Interaction of drug metabolizing cytochrome P450 2D6 poor metabolizers with cytochrome P450 2C9 and 2C19 genotypes modify the susceptibility to head and neck cancer and treatment response

Circadian rhythm-related genes index: A predictor for HNSCC prognosis, immunotherapy efficacy, and chemosensitivity

Background

Head and neck squamous cell carcinoma (HNSCC) is the most common head and neck cancer and is highly aggressive and heterogeneous, leading to variable prognosis and immunotherapy outcomes. Circadian rhythm alterations in tumourigenesis are of equal importance to genetic factors and several biologic clock genes are considered to be prognostic biomarkers for various cancers. The aim of this study was to establish reliable markers based on biologic clock genes, thus providing a new perspective for assessing immunotherapy response and prognosis in patients with HNSCC.

Methods

We used 502 HNSCC samples and 44 normal samples from the TCGA-HNSCC dataset as the training set. 97 samples from GSE41613 were used as an external validation set. Prognostic characteristics of circadian rhythm-related genes (CRRGs) were established by Lasso, random forest and stepwise multifactorial Cox. Multivariate analysis revealed that CRRGs characteristics were independent predictors of HNSCC, with patients in the high-risk group having a worse prognosis than those in the low-risk group. The relevance of CRRGs to the immune microenvironment and immunotherapy was assessed by an integrated algorithm.

Results

6-CRRGs were considered to be strongly associated with HNSCC prognosis and a good predictor of HNSCC. The riskscore established by the 6-CRRG was found to be an independent prognostic factor for HNSCC in multifactorial analysis, with patients in the low-risk group having a higher overall survival (OS) than the high-risk group. Nomogram prediction maps constructed from clinical characteristics and riskscore had good prognostic power. Patients in the low-risk group had higher levels of immune infiltration and immune checkpoint expression and were more likely to benefit from immunotherapy.

Conclusion

6-CRRGs play a key predictive role for the prognosis of HNSCC patients and can guide physicians in selecting potential responders to prioritise immunotherapy, which could facilitate further research in precision immuno-oncology.

Cytochrome P450 2C19 gene polymorphisms (CYP2C19*2 and CYP2C19*3) in chronic myeloid leukemia patients: in vitro and in silico studies

Polymorphisms in the CYP2C19 have a huge impact on drug processing, out of which CYP2C19*2 and CYP2C19*3 are the most common variants associated with reduced metabolism of drugs. Mechanism by which two variants contribute in poor metabolization of drugs and cancer is not well understood. Here, we hypothesized that the mutations in CYP2C19 gene might affect the risk of chronic myeloid leukemia patients (CML). Present study has two main objectives: first to investigate the allele frequencies of CYP2C19*2 and CYP2C19*3 associated gene polymorphisms in CML patients and to elucidate the structural stability, conformation and functions of protein encoded by such variants. Genotyping of CYP2C19 was performed in 103 CML patients and 103 matched healthy controls. Heterozygous genotype of CYP2C19*2 was higher in CML patients (13.59%) than the controls (4.85%). Whereas, CYP2C19*3 allele frequency was not observed in cases as well as in controls. Furthermore, molecular dynamics (MD) simulation was applied to monitor the structural and conformational effect of above mutants. MD simulation results demonstrated that these mutants formed unstable proteins with distorted conformations, altered residues network and affected drug binding site which led to malfunction of mutant proteins. Hence, the study provides the role of CYP2C19 gene polymorphisms in susceptibility to CML population and explored the molecular basis of malignancies caused which may aid in the development of precise medicine or adjusting the drug dosages so as to reduce the chemotherapeutic side effects.Communicated by Ramaswamy H. Sarma.

