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

Genetic dominance of transforming growth factor-β1 polymorphisms in chronic liver disease

Chronic liver disease (CLD) is an extremely common clinical condition accompanied by sustained inflammatory response leading to tissue damage. Transforming growth factor-β1 (TGF-β1) is known as a master immune regulator in CLDs, but the association between TGF-β1 polymorphisms and CLD risk is controversial and inconclusive, and the genetic dominance of CLDs remains unknown. In this study, the relationship between TGF-β1 polymorphisms and CLD susceptibility is systematically analyzed based on 35 eligible studies. Individuals with the TGF-β1-509 allele (TT or CT) or codon 10 allele (Pro/Pro) show an increased risk of CLDs. Subgroup analyses indicate TGF-β1-509C/T has a significant correlation with cirrhosis and chronic hepatitis C, codon 10 is associated with chronic hepatitis B occurrence, and codon 25 exhibits a relationship with autoimmune hepatitis risk. Missense mutations in G29E, A105S, D191N, and F321L of TGF-β1 are the genetic factors of HCC susceptibility. Furthermore, the TGF-β1 gene expression is significantly elevated in CLD patients, and the TGF-β1 codon 263 is located close to the region where the TGF-β1 dimerization interacts, indicating the TGF-β1 codon 263 variant may affect the secretion of TGF-β1 by altering its dimerization. Together, our findings provide new insights into the immune regulator gene TGF-β1 polymorphisms as susceptibility factors for CLD occurrence and regulators for TGF-β1 expression, which have implications for the regulation of immune factors during CLD development.

TGF-β1 rs1800469 gene polymorphism in the development of cirrhosis & hepatocellular carcinoma in Pakistani HCV patients

Hepatocellular carcinoma (HCC) has been increasing among Pakistani males. Aim: The main objective of this study was to evaluate the role of TGF-β-1 gene polymorphism as a risk factor in chronic hepatitis C virus (HCV) infected HCC patients in Pakistan. Patients & methods: A total of 286 subjects were recruited into three different groups (Group I: 96 healthy controls, Group II: 96 HCV, Group III: 94 HCC). Results: A significant increase in genotype and allele frequencies of TGF-β-1 gene was observed in HCC, HCV with OR = 1.9; 95% CI: 1.275–2.871; p > 0.05, OR = 1.6; 95% CI: 1.12–2.51; p > 0.05 and OR = 1.7; 95% CI: 1.036–1.923; p > 0.05. Conclusion: A higher frequency of the TT genotype and T allele of the TGF-β-1 gene is observed in Pakistani HCV and HCC patients.

Enhanced circulating transforming growth factor beta 1 is causally associated with an increased risk of hepatocellular carcinoma: a mendelian randomization meta-analysis

The aim of this study was to test the causal association between circulating transforming growth factor beta 1 (protein: TGF-β1 and coding gene: TGFB1) and hepatocellular carcinoma by choosing TGFB1 gene C-509T polymorphism as an instrument in a Mendelian randomization (MR) meta-analysis. Ten English articles were identified for analysis. Two authors independently assessed each article and abstracted relevant data. Odds ratio (OR) and weighted mean difference (WMD) with 95% confidence interval (CI) were synthesized under a random-effects model. Overall, the association of C-509T polymorphism with hepatocellular carcinoma was negative, but its association with circulating TGF-β1 was statistically significant, with a higher concentration observed in carriers of the -509TT genotype (WMD, 95% CI, P: 1.72, 0.67–2.78, 0.001) and -509TT/-509TC genotypes (WMD, 95% CI, P: 0.98, 0.43–1.53, < 0.001). In subgroup analysis, C-509T polymorphism was significantly associated with hepatocellular carcinoma in population-based studies under homozygous-genotype (OR, 95% CI, P: 1.74, 1.08–2.80, 0.023) and dominant (OR, 95% CI, P: 1.48, 1.01–2.17, 0.047) models. Further MR analysis indicated that per unit increase in circulating TGF-β1 was significantly associated with a 38% (95% CI: 1.03–4.65) and 49% (95% CI: 1.01–6.06) increased risk of hepatocellular carcinoma under homozygous-genotype and dominant models, respectively. Conclusively, based on a MR meta-analysis, our findings suggest that enhanced circulating TGF-β1 is causally associated with an increased risk of hepatocellular carcinoma.

Development of gene polymorphisms in meditators of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent liver disease worldwide, the morbidity of which closely correlates with diversity of ethnicity, minority, family and location. Its histology spans from simple steatosis, to nonalcoholic steatohepatitis, which ultimately results in fibrosis, cirrhosis and hepatocellular carcinoma. The accelerating prevalence of NAFLD is due to an incremental incidence of metabolic syndrome that is distinguished by dyslipidemia, glucose impairment, obesity, excessive oxidative stress and adipocytokine impairment. Additionally, the pathogenesis of NAFLD is thought to be a multifactorial and complicated disease associated with lifestyle habits, nutritional factors and genetics. However, the pathogenesis and underlying mechanism in the development of NAFLD caused by genetics remains unclear. People have been increasingly emphasizing on the relationship between NAFLD and gene polymorphisms in recent years, with the aim of having a comprehensive elucidation of associated gene polymorphisms influencing the pathogenesis of the disease. In the current article, the authors attempted to critically summarize the most recently identified gene polymorphisms from the facets of glucose metabolism, fatty acid metabolism, oxidative stress and related cytokines in NAFLD that contribute to promoting the progression of the disease.

