MDM2 SNP309T>G polymorphism with hepatocellular carcinoma risk: a meta-analysis

Systematic analyses and comprehensive field synopsis of genetic association studies in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancy in the world. In order to comprehensively examine the association between genetic variants and risk of HCC, a systematic literature search and meta-analyses of the evidences have been performed. With the data from 301 articles, we conducted meta-analyses for 69 polymorphisms involving 46 distinct genes. The result showed that 31 polymorphisms in 25 genes are significantly associated with HCC risk. Cumulative epidemiological evidence for a significant association with HCC risk was graded strong for one polymorphism (NQO1 rs1800566). Furthermore, we provided a database to integrate and analyze the association of genetic variants and HCC risk. To the best of our knowledge, this is the first comprehensive field synopsis and systematic meta-analysis of genetic association with HCC risk. We have provided a useful resource and platform for investigators to explore the association of sequence polymorphisms and HCC risk.

Association of rs2279744 and rs117039649 promoter polymorphism with the risk of gynecological cancer: A meta-analysis of case-control studies

BACKGROUND

Increasing evidence has suggested that rs2279744 is associated with rs117039649 polymorphism, which can increase the risk of gynecological cancers, including cervical, ovarian, breast, and endometrial cancer. The results are inconsistent so that we performed a meta-analysis of current literature to clarify the impacts of these polymorphisms on gynecological cancer.

METHODS

Eligible articles were identified through an exhaustive search of relevant databases including PubMed, Embase, Web of science, Springer Link, Chinese National Knowledge Infrastructure (CNKI), and Weipu database for the period up to July 2016. Data about the association between single nucleotide polymorphisms (SNPs) and cancer risk were refined from the selected articles as well as other information about cases and controls, and all of them were extracted by 2 independent researchers and pooled odds ratio with 95% confidence interval was calculated.

RESULTS

This analysis included 24 articles, 27 case-control studies of rs2279744 polymorphism and 3 case-control studies of rs117039649 polymorphism. Significant association with the risk of gynecological cancer was observed for both SNPs. Subgroup analysis by ethnicity and cancer type (cervical, ovarian, breast, and endometrial) also showed a positive relationship between rs2279744 polymorphism and gynecological cancer risk in Caucasian; and there was also a notable association between rs2279744 polymorphism and cervical cancer.

CONCLUSIONS

We found that rs2279744 (SNP309) and rs117039649 (SNP285) were both associated with the risk of gynecological cancers. Subgroup analysis showed that rs2279744 (SNP309) was associated with the risk of gynecological cancers in Caucasian and Asian according to the ethnicity and cancer type, especially for endometrial cancer.

Host nucleotide polymorphism in hepatitis B virus-associated hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is etiologically linked with hepatitis B virus (HBV) and is the leading cause of death amongst 80% of HBV patients. Among HBV affected patients, genetic factors are also involved in modifying the risk factors of HCC. However, the genetic factors that regulate progression to HCC still remain to be determined. In this review, we discuss several single nucleotide polymorphisms (SNPs) which were reportedly associated with increased or reduced risk of HCC occurrence in patients with chronic HBV infection such as cyclooxygenase (COX)-2 expression specifically at COX-2 -1195G/A in Chinese, Turkish and Egyptian populations, tumor necrosis factor α and the three most commonly studied SNPs: PAT-/+, Lys939Gln (A33512C, rs2228001) and Ala499Val (C21151T, rs2228000). In genome-wide association studies, strong associations have also been found at loci 1p36.22, 11q22.3, 6p21 (rs1419881, rs3997872, rs7453920 and rs7768538), 8p12 (rs2275959 and rs37821974) and 22q11.21. The genes implicated in these studies include HLA-DQB2, HLA-DQA1, TCF19, HLA-C, UBE2L3, LTL, FDX1, MICA, UBE4B and PG. The SNPs found to be associated with the above-mentioned genes still require validation in association studies in order to be considered good prognostic candidates for HCC. Screening of these polymorphisms is very beneficial in clinical experiments to stratify the higher or lower risk for HCC and may help in designing effective and efficient HCC surveillance programs for chronic HBV-infected patients if further genetic vulnerabilities are detected.

