0.36-0.79); FDR-P=3.90×10-3]. In both Validation#1 and #2 studies, BRIP1 'AAA' haplotype was significantly associated with an increased risk of HCC [OR, 1.71 (1.09-2.68); FDR-P=7.30×10-2; and OR, 6.45 (4.17-9.99); FDR-P=2.33×10-19, respectively]. Association between the BRIP1 locus and HCC risk suggests that impaired DNA mismatch repair might play a role in liver carcinogenesis, among patients with HCV- or HBV-related liver disease.

Overexpression of the metastasis-associated gene MTA3 correlates with tumor progression and poor prognosis in hepatocellular carcinoma

BACKGROUND AND AIM

Hepatocellular carcinoma (HCC) is one of the most common and aggressive cancers in the world. However, there remains a lack of effective diagnostic and treatment markers. We aimed to explore metastasis-associated protein 3 (MTA3) expression and function in HCC and its relationship with clinicopathological factors.

METHODS

We investigated the expression pattern and clinicopathological significance of MTA3 in 90 patients with HCC via immunohistochemistry and explored MTA3 function via gene knockdown of MTA3.

RESULTS

MTA3 was overexpressed in HCC cell nuclei and downregulated in HCC cell cytoplasm. The former finding correlated with metastasis (P = 0.010) and poor prognosis (P = 0.018). In addition, deleting MTA3 inhibited HCC cell growth, invasion, and metastasis in vitro, as shown in the colony formation, migration, and wound-healing assays.

CONCLUSIONS

These results indicate that MTA3 is an oncogene of HCC, predicts poor prognosis of HCC, and may be a future marker of HCC treatment.

HBV suppresses thapsigargin-induced apoptosis via inhibiting CHOP expression in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) accounts for a proportion of cancer-associated mortalities worldwide. Hepatitis B virus (HBV) infection is a major cause of HCC in China. Thapsigargin (TG) is a potential antitumor prodrug, eliciting endoplasmic reticulum (ER) stress via the inhibition of the ER calcium pump, effectively inducing apoptosis. The present study therefore examined the role of HBV in TG-induced apoptosis using two HCC cell lines, HBV positive HepG2.2.15 and HBV negative HepG2. When these two cell lines were treated with TG, HepG2.2.15 was less susceptible to apoptosis than HepG2. This phenomenon was confirmed by an MTT assay and Annexin V-FITC/propidium iodide staining. Reverse transcription quantitative polymerase chain reaction and western blotting were used to detect the expression levels of genes in the ER stress pathway subsequent to treatment with TG. Notably, the mRNA and protein levels of the apoptosis factor DNA damage inducible transcript 3 (CHOP) increased significantly in the HepG2 cells compared with the HepG2.2.15 cells. Additionally, the HepG2.2.15 cells treated with interferon-α exhibited higher levels of CHOP compared with the untreated cells. The overexpression or knockdown of CHOP microRNA in HepG2.2.15 or HepG2 cells may reduce the difference in apoptosis status between the two cell lines. These results suggest that HBV may inhibit the apoptosis induced by ER stress. These findings may be useful in the development of selective therapies for patients with HBV-positive tumors.

Association of VEGFA polymorphisms with susceptibility and clinical outcome of hepatocellular carcinoma in a Chinese Han population

Vascular endothelial growth factor A (VEGFA) is an important angiogenesis regulator, which plays an important role in angiogenesis and progression of tumor, including hepatocellular carcinoma (HCC). We aimed at determining whether single nucleotide polymorphisms of VEGFA gene influence the development and clinical outcomes of HCC. We analyzed four potential functional polymorphisms (936C/T, 634G/C, 1612G/A, 2578C/A) of VEGFA gene in 476 HCC patients and 526 controls using matrix-assisted laser desorption ionization time-of-flight mass spectrometry method. Serum VEGF levels were measured by enzyme-linked immunosorbent assay. The Kaplan-Meier methods with log-rank test and Cox regression models were used to compare survival of resected HCC patients according to the genotype. We found that only the VEGFA 2578C/A polymorphism was significantly associated with decreased risk of HCC (AA/AC vs. CC; adjusted OR = 0.69, 95% CI = 0.51-0.93). Furthermore, the 2578C/A polymorphism was associated with significantly decreased postoperative recurrence (AA/AC vs. CC, adjusted OR = 0.51; 95% CI, 0.29-0.88) and improved overall survival (AA/AC vs. CC, adjusted HR = 0.27, 95% CI = 0.13-0.52) of resected HCC patients. In addition, the VEGF serum levels in HCC patients were significantly higher than those in healthy controls, although no significant association between VEGFA genotype and serum levels of VEGF was observed. These results suggest that the VEGFA 2578 C/A polymorphism may play a potential role in the development and clinical outcome of HCC among Chinese Han population.

The contribution of serum hepatitis B virus load in the carcinogenesis and prognosis of hepatocellular carcinoma: evidence from two meta-analyses

BACKGROUND AND AIM

The meta-analysis aimed to quantify and summarize the contribution of serum hepatitis B virus (HBV) DNA load in the carcinogenesis and prognosis of hepatocellular carcinoma (HCC).

RESULTS

Nine independent studies with a total of 1162 cases and 9365 participants on risk of HCC and seventeen studies with 1342 cases and 2891 participants on recurrence of HCC were finally included. The non-liner dose-response association between HBV DNA level and HCC risk was observed, with P value equal to 0.02 for linear test. Compared with 2 log10copies/ml HBV DNA level carriers, the summary relative risk of HCC were 1.65(95% CI: 0.94-2.92) for 4.5 log10copies/ml, 2.20(95% CI: 1.00-4.85) for 5.5 log10copies/ml, 3.06(95% CI: 1.11-8.44) for 6.5 log10copies/ml. Moreover, individuals with high viral load (HBV DNA levels > 105copies/ml) presented significant association with increased risk of HCC recurrence, with the pooled RR of 1.69 (95% CI: 1.49-1.92).

MATERIALS AND METHODS

Pertinent studies were identified by searching PubMed, Embase and ISI Web of science databases up to January 2016 and by reviewing the references of retrieved articles. The dose-response meta-analysis was precisely performed to calculate the summary relative risks (RRs) by quantizing the association between HBV load and risk of HCC. Besides, the contribution of HBV load on recurrence of HCC was further clarified by general meta-analysis.

