Null genotype of glutathione S-transferase Tl contributes to colorectal cancer risk in the Asian population: a meta-analysis

Metabolic pathways in sporadic colorectal carcinogenesis: A new proposal

Given the reports made about geographical differences in Colorectal Cancer (CRC) occurrence, suggesting a link between dietary habits, genes and cancer risk, we hypothesise that there are four fundamental metabolic pathways involved in diet-genes interactions, directly implicated in colorectal carcinogenesis: folate metabolism; lipid metabolism; oxidative stress response; and inflammatory response. Supporting this hypothesis are the evidence given by the significant associations between several diet-genes polymorphisms and CRC, namely: MTHFR, MTR, MTRR and TS (involved in folate metabolism); NPY, APOA1, APOB, APOC3, APOE, CETP, LPL and PON1 (involved in lipid metabolism); MNSOD, SOD3, CAT, GSTP1, GSTT1 and GSTM1 (involved in oxidative stress response); and IL-1, IL-6, TNF-α, and TGF-β (involved in inflammatory response). We also highlight the association between some foods/nutrients/nutraceuticals that are important in CRC prevention or treatment and the four metabolic pathways proposed, and the recent results of genome-wide association studies, both assisting our hypothesis. Finally, we propose a new line of investigation with larger studies, using accurate dietary biomarkers and investigating the four metabolic pathways genes simultaneously. This line of investigation will be essential to understand the full complexity of the association between nature and nurture in CRC and perhaps in other types of cancers. Only with this in-depth knowledge will it be possible to make personalised nutrition recommendations for disease prevention and management.

Individual and combined effects of GSTM1 and GSTT1 polymorphisms on colorectal cancer risk: an updated meta-analysis

BACKGROUND

The presence or absence of glutathione S-transferase M1 gene (GSTM1) and glutathione S-transferase T1 gene (GSTT1) polymorphisms, and their combined effects have been suggested as a risk factor for colorectal cancer (CRC). However, the results are inconsistent.

OBJECTIVES

An updated meta-analysis was performed to solve the controversy.

METHODS

Meta-analyses of Observational Studies in Epidemiology (MOOSE) guidelines were used.

RESULTS

Overall, the GSTM1 null genotype was associated with an increased CRC risk in Caucasians (odds ratio (OR) = 1.14, 95% confidence interval (CI): 1.05-1.23), Asians (OR = 1.19, 95% CI: 1.08-1.32), high-quality studies (OR = 1.12, 95% CI: 1.06-1.18). Moreover, the GSTM1 null genotype was also associated with an increased colon cancer risk (OR = 1.32, 95% CI: 1.16-1.51). The GSTT1 null genotype was also associated with an increased CRC risk in Asians (OR = 1.08, 95% CI: 1.02-1.15) and Caucasians (OR = 1.24, 95% CI: 1.09-1.41). Moreover, The GSTT1 null genotype was associated with an increased rectal cancer risk (OR = 1.13, 95% CI: 1.01-1.27, I2 = 8.3%) in subgroup analysis by tumor location. Last, the GSTM1 null/GSTT1 null genotype was associated with an increased CRC risk in Asians.

CONCLUSION

This meta-analysis indicates that the GSTM1 and GSTT1 null genotypes are associated with increased CRC risk in Asians and Caucasians, and the GSTM1 null/GSTT1 null genotype was associated with increased CRC risk in Asians.

Does Turmeric/curcumin Supplementation Change Anthropometric Indices in Patients with Non-alcoholic Fatty Liver Disease? A Systematic Review and Meta-analysis of Randomized Controlled Trials

Curcumin is the principal polylphenol of turmeric that has been used to treat various disorders. However, its anti-obesity effects in patients with non-alcoholic fatty liver disease (NAFLD) remain controversial. Therefore, we aimed to perform a meta-analysis on the effects of supplementation with turmeric/curcumin on body weight, body mass index (BMI) and waist circumference (WC) in these patients. PubMed, Scopus, Cochrane Library, and ISI Web of Science were searched until January 2019, without any restrictions. Clinical trials that reported body weight, BMI and WC in patients with NAFLD were included. Weighted mean differences (WMDs) were pooled using a random-effects model. Eight studies (449 participants) fulfilled the eligibility criteria of the present meta-analysis. Overall, meta-analysis could not show any beneficial effect of turmeric/curcumin supplementation on body weight (WMD, -0.54 kg; 95% confidence interval [CI], -2.40, 1.31; p = 0.56; I2 = 0.0%), BMI (WMD, -0.21 kg/m2; 95% CI, -0.71, 0.28; p = 0.39; I2 = 0.0%) and WC (WMD, -0.88 cm; 95% CI, -3.76, 2.00; p = 0.54; I2 = 0.0%). Subgroup analysis based on participants' baseline BMI, type of intervention, and study duration did not show any significant association in all subgroups. The results showed that turmeric/curcumin supplementation had no significant effect on body weight, BMI and WC in patients with NAFLD. Further studies with large-scale are needed to find out possible anti-obesity effects of turmeric/curcumin.

Association of GSTO2 (N142D), GSTT1, and GSTM1 Polymorphisms With Graft-Versus-Host Disease in Allogeneic Hematopoietic Stem Cell Transplant Recipients

OBJECTIVES

Graft-versus-host disease is a major problem after bone marrow transplant. GSTM1, GSTT1, and GSTO2 are important genes that interfere with xenobiotic and drug metabolism. Polymorphisms of these genes may influence the metabolism of immunosuppressive drugs given for inhibition of graft-versus-host disease and may influence their susceptibility to diseases, which bone marrow transplant could alleviate.

