Chromosome 5p Region SNPs Are Associated with Risk of NSCLC among Women

Prediagnostic selenium status, selenoprotein gene variants and association with breast cancer risk in a European cohort study

Selenium (Se) may help prevent breast cancer (BC) development. Owing to limited observational evidence, we investigated whether prediagnostic Se status and/or variants in the selenoprotein genes are associated with BC risk in a large European cohort. Se status was assessed by plasma measures of Se and its major circulating proteins, selenoprotein P (SELENOP) and glutathione peroxidase 3 (GPX3), in matched BC case-control pairs (2208 for SELENOP; 1785 for GPX3 and Se) nested within the European Prospective Investigation into Cancer and Nutrition (EPIC). Single nucleotide polymorphisms (SNPs, n = 452) in 55 selenoprotein and Se metabolic pathway genes and an additional 18 variants previously associated with Se concentrations were extracted from existing genotyping data within EPIC for 1564 case-control pairs. Multivariable-adjusted logistic regression models were used to calculate the odds ratios (ORs) and 95 % confidence intervals (CIs) of the association between Se status markers, SNP variants and BC risk. Overall, there was no statistically significant association of Se status with BC risk. However, higher GPX3 activity was associated with lower risk of premenopausal BC (4th versus 1st quartile, OR = 0.54, 95 % CI: 0.30-0.98, Ptrend = 0.013). While none of the genetic variant associations (P ≤ 0.05) retained significance after multiple testing correction, rs1004243 in the SELENOM selenoprotein gene and two SNPs in the related antioxidant TXN2 gene (rs4821494 and rs5750261) were associated with respective lower and higher risks of BC at a significance threshold of P ≤ 0.01. Fourteen SNPs in twelve Se pathway genes (P ≤ 0.01) in interaction with Se status were also associated with BC risk. Higher Se status does not appear to be associated with BC risk, although activity of the selenoenzyme GPX3 may be inversely associated with premenopausal BC risk, and SNPs in the Se pathway alone or in combination with suboptimal Se status may influence BC risk.

Review of clonal hematopoiesis, subtypes and its role in neoplasia and different morbidities

Clonal hematopoiesis (CH) is the development of a certain cell lineage which is the cornerstone of hematologic malignancy especially myeloid neoplasms, however, can also be found in old age (6th-7th decade). CH is caused by many different somatic mutations most commonly in DNMT3A, TET2, ASXL1, SF3B1 and TP53. It is detected by different sequencing methods, the most commonly used ones are next generation sequencing (NGS) which can be whole exome, whole genome sequencing or a panel for certain genes. CH is divided into multiple categories depending on the clinical picture associated with it into: clonal monocytosis of undetermined significance (CMUS), clonal hematopoiesis of indeterminate significance (CHIP), clonal cytopenia and monocytosis of undetermined significance (CCMUS) and clonal cytopenia of undetermined significance (CCUS). In order to diagose CH, first other hematologic malignancies must be ruled out CH is also associated with many different entities including lung cancer and some studies have shown that COVID-19 infections are affected by CH. Certain traits and infections are associated with CH including smoking, obesity, and cardiovascular disease. A minority of patients with CH progress to a malignant process (between 0.5 %-2 %) which do not require treatment, however, any patient with CH should be kept under surveillance in order to detect any malignancy early and be treated accordingly. SIMPLE SUMMARY: Clonal hematopoiesis (CH) is considered to be the predisposing factor for development of different hematologic neoplasms. With the help of NGS, patients with CH can be monitored more closely. Several studies have shown that these patients might develop hematologic neoplasms in their lifetime. It has been subdivided into multiple groups according to the clinical picture and/or blood counts.

Identification of rs2736099 as a novel cis-regulatory variation for TERT and implications for tumorigenesis and cell proliferation

PURPOSE

Lung cancer is a malignant tumor with obvious genetic predisposition. Association studies have proposed that rs2853677, a SNP localizing at intron region of TERT (telomerase reverse transcriptase), is significantly associated with TERT expression, telomere length and eventually lung cancer risk. However, functional genomics work indicates that rs2853677 is not with the ability to alter gene expression. All these facts make us hypothesize that some other genetic variation(s) are in linkage disequilibrium (LD) with rs2853677 and influence TERT expression.

METHODS

LD pattern in rs2853677 nearby region was analyzed based on 1000 genomes data for three representative populations in the world and functional genomics research was performed for this locus.