The ubiquitin-proteasome system and its potential application in hepatocellular carcinoma therapy

The ubiquitin-proteasome system (UPS) is a complicated tightly controlled system in charge of degrading 80-90% of proteins, and is central to regulating cellular function and keeping protein homeostasis. Therefore, the components of UPS attract considerable attention as potential targets for hepatocellular carcinoma (HCC) therapy. The clinical success of bortezomib in multiple myeloma and mantle cell lymphoma patients has set the precedent for therapeutically targeting this pathway. This review will provide an overview of the UPS in HCC and the current status of therapeutic strategies.

MDM2 oncogene, E3 ubiquitin protein ligase T309G polymorphism and risk of oesophageal or gastric cancer: meta-analysis of 15 studies

OBJECTIVE

To investigate the association between potentially functional MDM2 oncogene, E3 ubiquitin protein ligase (MDM2) T309G polymorphism and susceptibility to oesophageal or gastric cancer.

METHODS

Two investigators independently searched the PubMed and Chinese National Knowledge Infrastructure databases for studies published before September 2013.

RESULTS

Pooled results showed that the variant homozygous 309 GG genotype (versus TT) was significantly associated with increased risk of both oesophageal (odds ratio [OR] 0.77; 95% confidence interval [CI] 0.65, 0.90) and gastric cancer (OR 0.52; 95% CI 0.38, 0.72). Subgroup analysis revealed a 309 GG-associated increased risk for both cancer types in Asian populations, particularly among Chinese and Japanese ethnicity. When stratified for Helicobacter pylori infection and histological type of gastric cancer, the 309 GG-related risk was higher in H. pylori-positive patients (T versus G: OR 0.37; 95% CI 0.22, 0.63) and the association was stronger with intestinal (TT + TG versus GG: OR 0.68; 95% CI 0.54, 0.87) rather than diffuse gastric-cancer type.

CONCLUSIONS

The MDM2 T309G polymorphism may be significantly associated with increased susceptibility to oesophageal or gastric cancer, particularly among Eastern Asian populations.

Quantitative assessment of the association between HDMX polymorphism and sarcoma

To investigate the effects of the HDMX polymorphism on sarcoma risk. Relevant studies were identified by searching the PubMed, Embase, and Web of Science databases. Data were extracted by two independent investigators. Odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated using a fixed-effects model to assess the association between the HDMX polymorphism and sarcoma risk. We also conducted heterogeneity test, sensitivity analysis, and publication bias test. A meta-analysis of four published case-control studies involving 1,115 subjects (379 cases and 736 controls) showed no statistical association between the HDMX polymorphism and sarcoma risk (ORTT vs. GG 0.88, 95 % CI 0.68-1.14, P heterogeneity 0.819; ORTT + TG vs. GG 0.95, 95 % CI 0.79-1.15, P heterogeneity 0.937; ORTT vs. TG + GG 0.82, 95 % CI 0.65-1.04, P heterogeneity 0.589; ORT allele vs. G allele 0.91, 95 % CI 0.79-1.05, P heterogeneity 0.727; ORTG vs. GG 0.95, 95 % CI 0.74-1.22, P heterogeneity = 0.869). This null result did not alter when data were stratified according to ethnicity. Our meta-analysis indicates that the HDMX polymorphism is unlikely to contribute to individual susceptibility to sarcoma.