The Synergistic Effect of TNFα -308 G/A and TGFβ1 -509 C/T Polymorphisms on Hepatic Fibrosis Progression in Hepatitis C Virus Genotype 4 Patients

Tumor necrosis factor-alpha (TNFα) and transforming growth factor-beta (TGFβ1) cytokines are highly implicated in liver fibrosis. Polymorphisms in these cytokines affect their expression, secretion, and activity. This study aimed to evaluate the influence of TNFα -308 G/A and TGFβ1 -509 C/T polymorphism on hepatic fibrosis progression in Egyptian patients with hepatitis C virus (HCV) genotype 4. Genotyping of TNFα -308 G/A and TGFβ1 -509 C/T was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis in 122 subjects (50 healthy controls and 72 HCV patients). Also, serum TNFα and TGFβ1 levels were detected by enzyme-linked immunosorbent assay (ELISA). The genotyping results of early (F0-F1, n = 36) and late (F2-F4, n = 36) HCV fibrosis patients showed that late fibrosis patients had higher TNFα -308 AA genotype and TGFβ1 -509 TT genotype than early fibrosis patients (p = 0.016, 0.028, respectively). Moreover, the TNFα and TGFβ1 serum levels were significantly higher in HCV patients with TNFα A containing genotypes (GA+AA) (p = 0.004) and patients with TGFβ1 T containing genotypes (CT+TT) (p = 0.001), respectively. The combined unfavorable TNFα (GA/AA) and TGFβ1 (CT/TT) genotypes were highly associated with abnormal liver function parameters and were significantly higher in high activity (A2-A3) and late fibrosis (F2-F4) HCV patients (p = 0.023, 0.029). The multivariate analysis results confirmed that the combined TNFα-308 (AA) and TGFβ1 -509 (TT) unfavorable genotypes increased the risk of hepatic fibrosis progression by 6.4-fold than combined favorable genotypes (odds ratio: 6.417, 95% confidence interval [1.490-27.641], p = 0.013). In conclusion, both TNFα -308 G/A and TGFβ1 -509 C/T polymorphisms synergistically influence the hepatic fibrosis progression and can be used as potential biomarkers to predict hepatic disease progression in chronic hepatitis C patients.

Lack of Association of Tumor Necrosis Factor-α G-308A and Transforming Growth Factor-β1 C-509T Polymorphisms in Patients with Deep Neck Space Infections

Deep neck space infections are defined as infections that spread along the fascial planes and spaces of the head and neck. Even in the era of antibiotics, these infections can and have been potentially life-threatening conditions. The role of single nucleotide polymorphisms (SNPs) of tumor necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β1) genes in deep neck infections has not been studied. Thus, the aim of this study was to investigate the distribution of the TNF-α G-308A and TGF-β1 C-509T polymorphisms in patients suffering from infections of deep neck spaces and to determine the correlation of these polymorphisms with the values of inflammation markers [C-reactive protein (CRP) and white blood cell (WBC) count]. A total of 41 patients with infections of deep neck spaces and 44 healthy controls were screened for TNF-α G-308A and TGF-β1 C-509T polymorphisms using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The distribution of the TNF-α G-308A genotype in patients did not reveal statistically significant correlation compared to con-trols (p = 0.483, χ(2) = 0.491) as well as the distribution of the TGF-β1 C-509T genotypes (p = 0.644, χ(2) = 0.725). The distribution of TNF-α -308 and TGF-β1 -509 alleles was not significantly different in patients compared to controls. Moreover, CRP levels and WBC counts were not associated with TNF-α G-308A and TGF-β1 C-509T promoter polymorphisms in patients with deep neck infections. In conclusion, our study suggests that the TNF-α G-308A and TGF-β1 C-509T polymorphisms are not associated with infections of deep neck spaces.

Important roles played by TGF-β in hepatitis B infection

Hepatitis B virus (HBV) which includes, fulminant, acute, chronic, asymptomatic, and occult HBV infection is the most prevalent virus that leads to human liver diseases. Chronic, asymptomatic, and occult infection can induce further sever diseases such as hepatocellular carcinoma (HCC) and cirrhosis of the liver. The underlying mechanisms that allow progression of the prolonged forms of the infection and subsequent HCC or cirrhosis of the liver are yet to be clarified. However, many researchers have suggested that immunological and genetic parameters may play important roles in the etiology of hepatitis B. Transforming growth factor beta (TGF-β) is an important cytokine with dual regulatory functions in the immune system and in the responses against viral infections. However, the pathways and mechanisms controlling these are not fully understood. The crucial roles of TGF-β in the development of Th17 and T regulatory lymphocytes, the main cell types involved in autoimmunity and destructive immune related diseases, have been documented and this provides insights into TGF-β function during hepatitis infection and subsequent HCC and cirrhosis of the liver. Recent findings also confirm that TGF-β directly alters hepatocyte function during hepatitis B, hence, the aim of this review is to address the current data regarding the association and status of TGF-β with hepatitis B infection and its related disorders including HCC and cirrhosis of the liver.