RESULTS

Only one SNP, rs2736099, is in strong LD with rs2853677 in East Asian. Dual-luciferase reporter assay verifies that rs2736099 can regulate gene expression and should be the causal SNP for this disease. Through chromosome conformation capture assay, it is disclosed that the enhancer surrounding rs2736099 can interact with TERT promoter. Through chromatin immunoprecipitation, the transcription factor SP1 (Sp1 transcription factor) is recognized for the chromatin segment spanning rs2736099.

CONCLUSIONS

Our results provide the missing piece between genetic variation at this locus and lung cancer risk, which is also applied to tumorigenesis in other tissues and cell proliferation.

Chronic obstructive pulmonary disease (COPD) and lung cancer: common pathways for pathogenesis

Chronic obstructive pulmonary disease (COPD) and lung cancer comprise the leading causes of lung disease-related mortality worldwide. Exposure to tobacco smoke is a mutual aetiology underlying the two diseases, accounting for almost 90% of cases. There is accumulating evidence supporting the role of immune dysfunction, the lung microbiome, extracellular vesicles and underlying genetic susceptibility in the development of COPD and lung cancer. Further, epigenetic factors, involving DNA methylation and microRNA expression, have been implicated in both diseases. Chronic inflammation is a key feature of COPD and could be a potential driver of lung cancer development. Using next generation technologies, further studies investigating the genomics, epigenetics and gene-environment interaction in key molecular pathways will continue to elucidate the pathogenic mechanisms underlying the development of COPD and lung cancer, and contribute to the development of novel diagnostic and prognostic tools for early intervention and personalised therapeutic strategies.

Growth Hormone's Links to Cancer

Several components of the GH axis are involved in tumor progression, and GH-induced intracellular signaling has been strongly associated with breast cancer susceptibility in genome-wide association studies. In the general population, high IGF-I levels and low IGF-binding protein-3 levels within the normal range are associated with the development of common malignancies, and components of the GH-IGF signaling system exhibit correlations with clinical, histopathological, and therapeutic parameters in cancer patients. Despite promising findings in preclinical studies, anticancer therapies targeting the GH-IGF signaling system have led to disappointing results in clinical trials. There is substantial evidence for some degree of protection against tumor development in several animal models and in patients with genetic defects associated with GH deficiency or resistance. In contrast, the link between GH excess and cancer risk in acromegaly patients is much less clear, and cancer screening in acromegaly has been a highly controversial issue. Recent studies have shown that increased life expectancy in acromegaly patients who attain normal GH and IGF-I levels is associated with more deaths due to age-related cancers. Replacement GH therapy in GH deficiency hypopituitary adults and short children has been shown to be safe when no other risk factors for malignancy are present. Nevertheless, the use of GH in cancer survivors and in short children with RASopathies, chromosomal breakage syndromes, or DNA-repair disorders should be carefully evaluated owing to an increased risk of recurrence, primary cancer, or second neoplasia in these individuals.

A growth hormone receptor SNP promotes lung cancer by impairment of SOCS2-mediated degradation

Both humans and mice lacking functional growth hormone (GH) receptors are known to be resistant to cancer. Further, autocrine GH has been reported to act as a cancer promoter. Here we present the first example of a variant of the GH receptor (GHR) associated with cancer promotion, in this case lung cancer. We show that the GHRP495T variant located in the receptor intracellular domain is able to prolong the GH signal in vitro using stably expressing mouse pro-B-cell and human lung cell lines. This is relevant because GH secretion is pulsatile, and extending the signal duration makes it resemble autocrine GH action. Signal duration for the activated GHR is primarily controlled by suppressor of cytokine signalling 2 (SOCS2), the substrate recognition component of the E3 protein ligase responsible for ubiquitinylation and degradation of the GHR. SOCS2 is induced by a GH pulse and we show that SOCS2 binding to the GHR is impaired by a threonine substitution at Pro 495. This results in decreased internalisation and degradation of the receptor evident in TIRF microscopy and by measurement of mature (surface) receptor expression. Mutational analysis showed that the residue at position 495 impairs SOCS2 binding only when a threonine is present, consistent with interference with the adjacent Thr494. The latter is key for SOCS2 binding, together with nearby Tyr487, which must be phosphorylated for SOCS2 binding. We also undertook nuclear magnetic resonance spectroscopy approach for structural comparison of the SOCS2 binding scaffold Ile455-Ser588, and concluded that this single substitution has altered the structure of the SOCS2 binding site. Importantly, we find that lung BEAS-2B cells expressing GHRP495T display increased expression of transcripts associated with tumour proliferation, epithelial-mesenchymal transition and metastases (TWIST1, SNAI2, EGFR, MYC and CCND1) at 2 h after a GH pulse. This is consistent with prolonged GH signalling acting to promote cancer progression in lung cancer.