Current evidence on the relationship between murine double minute 2 T309G polymorphism and esophageal cancer susceptibility

The relationship between murine double minute 2 (MDM2) T309G polymorphism and esophageal cancer risk has been discussed with discrepant results. The aim of our study is to investigate the systematic association between the potentially functional MDM2 T309G polymorphism and esophageal cancer risk. Eligible studies were included through searching the databases of PubMed, EMBASE, and Chinese National Knowledge Infrastructure (up to April 2014). The crude odds ratio (OR) and 95% confidence interval (CI) were used to estimate the strength of the association. Six published case-control studies, including 1899 cases and 3016 controls, were identified. Overall, our study suggested that MDM2 T309G polymorphism was significantly associated with increased risk of esophageal cancer (TT vs. GG: OR = 0.77, 95% CI = 0.65-0.90, P = 0.002; T vs. G: OR = 0.88, 95% CI = 0.81-0.96, P = 0.002). In subgroup analyses stratified by source of controls, ethnicity, and quality score assessment, respectively, similar results were obtained (TT vs. GG: OR = 0.65, 95% CI = 0.48-0.89, P = 0.007 for hospital-based studies; T vs. G: OR = 0.90, 95% CI = 0.81-0.99, P = 0.04 for population-based studies; and T vs. G: OR = 0.85, 95% CI = 0.78-0.93, P = 0.004 for Asians). The results of Begg's test and Egger's test did not suggest publication bias in the studies. Therefore, the MDM2 T309G polymorphism may be significantly associated with increased esophageal cancer risk, especially among Asians.

Lack of association of the TP53BP1 Glu353Asp polymorphism with risk of cancer: a systematic review and meta-analysis

Objective

The TP53BP1 gene may be involved in the development of cancer through disrupting DNA repair. However, studies investigating the relationship between TP53BP1 Glu353Asp (rs560191) polymorphism and cancer yielded contradictory and inconclusive outcomes. In order to realize these ambiguous findings, a meta-analysis was performed to assess the association between the TP53BP1 Glu353Asp (rs560191) polymorphism and susceptibility to cancer.

Methods

We conducted a search of all English reports on studies for the association between the TP53BP1 Asp353Glu (rs560191) polymorphism and susceptibility to cancer using Medline, the Cochrane Library, EMbase, Web of Science, Google (scholar), and all Chinese reports were identified manually and on-line using CBMDisc, Chongqing VIP database, and CNKI database. The strict selection criteria and exclusion criteria were determined, and odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. The fixed or random effect model was selected based on the heterogeneity test among studies. Publication bias was estimated using funnel plots and Egger’s regression test.

Results

A total of seven studies were included in the meta-analysis including 3,213 cases and 3,849 controls. The results indicated that the Glu353Asp (rs560191) polymorphism in TP53BP1 gene had no association with cancer risk for all genetic models. In the subgroup analysis, the results suggested that Glu353Asp polymorphism was not associated with the risk of cancer according to ethnicity, cancer type, genotyping method, adjusted with control or not, HWE and quality score.

Conclusions

This meta-analysis suggested that the Glu353Asp (rs560191) polymorphism in TP53BP1 gene was not associated with risk of cancer.

The role and therapeutic implications of RING-finger E3 ubiquitin ligases in hepatocellular carcinoma

Increasing evidence indicates that deregulation of RING-finger ubiquitin-protein ligases (E3s) involves in the development of hepatocellular carcinoma (HCC). These RING-finger E3s serve as oncoproteins or tumor suppressors in HCC under specific conditions. In this review, we summarize current knowledge about abnormal RING-finger E3s and their clinical significance in the development of HCC, and discuss parts of critical substrates for these RING-finger E3s in detail. Furthermore, in light of success of Bortezomib in treating hematological malignancies, we describe the preclinical and clinical studies of therapeutic approaches targeting aberrant RING-finger E3s in HCC.

