Association of the CHRNA3 locus with lung cancer risk and prognosis in Chinese Han population. J Thorac Oncol. 2010;5:658-666. [PMID: 20234319 DOI: 10.1097/jto.0b013e3181d5e447]

Chronic Obstructive Pulmonary Disease Risk and Smoking Cessation Changes Induced by CHRNA5-A3 and CHRNB3-A6 Variation in a Chinese Male Population

Most studies in the field of CHRNA5-A3 and CHRNB3-A6 have only focused on lung cancer risk; however, the associations with chronic obstructive pulmonary disease (COPD) risk and smoking cessation is less understood, particularly in the Chinese male population. In this study, samples from 823 male patients with COPD (non smokers: 416; still smoking: 407) and 435 smoking male healthy control subjects were performed with DNA extraction and single nucleotide polymorphism (SNP) genotyping. We studied three SNPS in two genes, namely rs667282 and rs3743073 in CHRNA5-A3 and rs4950 in CHRNB3-A6, and their distributions in the three groups are not statistically different (p >0.05). We grouped COPD patients according to whether they had successfully quit smoking, the CT genotype of rs667282 demonstrated association with an increased rate of successful smoking cessation compared with the TT genotype [adjusted odds ratio (OR) = 0.54, 95% confidence interval (95% CI) = 0.37-0.7, p <0.001); rs4950 AG genotypes were distinctly associated with increased rates of successful smoking cessation (adjusted OR = 0.55, 95% CI = 0.40-0.76, p <0.001). The effect is significant under the assumption of an over dominant mode of inheritance (adjusted OR = 0.58, 95% CI = 0.43 to 0.79, p <0.001). No significant difference in rs3743073 was found (p >0.05). Our findings confirmed the hypothesis that CHRNA5-A3 and CHRNB3-A6 variation are not associated with the risk of COPD. We found CHRNA5-A3 and CHRNB3-A6 were significantly associated with successful smoking cessation in smoking COPD patients.

Impact of CHRNA5 polymorphisms on the risk of schizophrenia in the Chinese Han population

BACKGROUND

Schizophrenia is a complex mental disease whose cause is still unknown. Neuronal nicotinic acetylcholine receptors (nAChRs) have been implicated in various neurological disorders, including schizophrenia. The previous reports have shown that CHRNA polymorphisms were involved in schizophrenia. This study is to explore the potential association between CHRNA5 (OMIM#118505) polymorphisms and schizophrenia susceptibility in a Chinese population.

METHODS AND RESULTS

A case-control study was conducted with 384 schizophrenia patients and 687 controls. We genotyped eight single nucleotide polymorphisms (SNPs) distributed in CHRNA5. Regulome DB, HaploReg, and GTEx databases were used to calculate possible functional effects of the polymorphisms. The χ² test, genetic model analysis, and haplotype analysis were involved in assessing genetic association between variants and schizophrenia risk. The results exhibited that rs17486278 (NC_000015.10:g.78575140A>C) was associated with a decreased risk of schizophrenia on the basis of the recessive model (adjusted OR = 0.37, 95%CI: 0.15-0.93) in females. Moreover, we found that the four variants rs588765, rs6495306, rs680244, rs692780 were extremely significant after being stratified by ≥45 years.

CONCLUSIONS

Overall, our findings supported that the potential association existed between CHRNA5 polymorphisms and schizophrenia susceptibility in a Chinese population. But, large sample validation is needed to enhance the accuracy of our results.

Association Between Nicotine-dependent Gene Polymorphism and Smoking Cessation in Patients With Lung Cancer

BACKGROUND

Patients with lung cancer continue to smoke owing to complex factors. Failure to quit smoking (defined as nicotine dependence) is significantly associated with genetic status. This study aimed to investigate the relationship between polymorphisms in nicotine dependence genes and smoking status after the diagnosis of lung cancer.

PATIENTS AND METHODS

A total of 240 patients with lung cancer were included from July 2017 to March 2018. According to the actual smoking condition after lung cancer diagnosis, eligible patients were divided into 3 groups: the never-smoking group, the failure to quit smoking group, and the successful smoking cessation group. Fagerstrom Test for Nicotine Dependence scores were used to evaluate the smoking status of each group. Three nicotine-dependent genes with 6 loci were detected.