Genetic variations at the human growth hormone receptor (GHR) gene locus are associated with idiopathic short stature

GH plays an essential role in the growing child by binding to the growth hormone receptor (GHR) on target cells and regulating multiple growth promoting and metabolic effects. Mutations in the GHR gene coding regions result in GH insensitivity (dwarfism) due to a dysfunctional receptor protein. However, children with idiopathic short stature (ISS) show growth impairment without GH or GHR defects. We hypothesized that decreased expression of the GHR gene may be involved. To test this, we investigated whether common genetic variants (microsatellites, SNPs) in regulatory regions of the GHR gene region were associated with the ISS phenotype. Genotyping of a GT‐repeat microsatellite in the GHR 5′UTR in a Montreal ISS cohort (n = 37 ISS, n = 105 controls) revealed that the incidence of the long/short (L/S) genotype was 3.3× higher in ISS children than controls (P = 0.04, OR = 3.85). In an Italian replication cohort (n = 143 ISS, n = 282 controls), the medium/short (M/S) genotype was 1.9× more frequent in the male ISS than controls (P = 0.017, OR = 2.26). In both ISS cohorts, logistic regression analysis of 27 SNPs showed an association of ISS with rs4292454, while haplotype analysis revealed specific risk haplotypes in the 3′ haploblocks. In contrast, there were no differences in GT genotype frequencies in a cohort of short stature (SS) adults versus controls (CARTaGENE: n = 168 SS, n = 207 controls) and the risk haplotype in the SS cohort was located in the most 5′ haploblock. These data suggest that the variants identified are potentially genetic markers specifically associated with the ISS phenotype.

Genome-wide association study confirms lung cancer susceptibility loci on chromosomes 5p15 and 15q25 in an African-American population

OBJECTIVES

Genome-wide association studies (GWAS) of lung cancer have identified regions of common genetic variation with lung cancer risk in Europeans who smoke and never-smoking Asian women. This study aimed to conduct a GWAS in African Americans, who have higher rates of lung cancer despite smoking fewer cigarettes per day when compared with Caucasians. This population provides a different genetic architecture based on underlying African ancestry allowing the identification of new regions and exploration of known regions for finer mapping.

MATERIALS AND METHODS

We genotyped 1,024,001 SNPs in 1737 cases and 3602 controls in stage 1, followed by a replication phase of 20 SNPs (p<1.51×10(-5)) in an independent set of 866 cases and 796 controls in stage 2.

RESULTS AND CONCLUSION

In the combined analysis, we confirmed two loci to be associated with lung cancer that achieved the threshold of genome-wide significance: 15q25.1 marked by rs2036527 (p=1.3×10(-9); OR=1.32; 95% CI=1.20-1.44) near CHRNA5, and 5p15.33 marked by rs2853677 (p=2.8×10(-9); OR=1.28; 95% CI=1.18-1.39) near TERT. The association with rs2853677 is driven by the adenocarcinoma subtype of lung cancer (p=1.3×10(-8); OR=1.37; 95% CI=1.23-1.54). No SNPs reached genome-wide significance for either of the main effect models examining smoking - cigarettes per day and current or former smoker. Our study was powered to identify strong risk loci for lung cancer in African Americans; we confirmed results previously reported in African Americans and other populations for two loci near plausible candidate genes, CHRNA5 and TERT, on 15q25.1 and 5p15.33 respectively, are associated with lung cancer. Additional work is required to map and understand the biological underpinnings of the strong association of these loci with lung cancer risk in African Americans.