MDM2 SNP309T>G polymorphism and hepatocellular carcinoma risk: a meta-analysis

Case-control studies on the association between mouse double-minute 2 homolog (MDM2) SNP309T>G polymorphism and hepatocellular carcinoma have provided either controversial or inconclusive results. To clarify the effect of MDM2 SNP309T>G polymorphism on the risk of hepatocellular carcinoma, a meta-analysis of all case-control observational studies was performed. Pooled odds ratios (ORs) for various polymorphisms were estimated using random and fixed effects models. The Q-statistic was used to evaluate the homogeneity, and Egger and Begg tests were used to assess publication bias. Overall, the MDM2 SNP309T>G polymorphism was associated with a risk of hepatocellular carcinoma (OR = 0.68; 95% CI = 0.54-0.85 for allele contrast, p = 0.0005, phet = 0.004). The contrast of homozygotes and the recessive and dominant models produced the same pattern of results as the allele contrast. In the analysis stratified by ethnicity, significant associations were found in the Caucasian population in all of the genetic models. In addition, heterogeneity disappeared in subgroups of Caucasian subjects. Our pooled data suggest evidence for a major role of MDM2 SNP309T>G polymorphism in the carcinogenesis of hepatocellular carcinoma, especially among Caucasian populations.

Human genetic variation and the risk of hepatocellular carcinoma development

Our understanding of the patho-physiology of hepatocellular carcinoma (HCC) is still much fragmented making difficult the improvement of the clinical outcome for the majority of HCC patients. Discovery of single nucleotide polymorphisms (SNPs) associated with individual susceptibility to HCC may enable the persons at risk to adapt their lifestyle and legitimate implementation by their doctors of surveillance programs facilitating early detection and subsequent management of the disease. To shed light on the influence of human genetic variation on HCC, we conducted a review of the meta-analyses of candidate SNPs and genome wide association studies (GWAS) performed for HCC by search of PubMed and Google Scholar databases. Genetic variations occurring in pathways historically considered as instrumental for liver tumorigenesis (TP53/MDM2, HLA, glutathione-S-transferases/cytochrome P540, TNFα/TGFβ, etc…) are discussed. An immense majority of the data has been produced in Eastern Asia (China, Japan, Korea). These meta-analyses indicate that the TP53, the MDM2 SNP309 G and the GSTT1 null genotype contribute to an increased risk of HCC both in Asians and Caucasians. Significant differences of odds ratios are, however, commonly observed between Eastern-Asians and other populations. Amazingly, GWAS studies performed so far exclusively with HCC patients from Eastern Asia produced drastically different outcomes pointing at unrelated biological pathways. The small magnitude of the risk associated with the genetic variants raises the question of their future utility as markers in clinical practice. An assessment of their impact on tumor progression (vascular invasion, metastases) remains, however, to be done and may prove to be more useful for clinicians. Finally, the evaluation of these variants is not available for various populations of the world and particularly for Subsaharan Africans who are especially affected by HCC.

Ewing Sarcoma: influence of TP53 Arg72Pro and MDM2 T309G SNPs

The Ewing Sarcoma is an important tumor of bone and soft tissue. The SNPs Arg72Pro of TP53 and T309G of MDM2 have been associated with many cancer types and have been differently distributed among populations worldwide. Based on a case-control design, this study aimed to assess the role of these SNPs in 24 Ewing Sarcoma patients, compared to 91 control individuals. DNA samples were extracted from blood and genotyped for both SNPs by PCR-RFLP and confirmed by DNA sequencing. The results showed an association between the G allele of the T309G and Ewing Sarcoma (P=0.02). Comparing to the TT carriers, the risk of G allele carriers was 3.35 (95% CI=1.22-9.21) with P=0.02. At the genotypic level, an association of the TT genotype with the control group (P=0.03) was found. Comparing to the TT genotype, the risk of TG and GG was 2.97 (95% CI=1.03-8.58) with P=0.04 and 5.00 (95% CI=1.23-20.34) with P=0.02, respectively. No associations regarding the Arg72Pro SNP were found. Considering that the T309G has been associated with several types of cancer, including sarcomas, our results indicate that this SNP may also be important to Ewing Sarcoma predisposition.

