Poor metabolizers at the cytochrome P450 2C19 loci is at increased risk of developing cancer in Asian populations

CYP2C19 gene polymorphism in Ningxia

BACKGROUND

Poor metabolizer (PM) status of CYP2C19 can be a predisposing factor for developing gastric cancer in H. pylori-infected patients. It is unclear whether PM status of CYP2C19 can also be a potential factor for H.pylori infection in healthy people.

METHODS

We used high-throughput sequencing to detect single nucleotide polymorphisms (SNPs) at just three loci, rs4244285 (CYP2C19*2), rs4986893 (CYP2C19*3) and rs12248560 (CYP2C19*17), to identify the exact CYP2C19 alleles corresponding to the mutated sites. We determined CYP2C19 genotypes of 1050 subjects from 5 cities of Ningxia from September 2019 to September 2020 and evaluated the potential correlation between H.pylori and CYP2C19 gene polymorphisms. Clinical data were analyzed using χ2 tests.

RESULTS

The frequency of CYP2C19*17 in Hui (3.7%) was higher as compared to Han (1.4%) in Ningxia (p = 0.001). The frequency of CYP2C19*1/*17 of Hui (4.7%) was higher as compared to Han (1.6%) in Ningxia (p = 0.004). The frequency of CYP2C19*3/*17 of Hui (1%) was higher as compared to Han (0%) in Ningxia (p = 0.023). The frequencies of alleles (p = 0.142) and genotypes (p = 0.928) were not found to be significantly different among the different BMI groups. The frequencies of four alleles between H. pylori positive and negative groups were not found to be statistically different (p = 0.794). The frequencies of the different genotypes between H. pylori positive and negative groups were not statistically different (p = 0.974), and no statistical difference was observed between the different metabolic phenotypes (p = 0.494).

CONCLUSION

There were regional differences observed in CYP2C19*17 distribution in Ningxia. The frequency of CYP2C19*17 in Hui was higher than in Han of Ningxia. No significant relationship was found between CYP2C19 gene polymorphism and susceptibility to H. pylori infection.

Evaluating the Association of Genetic Polymorphism of Cytochrome p450 (CYP2C9*3) in Gastric Cancer Using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP)

Background and aim

As a distinguished system, the cytochrome P450 (CYP) enzyme superfamily is involved in the biotransformation of several endogenous and exogenous substances including drugs, toxins, and carcinogens. Reports on the role of CYP enzyme in gastric cancer (GC) from the Eastern region of India are scarce. The present study aimed to evaluate the effect of single nucleotide polymorphisms (SNP) in cytochrome P450 family 2 subfamily C member 9 (CYP2C9*3) among cases with gastric malignancy.

Material and methods

The current study is a cross-sectional observational study carried out among 113 GC cases attending the Institute of Medical Sciences and SUM Hospital, Bhubaneswar, India, and Srirama Chandra Bhanja Medical College and Hospital, Cuttack, India. Two ml of venous blood was collected from the confirmed cases of GC. The samples were subjected to genomic DNA isolation followed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (PCR-RFLP).

Results

The prevalence of both homozygous and heterozygous mutation in GC cases is 4% and 8%, respectively. The overall association of cytochrome P450 family 2 subfamily C member 9 (CYP2C9) mutation in GC cases is 12% whereas 88% were detected as wild/standard type. The mutation CYP2C9 SNP has been seen in Helicobacter pylori-infected cases and as well as those without H. pylori infection.

Conclusions

The CYP2C9*3 genetic polymorphism might play a significant role as a risk factor for the development of gastric malignancy irrespective of H. pylori infection, among the eastern Indian population.