Distribution of CYP2D6 genotypes in the Indian population - preliminary report

Background

Cytochrome P450 2D6 (CYP2D6) allelic distribution exhibits differences amongst worldwide populations. There is lack of data from Mumbai, Western India, on the major CYP2D6 alleles *2, *3, *4, *5, *10 and *41, and gene multiplication alleles. Hence, the present study was undertaken to determine the distribution of these clinically relevant CYP2D6 alleles.

Methods

Fifty-two healthy individuals were screened using TaqMan SNP genotyping and copy number variation (CNV) assays by real-time polymerase chain reaction.

Results

The allele frequencies of CYP2D6*2, *3, *4, *5, *10 and *41 alleles were observed to be 30.8%, 0%, 11.5%, 3.9%, 19.2% and 17.3%, respectively. The frequency of CYP2D6 gene one copy, two copies, three copies and four copies were observed to be 7.7%, 76.9%, 13.5% and 1.9%, respectively. The predicted phenotype frequency was observed to be 78.9%, 3.9% and 9.6% for extensive, intermediate, and ultrarapid metabolizers, respectively, whereas poor metabolizers were not detected.

Conclusions

CYP2D6 allele frequencies showed heterogeneous distribution in the present study as compared to worldwide populations. High frequency of CYP2D6*41 allele, gene duplication alleles and UMs was observed. The scarcity and/or lack of data from the Indian population on these alleles further substantiates the need for screening of CYP2D6 genotyping.

Role of Genetic Variations in Determining Treatment Outcome in Head and Neck Cancer

Worldwide, head and neck squamous cell carcinoma (HNSCC) is responsible for >550,000 diagnoses and 380,000 deaths annually. It originates in the upper aerodigestive tract and has a multifactorial origin involving both genetic and lifestyle risk factors. The clinical management of HNSCC involves surgery, radiotherapy, and chemotherapy. Several studies point to the role of genetic variations in predicting drug efficacy and toxicity. Cancer pharmacogenomics has fast emerged as a new and promising field for the early identification of genetic markers that can predict drug response or toxicity, with the number of studies of genetic polymorphisms as prognostic factors of HNSCC treatment outcomes growing. The number of studies evaluating the association of candidate polymorphisms in drug-metabolising Phase I and II enzymes with treatment outcome far exceed the studies involving other candidate genes, such as those involved in drug metabolism, DNA repair, and cell cycle regulation. This review focusses on the relevance of genetic variations in genes, where the corresponding gene products play an important role in drug metabolism (TPMT, DPD), DNA repair (X-ray repair cross complementing 1), cell cycle (tumour protein P53), and carcinogenesis (matrix metalloproteinase 3 and 7), thereby contributing to the treatment outcome for HNSCC. This could greatly help clinicians in identifying genetic markers useful for the selection of optimal drugs, dose, and treatment duration on an individual basis, resulting in improved drug efficacy and decreased toxicity. However, further studies are needed in well characterised and larger HNSCC populations with proper validation of pharmacogenetic markers in experimental settings before application in clinical routine diagnostics.

Association of Genetic Variants of CYP2C19 and CYP2D6 with Esophageal Squamous Cell Carcinoma Risk in Northern India, Kashmir

Genetic polymorphism in xenobiotic metabolizing enzymes (XMEs) is associated with various malignancies. However, the association of esophageal cancer with XMEs is mixed. The current study was aimed to explore the association of genetic polymorphisms of cytochrome (CYP) 2C19 and CYP2D6 genotypes with esophageal squamous cell carcinoma (ESCC) risk in Kashmir, India. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing methods were used for genotyping of 492 ESCC cases and equal number of individually matched controls. Conditional logistic regression models were used to assess odds ratios (ORs) and 95% confidence intervals. Increased ESCC risk was observed in subjects with variant genotypes of CYP2C19 (OR = 3.3) or CYP2D6 (OR = 2.1) and risk was higher (OR = 4.6) in subjects who harbored both the genotypes. Almost same but higher risk turned when subjects were smokers and carried a variant genotype of CYP2C19 (OR = 4.4) or CYP2D6 (OR = 4.7). Risk was appreciably increased in subjects who had family history of any cancer and also harbored a variant genotype of either CYP2C19 (OR = 15.5) or CYP2D6 (OR = 9.7). Subjects harboring a variant genotype of CYP2D6 showed an added risk when they used biomass as fuel (OR = 4.6). In conclusion, variant genotypes of CYP2C19 and CYP2D6 are associated with an increased risk of ESCC.