The glutathione S-transferase P1 341C>T polymorphism and cancer risk: a meta-analysis of 28 case-control studies

Background

GSTP1, which is one major group of the glutathione S-transferase family, plays an important role in the metabolism of carcinogens and toxins, reducing damage of DNA as a suppressor of carcinogenesis. The 341C>T polymorphism of the GSTP1 has been implicated in cancer risk through cutting down its metabolic detoxification activities. However, results from previous studies remain conflicting rather than conclusive. To clarify the correlation and provide more statistical evidence for detecting the significance of 341C>T, a meta-analysis was conducted.

Methodology/Principal Findings

The relevant studies were identified through searching of PubMed, Embase, ISI Web of Knowledge and China National Knowledge Infrastructure in August 2012, and selected based on the established inclusion criteria for publications, then a meta-analysis was performed to quantitatively summarize the association of GSTP1 341C>T polymorphism with cancer susceptibility. Stratified analyses were employed to identify the source of heterogeneity. Publication bias was evaluated as well as sensitivity analysis. Based on 28 case-control studies with 13249 cases and 16798 controls, the pooled results indicated that the variant genotypes significantly increased the risk of cancer in homozygote comparison (TT versus CC: P = 0.012, OR = 1.40, 95% CI: 1.08–1.81, P_het. = 0.575), and recessive model (TT versus CT/CC: P = 0.012, OR = 1.40, 95% CI: 1.08–1.81, P_het. = 0.562). This was confirmed when stratified analyses were conducted according to ethnicity, source of control, matched control, quality score and cancer types. Moreover, significantly increased risk of cancer was also found in lung cancer (heterozygote comparison and dominant model). The stability of these observations was confirmed by a sensitivity analysis. Begger's funnel plot and Egger's test did not reveal any publication bias.

Conclusions/Significance

This meta-analysis suggests that the GSTP1 341C>T polymorphism may contribute to genetic susceptibility to cancer, especially to lung cancer, and in Asian population. Nevertheless, additional well-designed studies focusing on different ethnicity and cancer types are needed to provide a more exact and comprehensive conclusion.

The MDM2 309T>G polymorphism and ovarian cancer risk: a meta-analysis of 1534 cases and 2211 controls

Background

Recently, there have been a number of studies on the association between MDM2 (Murine Double Minute 2) 309 polymorphism and ovarian cancer risk. However, the results of previous reports remain controversial and ambiguous. Thus, we performed a meta-analysis to explore more precisely the association between MDM2 309 polymorphism and the risk of ovarian cancer.

Methods

A meta-analysis was performed to examine the association between MDM2 309T>G polymorphism and ovarian cancer risk. Odds ratio (OR) and its 95% confidence interval (CI) were used for statistical analysis.

Results

Our publication search identified a total of 6 studies with 1534 cases and 2211 controls. No significant association was found between MDM2 309T>G polymorphism and ovarian cancer risk in total population analysis. In the subgroup meta-analysis by ethnicity, a negative association was shown in Asian subgroup (G vs. T OR = 0.774, 95% CI = 0.628–0.955, P = 0.017, P_het = 0.327; GG vs. TT: OR = 0.601, 95% CI = 0.395–0.914, P = 0.017, P_het = 0.417; dominant model TG+GG vs. TT: OR = 0.661, 95% CI = 0.468–0.934, P = 0.019, P_het = 0.880), and no significant association in any genetic models among Caucasians was observed.

Conclusions

This meta-analysis provides evidence for the association between MDM2 309 polymorphism and ovarian cancer risk, supporting the hypothesis that MDM2 SNP309 G allele acts as an important ovarian cancer protective factor in Asians but not in Caucasians.

Association of MDM2 SNP309 variation with lung cancer risk: evidence from 7196 cases and 8456 controls

Background

Evidence suggests that MDM2 T309G polymorphism may be a risk factor for several cancers. Increasing investigations have been conducted on the association of MDM2 T309G polymorphisms with lung cancer risk and have yielded conflicting results. Previous meta-analyses on this issue have reported inconclusive data. The aim of the present study was to derive a more precise estimation of the relationship.