Germ line variants predispose to both JAK2 V617F clonal hematopoiesis and myeloproliferative neoplasms

We conducted a genome-wide association study (GWAS) to identify novel predisposition alleles associated with Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) and JAK2 V617F clonal hematopoiesis in the general population. We recruited a web-based cohort of 726 individuals with polycythemia vera, essential thrombocythemia, and myelofibrosis and 252 637 population controls unselected for hematologic phenotypes. Using a single-nucleotide polymorphism (SNP) array platform with custom probes for the JAK2 V617F mutation (V617F), we identified 497 individuals (0.2%) among the population controls who were V617F carriers. We performed a combined GWAS of the MPN cases plus V617F carriers in the control population (n = 1223) vs the remaining controls who were noncarriers for V617F (n = 252 140). For these MPN cases plus V617F carriers, we replicated the germ line JAK2 46/1 haplotype (rs59384377: odds ratio [OR] = 2.4, P = 6.6 × 10(-89)), previously associated with V617F-positive MPN. We also identified genome-wide significant associations in the TERT gene (rs7705526: OR = 1.8, P = 1.1 × 10(-32)), in SH2B3 (rs7310615: OR = 1.4, P = 3.1 × 10(-14)), and upstream of TET2 (rs1548483: OR = 2.0, P = 2.0 × 10(-9)). These associations were confirmed in a separate replication cohort of 446 V617F carriers vs 169 021 noncarriers. In a joint analysis of the combined GWAS and replication results, we identified additional genome-wide significant predisposition alleles associated with CHEK2, ATM, PINT, and GFI1B All SNP ORs were similar for MPN patients and controls who were V617F carriers. These data indicate that the same germ line variants endow individuals with a predisposition not only to MPN, but also to JAK2 V617F clonal hematopoiesis, a more common phenomenon that may foreshadow the development of an overt neoplasm.

The study of the relation of DNA repair pathway genes SNPs and the sensitivity to radiotherapy and chemotherapy of NSCLC

To analyze the relation between SNPs in DNA repair pathway-related genes and sensitivity of tumor radio-chemotherapy, 26 SNPs in 20 DNA repair genes were genotyped on 176 patients of NSCLC undertaking radio-chemotherapy treatment. In squamous cell carcinoma (SCC), as the rs2228000, rs2228001 (XPC), rs2273953 (TP73), rs2279744 (MDM2), rs2299939 (PTEN) and rs8178085, rs12334811 (DNA-PKcs) affected the sensitivity to chemotherapy, so did the rs8178085, rs12334811 to radiotherapy. Moreover rs344781, rs2273953 and rs12334811 were related with the survival time of SCC. In general, the “good” genotype GG (rs12334811) showed greater efficacy of radio-chemotherapy and MSF (24 months) on SCC. In adenocarcinoma, as the rs2699887 (PIK3), rs12334811 (DNA-PKcs) influenced the sensitivity to chemotherapy, so did the rs2299939, rs2735343 (PTEN) to radiotherapy. And rs402710, rs80270, rs2279744 and rs2909430 impacted the survival time of the adenocarcinoma patients. Both GG (rs2279744) and AG (rs2909430) showed a shorter survival time (MFS = 6). Additionally, some SNPs such as rs2228000, rs2228001 and rs344781 were found to regulate the expression of DNA repair pathway genes through eQTLs dataset analysis. These results indicate that SNPs in DNA repair pathway genes might regulate the expression and affect the DNA damage repair, and thereby impact the efficacy of radio-chemotherapy and the survival time of NSCLC.

Case-Control Study on Impact of the Telomerase Reverse Transcriptase Gene Polymorphism and Additional Single Nucleotide Polymorphism (SNP)- SNP Interaction on Non-Small Cell Lung Cancers Risk in Chinese Han Population

AIMS

To investigate the impact of telomerase reverse transcriptase (TERT) gene polymorphism and additional SNP-SNP interaction on non-small cell lung cancer (NSCLC) risk in Chinese population.

METHODS

A total of 828 participants (526 males, 302 females), with a mean age of 71.3 ± 15.7 years old, were selected, including 410 NSCLC patients and 418 normal participants. Logistic regression was performed to investigate association between single nucleotide polymorphism (SNP) and NSCLC risk. Generalized multifactor dimensionality reduction (GMDR) was used to analysis the interaction among four SNPs.

RESULTS

Non-small cell lung cancer risk was significantly higher in carriers of G allele of the rs2736100 polymorphism than those with TT (TG + GG vs. TT, adjusted OR (95%CI = 1.68 (1.28-2.07). In addition, we also found that NSCLC risk was also significantly higher in carriers of A allele of the rs2736098 polymorphism than those with GG (GA + AA vs. GG, adjusted OR (95%CI) = 1.52 (1.19-1.93). GMDR analysis indicated that there was a significant two-locus model (P = 0.0100) involving rs2736098 and rs2736100, indicating a potential gene-gene interaction between rs2736098 and rs2736100. Overall, the two-locus models had a cross-validation consistency of 10 of 10, and had the testing accuracy of 62.17%. We found that patients with GA or AA of rs2736098 and TG or GG of rs2736100 genotype have the highest NSCLC risk, compared to patients with GG of rs2736098 and TT of rs2736100 genotype, OR (95%CI) was 2.52 (1.68-3.68), after covariates adjustment.