CONCLUSIONS

These findings indicated a non-linear dose-response relationship between serum HBV DNA level and risk of HCC, and confirmed the significant contribution of serum HBV DNA level in the prognosis of HCC.

Nine susceptibility loci for hepatitis B virus-related hepatocellular carcinoma identified by a pilot two-stage genome-wide association study

Previous studies have indicated that complex interactions among viral, environmental and genetic factors lead to hepatocellular carcinoma (HCC). To identify susceptibility alleles for hepatitis B virus (HBV)-related HCC, the present study conducted a pilot two-phase genome-wide association study (GWAS) in 660 Han Chinese individuals. In phase 1, a total of 500,447 single-nucleotide polymorphisms (SNPs) were genotyped in 50 HCC cases and 50 controls using Affymetrix GeneChip 500k Array Set. In phase 2, 1,152 SNPs were selected from phase 1 and genotyped in 282 cases and 278 controls using the Illumina GoldenGate platform. The prior probability of HCC in control subjects was assigned at 0.01, and false-positive report probability (FPRP) was utilized to evaluate the statistical significance. In phase 1, one SNP (rs2212522) showed a significant association with HCC (Pallele=5.23×10-8; ORallele=4.96; 95% CI, 2.72-9.03). In phase 2, among 27 SNPs with unadjusted Pallele<0.05, 9 SNPs were associated with HCC based on FPRP criteria (FPRP <0.20). The strongest statistical evidence for an association signal was with rs2120243 (combined ORallele=1.76; 95% CI, 1.39-2.22; P=2.00×10-6), which maps within the fourth intron of VEPH1. The second strongest statistical evidence for an association was identified for rs1350171 (combined ORallele=1.66; 95% CI, 1.33-2.07; P=6.48×10-6), which maps to the region downstream of the FZD4 gene. The other potential susceptibility genes included PCDH9, PRMT6, LHX1, KIF2B and L3MBTL4. In conclusion, this pilot two-phase GWAS provides the evidence for the existence of common susceptibility loci for HCC. These genes involved various signaling pathways, including those associated with transforming growth factor β, insulin/phosphoinositide 3 kinase, Wnt and epidermal growth factor receptor. These associations must be replicated and validated in larger studies.

Genetic variations in STAT4,C2,HLA-DRB1 and HLA-DQ associated with risk of hepatitis B virus-related liver cirrhosis

Recent genome-wide associated studies (GWASs) have revealed several common loci associated with the risk of hepatitis B virus (HBV)- or hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC). We selected 15 single nucleotide polymorphisms (SNPs) identified through GWASs on HBV- or HCV-related HCC, and genotyped them in two independent Chinese cohorts of chronic HBV carriers, including 712 LC cases and 2601 controls. The association of each SNP with the risk of HBV-related LC was assessed by meta-analysis of the two cohorts. Of the 12 SNPs reported in HBV-related HCC GWASs, five SNPs (rs7574865 in STAT4, rs9267673 near C2, rs2647073 and rs3997872 near HLA-DRB1 and rs9275319 near HLA-DQ), were found to be significantly associated with the risk of HBV-related LC (rs7574865: P = 1.79 × 10(-2), OR = 1.17, 95% CI = 1.03-1.34; rs9267673: P = 4.91 × 10(-4), OR = 1.37, 95% CI = 1.15-1.63; rs2647073: P = 3.53 × 10(-5), OR = 1.63, 95% CI = 1.29-2.06; rs3997872: P = 4.22 × 10(-4), OR = 1.86, 95% CI = 1.32-2.62; rs9275319: P = 1.30 × 10(-2), OR = 1.32, 95% CI = 1.06-1.64). However, among the three SNPs associated with the risk of HCV-related HCC in previous GWASs, none of them showed significant association with the risk of HBV-related LC. Our results suggested that genetic variants associated with HBV-related hepatocarcinogenesis may already play an important role in the progression from CHB to LC.

Association between indel polymorphism in the promoter region of lncRNA GAS5 and the risk of hepatocellular carcinoma

The growth arrest special 5 (GAS5) is known to be involved in various cancers. However, its expression regulation remains unclear. Polymorphisms in the promoter region of GAS5 may affect its expression and be associated with cancer susceptibility. In this research, we first evaluated the association of a 5-base pair indel polymorphism (rs145204276) in the promoter region of GAS5 with hepatocelluar carcinoma (HCC) susceptibility in Chinese populations. Logistic regression analysis showed that the deletion allele of rs145204276 significantly increased the risk of HCC in two independent case control sets (1034 HCC and 1054 controls). Further genotype-phenotype association analysis revealed that the deletion allele was markedly correlated with higher expression of GAS5 in HCC tissues. The luciferase activity analysis in an in vitro reporter gene system suggested that the deletion allele improved an increased expression of GAS5 in three hepatoma cell lines. Intriguingly, overexpression of GAS5 displayed an anti-apoptosis effect in HCC cell lines, GAS5 knockdown could partially revert this anti-apoptosis effect, suggesting that GAS5 may act as a proto-oncogene in HCC, in contrast with its inhibitory role in other cancers. Further pyrosequencing revealed that the genotypes of rs145204276 were associated with methylation status of GAS5 promoter region. Taken together, our findings provided evidence that rs145204276 may contribute to hepatocarcinogenesis by affecting methylation status of the GAS5 promoter and subsequently its transcriptional activity thus serving as a potential therapy target for HCC.

Epigenetically silenced long noncoding-SRHC promotes proliferation of hepatocellular carcinoma

PURPOSE

To investigate the expression of SRHC and the role of SRHC in the pathogenesis of hepatocellular carcinoma (HCC).

METHODS

We analyzed HCC samples and matched non-tumor liver tissues (controls) collected from 81 patients who underwent hepatectomy in Shanghai, China. The expression levels of SRHC were determined by quantitative reverse-transcription polymerase chain reaction. Statistical analyses were used to associate the levels of SRHC with tumor features and patient outcomes.

RESULTS

We found that a lower SRHC expression level was significantly more frequent in tissues with a high serum a-fetoprotein level (positive, >20 µg/L, P = 0.004) and a low degree of differentiated tumors (poorly differentiated, P = 0.017). Furthermore, we found that the promoter region of SRHC contains a CpG-rich island and that SRHC is down-regulated in tumors by DNA methylation.

CONCLUSION

Here, we identified a new long noncoding RNA designated as SRHC that is capable of inhibiting cancer proliferation and is down-regulated in tumors at least partly by DNA methylation.