RESULTS

Among the 240 patients, 86 were never-smokers, 51 failed to quit smoking, and 104 successfully quit smoking. The initial age of smoking in the failure to quit smoking group was significantly younger than those in the successful smoking cessation group (P = .001). There was a significant difference in the GG and AG and AA genotype distributions of CHRNA3 (rs578776) among the 3 groups (P = .003). There was also a significant difference in the distribution of CHRNA4 (rs2229959) genotypes among the 3 groups (P = .003). However, there was no significant difference in the genotype distribution of CHRNA5 (rs588765) among the 3 groups (P = .277).

CONCLUSIONS

Gene polymorphisms of CHRNA3 (rs578776) and CHRNA4 (rs1044396 and rs2229959) were associated with the success of smoking cessation after the diagnosis of lung cancer, which should be considered in the management of smoking cessation after patients are diagnosed with lung cancer.

Genetic variants of CHRNA5-A3 and CHRNB3-A6 predict survival of patients with advanced non-small cell lung cancer

Nicotinic acetylcholine receptors (nAChRs) play a key role in carcinogenesis and progression of lung cancer; and polymorphisms in CHRNA5-A3 and CHRNB3-A6, two gene clusters encoding nAChR subunits, have been associated with lung cancer risk. In this study, we investigated whether variants in the two gene clusters were associated with prognosis of advanced non-small cell lung cancer (NSCLC). A total of 165 stage IIIB–IV NSCLC patients were enrolled in this study. Three polymorphisms (rs667282 and rs3743073 in CHRNA5-A3 and rs13280604 in CHRNB3-A6) were genotyped using the TaqMan method. Overall survival (OS) was estimated using the log-rank test and the Cox models. Our results showed that patients with CHRNA5-A3 rs667282 TT or TC genotypes had a significantly shorter OS than those carrying the CC genotype (Log-rank, P = 0.043). Furthermore, multivariate Cox regression analysis showed that rs667282 TT/TC genotypes are significantly associated with increased risk of overall deaths (adjusted hazard ratio, 1.7; 95% CI, 1.1–2.7). However, the similar results were not observed for other two polymorphisms. Furthermore, no evident association was found between these variants and clinicopathologic features of advanced NSCLC. Our present study suggested that rs667282 in CHRNA5-A3 may modify the prognosis of patients with advanced NSCLC.

An efficient method to genotype the polymorphisms of cholinergic nicotinic receptor subunit genes and their associations with COPD onset risk

BACKGROUND

Single-nucleotide polymorphisms (SNPs) in the cholinergic nicotinic receptor subunit genes on chromosome 15q25.1, including CHRNA3, CHRNB4 and CHRNA5, are well-established biomarkers of chronic obstructive pulmonary disease (COPD) and lung cancer. Thus, there is great demand for a rapid, easy and inexpensive method to detect these variations for purpose of risk prediction in large populations.

AIM OF THE STUDY

The aim of this study was to establish an accurate and efficient method for genotyping CHRN SNPs and testing their association with age at onset of COPD in Chinese population as well as the clinical stage in COPD patients.

MATERIALS AND METHODS

We designed a method to specifically genotype 5 SNPs of CHRN genes based on a modified high-resolution melt (HRM) method and then validated the genotyping results by direct sequencing of 120 samples. We further used the HRM method to genotype these 5 SNPs in 1,013 COPD patients.

RESULTS

Requiring little time, few material costs and only a simplified protocol, the modified HRM method could accurately distinguish the genotypes of CHRN SNPs, demonstrating kappa coefficients >0.96 based on the results from direct sequencing. Furthermore, the data showed that the GG genotype of SNP rs56218866 was associated with a significantly earlier age of COPD onset than A (AA+AG) genotypes (61.0 ± 8.93 vs. 67.8 ± 9.88; P = 0.031), which was not found for the other SNPs. No significant association was observed between the COPD stages and any of the above SNPs.