CONCLUSIONS

Minor allele of rs2736098 and rs2736100 in TERT gene and interaction between the two SNP were associated with increased risk of NSCLC risk.

Multivariate models from RNA-Seq SNVs yield candidate molecular targets for biomarker discovery: SNV-DA

BACKGROUND

It has recently been shown that significant and accurate single nucleotide variants (SNVs) can be reliably called from RNA-Seq data. These may provide another source of features for multivariate predictive modeling of disease phenotype for the prioritization of candidate biomarkers. The continuous nature of SNV allele fraction features allows the concurrent investigation of several genomic phenomena, including allele specific expression, clonal expansion and/or deletion, and copy number variation.

RESULTS

The proposed software pipeline and package, SNV Discriminant Analysis (SNV-DA), was applied on two RNA-Seq datasets with varying sample sizes sequenced at different depths: a dataset containing primary tumors from twenty patients with different disease outcomes in lung adenocarcinoma and a larger dataset of primary tumors representing two major breast cancer subtypes, estrogen receptor positive and triple negative. Predictive models were generated using the machine learning algorithm, sparse projections to latent structures discriminant analysis. Training sets composed of RNA-Seq SNV features limited to genomic regions of origin (e.g. exonic or intronic) and/or RNA-editing sites were shown to produce models with accurate predictive performances, were discriminant towards true label groupings, and were able to produce SNV rankings significantly different from than univariate tests. Furthermore, the utility of the proposed methodology is supported by its comparable performance to traditional models as well as the enrichment of selected SNVs located in genes previously associated with cancer and genes showing allele-specific expression. As proof of concept, we highlight the discovery of a previously unannotated intergenic locus that is associated with epigenetic regulatory marks in cancer and whose significant allele-specific expression is correlated with ER+ status; hereafter named ER+ associated hotspot (ERPAHS).

CONCLUSION

The use of models from RNA-Seq SNVs to identify and prioritize candidate molecular targets for biomarker discovery is supported by the ability of the proposed method to produce significantly accurate predictive models that are discriminant towards true label groupings. Importantly, the proposed methodology allows investigation of mutations outside of exonic regions and identification of interesting expressed loci not included in traditional gene annotations. An implementation of the proposed methodology is provided that allows the user to specify SNV filtering criteria and cross-validation design during model creation and evaluation.

Association of human telomerase reverse transcriptase gene polymorphisms, serum levels, and telomere length with renal cell carcinoma risk and pathology

Human telomerase reverse transcriptase (hTERT) is the catalytic subunit of the human telomerase and plays a key role in telomere restitution and gene regulation. Evidence suggests that hTERT is linked with the risk and progression of several malignancies, but there are no comprehensive data in renal cell carcinoma (RCC). In this case-control study, we assessed seven polymorphic hTERT gene variants (MNS16A, rs2736100, rs2736098, rs7726159, rs2853677, rs13172201, and rs10069690), hTERT serum levels, and the telomere length of 663 individuals, including 243 with clear cell RCC and 420 age- and gender-matched healthy controls. The SL and SS genotypes of MNS16A were associated with a decreased risk for RCC on the multivariable logistic regression analysis (SL-OR 0.72, SS-OR 0.37, P < 0.001). The GG genotype of rs2736098 was associated with a decreased risk for RCC compared with AA (OR 0.18, P < 0.001). Both telomere length and hTERT serum levels increased with every G allele in rs2736098 (P = 0.008). Pretherapeutic hTERT serum levels were higher in patients with advanced tumor stages (P = 0.037) and distant metastases (P = 0.006). Rs2736100, rs7726159, rs2853677, rs13172201, and rs10069690 were not linked with RCC risk, and none of the polymorphisms was associated with RCC pathology. In conclusion, the polymorphic number of tandem repeats in hTERT (MNS16A) and rs2736098 may be linked with the risk for RCC. Rs2736098 may have an important role in telomere length restitution and serum hTERT levels may represent a novel biomarker for RCC. © 2015 Wiley Periodicals, Inc.