MATERIALS AND METHODS

We examined the polymorphisms of 2 groups: The first group was composed of 88 patients who had undergone a bone marrow transplant and 100 otherwise healthy persons; the second group was composed of 54 patients without graft-versus-host disease and 34 patients with graft-versus-host disease. We used polymerase chain reaction-restriction fragment length polymorphism method for genotyping GSTO2 and also for multiplexing polymerase chain reactions for GSTT1 and GSTM1 genotypes.

RESULTS

No significant association existed between the genotypes GSTO2 (DD: P = .458, OR 0.422), GSTM1 (P = .349, OR 1.52), or GSTT1 (P = .887, OR 1.086), and the incidence of GVHD. Moreover, we saw no association between these polymorphisms and the problems that lead to bone marrow transplant (GSTO2: DD, P = .181, OR 0.465; GSTM1: P = .699, OR 0.892; GSTT1: P = .656, OR 0.845). We showed that men have more bone marrow transplants than do women (P = .019, OR 2.034).

CONCLUSIONS

Our results show that these poly-morphisms may have no effect on the metabolism of drugs used to treat graft-versus-host disease and also, may play no significant role in creating the problems that lead to bone marrow transplant.

Null genotype of GSTT1 contributes to increased Parkinson's disease risk in Caucasians: evidence from a meta-analysis

Conflicting results in previous case-control studies on the association between Glutathione S-transferase T1 (GSTT1) gene polymorphism and Parkinson's disease (PD) risk have been reported, so we conducted this meta-analysis. We searched and extracted data from 3 Chinese and 3 English web-based electronic databases to evaluate the associations by odds ratio (OR) and its 95% confidence interval (CI) under the recessive genetic comparison model (null genotype vs. present genotype). We also conducted subgroup analyses by ethnicity and adjusted status of OR, respectively. Meta-analyses and subgroup analyses of larger studies (sample size ≥300) were also reanalyzed. When 18 eligible studies (3,963 PD cases and 5,472 controls) were pooled to analyze the association, we found no statistically significant result (OR 1.24, 95% CI 0.96-1.60). In the subgroup analyses by ethnicity, there was statistically significant association between the null genotype of GSTT1 and PD risk among Caucasians, while the associations were not found among Asians and Latinos. In the subgroup analyses by adjusted status of OR, there were no significant associations both in studies with crude OR and adjusted OR. Meta-analyses and subgroup analyses of larger studies (sample size ≥300) were also confirmed the associations mentioned above. Power analysis indicated only meta-analysis of Caucasians had enough evidence to claim the association. In conclusion, the meta-analysis suggests that the null genotype of GSTT1 contributes to PD risk in Caucasians, and no association in Asians is needed more studies to confirm.

Postoperative therapy options for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is associated with poor prognosis and often recurs even after curative hepatic resection (HR) or radiofrequency ablation (RFA). In fact, recurrence is the most frequent cause of postoperative death in patients with HCC; it can arise through intrahepatic metastasis by the primary tumor or through the emergence of de novo tumors. Even though studies have examined numerous adjuvant therapies and chemotherapies for their ability to prevent recurrence, no consensus recommendations exist about their clinical application. To gain a comprehensive picture of clinical options, we identified 39 randomized controlled trials, involving 4113 participants, which explore the efficacy of adjuvant or chemotherapies to prevent HCC recurrence after potentially curative HR or RFA. The available evidence suggests a significant improvement in recurrence-free survival and overall survival when transarterial chemoembolization is used for patients who are at high risk for recurrence, lamivudine for patients with hepatitis B virus (HBV)-related HCC (>500 copies of HBV DNA/ml), and interferon-α for patients with hepatitis C virus (HCV)-infected HCC. In contrast, available evidence does not definitively establish clinical benefits of interferon-β for patients with HCV-related HCC, interferon-α for patients with HBV-related HCC, or any of the following therapies for patients with HCC: iodine-125 brachytherapy, autologous tumor vaccination, adoptive immunotherapy, or therapy involving acyclic retinoid, vitamin K2 analog, iodine-131-labeled lipiodol, sorafenib, heparanase inhibitor PI-88, or capecitabine. Though the findings of our review should be interpreted with caution because of clinical heterogeneity and small sample size in the included trials, they highlight gaps in the evidence base, and therefore, may guide future research.

A meta-analysis of the relationship between glutathione S-transferases gene polymorphism and hepatocellular carcinoma in Asian population

The results from the published studies on the association between glutathione S-transferases (GST) gene polymorphism and hepatocellular carcinoma (HCC) in Asian population are still conflicting. GSTM1, GSTT1 and GSTP1 are the mainly mutant sites reported at present. This meta-analysis was performed to evaluate the relationship between GST gene polymorphism and HCC risk in Asians. Association studies were identified from the databases of PubMed, Embase, Cochrane Library and CBM-disc (China Biological Medicine Database) on February 1, 2012, and eligible investigations were synthesized using meta-analysis method. Results were expressed with odds ratios (OR) for dichotomous data, and 95 % confidence intervals (CI) were also calculated. Twenty-five investigations were identified for the analysis of association between polymorphic deletion of GSTM1 and HCC, consisting of 3,547 patients with HCC and 6,132 controls. There was a marked association between GSTM1 null genotype and HCC susceptibility (OR 1.48, 95 % CI 1.19-1.85, P = 0.0004). GSTM1 null genotype was associated with HCC risk in Chinese. Furthermore, null genotype of GSTT1 was associated with HCC susceptibility in Asians. For the GSTM1-GSTT1 interaction analysis, the dual null genotype of GSTM1/GSTT1 was significantly associated with HCC susceptibility in Asian population. However, GSTP1 ile105 val gene polymorphism was not associated with HCC risk in Asian population. In conclusion, GSTM1/GSTT1 null genotype is associated with the HCC susceptibility. However, GSTP1 gene polymorphism is not associated with HCC risk.