Genetic polymorphisms in antioxidant enzyme genes and susceptibility to hepatocellular carcinoma in Chinese population: a case-control study

An increased oxidant burden has been implicated in hepatocarcinogenesis, and several antioxidant enzymes counteract potential oxidative damage. So, polymorphisms in the genes encoding antioxidant enzymes may play an important role in the development of hepatocellular carcinoma (HCC). To test this hypothesis, we investigated the association of polymorphisms in antioxidant enzyme genes, including three superoxide dismutases (SODs), catalase (CAT), and glutathione peroxidase (GPx), with HCC in a Chinese population consisting of 434 HCC patients and 480 control subjects. Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Odds ratios (ORs) and 95 % confidence intervals (95 % CIs) were estimated by unconditional logistic regression. For the ECSOD Ala40Thr polymorphism, a significant association was observed between this polymorphism and HCC risk in non-hepatitis B virus (HBV) carriers but not in HBV carriers, and individuals with one 40Thr allele (Ala/Thr genotype) (OR = 2.13, 95 % CI = 1.25-3.64, P = 0.006) or at least one 40Thr allele (Ala/Thr and Thr/Thr genotype) (OR = 1.90, 95 % CI = 1.15-3.15, P = 0.012) showed significantly higher risk to HCC, compared with Ala/Ala genotype. No significant associations were observed between three other polymorphisms (MnSOD Ala16Val, CAT-262C/T, GPx Pro198Leu) and HCC susceptibility in both HBV carriers and non-HBV carriers. Furthermore, no other signs of combined effects, except for a combined effect of ECSOD Ala40Thr and MnSOD Val16Ala in non-HBV carriers, were observed for each combination of these four polymorphisms. In conclusion, our results indicate that the antioxidant enzyme gene polymorphisms at least partially contribute to the susceptibility to HCC.

Polymorphisms in microRNA target sites of forkhead box O genes are associated with hepatocellular carcinoma

The forkhead box O (FOXO) transcription factors play important roles in various cancer development including Hepatocellular Carcinoma (HCC). In this study we conducted a hospital-based case control study including 1049 cases (HCC patients) and 1052 controls (non-tumor patients) to examine whether single nucleotide polymorphisms (SNPs) within microRNA (miRNA) target sites of FOXO genes confer HCC susceptibility. A total of three miRNA target site SNPs in the 3’ untranslated regions (UTR) of FOXO1 (rs17592236), FOXO3 (rs4946936) and FOXO4 (rs4503258) were analyzed. No statistically significant differences were found in genotype distribution for rs17592236, rs4946936, and rs4503258 between the HCC patient group and the tumor-free control group using single factor chi-square analysis (P>0.05). However, multivariate logistic regression analysis showed that the CT/TT genotype in rs17592236 was significantly associated with decreased risk of HCC development (P = 0.010, OR = 0.699, 95% CI: 0.526–0.927) as compared to the CC genotype in rs17592236. Additionally, a genetic interaction was found between rs17592236 and rs4503258 (P = 0.003, OR = 0.755, 95% CI: 0.628–0.908). Functional dual luciferase reporter assays verified that the rs17592236 SNP was a target site of human miRNA miR-137. Together, these results indicate that the rs17592236 polymorphism is associated with decreasing of HCC hereditary susceptibility likely through modulating the binding affinity of miR-137 to the 3’UTR in FOXO1 messenger RNA (mRNA). Further knowledge obtained from this study may provide important evidence for the prevention and targeted therapy of HCC.

Variants identified by hepatocellular carcinoma and chronic hepatitis B virus infection susceptibility GWAS associated with survival in HBV-related hepatocellular carcinoma

Recent genome-wide association studies (GWAS) have identified several common susceptibility loci associated with the risk of hepatocellular carcinoma (HCC) or chronic hepatitis B infection (CHB). However, the relationship between these genetic variants and survival of patients with hepatitis B virus (HBV)-related HCC is still unknown. In this study, 22 single nucleotide polymorphisms (SNPs) were genotyped among 330 HBV-related HCC patients using the MassARRAY system from Sequenom. Cox proportional hazards regression was used to examine the effects of genotype on survival time under an additive model with age, sex, smoking status and clinical stage as covariates. We identified four SNPs on 6p21 (rs1419881 T>C, rs7453920 G>A,rs3997872 G>A and rs7768538 T>C), and two SNPs on 8p12 (rs2275959 C>T and rs7821974 C>T) significantly associated with survival time of HBV-related HCC patients. Our results suggest that HCC or CHB susceptibility loci might also affect the prognosis of patients with HBV-related HCC.

Incomplete hepatitis B immunization, maternal carrier status, and increased risk of liver diseases: a 20-year cohort study of 3.8 million vaccinees

Hepatitis B immunization has been documented to prevent fulminant hepatic failure (FHF) and hepatocellular carcinoma (HCC) by historical comparison studies in Taiwan. This study aimed to assess long-term risks and predictors of various liver diseases associated with incomplete immunization in 3.8 million vaccinees. Profiles of the National Hepatitis B Immunization Registry, National Cancer Registry, and National Death Certification Registry were linked to ascertain newly diagnosed cases of HCC and deaths from FHF and chronic liver diseases (CLDs) from infancy to early adulthood of 3,836,988 newborn vaccinees. Cox's proportional hazards models were used to estimate hazard ratios (HRs) for various risk predictors. There were 49 newly developed cases of HCC, 73 deaths from FHF, and 74 deaths from CLDs during the follow-up of 41,854,715 person-years. There were striking differences between unvaccinated and vaccinated newborns after the launch of a national immunization program for HCC incidence (0.293 vs. 0.117 per 100,000 person-years), FHF mortality (0.733 vs. 0.174 per 100,000 person-years), and CLD mortality (2.206 vs. 0.177 per 100,000 person-years). Among vaccinees, incomplete immunization was the most important risk predictor of HCC, FHF, and CLDs, showing an HR (95% confidence interval, P value) of 2.52 (1.25-5.05; P = 0.0094), 4.97 (3.05-8.11; P < 0.0001), and 6.27 (3.62-10.84; P < 0.0001), respectively, after adjustment for maternal hepatitis B serostatus.