Association study of nicotinic acetylcholine receptor genes identifies a novel lung cancer susceptibility locus near CHRNA1 in African-Americans

Studies in European and East Asian populations have identified lung cancer susceptibility loci in nicotinic acetylcholine receptor (nAChR) genes on chromosome 15q25.1 which also appear to influence smoking behaviors. We sought to determine if genetic variation in nAChR genes influences lung cancer susceptibly in African-Americans, and evaluated the association of these cancer susceptibility loci with smoking behavior. A total of 1308 African-Americans with lung cancer and 1241 African-American controls from three centers were genotyped for 378 single nucleotide polymorphisms (SNPs) spanning the sixteen human nAChR genes. Associations between SNPs and the risk of lung cancer were estimated using logistic regression, adjusted for relevant covariates. Seven SNPs in three nAChR genes were significantly associated with lung cancer at a strict Bonferroni-corrected level, including a novel association on chromosome 2 near the promoter of CHRNA1 (rs3755486: OR = 1.40, 95% CI = 1.18-1.67, P = 1.0 x 10-4). Association analysis of an additional 305 imputed SNPs on 2q31.1 supported this association. Publicly available expression data demonstrated that the rs3755486 risk allele correlates with increased CHRNA1 gene expression. Additional SNP associations were observed on 15q25.1 in genes previously associated with lung cancer, including a missense variant in CHRNA5 (rs16969968: OR = 1.60, 95% CI = 1.27-2.01, P = 5.9 x 10-5). Risk alleles on 15q25.1 also correlated with an increased number of cigarettes smoked per day among the controls. These findings identify a novel lung cancer risk locus on 2q31.1 which correlates with CHRNA1 expression and replicate previous associations on 15q25.1 in African-Americans.

Telomerase at the intersection of cancer and aging

Although cancer and aging have been studied as independent diseases, mounting evidence suggests that cancer is an aging-associated disease and that cancer and aging share many molecular pathways. In particular, recent studies validated telomerase activation as a potential therapeutic target for age-related diseases; in addition, abnormal telomerase expression and telomerase mutations have been associated with many different types of human tumor. Here, we revisit the connection between telomerase and cancer and aging in light of recent findings supporting a role for telomerase not only in telomere elongation, but also in metabolic fitness and Wnt activation. Understanding the physiological impact of telomerase regulation is fundamental given the therapeutic strategies that are being developed that involve telomerase modulation.

Significant association of 5p15.33 (TERT-CLPTM1L genes) with lung cancer in Chinese Han population

Lung cancer is a leading cause of cancer-related deaths throughout the world. Recent genome-wide association studies and consecutive validation supported that the 5p15.33 region containing telomerase reverse transcriptase gene (TERT) and cleft lip and palate transmembrane protein 1-like (CLPTM1L) gene showed significant association with lung cancer in multiple populations. Here we studied a large Chinese Han cohort consisting of 1759 cases and 1804 controls. In the 1st stage (784 cases versus 782 controls) we genotyped 13 tag SNPs within 5p15.33 region to further investigate the association. After the 2nd stage validation (975 cases versus 1022 controls), the study clarified the association that rs2736100 of the TERT gene conferred the highest significant risk of lung cancer (P=4×10(-3) in the 1st stage association, P=4×10(-4) in the 2nd stage validation, and P=1×10(-5), odds ratio=1.24 in the combined population). The results provided the evidence of a cross-race susceptibility of the lung cancer locus.

Fine-mapping of the 5p15.33, 6p22.1-p21.31, and 15q25.1 regions identifies functional and histology-specific lung cancer susceptibility loci in African-Americans

BACKGROUND

Genome-wide association studies of European and East Asian populations have identified lung cancer susceptibility loci on chromosomes 5p15.33, 6p22.1-p21.31, and 15q25.1. We investigated whether these regions contain lung cancer susceptibly loci in African-Americans and refined previous association signals by using the reduced linkage disequilibrium observed in African-Americans.

METHODS

1,308 African-American cases and 1,241 African-American controls from 3 centers were genotyped for 760 single-nucleotide polymorphisms (SNP) spanning 3 regions, and additional SNP imputation was carried out. Associations between polymorphisms and lung cancer risk were estimated using logistic regression, stratified by tumor histology where appropriate.