Pleiotropic Functions of Cytochrome P450 Monooxygenase-Derived Eicosanoids in Cancer

Eicosanoids are a class of functionally bioactive lipid mediators derived from the metabolism of long-chain polyunsaturated fatty acids (PUFAs) mediated by multiple enzymes of three main branches, including cyclooxygenases (COXs), lipoxygenases (LOXs), and cytochrome P450s (CYPs). Recently, the role of eicosanoids derived by COXs and LOXs pathways in the control of physiological and pathological processes associated with cancer has been well documented. However, the role of CYPs-mediated eicosanoids, such as epoxyeicosatrienoic acids (EETs), epoxyoctadecenoic acids (EpOMEs), epoxyeicosatetraenoic acids (EpETEs), and epoxydocosapentaenoic acids (EDPs), as well as hydroxyeicosatetraenoic acids (HETEs), in tumorigenesis and cancer progression have not been fully elucidated yet. Here we summarized the association of polymorphisms of CYP monooxygenases with cancers and the pleiotropic functions of CYP monooxygenase-mediated eicosanoids (EETs, EpOMEs, EpETE, EDPs, and 20-HETE) in the tumorigenesis and metastasis of multiple cancers, including but not limited to colon, liver, kidney, breast and prostate cancers, which hopefully provides valuable insights into cancer therapeutics. We believe that manipulation of CYPs with or without supplement of ω-3 PUFAs to regulate eicosanoid profile is a promising strategy to prevent and/or treat cancers.

The down-regulation of the CYP2C19 gene is associated with aggressive tumor potential and the poorer recurrence-free survival of hepatocellular carcinoma

Project HOPE (High-tech Omics-based Patient Evaluation) began in 2014 using integrated gene expression profiling (GEP) of cancer tissues as well as diathesis of each patient who underwent an operation at our institution. The aim of this study was to clarify the association between the expression of cytochrome P450s (CYP) genes and recurrence of hepatocellular carcinoma (HCC). The present study included 92 patients. Genes with aberrant expression were selected based on a ≥10-fold difference in the expression between tumor and non-tumor tissues. The GEP analysis showed that the down-regulated genes in tumor tissue were CYP3A4 in 56 patients (61%), CYP2C8 in 44 patients (48%), CYP2C19 in 30 patients (33%), CYP2D6 in 11 patients (12%), CYP3A5 in 7 patients (8%) and CYP1B1 in 2 patients (2%). There was no patients with down-regulation of the CYP17A1 gene. A multivariate analysis revealed that the presence of microscopic portal invasion (hazard ratio [HR] 2.57, 95% confidence interval [CI] 1.30–5.05 P = 0.006), the presence of intrahepatic-metastasis (HR 3.09 95% CI 1.52–6.29 P = 0.002) and down-regulation of the CYP2C19 gene (HR 3.69 95% CI 1.83–7.46 P < 0.001) were independent predictors for the recurrence-free survival (RFS). The down-regulation of the CYP2C19 gene were correlated with the RFS in HCC.

Evidence for extensive pleiotropy among pharmacogenes

AIM

We sought to identify potential pleiotropy involving pharmacogenes.

METHODS

We tested 184 functional variants in 34 pharmacogenes for associations using a custom grouping of International Classification and Disease, Ninth Revision billing codes extracted from deidentified electronic health records of 6892 patients.

RESULTS

We replicated several associations including ABCG2 (rs2231142) and gout (p = 1.73 × 10(-7); odds ratio [OR]: 1.73; 95% CI: 1.40-2.12); and SLCO1B1 (rs4149056) and jaundice (p = 2.50 × 10(-4); OR: 1.67; 95% CI: 1.27-2.20).

CONCLUSION

In this systematic screen for phenotypic associations with functional variants, several novel genotype-phenotype combinations also achieved phenome-wide significance, including SLC15A2 rs1143672 and renal osteodystrophy (p = 2.67 × 10(-) (6); OR: 0.61; 95% CI: 0.49-0.75).

Noncoding Genomics in Gastric Cancer and the Gastric Precancerous Cascade: Pathogenesis and Biomarkers

Gastric cancer is the fifth most common cancer and the third leading cause of cancer-related death, whose patterns vary among geographical regions and ethnicities. It is a multifactorial disease, and its development depends on infection by Helicobacter pylori (H. pylori) and Epstein-Barr virus (EBV), host genetic factors, and environmental factors. The heterogeneity of the disease has begun to be unraveled by a comprehensive mutational evaluation of primary tumors. The low-abundance of mutations suggests that other mechanisms participate in the evolution of the disease, such as those found through analyses of noncoding genomics. Noncoding genomics includes single nucleotide polymorphisms (SNPs), regulation of gene expression through DNA methylation of promoter sites, miRNAs, other noncoding RNAs in regulatory regions, and other topics. These processes and molecules ultimately control gene expression. Potential biomarkers are appearing from analyses of noncoding genomics. This review focuses on noncoding genomics and potential biomarkers in the context of gastric cancer and the gastric precancerous cascade.