CONCLUSION

Hepatitis B immunization can significantly prevent the long-term risk of HCC, FHF, and CLDs from infancy to early adulthood. Incomplete immunization with hepatitis B immunoglobulin or vaccines was the most important risk predictor of the liver disease among vaccinees.

A missense polymorphism in ATF6 gene is associated with susceptibility to hepatocellular carcinoma probably by altering ATF6 level

Accumulated evidences indicate that single nucleotide polymorphisms (SNP) are associated with risk of hepatocellular carcinoma (HCC). Activating transcription factor 6 (ATF6) is an important modulator of the unfolded protein response (UPR), which is regarded to be involved in carcinogenesis. So we speculate that SNPs in ATF6 may be associated with susceptibility to HCC. We carried out a two-stage association study in three independent case-control groups in a total of 1,082 chronic hepatitis B (CHB) patients and 816 hepatitis B virus (HBV) related HCC patients in Han Chinese. Four SNPs which can represent all potential functional SNPs with MAF > 0.1 recorded in HapMap database in ATF6 gene were genotyped using TaqMan methods. Functional analyses were conducted to verify the biological significances of the associated SNP. We identified a missense SNP (rs2070150) was significantly associated with susceptibility to HCC (p = 0.008, 0.001 and 0.007 in Beijing_302, Beijing_You'an and Guangxi samples, respectively). This SNP was further validated in four independent groups of major HBV outcomes, indicating it may associate exclusively to HCC. ATF6 mRNA expression was significantly decreased as the disease progressed (p <0.001). Functional analyses show that the protective allele of rs2070150 could significantly increase the expression levels of ATF6 mRNA, as well as ATF6 regulated genes such as GRP78, XBP1 and CHOP. These findings indicate that a common missense SNP in ATF6 may contribute to susceptibility of HCC functionally.

Allele-specific imbalance of oxidative stress-induced growth inhibitor 1 associates with progression of hepatocellular carcinoma

BACKGROUND & AIMS

Although there are a few highly penetrant mutations that are linked directly to cancer initiation, more less-penetrant susceptibility alleles have been associated with cancer risk and progression. We used RNA sequence analysis to search for genetic variations associated with pathogenesis of hepatocellular carcinoma (HCC).

METHODS

We analyzed 400 paired HCC and adjacent nontumor tissues, along with clinical information, from patients who underwent surgery at Sun Yat-Sen University in Guangzhou, China. Total RNA was extracted from tissues and sequenced, and variations with allele imbalance were identified. Effects of variants on cell functions were investigated in HCC cell lines and tumor xenografts in mice. Variants were associated with patient outcomes.

RESULTS

We found a high proportion of allele imbalance in genes related to cellular stress. A nucleotide variation in the Oxidative Stress-Induced Growth Inhibitor 1 (OSGIN1) gene (nt 1494: G-A) resulted in an amino acid substitution (codon 438: Arg-His). The variant form of OSGIN1 was specifically retained in the tumor tissues. Functional assays showed that the common form of OSGIN1 functioned as a tumor suppressor, sensitizing HCC cells to chemotherapeutic agents by inducing apoptosis. However, the variant form of OSGIN1 was less effective. It appeared to affect the translocation of OSGIN1 from the nucleus to mitochondria, which is important for its apoptotic function. The expression pattern and localization of OSGIN1 was altered in HCC specimens, compared with adjacent liver tissue. Levels of OSGIN1 messenger RNA were reduced in 24.7% of HCC specimens, and down-regulation was associated with shorter overall and disease-free survival times of patients. Patients with the OSGIN1 1494A variant had the shortest mean survival time (32.68 mo) among patient subgroups, and their tumor samples had the lowest apoptotic index.

CONCLUSIONS

We identified OSGIN1 as a tumor suppressor that is down-regulated or altered in human HCCs. Variants of OSGIN1 detected in HCC samples reduce apoptosis and are associated with shorter survival times of patients.

Cyclin D1 G870A polymorphism and the risk of hepatocellular carcinoma in a Chinese population

Cyclin D1, encoded by the gene CCND1, is a regulatory protein in the cell cycle transition from G1 phase to S phase. A common polymorphism (G870A) in the exon 4 of CCND1 gene affects splicing of the CCND1 transcript and may cause uncontrollable cellular growth. Therefore, the CCND1 G870A polymorphism may influence an individual's susceptibility to the development of certain tumors. The present study was performed to test the association between G870A polymorphism in the CCND1 gene and hepatocellular carcinoma (HCC) risk in a Chinese population. We extracted the peripheral blood samples from 220 patients with HCC and 220 age- and gender-matched healthy controls. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis and direct DNA sequencing were performed to detect the polymorphism. The CCND1 genotype distribution among HCC patients was not significantly different from that among healthy controls (P=0.08). Compared with the wild-type GG genotype, neither the variant AA genotype nor the variant genotypes containing the A allele were associated with risk of HCC. However, stratification analysis by HBV carrier status revealed that the variant genotypes containing the A allele were associated with a significantly increased risk of HCC among HBsAg-positive individuals (adjusted OR=3.87; 95 % CI=1.12, 13.30). These results suggest that the CCND1 G870A polymorphism may increase the risk of HBV-related HCC in the Chinese population.

Epidemiology of virus infection and human cancer

The International Agency for Research on Cancer (IARC) has comprehensively assessed the human carcinogenicity of biological agents. Seven viruses including Epstein-Barr virus (EBV), hepatitis B virus (HBV), hepatitis C virus (HCV), Kaposi's sarcoma herpes virus (KSHV), human immunodeficiency virus, type-1 (HIV-1), human T cell lymphotrophic virus, type-1 (HTLV-1), and human papillomavirus (HPV) have been classified as Group 1 human carcinogens by IARC. The conclusions are based on the findings of epidemiological and mechanistic studies. EBV, HPV, HTLV-1, and KSHV are direct carcinogens; HBV and HCV are indirect carcinogens through chronic inflammation; HIV-1 is an indirect carcinogen through immune suppression. Some viruses may cause more than one cancer, while some cancers may be caused by more than one virus. However, only a proportion of persons infected by these oncogenic viruses will develop specific cancers. A series of studies have been carried out to assess the viral, host, and environmental cofactors of EBV-associated nasopharyngeal carcinoma, HBV/HCV-associated hepatocellular carcinoma, and HPV-associated cervical carcinoma. Persistent infection and high viral load are important risk predictors of these virus-caused cancers. Risk calculators incorporating host and viral factors have also been developed for the prediction of long-term risk of hepatocellular carcinoma. These risk calculators are useful for the triage and clinical management of infected patients. Both clinical trials and national programs of immunization or antiviral therapy have demonstrated a significant reduction in the incidence of cancers caused by HBV, HCV, and HPV. Future researches on gene-gene and gene-environment interaction of oncogenic viruses and human host are in urgent need.