CYP1A1 MspI polymorphism and the risk of oral squamous cell carcinoma: Evidence from a meta-analysis

Numerous case-control studies have investigated whether the CYP1A1 gene polymorphism is involved in the occurrence of oral squamous cell carcinoma (OSCC); however, the conclusions are inconsistent. In order to further explore the correlation and obtain a strong conclusion, a meta-analysis was performed to systematically assess the association between the CYP1A1 MspI polymorphism and risk of OSCC. In the present meta-analysis, the odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were used to assess the association. The statistical analyses were performed with STATA 11.0 software. The heterogeneity was assessed by Q test and I²test. The final analysis included 10 studies of 1,505 cases and 1,967 controls. The overall results suggested that the CYP1A1 MspI polymorphism was significantly associated with an increased risk of OSCC (CC+TC vs. TT: OR, 1.31; 95% CI, 1.01-1.70; P=0.043; CC vs. TC+TT: OR, 2.38; 95% CI, 1.58-3.58; P<0.001; CC vs. TT: OR, 2.52; 95% CI, 1.60-3.96; P<0.001; and C vs. T: OR, 1.45; 95% CI, 1.15-1.83; P<0.001). In a stratified analysis by ethnicity, a statistically significant correlation existed in the Asian population, but not mixed-race and Caucasian populations. In conclusion, despite several limitations, the present meta-analysis established that the CYP1A1 MspI polymorphism may be a risk factor for OSCC, particularly among the Asian population.

Family history of cancer and the risk of squamous cell carcinoma of oesophagus: a case-control study in Kashmir, India

Background:

Only a few studies have examined the association between family history of cancer (FHC) and the risk of oesophageal squamous cell carcinoma (ESCC) in high incidence areas of ESCC. We conducted a case–control study to evaluate the relationship between FHC and ESCC risk in Kashmir, India, with analysis of detailed epidemiological data and information on multiple gene polymorphisms.

Methods:

We collected detailed information on FHC and a number of socio-demographic and lifestyle factors, and also obtained blood samples for genetic analysis from 703 histopathologically confirmed ESCC cases and 1664 individually matched controls. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs).

Results:

Participants who had FHC showed a strong association with ESCC risk, and the risk was stronger when first-degree relatives (FDRs) had FHC (OR=6.8; 95% CI=4.6–9.9). Having a sibling with a cancer showed the strongest association (OR=10.8; 95% CI=6.0–19.3), but having a child with a cancer was not associated with ESCC risk. A history of any cancer in the spouse was also associated with ESCC risk (OR=4.1; 95% CI=1.6–10.2). Those with two or more relatives with FHC were at a higher risk of ESCC. After restricting FHC to familial ESCC only, the above associations were strengthened, except when spouses were affected with ESCC (OR=2.5; 95% CI=0.7–8.9). When we examined the associations between several single-nucleotide polymorphisms and ESCC in those with and without FHC, the associations of variant genotypes in cytochrome P450 (CYP) 2C19 and CYP2D6 and the wild genotype of CYP2E1 with ESCC were much stronger in those with FHC. The FHC had an additive interaction with several risk factors of ESCC in this population.

Conclusion:

Our results showed that FHC was strongly associated with ESCC risk in Kashmir. It seems both genetic factors and shared environment are involved in this association.

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.