Updated meta-analysis of the association between CYP2E1 RsaI/PstI polymorphisms and lung cancer risk in Chinese population

BACKGROUND

A number of studies have reported relationships of CYP2E1 RsaI/PstI polymorphisms with susceptibility to lung cancer in Chinese population. However, the epidemiologic results have been conflictive rather than conclusive. The purpose of this study was to address the associations of CYP2E1 RsaI/PstI polymorphisms with lung cancer risk in Chinese population comprehensively.

MATERIALS AND METHODS

Systematic searches were conducted in the PubMed, Science Direct, Elsevier, CNKI and Chinese Biomedical Literature Databases. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of association.

RESULTS

Overall, we observed a decreased lung cancer risk among subjects carrying CYP2E1 RsaI/PstI c1/ c2 and c1/c2+c2/c2 genotypes (OR=0.76, 95%CI: 0.64-0.90 and OR=0.78, 95%CI: 0.66-0.93, respectively), as compared with subjects carrying the c1/c1 genotype. In subgroup analysis, we observed a decreased lung cancer risk among c1/c2 carriers in hospital-based studies (OR=0.81, 95%CI: 0.68-0.98) and among carriers with c1/ c2 and c1/c2+c2/c2 genotypes in population-based studies(OR=0.57, 95%CI: 0.42-0.79 and OR=0.58, 95%CI: 0.43-0.79, respectively), as compared with subjects carrying the c1/c1 genotype. Limiting the analysis to studies with controls in Hardy-Weinberg equilibrium (HWE), we similarly observed a decreased lung cancer risk among c1/c2 and c1/c2+c2/c2 carriers (OR=0.73, 95%CI: 0.60-0.88 and OR=0.73, 95%CI: 0.60-0.88, respectively), as compared with c1/c1.

CONCLUSIONS

Our results suggested that CYP2E1 RsaI/PstI c1/c2 and c1/c2+c2/c2 variants might be a protective factor for developing lung cancer in Chinese population. Further well-designed studies with larger sample size are required to verify our findings.

Independent and combined effects of environmental factors and CYP2C19 polymorphisms on the risk of esophageal squamous cell carcinoma in Fujian Province of China

Background

The purpose of this study was to explore the effects of CYP2C19 gene polymorphisms and various environmental factors and their interactions on the risk of esophageal squamous cell carcinoma (ESCC) in a Chinese Han population.

Methods

A 1:2 frequency-matched case control study of 285 patients and 570 controls was conducted from June 2010 to May 2011 in AnXi of Fujian province, China. Environmental factors were investigated using a self-administered questionnaire and genotypes were determined using polymerase chain reaction restriction fragment length polymorphism based methods. Unconditional logistic regression models were used for statistical evaluation.

Results

Current or former smoking, consumption of pickled vegetables or hot beverages/food, having a first degree relative with ESCC and history of reflux esophagitis were significantly associated with increased ESCC risk, whereas tea drinking and consumption of fresh vegetables and fruits were significantly associated with decreased risk. The CYP2C19*2 GA/AA genotype was significantly more prevalent in ESCC patients and individuals with at least one copy of the CYP2C19*2 A allele had a 3.19-fold increased risk (adjusted 95% confidence interval (CI): 2.21–4.61, P < 0.001) of ESCC compared with those without this allele. We found no significant associations between CYP2C19*3 genotypes and ESCC. The Cyp2C19*2 polymorphism appeared to have a multiplicative joint effect with tea drinking and hot beverage/food consumption (gene–tea drinking: P_interaction = 0.042; hot beverage/food consumption: P_interaction = 6.98 × 10⁻⁶) and an additive joint effect with pickled vegetable consumption (interaction contrast ratio = 1.96, 95% CI: 0.12–3.80).