CONCLUSION

A simple, rapid and efficient HRM method was introduced for CHRN SNP genotyping and a suggestion that the SNP rs56218866A>G is associated with early-onset COPD in a Chinese population was found.

Duplicated copy of CHRNA7 increases risk and worsens prognosis of COPD and lung cancer

Recent genome-wide association studies implicated that the nicotinic acetylcholine receptors (nAChRs) are common susceptible genes of two contextual diseases: chronic obstructive pulmonary disease (COPD) and lung cancer. We aimed to test whether the copy number variations (CNVs) in nAChRs have hereditary contributions to development of the two diseases. In two, two-stage, case-control studies of southern and eastern Chinese, a common CNV-3956 that duplicates the cholinergic receptor, nicotinic, α7 (CHRNA7) gene was genotyped in a total of 7880 subjects and its biological phenotype was assessed. The ≥4-copy of CNV-3956 increased COPD risk (≥4-copy vs 2/3-copy: OR=1.44, 95% CI=1.23-1.68) and caused poor lung function, and it similarly augmented risk (OR=1.49, 95% CI=1.29-1.73) and worsened prognosis (hazard ratio (HR)=1.25, 95% CI=1.07-1.45) of lung cancer. The ≥4-copy was estimated to account for 1.56% of COPD heritability and 1.87% of lung cancer heritability, respectively. Phenotypic analysis further showed that the ≥4-copy of CNV-3956 improved CHRNA7 expression in vivo and increased the carriers' smoking amount. The CNV-3956 of CHRNA7 contributed to increased risks and poor prognoses of both COPD and lung cancer, and this may be a genetic biomarker of the two diseases.

Acetylcholine receptor pathway in lung cancer: New twists to an old story

Genome-wide association studies revealed that allelic variation in the α5-α3-β4 nicotine acetylcholine receptor (nAChR) cluster on chromosome 15q24-15q25.1 was associated with lung cancer risk. nAChRs are membrane ligand-gated cation channels whose activation is triggered by the binding of the endogenous neurotransmitter acetylcholine (ACh) or other biologic compounds including nicotine. nAChRs have been found on lung cancer cells, underscoring the idea that the non-neuronal nAChR pathway has important implications for lung cancer. Several studies focusing on the treatment with nAChR antagonists with improved selectivity might trigger novel strategies for the intervention and prevention of lung cancer. Here we review the genetic risk factors for lung cancer in the nAChR gene cluster, the roles of nicotine receptors, and the molecular mechanisms of acetylcholine receptor pathways to lead to more opportunities for intervention and prevention of lung cancer.

Four SNPs in the CHRNA3/5 alpha-neuronal nicotinic acetylcholine receptor subunit locus are associated with COPD risk based on meta-analyses

Background

Several single nucleotide polymorphisms (SNPs) in an α-neuronal nicotinic acetylcholine receptor subunit (CHRNA3/5) were identified to be associated with chronic obstructive pulmonary disease (COPD) in a study based on a Norwegian population. However, results from subsequent studies have been controversial, particularly in studies recruiting Asians. In the present study, we conducted a comprehensive search and meta-analyses to identify susceptibility SNPs for COPD in the CHRNA3/5 locus.

Methods

A comprehensive literature search was conducted to find studies that have reported an association between SNPs in the CHRNA3/5 locus and COPD risk. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) for each SNP were calculated with the major allele or genotype as the reference group. The influence of individual studies on pooled measures was assessed, in addition to publication bias.

Results

A total of 12 articles with 14 eligible studies were included in this analysis. Association between 4 SNPs in the CHRNA3/5 locus and COPD was evaluated and included rs1051730, rs8034191, rs6495309, and rs16969968. Significant associations between the 4 SNPs and COPD were identified under allele (rs1051730: OR = 1.14, 95%CI = 1.10–1.18; rs8034191: OR = 1.29, 95%CI = 1.18–1.41; rs6495309: OR = 1.26, 95%CI = 1.09–1.45; rs16969968: OR = 1.27, 95%CI = 1.17–1.39) and genotype models. Subgroup analysis conducted for rs1051730 showed a significant association between this SNP and COPD risk in non-Asians (OR = 1.14, 95%CI = 1.10–1.18), but not Asians (OR = 1.23, 95%CI = 0.91–1.67). Rs1051730 and rs6495309 were also significantly associated with COPD after adjusting for multiple variables, including age and smoking status.