RESULTS

The strongest associations were observed on 15q25.1 in/near CHRNA5, including a missense substitution [rs16969968: OR, 1.57; 95% confidence interval (CI), 1.25-1.97; P, 1.1 × 10(-4)) and variants in the 5'-UTR. Associations on 6p22.1-p21.31 were histology specific and included a missense variant in BAT2 associated with squamous cell carcinoma (rs2736158: OR, 0.64; 95% CI, 0.48-0.85; P, 1.82 × 10(-3)). Associations on 5p15.33 were detected near TERT, the strongest of which was rs2735940 (OR, 0.82; 95% CI, 0.73-0.93; P, 1.1 × 10(-3)). This association was stronger among cases with adenocarcinoma (OR, 0.75; 95% CI, 0.65-0.86; P, 8.1 × 10(-5)).

CONCLUSIONS

Polymorphisms in 5p15.33, 6p22.1-p21.31, and 15q25.1 are associated with lung cancer in African-Americans. Variants on 5p15.33 are stronger risk factors for adenocarcinoma and variants on 6p21.33 associated only with squamous cell carcinoma.

IMPACT

Results implicate the BAT2, TERT, and CHRNA5 genes in the pathogenesis of specific lung cancer histologies.

Genetic variant in the telomerase gene modifies cancer risk in Lynch syndrome

Lynch syndrome (LS) is an inherited cancer-predisposing disorder caused by germline mutations in the mismatch repair (MMR) genes. The high variability in individual cancer risk observed among LS patients suggests the existence of modifying factors. Identifying genetic modifiers of risk could help implement personalized surveillance programs based on predicted cancer risks. Here we evaluate the role of the telomerase (hTERT) rs2075786 SNP as a cancer-risk modifier in LS, studying 255 and 675 MMR gene mutation carriers from Spain and the Netherlands, respectively. The study of the Spanish sample revealed that the minor allele (A) confers increased cancer risk at an early age. The analysis of the Dutch sample confirmed the association of the A allele, especially in homozygosity, with increased cancer risk in mutation carriers under the age of 45 (relative riskLSca<45_AA=2.90; 95% confidence interval=1.02-8.26). Rs2075786 is associated with colorectal cancer (CRC) risk neither in the general population nor in non-Lynch CRC families. In silico studies predicted that the SNP causes the disruption of a transcription binding site for a retinoid receptor, retinoid X receptor alpha, probably causing early telomerase activation and therefore accelerated carcinogenesis. Notably, cancer-affected LS patients with the AA genotype have shorter telomeres than those with GG. In conclusion, MMR gene mutation carriers with hTERT rs2075786 are at high risk to develop a LS-related tumor at an early age. Cancer-preventive measures and stricter cancer surveillance at early ages might help prevent or early detect cancer in these mutation carriers.

The TERT variant rs2736100 is associated with colorectal cancer risk

Background:

Polymorphic variation at the 5p15.33 (TERT–CLPTM1L) locus is associated with the risk of many cancers but a relationship with colorectal cancer (CRC) risk has yet to be defined.

Methods:

We used data from six genome-wide association studies (GWAS) of CRC, linkage disequilibrium mapping and imputation, to examine the relationship between 73 single-nucleotide polymorphisms at 5p15.33 and CRC risk in detail.

Results:

rs2736100, which localises to intron 2 of TERT, provided the strongest evidence of an association with CRC (P=2.28 × 10⁻⁴). The association was also shown in an independent series of 10 047 CRC cases and 6918 controls (P=0.02). A meta-analysis of all seven studies (totalling 16 039 cases, 16 430 controls) provided increased evidence of association (P=2.49 × 10⁻⁵; per allele odds ratio=1.07). The association of rs2736100 on CRC risk was shown to be independent of 15 low-penetrance variants previously identified.

Conclusion:

The rs2736100 association demonstrates an influence of variation at 5p15.33 on CRC risk and further evidence that the 5p15.33 (TERT–CLPTM1L) locus has pleiotropic effects (reflecting generic or lineage-specific effects) on cancer risk.

Telomerase reverse transcriptase locus polymorphisms and cancer risk: a field synopsis and meta-analysis

BACKGROUND

Several recent studies have provided evidence that polymorphisms in the telomerase reverse transcriptase (TERT) gene sequence are associated with cancer development, but a comprehensive synopsis is not available. We conducted a systematic review and meta-analysis of the available molecular epidemiology data regarding the association between TERT locus polymorphisms and predisposition to cancer.

