The association between the rs6495309 polymorphism in CHRNA3 gene and lung cancer risk in Chinese: a meta-analysis

Study on polymorphisms in CHRNA5/CHRNA3/CHRNB4 gene cluster and the associated with the risk of non-small cell lung cancer

CHRNA5/CHRNA3/CHRNB4 gene cluster is located on chromosome 15q25.1 and was reported to be associated with risk of lung cancer. So far, the effect of three single nucleotide polymorphisms rs6495309, rs8040868, rs1948 in this gene cluster was unclear about lung cancer risk. The aim of the present study was to evaluate the associations of rs6495309, rs8040868, rs1948 polymorphism, smoking exposure and the interaction with non-small cell lung cancer risk in Chinese population. In this hospital-based case-control study, 306 lung cancer patients and 306 cancer-free controls were interviewed to collect demographic data and exposure status of smoking, and then donate 2ml venous blood which was used to be genotyped by Taqman allelic discrimination method. Our study found that subjects carrying rs1948 CT genotype stated to be a risk factor in Chinese Han population (adjusted OR = 1.594, 95% CI = 1.066-2.383, P = 0.023) and in non-smoking population (adjusted OR = 1.896, 95%CI = 1.069-3.362, P = 0.029). rs8040868 CC genotype indicated a higher risk for lung cancer in non-smokers in a recessive model (adjusted OR = 2.496, 95%CI = 1.044-5.965, P = 0.040) and in age-based stratified analysis (age <= 60, adjusted OR = 4.213, 95%CI = 1.062-16.708, P = 0.041). All smoking interaction were positive in the multiplicative interaction of the SNPs and smoking status (-/+) compared with recessive model. Overall, these finding suggested that rs1948(C > T) and rs8040868(T > C) could be meaningful as genetic markers for lung cancer risk in Chinese Han population.

Genetic polymorphisms and lung cancer risk: Evidence from meta-analyses and genome-wide association studies

A growing number of studies investigating the association between Single Nucleotide Polymorphisms (SNPs) and lung cancer risk have been published since over a decade ago. An updated integrative assessment on the credibility and strength of the associations is required. We searched PubMed, Medline, and Web of Science on or before August 29^th, 2016. A total of 198 articles were deemed eligible for inclusion, which addressed the associations between 108 variants and lung cancer. Among the 108 variants, 63 were reported to be significantly associated with lung cancer while the remaining 45 were reported non-significant. Further evaluation integrating the Venice Criteria and false-positive report probability (FPRP) was performed to determine the strength of cumulative epidemiological evidence for the 63 significant associations. As a result, 15 SNPs on or near 12 genes and one miRNA with strong evidence of association with lung cancer risk were identified, including TERT (rs2736098), CHRNA3 (rs1051730), AGPHD1 (rs8034191), CLPTM1L (rs401681 and rs402710), BAT3 (rs3117582), TRNAA (rs4324798), ERCC2 (Lys751Gln), miR-146a2 (rs2910164), CYP1B1 (Arg48Gly), GSTM1 (null/present), SOD2 (C47T), IL-10 (-592C/A and -819C/T), and TP53 (intron 6). 19 SNPs were given moderate rating and 17 SNPs were rated as having weak evidence. In addition, all of the 29 SNPs identified in 12 genome-wide association studies (GWAS) were proved to be noteworthy based on FPRP value. This review summarizes and evaluates the cumulative evidence of genetic polymorphisms and lung cancer risk, which can serve as a general and useful reference for further genetic studies.

Genetic predisposition to lung cancer: comprehensive literature integration, meta-analysis, and multiple evidence assessment of candidate-gene association studies

More than 1000 candidate-gene association studies on genetic susceptibility to lung cancer have been published over the last two decades but with few consensuses for the likely culprits. We conducted a comprehensive review, meta-analysis and evidence strength evaluation of published candidate-gene association studies in lung cancer up to November 1, 2015. The epidemiological credibility of cumulative evidence was assessed using the Venice criteria. A total of 1018 publications with 2910 genetic variants in 754 different genes or chromosomal loci were eligible for inclusion. Main meta-analyses were performed on 246 variants in 138 different genes. Twenty-two variants from 21 genes (APEX1 rs1130409 and rs1760944, ATM rs664677, AXIN2 rs2240308, CHRNA3 rs6495309, CHRNA5 rs16969968, CLPTM1L rs402710, CXCR2 rs1126579, CYP1A1 rs4646903, CYP2E1 rs6413432, ERCC1 rs11615, ERCC2 rs13181, FGFR4 rs351855, HYKK rs931794, MIR146A rs2910164, MIR196A2 rs11614913, OGG1 rs1052133, PON1 rs662, REV3L rs462779, SOD2 rs4880, TERT rs2736098, and TP53 rs1042522) showed significant associations with lung cancer susceptibility with strong cumulative epidemiological evidence. No significant associations with lung cancer risk were found for other 150 variants in 98 genes; however, seven variants demonstrated strong cumulative evidence. Our findings provided the most updated summary of genetic risk effects on lung cancer and would help inform future research direction.