Conclusions

Our findings suggest that the CYP2C19*2 polymorphism plays an important role in the development of ESCC in the Chinese population, modified by tea drinking and consumption of pickled vegetables or hot beverages/food. Further studies are warranted to confirm our results.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-015-0156-3) contains supplementary material, which is available to authorized users.

Herbal medicines in Brazil: pharmacokinetic profile and potential herb-drug interactions

A plethora of active compounds found in herbal medicines can serve as substrate for enzymes involved in the metabolism of xenobiotics. When a medicinal plant is co-administered with a conventional drug and little or no information is known about the pharmacokinetics of the plant metabolites, there is an increased risk of potential herb-drug interactions. Moreover, genetic polymorphisms in a population may act to predispose individuals to adverse reactions. The use of herbal medicines is rapidly increasing in many countries, particularly Brazil where the vast biodiversity is a potential source of new and more affordable treatments for numerous conditions. Accordingly, the Brazilian Unified Public Health System (SUS) produced a list of 71 plant species of interest, which could be made available to the population in the near future. Physicians at SUS prescribe a number of essential drugs and should herbal medicines be added to this system the chance of herb-drug interactions further increases. A review of the effects of these medicinal plants on Phase 1 and Phase 2 metabolic mechanisms and the transporter P-glycoprotein was conducted. The results have shown that approximately half of these medicinal plants lack any pharmacokinetic data. Moreover, most of the studies carried out are in vitro. Only a few reports on herb-drug interactions with essential drugs prescribed by SUS were found, suggesting that very little attention is being given to the safety of herbal medicines. Here we have taken this information to discuss the potential interactions between herbal medicines and essential drugs prescribed to Brazilian patients whilst taking into account the most common polymorphisms present in the Brazilian population. A number of theoretical interactions are pinpointed but more pharmacokinetic studies and pharmacovigilance data are needed to ascertain their clinical significance.

Individuals having variant genotypes of cytochrome P450 2C19 are at increased risk of developing primary liver cancer in Han populations, without infection with the hepatitis virus

Recently, many researchers have reported that the genetic polymorphisms of CYP2C19 may account for the interpatient variability of the clinical course in cancers including primary liver cancer (PLC). Besides the genetic polymorphisms of CYP2C19, hepatitis viruses (HV, including HAV, HBV, HCV, HDV, HEV, especially HBV and/or HCV) also account for the interpatient variability of the clinical course in PLC. This research covered the above two factors and divided the patients with PLC into two groups (one group with HBV infection and another without any HV infection) to find out whether the genetic polymorphisms of CYP2C19 have different effects in the progressing of PLC in different groups of patients. Eight hundred sixty-four cancer-free Han people (controls, named group 1), 207 Han PLC patients with HBV infection (group 2), and 55 Han PLC patients without any HV infection (group 3) were involved in this study. A wild-type allele (CYP2C19*1) and two mutated alleles (CYP2C19*2 and CYP2C19*3) were identified. The frequencies of the mutant alleles and genotypes were then compared with each other. The frequencies of the homozygous and heterozygous variant genotypes (*2/*2, *2/*3, *3/*3) in group 3 (25.5 %) were significantly higher than those in other groups (11.9 % in group 1 and 13.5 % in group 2, P = 0.014, 95 % confidence interval (CI)). The differences were statistically significant between group 1 and group 3 (P = 0.004, 95 % CI), but they were not statistically significant between group 1 and group 2 (P = 0.527, 95 % CI). Thus, we conclude that people which were not infected with HV but with the homozygous or heterozygous variant genotypes (*2/*2, *2/*3, *3/*3) of CYP2C19 may have higher possibilities of getting PLC than people with other allelic genotypes (*1/*1, *1/*2, *1/*3) (odds ratio (OR) = 2.523, 95 % CI = 1.329 ~ 4.788). However, in patients with HBV infection, the genetic polymorphisms of CYP2C19 did not seem to be an important factor in the risk of developing PLC (OR = 1.156, 95 % CI = 0.738 ~ 1.810).