Conclusion

Our results indicate that 4 SNPs in the CHRNA3/5 locus are associated with COPD risk. Rs1051730 was particularly associated with COPD in non-Asians, but its role in Asians still needs to be verified. Additional studies will be necessary to assess the effect of rs6495309 on COPD. Although rs1051730 and rs6495309 were shown to be independent risk factors for COPD, validation studies should be performed.

Plasminogen Activator Inhibitor Type 1 (PAI-1) A15T Gene Polymorphism Is Associated with Prognosis in Patients with EGFR Mutation Positive Pulmonary Adenocarcinoma

Background

Plasminogen activator inhibitor type 1 (PAI-1), an important regulator of plasminogen activator system which controls degradation of extracellular membrane and progression of tumor cells, and PAI-1 gene polymorphic variants have been known as the prognostic biomarkers of non-small cell lung cancer patients. Recently, experimental in vitro study revealed that transforming growth factor-β1 initiated PAI-1 transcription through epithelial growth factor receptor (EGFR) signaling pathway. However, there is little clinical evidence on the association between PAI-1 A15T gene polymorphism and prognosis of Korean population with pulmonary adenocarcinoma and the influence of activating mutation of EGFR kinase domain.

Methods

We retrospectively reviewed the medical records of 171 patients who were diagnosed with pulmonary adenocarcinoma and undergone EGFR mutation analysis from 1995 through 2009.

Results

In all patients with pulmonary adenocarcinoma, there was no significant association between PAI-1 A15T polymorphic variants and prognosis for overall survival. However, further subgroup analysis showed that the group with AG/AA genotype had a shorter 3-year survival time than the group with GG genotype in patients with EGFR mutant-type pulmonary adenocarcinoma (mean survival time, 24.9 months vs. 32.5 months, respectively; p=0.015). In multivariate analysis of 3-year survival for patients with pulmonary adenocarcinoma harboring mutant-type EGFR, the AG/AA genotype carriers had poorer prognosis than the GG genotype carriers (hazard ratio, 7.729; 95% confidence interval, 1.414-42.250; p=0.018).

Conclusion

According to our study of Korean population with pulmonary adenocarcinoma, AG/AA genotype of PAI-1 A15T would be a significant predictor of poor short-term survival in patients with pulmonary adenocarcinoma harboring mutant-type EGFR.

Association of CHRNA5-A3-B4 variation with esophageal squamous cell carcinoma risk and smoking behaviors in a Chinese population

BACKGROUND

CHRNA5-A3-B4, the gene cluster encoding nicotinic acetylcholine receptor subunits, is associated with lung cancer risk and smoking behaviors in people of European descent. Because cigarette smoking is also a major risk factor for esophageal squamous cell carcinoma (ESCC), we investigated the associations between variants in CHRNA5-A3-B4 and ESCC risk, as well as smoking behaviors, in a Chinese population.

METHODS

A case-control study of 866 ESCC patients and 952 healthy controls was performed to study the association of polymorphisms (rs667282 and rs3743073) in CHRNA5-A3-B4 with cancer risk using logistic regression models. The relationships between CHRNA5-A3-B4 polymorphisms and smoking behaviors that can be quantified by cigarettes smoked per day (CPD) and pack-years of smoking were separately estimated with Kruskal-Wallis tests among all 840 smokers.

RESULTS

CHRNA5-A3-B4 rs667282 TT/TG genotypes were associated with significantly increased risk of ESCC [adjusted odds ratio (OR) = 1.32, 95% confidence interval (CI) = 1.03 - 1.69, P = 0.029]. The increased ESCC risk was even higher among younger subjects (≤60 years) (OR = 1.44, 95% CI = 1.04 - 1.98, P = 0.024). These effects were not found in another polymorphism rs3743073. No evident association between the two polymorphisms and smoking behaviors was observed.