A novel tetranucleotide repeat polymorphism within KCNQ1OT1 confers risk for hepatocellular carcinoma

KCNQ1 overlapping transcript 1 (KCNQ1OT1), a long noncoding RNA responsible for silencing a cluster of genes in cis, has been shown to be involved in multiple cancers. However, much remains unclear of how KCNQ1OT1 contributes to carcinogenesis. By thoroughly analyzing 510 hepatocellular carcinoma (HCC) cases and 1014 healthy controls in a Chinese population, we identified a novel short tandem repeat (STR) polymorphism (rs35622507) within the KCNQ1OT1 coding region and evaluated its association with HCC susceptibility. Logistic regression analysis showed that compared with individuals carrying the homozygote 10-10 genotype, those heterozygote subjects who carry only one allele 10 had a significantly decreased risk of HCC (adjusted odds ratio [OR]=0.67, 95% confidence interval [CI]=0.53-0.86, p=0.0009), with the risk decreased even further in those without allele 10 (adjusted OR=0.38, 95% CI=0.21-0.69, p=0.0005). Furthermore, genotype-phenotype correlation studies using four hepatoma cell lines support a significant association between STR genotypes and the expression of KCNQ1OT1. Cell lines without allele 10 conferred a 20.9-33.3-fold higher expression of KCNQ1OT1. Meanwhile, KCNQ1OT1 expression was reversely correlated with the expression of the cyclin-dependent kinase inhibitor 1C (CDKN1C), a tumor suppressor gene located within the CDKN1C/KCNQ1OT1 imprinted region, in three hepatoma cell lines. Finally, in silico prediction suggested that different alleles could alter the local structure of KCNQ1OT1. Taken together, our findings suggest that the STR polymorphism within KCNQ1OT1 contributes to hepatocarcinogenesis, possibly by affecting KCNQ1OT1 and CDKN1C expression through a structure-dependent mechanism. The replication of our studies and further functional studies are needed to validate our hypothesis and understand the roles of KCNQ1OT1 polymorphisms in predisposition for HCC.

Association between an insertion/deletion polymorphism within 3'UTR of SGSM3 and risk of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary hepatic malignancy, and multiple host genetic factors are believed to contribute to HCC development. The small G protein signaling modulator 3 (SGSM3) has been shown to be associated with small G protein coupled receptor signal transduction pathway, suggesting a potential role in HCC susceptibility. We carried out a case-control study in a Chinese population (502 cases and 513 controls) to determine whether the 4-bp insertion/deletion polymorphism (rs56228771) in 3' untranslated region of SGSM3 could affect HCC susceptibility. Logistic regression analysis showed that compared with the del/del genotype, the ins/del genotype of rs56228771 was associated with a significantly decreased risk of HCC [adjusted odd ratio = 0.55, 95% confidence interval (CI) = 0.42-0.73, P = 1.93 × 10(-5)]. The combined ins/del + ins/ins genotypes contributed to a 45% decreased HCC risk (95% CI = 0.42-0.73, P = 1.03 × 10(-5)). This protective trend was more prominent in the HBsAg-negative subgroup. Furthermore, in vivo experiments showed that mRNA levels of SGSM3 from HCC tumor tissues and adjacent non-HCC tissues were correlated with rs56228771 genotypes. Tissue samples with ins/ins genotype have the highest level of SGSM3, which are 2.85-3.00-fold and 1.46-1.57-fold higher than that with ins/del and del/del genotype, respectively. Similar results were also observed with four common hepatoma cell lines in vitro. In addition, compared with HCC tissues, significantly higher SGSM3 expression was observed in adjacent non-HCC tissues (fold change = 2.48), implying its tumor suppressor roles in HCC. Bioinformatics prediction showed that the insertion allele disrupted a binding site for microRNA (miRNA)-151-5p, which would upregulate SGSM3. Taken together, we provided initial evidence that rs56228771 may contribute to hepatocarcinogenesis, possibly by affecting SGSM3 expression through a miRNA-mediated regulation. The replication of our studies in other populations and functional analysis will further strengthen the underlining mechanism.

Promoter polymorphisms of DNA methyltransferase 3B and risk of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common solid tumors worldwide. Epigenetic changes in gene expression, including DNA methylation and histone modifications, may contribute to the development of HCC. Polymorphisms of the DNA methyltransferase 3B (DNMT3B) gene may affect the activity of this enzyme and increase the susceptibility to several types of cancer, including HCC. To confirm this hypothesis, we investigated the association between single-nucleotide polymorphisms-149C>T (rs2424913) and -579G>T (rs1569686) in the promoter region of DNMT3B and the risk of HCC. DNMT single-nucleotide polymorphisms (SNPs) were genotyped by polymerase chain reaction-restriction fragment length polymorphism in 108 HCC patients and 240 healthy controls matched for age, gender and ethnicity. The DNMT3B-149 TT genotype was not significantly associated with an increased risk of HCC. The frequency of DNMT3B-149C was 0.46% in HCC patients and 1.39% in healthy individuals, whereas the frequency of DNMT3B-579G was 8.33% in HCC patients and 10.42% in healthy individuals. No significant differences were observed in the genotype or allelic distribution between HCC patients and controls. In conclusion, DNMT3B-149C>T and -579G>T polymorphisms are not significantly associated with an increased risk of HCC. These results demonstrated that these particular SNPs may not be used as biomarkers to predict susceptibility to HCC.

Insertion/deletion polymorphisms in the promoter region of BRM contribute to risk of hepatocellular carcinoma in Chinese populations

BACKGROUND

BRM (Brahma homologue) is well known for its critical role in tumor suppression and cancer development. Genetic variations in the promoter region of BRM have been suggested to be associated with loss of BRM expression and lung cancer risk. To the authors' knowledge, no study on the role of BRM genetic polymorphisms in hepatocellular carcinoma (HCC) risk has been performed.