Methods and Findings

Updated meta-analyses examining the association between MDM2 T309G polymorphism and lung cancer risk were performed. Separate analyses on ethnicity, smoking status, histological types and gender as well as source of controls were also implemented. Eligible studies were identified for the period up to Feb 2012. Lastly, ten publications including eleven case-control studies were selected for analysis. The overall data failed to indicate a significant association between MDM2 T309G polymorphism and lung cancer risk (GG vs TT OR = 1.14; 95%CI = 0.95−1.37; dominant model: OR = 1.05; 95%CI = 0.92−1.19; recessive model: OR = 1.12; 95%CI = 0.99−1.27). In a subgroup analysis by smoking status, increased lung cancer risk was shown among never-smokers (GG vs TT: OR = 1.76; 95%CI = 1.36−2.29; dominant model: OR = 1.48; 95%CI = 1.22−1.81; recessive model: OR = 1.37; 95%CI = 1.11−1.69). In subgroup analysis by gender, elevated risk was presented among women under a recessive model (OR = 1.29; 95%CI = 1.04−1.59). In the subgroup analysis by ethnicity, histological types and source of controls, no marked associations were observed.

Conclusions

Compared to the previous meta-analyses, the results of this study confirmed that MDM2 T309G polymorphism might be a risk factor for lung cancer among never-smokers. However, the data failed to suggest a marked association between the G allele of MDM2 T309G and lung cancer risk among Asians. More interestingly, subgroup analysis by gender indicated that homozygous GG alleles might raise lung cancer risk among females.

Murine double minute 2 promoter SNP309 polymorphism and prostate cancer risk: a meta-analysis

OBJECTIVE

The murine double minute 2 gene encodes a negative regulator of the tumor protein p53. A single nucleotide polymorphism in murine double minute 2 promoter, SNP309 T>G, has been reported to alter murine double minute 2 protein expression and to accelerate tumor formation in humans. We carried out a meta-analysis to explore the association between this polymorphism and prostate cancer risk.

METHODS

All eligible studies were searched in PubMed. Crude odds ratios, with 95% confidence intervals, were assessed for the association using fixed- and random-effects models.

RESULTS

Overall, five case-control studies (872 cases, 1005 controls) were included in the meta-analysis. A significant association between murine double minute 2 SNP309 and prostate cancer risk was observed for homozygote genetic model GG versus TT (odds ratio 0.72, 95% confidence interval 0.55-0.95, P < 0.05, P = 0.130 for heterogeneity), and for dominant model TG + GG versus TT (odds ratio 0.79, 95% confidence interval 0.65-0.96, P < 0.05, P = 0.119 for heterogeneity). The stratified analysis based on ethnicity showed a significant effect of the polymorphism on prostate cancer risk in Caucasians for GG versus TT.

CONCLUSIONS

Findings of the present meta-analysis suggest that the murine double minute 2 309 G allele might be associated with a reduced risk of prostate cancer. The effect of murine double minute 2 309 G allele on tumorigenesis might be influenced by sex and hormonal status.

MDM2 SNP309 variation contributes to leukemia risk: meta-analyses based on 7259 subjects

Evidence implicates MDM2 (murine double minute-2) T309G polymorphism as a risk factor for several cancers. Increasing numbers of studies have been carried out on the association of MDM2 T309G polymorphism with susceptibility to leukemia and have generated conflicting results. The aim of the present study was to derive a more precise estimation of the relationship. Meta-analyses assessing the association of MDM2 T309G variation with leukemia were conducted. Separate analyses on ethnicity and clinical types were also performed. Eligible studies were identified for the period up to February 2012. Consequently, seven publications including eight case-control studies with 1777 cases and 5482 controls were selected for analysis. The overall data indicated a significant association of the MDM2 T309G polymorphism with leukemia risk (GG vs. TT: odds ratio [OR] = 1.62; 95% confidence interval [CI] = 1.14-2.29; dominant model: OR = 1.20; 95% CI = 1.06-1.36; recessive model: OR = 1.47; 95% CI = 1.07-2.03). In subgroup analysis by ethnicity, the G allele may increase leukemia susceptibility among Asians (GG vs. TT: OR = 3.06; 95% CI = 2.05-4.56; dominant model: OR = 1.82; 95% CI = 1.31-2.51; recessive model: OR = 2.32; 95% CI = 1.69-3.19) but not Caucasians. In subgroup analysis by clinical types, data suggested increased risk for acute myeloid leukemia (AML) and chronic myeloid leukemia (CML) under additive and recessive models, respectively. Similarly, elevated risk for chronic lymphocytic leukemia (CLL) was shown under the dominant model. Collectively, the results of the present study suggest that MDM2 T309G polymorphism might be a low-penetrant risk factor for leukemia among Asians but not Caucasians. The G allele might increase CLL susceptibility and homozygous GG might elevate AML and CML risk.