CONCLUSIONS

These results support the hypothesis that CHRNA5-A3-B4 is a susceptibility gene cluster for ESCC. The relationship between CHRNA5-A3-B4 and smoking behaviors in a Chinese population needs further investigation.

Genetic susceptibility to lung cancer--light at the end of the tunnel?

Lung cancer is one of the most common and deadliest cancers in the world. The major socio-environmental risk factor involved in the development of lung cancer is cigarette smoking. Additionally, there are multiple genetic factors, which may also play a role in lung cancer risk. Early work focused on the presence of relatively prevalent but low-penetrance alterations in candidate genes leading to increased risk of lung cancer. Development of new technologies such as genomic profiling and genome-wide association studies has been helpful in the detection of new genetic variants likely involved in lung cancer risk. In this review, we discuss the role of multiple genetic variants and review their putative role in the risk of lung cancer. Identifying genetic biomarkers and patterns of genetic risk may be useful in the earlier detection and treatment of lung cancer patients.

Polymorphisms of CHRNA5-CHRNA3-CHRNB4 Gene Cluster and NSCLC Risk in Chinese Population

AIM

To explore the potential association between single-nucleotide polymorphisms (SNPs) and haplotypes of the CHRNA5-CHRNA3-CHRNB4 gene cluster and the non-small cell lung cancer (NSCLC) susceptibility in never-smoking Chinese.

METHODS

A case-control study was conducted with 200 NSCLC patients and 200 healthy controls, matched on age and sex. Five SNPs distributed in CHRNA5-CHRNA3-CHRNB4 gene cluster were selected for genotyping. The association between genotype and lung cancer risk was evaluated by computing the odds ratio (OR) and 95% confidence interval (CI) from multivariate unconditional logistic regression analyses with adjustment for gender and age.

RESULTS

For CHRNA3 rs578776 status, data were available in 199 NSCLC patients and 199 controls. The G/G homozygote in CHRNB4 rs7178270 had a reduced risk of developing NSCLC (OR = 0.553; 95% CI = 0.309-0.989; P = .0437), especially squamous cell carcinoma (SQC) (OR = 0.344; 95% CI = 0.161-0.732; P = .0043), compared with those who carry at least one C allele (C/C and C/G). The polymorphisms of rs578776, rs938682, rs17486278, and rs11637635 were not significantly different between controls and cases or between controls and histologic subgroups, adenocarcinoma and SQC, respectively.

CONCLUSIONS

In our study, we found that the SNP of CHRNB4 rs7178270 is significantly associated with reduced risk of NSCLC, especially with reduced risk of SQC in never-smoking Chinese population.

Correlation between polymorphisms of nicotine acetylcholine acceptor subunit CHRNA3 and lung cancer susceptibility

Both environmental and genetic factors participate in the pathogenesis of lung cancer. The aim of this study was to explore the association between CHRNA3 polymorphisms of the nicotinic acetylcholine receptor gene and lung cancer risk in a hospital-based, case-controlled study. Single nucleotide polymorphisms (SNPs) in CHRNA3 rs3743073 (A>G) were determined using the TaqMan-MGB probe technique in 600 lung cancer cases and 600 normal controls. The differences in genotype and allele frequency were compared between groups and their association with lung cancer. The genotype frequency of rs3743073 (A>G) demonstrated Hardy-Weinberg equilibrium (P<0.05). The genotype and allele frequencies were significantly different between the cancer and control groups (P<0.05). Compared with patients with the TT genotype, lung cancer incidence was increased in patients with the TG and GG genotypes (OR=1.68; 95% CI, 1.30-2.19; P<0.05; OR=1.30; 95% CI, 1.05-1.61; P<0.05, respectively). Patients with rs3743073G variant alleles (TG and GG) were at greater risk (OR=0.65; 95% CI, 0.50-0.84; P<0.05) of developing lung cancer. Increased risk associated with rs3743073G variant alleles was observed in male smokers over the age of 60 (P<0.05). In this cohort, the CHRNA3 gene rs3743073G variant genotype significantly increased lung cancer risk, especially in male smokers over the age of 60.