METHODOLOGY/PRINCIPAL FINDINGS

In two independent case-control studies containing 796 HCC cases and 806 cancer-free individuals, we genotyped two putative functional insertion/deletion (indel) polymorphisms [BRM-1321 (rs3832613) and BRM-741 (rs34480940)] within promoter region of BRM in Chinese populations using a PCR-based method. Real-time RT-PCR analysis was used to explore the genotype-phenotype correlation between these polymorphisms and BRM expression in both tissue samples and HCC cell lines. Logistic regression analysis showed that compared to BRM-1321del/del genotype, the ins/del and ins/ins variant genotypes had an increased HCC risk [adjusted odds ratio (OR) = 1.47, 95% confidence interval (CI) = 1.19-1.82; adjusted OR = 2.55, 95% CI = 1.75-3.72, respectively]. No significant association between BRM-741 and HCC incidence was observed. However, stratification analysis revealed a significant association between ins/ins genotype of BRM-741 and increased HCC susceptibility in smokers (adjusted OR = 2.07, 95% CI = 1.33-3.22). Quantitative PCR analyses demonstrated that the genotypes of BRM-1321 and the corresponding haplotypes were significantly correlated with BRM expression in vivo. Compared with ins/ins genotype, subjects carrying ins/del and del/del genotype had 2.30 and 4.99 fold higher BRM expression in HCC tissue samples, respectively. Similar trends were observed in western blot analysis at protein level.

CONCLUSIONS/SIGNIFICANCE

Our findings suggest that BRM promoter polymorphism (BRM-1321) could regulate BRM expression and may serve as a potential marker for genetic susceptibility to HCC.

An insertion/deletion polymorphism within RERT-lncRNA modulates hepatocellular carcinoma risk

The Prolyl hydroxylase 1 (EGLN2) is known to affect tumorigenesis by regulating the degradation of hypoxia-inducible factor. Polymorphisms in EGLN2 may facilitate cancer cell survival under hypoxic conditions and directly associate with cancer susceptibility. Here, we examined the contribution of a 4-bp insertion/deletion polymorphism (rs10680577) within the distal promoter of EGLN2 to the risk of hepatocelluar carcinoma (HCC) in Chinese populations. The contribution of rs10680577 to HCC risk was investigated in 623 HCC cases and 1,242 controls and replicated in an independent case-control study consisting of 444 HCC cases and 450 controls. Logistic regression analysis showed that the deletion allele of rs10680577 was significantly associated with increased risk for HCC occurrence in both case-control studies [OR = 1.40; 95% confidence interval (CI) = 1.18-1.66, P < 0.0001; OR = 1.49; 95% CI = 1.18-1.88, P = 0.0007]. Such positive association was more pronounced in current smokers (OR = 3.49, 95% CI = 2.24-5.45) than nonsmokers (OR = 1.24, 95% CI = 1.03-1.50; heterogeneity P = 0.0002). Genotype-phenotype correlation studies showed that the deletion allele was significantly correlated with higher expression of both EGLN2 and RERT-lncRNA [a long noncoding RNA whose sequence overlaps with Ras-related GTP-binding protein 4b (RAB4B) and EGLN2)] in vivo and in vitro. Furthermore, RERT-lncRNA expression was also significantly correlated with EGLN2 expression in vivo, consistent with in vitro gain-of-function study that showed overexpressing RERT-lncRNA upregulated EGLN2. Finally, in silico prediction suggested that the insertion allele could disrupt the structure of RERT-lncRNA. Taken together, our findings provided strong evidence for the hypothesis that rs10680577 contributes to hepatocarcinogenesis, possibly by affecting RERT-lncRNA structure and subsequently EGLN2 expression, making it a promising biomarker for early diagnosis of HCC.

Genetic variants of p21 and p27 and hepatocellular cancer risk in a Chinese Han population: a case-control study

The p21 (Cip1/CDKN1A) and p27 (Kip1/CDKN1B) are members of the Cip/Kip family of cyclin-dependent kinase inhibitors, which can arrest cell proliferation and serve as tumour suppressors. We hypothesized that genetic variants in p21 and p27 may modify individual susceptibility to hepatocellular carcinoma (HCC). To test this hypothesis, we evaluated the associations of the polymorphisms of Ser31Arg and C+20T in p21 and C-79T and Gly109Val in p27, as well as their combinations, with HCC risk in a case-control study of 476 HCC cases and 526 cancer-free controls in a Chinese population. The matrix-assisted laser desorption ionisation time-of-flight (MALDI-TOF) mass spectrometry method was performed to detect these polymorphisms. We found that the variant genotypes of p21 Ser31Arg and p27 C-79T were individually associated with a significantly increased risk of HCC, but no associations were observed for other variant genotypes. Moreover, the combined variant genotypes of the four loci were associated with a significantly increased HCC risk (adjusted OR = 2.24, 95% CI = 1.72, 2.91 among subjects carrying 3 or more variant alleles), especially among HbsAg-positive individuals (adjusted OR = 3.09, 95% CI = 1.86, 5.14). Furthermore, the combined variant genotypes of the four loci (carrying three or more variant alleles) increased a 1.93-fold (95% CI = 1.20, 3.09) and 1.76-fold (95% CI = 1.17, 2.64) risk of HCC among smokers and nonsmokers. The variant genotypes of the two genes in this study have negative correlation with the clinicopathologicals observed. These results suggest that p21 polymorphisms individually or in combination with p27 polymorphisms increases risk of HCC, particularly among HbsAg-positive individuals.

Soluble MICA and a MICA variation as possible prognostic biomarkers for HBV-induced hepatocellular carcinoma

MHC class I polypeptide-related chain A (MICA) molecule is induced in response to viral infection and various types of stress. We recently reported that a single nucleotide polymorphism (SNP) rs2596542 located in the MICA promoter region was significantly associated with the risk for hepatitis C virus (HCV)-induced hepatocellular carcinoma (HCC) and also with serum levels of soluble MICA (sMICA). In this study, we focused on the possible involvement of MICA in liver carcinogenesis related to hepatitis B virus (HBV) infection and examined correlation between the MICA polymorphism and the serum sMICA levels in HBV-induced HCC patients. The genetic association analysis revealed a nominal association with an SNP rs2596542; a G allele was considered to increase the risk of HBV-induced HCC (P = 0.029 with odds ratio of 1.19). We also found a significant elevation of sMICA in HBV-induced HCC cases. Moreover, a G allele of SNP rs2596542 was significantly associated with increased sMICA levels (P = 0.009). Interestingly, HCC patients with the high serum level of sMICA (>5 pg/ml) exhibited poorer prognosis than those with the low serum level of sMICA (≤5 pg/ml) (P = 0.008). Thus, our results highlight the importance of MICA genetic variations and the significance of sMICA as a predictive biomarker for HBV-induced HCC.