Genetic susceptibility of lung cancer in Chinese population: An overview of systematic reviews and meta-analyses

BACKGROUND

Genetic susceptibility of lung cancer has been widely studied for Chinese population, and meta-analysis of candidate gene association studies has also been performed for those genes. However, the overall evidence has not been well recognized.

OBJECTIVE

To investigate genetic association for the risk of lung cancer in Chinese.

METHOD

An overview of systematic reviews and meta-analyses of candidate gene association studies for lung cancer in Chinese was performed up to August 10^th , 2016. The AMSTAR tool was used to assess the quality of the included systematic reviews and meta-analyses. Bibliometric analysis was performed to analyze the characteristics of reviews.

RESULTS

A total of 21 variants in 17 genes from 20 meta-analyses were included in this study. All 20 meta-analyses were published from 2011 to 2016. The quality scores of AMSTAR ranged from 3 to 7. All included genes were in the pathogenesis of lung cancer, such as the CYPs genes, GSTs genes, and base excision repair genes. Three polymorphisms were found to be associated with decreased risk of lung cancer for Chinese, 15 polymorphisms were found to be associated with increased risk of lung cancer for Chinese, but three polymorphisms were found to be not associated with lung cancer risk for Chinese.

CONCLUSION

The current study supports the genetic risk factors of lung cancer for Chinese are more likely to be variants from genes that contribute to the etiology of lung cancer.

Transcriptomic comparison of primary bovine horn core carcinoma culture and parental tissue at early stage

Aim:

Squamous cell carcinoma or SCC of horn in bovines (bovine horn core carcinoma) frequently observed in Bos indicus affecting almost 1% of cattle population. Freshly isolated primary epithelial cells may be closely related to the malignant epithelial cells of the tumor. Comparison of gene expression in between horn’s SCC tissue and its early passage primary culture using next generation sequencing was the aim of this study.

Materials and Methods:

Whole transcriptome sequencing of horn’s SCC tissue and its early passage cells using Ion Torrent PGM were done. Comparative expression and analysis of different genes and pathways related to cancer and biological processes associated with malignancy, proliferating capacity, differentiation, apoptosis, senescence, adhesion, cohesion, migration, invasion, angiogenesis, and metabolic pathways were identified.

Results:

Up-regulated genes in SCC of horn’s early passage cells were involved in transporter activity, catalytic activity, nucleic acid binding transcription factor activity, biogenesis, cellular processes, biological regulation and localization and the down-regulated genes mainly were involved in focal adhesion, extracellular matrix receptor interaction and spliceosome activity.

Conclusion:

The experiment revealed similar transcriptomic nature of horn’s SCC tissue and its early passage cells.

Novel Mutations of the CHRNA3 Gene in Non-Small Cell Lung Cancer in an Iranian Population

Background: Lung cancer, the leading cause of cancer-related worldwide deaths, largely results from the combined effects of smoking exposure and genetic susceptibility. CHRNA3, a nicotinic acetylcholine receptor gene, is associated with lung cancer risk. This study sought to identify variations in exon 3 of CHRNA3 in an Iranian population with non-small cell lung cancer (NSCLC). Materials and methods: A case-control study including 147 individuals with lung cancer and 145 healthy individuals was conducted. As mobility shift caused by nucleotide substitutions might be due to a conformational change of single-stranded DNAs, we designated these as single-strand conformation polymorphisms (SSCPs). PCR amplified products with SSCP were subjected to DNA sequencing. Results: The sequencing results showed 3 polymorphisms in exon 3 of CHRNA3, rs8040868, rs763384023 and rs2869547 , the latter two of which have not been reported in NSCLC, previously. Conclusion: It appears that the rs8040868 may be considered as a pathogenic mutation associated with the clinical phenotype. Polymorphisms are important factors for development of cancers and may provide additional insights into mechanisms underlying NSCLC.

Association between two CHRNA3 variants and susceptibility of lung cancer: a meta-analysis

Genome-wide association studies (GWAS) have identified two CHRNA3 polymorphisms (rs578776 and rs938682) associated with lung cancer risk. Furthermore, these polymorphisms were investigated and genotyped by PCR analysis. All eligible case-control studies published up to Mar 1st 2015 were identified by searching Pubmed and Embase database. Negative association between rs578776-T allele and risk of lung cancer was obtained without obvious heterogeneity (OR: 0.83, 95% CI: 0.79-0.86; p = 0.898 for Q test). Rs938682-C allele carriers had a 12% to 28% decreased risk. Genotype model analysis showed results of dominant model for rs578776 (OR with 95% CI: 0.839(0.718-0.981)), dominant model for rs938682 (OR with 95% CI: 0.778(0.663-0.912)) and homozygous model for rs938682 (OR with 95% CI: 0.767(0.708-0.831)) were statistically significant. Subgroup analysis indicated rs578776-T variant had protective effect in Smokers, Caucasians, two histology subgroups, and two match subgroups. Meanwhile, rs938682-C allele was associated with decreased risk in Smokers, Caucasians, Lung cancer, and two match subgroups. Meta-regression suggested ethnicity might be the major source of heterogeneity in allele model and homozygous model for rs938682. Moreover, smoking status might contribute to part of heterogeneity under allele model. In summary, this meta-analysis suggested both rs578776 and rs938682 were significantly associated with the susceptibility of lung cancer.