Cytochrome P450 in Cancer Susceptibility and Treatment

Cytochrome 450 (CYP450) designates a group of enzymes abundant in smooth endoplasmic reticulum of hepatocytes and epithelial cells of small intestines. The main function of CYP450 is oxidative catalysis of various endogenous and exogenous substances. CYP450 are implicated in phase I metabolism of 80% of drugs currently in use, including anticancer drugs. They are also involved in synthesis of various hormones and influence hormone-related cancers. CYP450 genes are highly polymorphic and their variants play an important role in cancer risk and treatment. Association studies and meta-analyses have been performed to decipher the role of CYP450 polymorphisms in cancer susceptibility. Cancer treatment involves multimodal therapies and evaluation of CYP450 polymorphisms is necessary for pharmacogenetic assessment of anticancer therapy outcomes. In addition, CYP450 inhibitors are being evaluated for improved pharmacokinetics and oral formulation of several anticancer drugs.

Association of cytochrome P450 2C9 polymorphism with locally advanced head and neck squamous cell carcinoma and response to concurrent cisplatin-based radical chemoradiation

Aims:

The aim of the present study is to investigate the association between polymorphism of cytochrome P450 2C9 (CYP2C9) enzyme with head and neck squamous cell carcinoma (HNSCC) and response in patients receiving cisplatin-based radical chemoradiation (CT-RT).

Materials and Methods:

Four hundred and sixty patients suffering from locally advanced HNSCC and an equal number of healthy controls were genotyped for CYP2C9*2 and CYP2C9*013, leading to poor metabolizers (PMs) by polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP). Each case was assessed thoroughly for treatment response as per the World Health Organization (WHO) criteria.

Results and Analysis:

The frequency of heterozygous genotypes of both CYP2C9*2 (27.8%) and CYP2C9*3 (25%) were found to be significantly higher in the HNSCC cases as compared to the healthy controls. Tobacco intake in the form of chewing or smoking and alcohol intake resulted in several folds increase in the risk to HNSCC in the cases carrying variant genotypes of CYP2C9*2 or CYP2C9*013. Further, majority of the cases assessed for response (n = 436) carrying variant alleles of CYP2C9*2 (69.6%) or CYP2C9*3 (65.2%) were found to respond poorly to cisplatin-based radical CT-RT.

Conclusion:

The data suggests a significant association of the CYP2C9 polymorphism with HNSCC and treatment outcome underlining the importance of pretherapeutic genotyping in determining the treatment protocol.

Meta-analyses of the effect of CYP1A1 and CYP2D6 polymorphisms on the risk of head and neck squamous cell carcinoma

BACKGROUND

CYP1A1 and CYP2D6 are important genes encoding enzymes involved in the metabolism of toxic chemicals and carcinogens. However, inconclusive results for the association between CYP1A1 and CYP2D6 polymorphisms and the risk of head and neck squamous cell carcinoma (HNSCC) have been reported. We conducted a meta-analysis to evaluate the association of CYP1A1 and CYP2D6 polymorphisms with the risk of HNSCC.

METHODS

A database search yielded 19 relevant studies. 3 polymorphisms were included in the meta-analysis: CYP1A1, CYP2D6*4 and CYP2D6*10. Random or fixed effect models were used in the analysis.

RESULTS

The CYP1A1 polymorphism was associated with HNSCC (for m1m1 vs. m1m2: odds ratio (OR) = 1.26, 95% confidence interval (CI) = 1.030-1.542, pheterogeneity = 0.025; for the recessive model: OR = 1.316, 95% CI = 1.065-1.625, pheterogeneity = 0.001). The analysis showed evidence for association between the CYP2D6*4 polymorphism and HNSCC in Asian populations; however, negative results were also observed in other models. A significant association was also observed between CYP2D6*10 polymorphism and HNSCC risk.

CONCLUSIONS

The current study demonstrates that the CYP1A1 and CYP2D6 polymorphisms are associated with susceptibility to both development and progression of HNSCC.