MDM2 SNP309T>G polymorphism increases susceptibility to hepatitis B virus-related hepatocellular carcinoma in a northeast Han Chinese population

BACKGROUND AND AIMS

The murine double minute 2 (MDM2) gene encodes a negative regulator of the tumour protein p53. A single nucleotide polymorphism (SNP) in MDM2 promoter, SNP309 T > G, has been showed to influence MDM2 protein expression and accelerate tumour formation. To investigate further the role of this locus, we examined the association of the SNP with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) in a northeast Han Chinese population.

METHODS

MDM2 SNP309 was genotyped in 310 HBV-related HCC patients, 314 non-HCC subjects with HBV infection and 480 healthy controls by using a PCR-RFLP method.

RESULTS

Significant differences of MDM2 SNP309 were detected between HBV-related HCC patients and healthy controls (OR 1.729, 95%CI 1.369-2.183, P < 0.0001) or non-HCC subjects with HBV infection (OR 1.351, 95% CI 1.060-1.722, P = 0.015) by a logistic regression analysis. Our data also revealed that subjects with the G allele had higher HBV-related HCC susceptibility than those with the T allele in various genetic models. In a meta-analysis, where we pooled our data with other published studies, the association between this loci and the disease was further confirmed (pooled OR 1.54, 95% CI 1.37-1.72, P < 0.0001).

CONCLUSIONS

These results suggested that the MDM2 SNP309 might influence the risk of developing HBV-related HCC in a northeast Han Chinese population.

Fifteen-year population attributable fractions and causal pies of risk factors for newly developed hepatocellular carcinomas in 11,801 men in Taiwan

Development of hepatocellular carcinoma (HCC) is a multi-factorial process. Chronic infections with hepatitis B virus (HBV) and hepatitis C virus (HCV) are important risk factors of HCC. Host factors, such as alcohol drinking, may also play a role. This study aims to provide a synthesis view on the development of HCC by examining multiple risk factors jointly and collectively. Causal-pie modeling technique was applied to analyze a cohort of 11,801 male residents (followed up for 15 years) in Taiwan, during which a total of 298 incident HCC cases were ascertained. The rate ratios adjusted by age were further modeled by an additive Poisson regression. Population attributable fractions (PAFs) and causal-pie weights (CPWs) were calculated. A PAF indicates the magnitude of case-load reduction under a particular intervention scenario, whereas a CPW for a particular class of causal pies represents the proportion of HCC cases attributable to that class. Using PAF we observed a chance to reduce around 60% HCC risk moving from no HBV-related intervention to the total elimination of the virus. An additional ∼15% (or ∼5%) reduction can be expected, if the HBV-related intervention is coupled with an HCV-related intervention (or an anti-drinking campaign). Eight classes of causal pies were found to be significant, including four dose-response classes of HBV (total CPW=52.7%), one independent-effect class of HCV (CPW=14.4%), one HBV-alcohol interaction class (CPW=4.2%), one HBV-HCV interaction class (CPW=1.7%), and one all-unknown class (CPW=27.0%). Causal-pie modeling for HCC helps clarify the relative importance of each viral and host factor, as well as their interactions.

A 3' UTR SNP in COL18A1 is associated with susceptibility to HBV related hepatocellular carcinoma in Chinese: three independent case-control studies

Background

Accumulated evidences indicate that single nucleotide polymorphisms (SNP) in angiogenesis and tumorigenesis related genes are associated with risk of Hepatocellular carcinoma (HCC). COL18A1 encodes the precursor of endostatin, which is a broad-spectrum angiogenesis inhibitor, and we speculate that SNPs in COL18A1 may be associated with susceptibility to HCC.

Methods and Findings

We carried out a 2-stage association study in 3 independent case-control groups in a total of 1067 chronic hepatitis B (CHB) patients and 808 hepatitis B virus (HBV) related HCC patients in Han Chinese. Four SNPs which can represent all potential functional SNPs with MAF>0.1 recorded in HapMap database were genotyped using TaqMan methods. Levels of total COL18A1 mRNA were also examined using quantitative real-time RT-PCR. We found that rs7499 located in 3′-UTR to be strongly associated with HBV related HCC (P_combined = 0.0000005, OR = 0.72, 95%CI = 0.63–0.82). COL18A1 mRNA expression was significantly decreased as the disease progressed (P = 0.000026).

Conclusion

These findings indicate that COL18A1 rs7499 may contribute to the risk of HCC in Han Chinese.

Polymorphisms in the potential functional regions of the TGF-β 1 and TGF-β receptor genes and disease susceptibility in HBV-related hepatocellular carcinoma patients

Hepatocellular carcinoma (HCC) is a disease of multiple etiologies caused by the accumulation of genetic and epigenetic defects. Current evidence indicates that the transforming growth factor beta (TGF-β) signaling pathway has a significant impact on different cellular process. Members of the TGF-β superfamily (TGF-β1, the type I TGF-β receptor [TβRI], type II TGF-β receptor [TβRII], and type III TGF-β receptor]) play an important role in tumorigenesis. Numerous studies show that genetic polymorphisms in TGF-β superfamily genes are associated with HCC in East Asian populations. We studied 16 single nucleotide polymorphisms (SNPs) in four genes (TGF-β1, TβRI, TβRII, and TβRIII) to examine their associations with hepatocarcinogenesis. A total of 1228 Chinese Han participants were enrolled in the study (881 control participants who were negative for all hepatitis B virus [HBV] serum markers and 347 case participants with HBV-related HCC). Genotyping was conducted using the TaqMan method. The results showed that the frequency of the rs1805110 T allele was significantly higher in the case group than in the control group (P = 0.034). After stratification, the results for rs1805110 remained significant in male participants (P = 0.005), but there was no statistical difference in females. In males, the frequency of the C-C-G-C-A haplotype resulting from SNPs rs1805110, rs2810904, rs1805112, rs284878, and rs1804506 in TβRIII was significantly lower in the case group than in the control group (P = 0.001), whereas the reverse was true for the T-C-G-C-A haplotype (P = 0.036). We conclude that the rs1805110T allele is associated with susceptibility to HBV-related HCC in males.