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.

TGF-β1 -509C/T (or +869T/C) polymorphism might be not associated with hepatocellular carcinoma risk

Many studies have reported the role of transforming growth factor-β1 (TGF-β1) -509C/T or +869T/C polymorphism with hepatocellular carcinoma (HCC) risk. However, these studies have yielded conflicting results. Hence, we performed this meta-analysis to investigate the association between TGF-β1 -509C/T or +869T/C polymorphism and HCC. A total of 11 studies including 2,577 HCC cases and 4,107 controls were included in the meta-analysis. Overall, TGF-β1 -509C/T (or +869T/C) polymorphism was not associated with HCC risk (homogeneous co-dominant model: OR = 1.29, 95 % CI = 0.88-1.89; heterogeneous co-dominant model: OR = 1.15, 95 % CI = 0.91-1.45; dominant model: OR = 1.14, 95 % CI = 0.87-1.48; recessive model: OR = 1.15, 95 % CI = 0.89-1.49). In the subgroup analysis, TGF-β1 -509C/T (or +869T/C) polymorphism was significantly associated with HCC risk in Caucasians under the recessive model (OR = 1.65, 95 % CI = 1.07-2.55) but not in other genetic models. In addition, we did not observe significant association in Asians under all genetic models. In conclusion, our meta-analysis indicates that TGF-β1 -509C/T (or +869T/C) polymorphism was not associated with risk of HCC, although a marginal association was found for Caucasians. However, a study with the larger sample size is needed to further evaluate gene-environment interaction on the association.

Transforming growth factor-β genetic polymorphisms on development of liver cirrhosis in a meta-analysis

Transforming growth factor-β (TGF-β) protein has been supposed to be a risk factor for liver cirrhosis; however, the associations between its genes (TGF-β -509C>T and +869T>C) and liver cirrhosis remained unclear. This study was to quantitatively analyze the correlations by using a meta-analysis. Pubmed, Embase, Wanfang databases were retrieved up to November 1st, 2011. Odds ratio (OR) and 95 % confidence interval (95 %CI) were used to demonstrate the strength of association, and P < 0.05 of Z test indicated statistical significance. Combined analyses were performed by using fixed or random-effect model, depending on between-study heterogeneity. Seven studies were for TGF-β -509C>T polymorphism, and eight studies were for +869T>C polymorphism. Combined results indicated that neither TGF-β -509C>T nor +869T>C polymorphisms were associated with risk of liver cirrhosis [OR (95 % CI): 0.79 (0.60-1.04) for CT vs. TT of -509C>T and 0.87 (0.68-1.12) for CT vs. CC of +869T>C], with no between-study heterogeneity. In addition, subgroups analyses still inferred that two polymorphisms were not associated with risk of liver cirrhosis for HBV-infected patients, Asians and for Population-based studies. This meta-analysis indicated that neither TGF-β -509C>T nor +869T>C polymorphisms were associated with risk of liver cirrhosis, regardless of HBV infection or not.

Correlation between TGF-β1-509 C>T polymorphism and risk of digestive tract cancer in a meta-analysis for 21,196 participants

The association between transforming growth factor β1 (TGF-β1)-509 C>T and risk of digestive tract cancer (DTC) remained uncertain as previous studies reported conflicting results. The aim of this study was to assess the association by using a meta-analysis. The databases of MEDLINE, EMBASE and WANGFANG (Chinese database) were retrieved, and latest update was on 2nd February, 2012. Pooled odds ratio and 95% confidence interval (OR and 95% CI) were calculated by using a fixed- or random-effect model. Ultimately, twenty nine case-control studies with 8664 cases and 12,532 controls were included in this meta-analysis. Overall, there was no association between TGF-β1-509 C>T and risk of DTC in all genetic comparison models (OR and 95% CI: 0.96 and 0.81-1.15 for TT vs. CC, 0.98 and 0.91-1.05 for T carriers vs. C carriers). When subgroup analyses were conducted according to ethnicity, types of cancer and sample size, T allele was significantly associated with decreased risk of DTC for Caucasians and for large sample-sized studies, and was associated with decreased risk of colorectal cancer (OR and 95% CI for TT vs. CC: 0.82 and 0.70-0.97 for Caucasians, 0.80 and 0.68-0.98 for large sample-sized studies, 0.78 and 0.62-0.97 for colorectal cancer). This study indicated that TGF-β1-509 C>T polymorphism was probably associated with risk of DTC, especially for Caucasians. Because of modest limitation, our findings should be confirmed by future studies.