Polymorphisms in the human cytochrome P450 and arylamine N-acetyltransferase: susceptibility to head and neck cancers

The occurrence of head and neck cancer (HNC) is associated with smoking and alcohol drinking. Tobacco smoking exposes smokers to a series of carcinogenic chemicals. Cytochrome P450 enzymes (CYP450s), such as CYP1A1, CYP1B1, and CYP2D6, usually metabolize carcinogens to their inactive derivatives, but they occasionally convert the chemicals to more potent carcinogens. In addition, via CYP450 (CYP2E1) oxidase, alcohol is metabolized to acetaldehyde, a highly toxic compound, which plays an important role in carcinogenesis. Furthermore, two N-acetyltransferase isozymes (NATs), NAT1 and NAT2, are polymorphic and catalyze both N-acetylation and O-acetylation of aromatic and heterocyclic amine carcinogens. Genetic polymorphisms are associated with a number of enzymes involved in the metabolism of carcinogens important in the induction of HNC. It has been suggested that such polymorphisms may be linked to cancer susceptibility. In this paper, we select four cytochrome P450 enzymes (CYP1A1, CYP1BA1, CYP2D6, and CYP2E1), and two N-acetyltransferase isozymes (NAT1 and NAT2) in order to summarize and analyze findings from the literature related to HNC risk by focusing on (i) the interaction between these genes and the environment, (ii) the impact of genetic defect on protein activity and/or expression, and (iii) the eventual involvement of race in such associations.

Interaction between alcohol consumption and CYP 2C19 gene polymorphism in relation to oesophageal squamous cell carcinoma

OBJECTIVES

The purpose of this study is to explore the relationship between the interactions of CYP2C19 gene polymorphisms and several environmental factors and oesophageal squamous cell carcinoma (OSCC).

METHODS

In a case-control study of OSCC patients (n = 350) and healthy controls (n = 350), we investigated the roles of polymorphism in the CYP2C19 gene by the use of polymerase chain reaction--restriction fragment length polymorphism (PCR - RFLP) analysis.

RESULTS

The CYP2C19(*)3 AG+AA genotype was significantly more prevalent in OSCC patients (10.0% versus 3.43%; P<0.01). Multiple logistic regression analysis showed drinking (OR: 5.603, 95% CI: 3.431-11.112; P = 0.005) and smoking (OR: 4.341, 95% CI: 3.425-10.241; P = 0.001) was the independent risk factor of OSCC respectively, and there were significant interaction between CYP2C19(*)3 and drinking (OR: 8.747, 95% CI: 6.321-18.122; P = 0.009).

CONCLUSIONS

The CYP2C19(*)3 polymorphism and OSCC were synergistically and significantly associated in Chinese Han patients.

CYP2D6*4 allele and breast cancer risk: is there any association?

BACKGROUND

CYP2D6 is an important cytochrome P450 enzyme. These enzymes catalyse the oxidative biotransformation of about 25% of clinically important drugs as well as the metabolism of numerous environmental chemical carcinogens. The most frequent null allele of CYP2D6 in European populations, CYP2D6*4, has been studied here in order to elucidate whether a relationship exists between this allele and the risk of developing breast cancer in a Spanish population.

MATERIALS AND METHODS

Ninety-six breast cancer Spanish patients and one hundred healthy female volunteers were genotyped for the CYP2D6*4 allele using AmpliChip CYP450 Test technology.

RESULTS

Homozygous CYP2D6*4 frequency was significant lower in breast cancer patients than in the control group (OR=0.22, p=0.04). The heterozygous CYP2D6*4 group also displayed lower values in patients than in controls but the difference was not significant (OR=0.698, p=0.28). Therefore, the presence of the CYP2D6*4 allele seems to decrease susceptibility to breast carcinoma in the selected population.

CONCLUSIONS

A possible decreased transformation of procarcinogens by CYP2D6*4 poor metabolisers could result in a protective effect against carcinogens.