High hepatitis B virus load is associated with hepatocellular carcinomas development in Chinese chronic hepatitis B patients: a case control study

Background

Persistent hepatitis B virus (HBV) infection is a risk factor for hepatocellular carcinoma (HCC) development. This study aimed to clarify whether the high HBV DNA level is associated with HCC development by comparing HBV DNA levels between HBV infected patients with and without HCC.

Results

There were 78 male and 12 female patients in each group and there was no statistical difference between these two group patients' average ages. The HBV DNA level in the HCC patients was 4.73 ± 1.71 Log₁₀ IU/ml while 3.90 ± 2.01 Log₁₀ IU/ml in non-HCC patients (P < 0.01). The HBeAg positive rate was 42.2% (38/90) in the HCC group while 13.3% (12/90) in the non-HCC group (P < 0.001). Compared with patients with HBV DNA level of < 3 Log₁₀ IU/ml, the patients with level of 3 to < 4, 4 to < 5, 5 to < 6, or ≥ 6 Log₁₀ IU/ml had the odds ratio for HCC of 1.380 (95% CI, 0.544-3.499), 3.671 (95% CI, 1.363-9.886), 5.303 (95% CI, 1.847-15.277) or 3.030 (95% CI, 1.143-8.036), respectively.

Conclusions

HBV-related HCC patients had higher HBV DNA level than non-HCC counterparts. Our findings imply that active HBV replication is associated with the HCC development.

An insertion/deletion polymorphism in the 3' untranslated region of type I collagen a2 (COL1A2) is associated with susceptibility for hepatocellular carcinoma in a Chinese population

Hepatocellular carcinoma (HCC) is one of the most common and severe diseases in the world. Besides the influence of environmental factors, such as viral infection, an increasing number of novel genetic components identified by genome-wide association studies have been associated with predisposition to HCC. Thus, studies focusing on functional variants in these findings are indispensable. In the present study, based on in-silico analysis, we carried out a case-control study in a Chinese population (207 cases and 245 controls) to investigate the association between HCC susceptibility with a 7 base pair (bp) insertion/deletion polymorphism (rs3917) in the 3'UTR of COL1A2. Our results showed that the ins/del + del/del genotype had an odds ratio of 1.76 (95% C.I.=1.03-3.01; P=0.028) for developing HCC compared to the ins/ins genotype. Carriers for the "del" allele of rs3917 were associated with a 1.73-fold increased risk for HCC (95% C.I.=1.06-2.84; P(trend)=0.02). Computational modeling suggests that this polymorphism is located in the hsa-let-7 g potential target sequence in the COL1A2 3' untranslated region. Our data suggest that most likely, common genetic changes in COL1A2 may influence HCC risk, at least in part by let-7 g-mediated regulation, which is possibly involved in the pathogenesis of HCC. The replication of our studies in other populations will further strengthen our understanding of this association.

Evaluation of the association studies of single nucleotide polymorphisms and hepatocellular carcinoma: a systematic review

PURPOSE

For decades of years, hundreds of candidate gene-based association studies explored the relationship between single nucleotide polymorphisms (SNPs) and hepatocellular carcinoma (HCC). There was no systematic review summarized the results of these association studies of candidate SNPs and HCC to date. In order to summarize the results of the association studies, we conducted a concise systematic review.

METHODS

By searching Pubmed database before October 2010, we reviewed all the association studies about candidate SNPs and HCC. If the eligible study number on a given SNP was more than three, we conducted a meta-analysis. We reported here only the overall positive-association results with statistical significance and evaluated the reliability of the associations by using false-positive report probability (FPRP) analysis and the Venice guidelines on genetic epidemiology studies.

RESULTS

Six SNPs of five genes (rs1800562 of HFE, rs17868323 and rs11692021 of UGT1A7, rs2279744 of MDM2, rs1143627 of IL-1B, and rs4880 of MnSOD) showed overall significant associations with HCC. The eligible number of the studies varied from three to nine. Two SNPs (rs1800562 of HFE and rs2279744 of MDM2) passed the FPRP threshold (FPRP < 0.20). According to the Venice guidelines, the associations between the two SNPs (rs1800562 and rs2279744) and HCC were of moderate evidence.

CONCLUSIONS

Two SNPs (rs1800562 of HFE and rs2279744 of MDM2) were associated with HCC with moderate epidemiological evidence and deserve further study and additional biological and clinical assessment.

Natural history of chronic hepatitis B REVEALed

Chronic hepatitis B is a worldwide public health challenge. Knowledge of natural history of chronic hepatitis B is important for the management of the disease. A community-based prospective cohort study was carried out to evaluate the risk predictors of progression of chronic hepatitis B in Taiwan. A total of 23,820 participants were enrolled in 1991-1992 from seven townships in Taiwan. Their serum samples were collected at study entry and tested for hepatitis B surface antigen (HBsAg) and e antigen (HBeAg), antibodies against hepatitis C virus (anti-HCV), alanine aminotransferase (ALT), and α-fetoprotein (AFP). A subcohort of 3653 male and female participants who were seropositive for HBsAg and seronegative for anti-HCV was included in the Risk Evaluation of Viral Load Elevation and Associated Liver Disease/Cancer-Hepatitis B Virus (REVEAL-HBV) study. Newly developed cases of cirrhosis and hepatocellular carcinoma (HCC) were ascertained through follow-up examination and data linkage with profiles of the National Cancer Registry, National Health Insurance Database and Death Certification System. The incidence of both HCC and cirrhosis were significantly associated with serum HBV DNA levels in a dose-response relationship from <300 (undetectable) to ≥1,000,000 copies/mL. The biological gradients remained significant (P<0.001) after adjustment for age, sex, habits of cigarette smoking and alcohol drinking, HBeAg serostatus, and serum ALT level at cohort entry. A significant association with risk of cirrhosis and HCC was also observed for HBV genotype, precore G1896A mutant and basal core promoter A1762T/G1764A double mutant. Nomograms have been developed for the long-term risk prediction of cirrhosis and HCC for patients with chronic hepatitis B. Inactive carriers of HBV have an increased HCC incidence and liver-related mortality than HBsAg-seronegative controls. Serum HBV DNA level at study entry is a major predictor of spontaneous seroclearance of HBeAg, HBV DNA and HBsAg. These findings may inform the effective and efficient management of chronic hepatitis B.