Association between transforming growth factor-β1 polymorphisms and hepatocellular cancer risk: A meta-analysis

AIM

  The association between transforming growth factor-β1 (TGF-β1) gene polymorphisms and hepatocellular cancer (HCC) risk has been widely reported, but results were somewhat controversial. To derive a more precise estimation of the relationship between TGF-β1 polymorphisms and HCC risk, we conducted a meta-analysis of all available studies relating the C-509T and/or T869C polymorphisms of the TGF-β1 gene to the risk of developing HCC.

METHODS

  Two investigators independently searched the MEDLINE, PubMed, Web of Science, Embase, CNKI (China National Knowledge Infrastructure) and CBM (Chinese Biomedical Literature database) for the period up to August 2011.

RESULT

  A total of nine case-control articles were identified. Five studies with 1825 cases and 2869 controls for C-509T polymorphism, and six studies with 536 cases and 1496 controls for T869C polymorphism were included. In the overall analysis, no significant association between the polymorphisms and risk of HCC was observed. Stratified analysis showed that significant association between C-509T polymorphism and HCC was present only in controls with liver disease (T vs. C: odds ratio [OR] = 0.769, 95% confidence interval [CI] = 0.661-0.895; TT vs. CC: OR = 0.570, 95% CI = 0.412-0.788; TT/TC vs. CC: OR = 0.668, 95% CI = 0.523-0.854; TT vs.

TC/CC

OR = 0.717, 95% CI = 0.550-0.934), but not in healthy controls. With respect to T869C polymorphism, only a decreased risk was found in recessive models in controls with liver disease.

CONCLUSIONS

  This meta-analysis supports that the TGF-β1 C-509T polymorphism may act in a protecting role in HCC susceptibility in populations with related liver disease.

A 40-bp insertion/deletion polymorphism in the constitutive promoter of MDM2 confers risk for hepatocellular carcinoma in a Chinese population

The pathogenesis of HCC is a multistage process with the involvement of genetic factors. The aim of the present study is to investigate the possible association between a 40-bp insertion/deletion polymorphism (indel) at constitutive promoter of MDM2 and risk of hepatocellular carcinoma (HCC) in a Chinese population. Using 420 HCC patients and 423 control subjects, we genotyped the indel polymorphism (rs3730485) using polymerase chain reaction method. Logistic regression was used to analyze the association between the polymorphism and HCC susceptibility. Under co-dominant model, we found that the ins/del and del/del genotype of indel was associated with a significantly increased risk of HCC compared with its homozygote ins/ins (OR=1.39, 95%C.I.=1.03-1.87; OR=1.68, 95%C.I.=1.03-2.73, respectively). Presence of 40-bp deletion allele of MDM2 seemed to confer higher risk for HCC when compared with non-carriers (OR=1.30, 95%C.I.=1.06-1.60, P=0.011). Further stratification analysis showed that this association was more pronounced in patients with a family history of HCC, early tumor stage and higher serum alpha-fetoprotein (AFP). These findings indicated that the MDM2 indel polymorphism may be a genetic modifier for developing HCC in Chinese population.