METHODS

A systematic review of the English literature was conducted by searching PubMed, Embase, Cancerlit, Google Scholar, and ISI Web of Knowledge databases for studies on associations between TERT locus polymorphisms and cancer risk. Random-effects meta-analysis was performed to pool per-allele odds ratios for TERT locus polymorphisms and risk of cancer, and between-study heterogeneity and potential bias sources (eg, publication and chasing bias) were assessed. Because the TERT locus includes the cleft lip and palate transmembrane 1-like (CLPTM1L) gene, which is in linkage disequilibrium with TERT, CLPTM1L polymorphisms were also analyzed. Cumulative evidence for polymorphisms with statistically significant associations was graded as "strong," "moderate," and "weak" according to the Venice criteria. The joint population attributable risk was calculated for polymorphisms with strong evidence of association.

RESULTS

Eighty-five studies enrolling 490 901 subjects and reporting on 494 allelic contrasts were retrieved. Data were available on 67 TERT locus polymorphisms and 24 tumor types, for a total of 221 unique combinations of polymorphisms and cancer types. Upon meta-analysis, a statistically significant association with the risk of any cancer type was found for 22 polymorphisms. Strong, moderate, and weak cumulative evidence for association with at least one tumor type was demonstrated for 11, 9, and 14 polymorphisms, respectively. For lung cancer, which was the most studied tumor type, the estimated joint population attributable risk for three polymorphisms (TERT rs2736100, intergenic rs4635969, and CLPTM1L rs402710) was 41%. Strong evidence for lack of association was identified for five polymorphisms in three tumor types.

CONCLUSIONS

To our knowledge, this is the largest collection of data for associations between TERT locus polymorphisms and cancer risk. Our findings support the hypothesis that genetic variability in this genomic region can modulate cancer susceptibility in humans.

Fine-mapping of a region of chromosome 5p15.33 (TERT-CLPTM1L) suggests a novel locus in TERT and a CLPTM1L haplotype are associated with glioma susceptibility in a Chinese population

Two genome-wide association studies (GWAS) have identified 5p15.33 (TERT-CLPTM1L) as one of the susceptible regions for glioma in European background. A replication research of our group highlighted the association signals in the TERT gene of this region in a Chinese Han population. To comprehensively explore the region of glioma association at 5p15.33 and to refine the potential causal variants to a smaller critical region, we conducted a fine-mapping association study among 983 cases and 1,024 controls in a Chinese Han population. Using Hapmap3 datasets as a reference, we genotyped 16 tag SNPs across this 87.9-kb region encompassing TERT. Significant association with glioma risk was observed for rs2853677 [GG vs. GA: adjusted OR = 1.46, p = 5.51 × 10(-6), GG vs. AA: adjusted OR = 1.72, p = 7.64 × 10(-6), GG vs. GA and AA: adjusted OR = 1.96, p = 6.8 × 10(-6)] in TERT and an uncommon CLPTM1L haplotype G-T-A of rs4635969, rs6554759 and rs414965 (haplotype frequency = 0.07) was associated with higher glioma risk compared with the most common G-C-G haplotype (adjusted OR = 1.44, simulated p = 6.00 × 10(-3) under additive model). Our results indicate that sequence variants in the region flanking rs2853677 may account for the GWAS and replication signals identified in 5p15.33 for glioma susceptibility in Chinese population; besides, haplotype G-T-A in CLPTM1L also confers a risk to glioma suggesting CLPTM1L is also involved in the etiology of glioma. Additional studies especially those taking advantage of sequencing platforms are warranted to further confirm the conclusions and go deeper with our findings.

A multi-cohort study of polymorphisms in the GH/IGF axis and physical capability: the HALCyon programme

BACKGROUND

Low muscle mass and function have been associated with poorer indicators of physical capability in older people, which are in-turn associated with increased mortality rates. The growth hormone/insulin-like growth factor (GH/IGF) axis is involved in muscle function and genetic variants in genes in the axis may influence measures of physical capability.

METHODS

As part of the Healthy Ageing across the Life Course (HALCyon) programme, men and women from seven UK cohorts aged between 52 and 90 years old were genotyped for six polymorphisms: rs35767 (IGF1), rs7127900 (IGF2), rs2854744 (IGFBP3), rs2943641 (IRS1), rs2665802 (GH1) and the exon-3 deletion of GHR. The polymorphisms have previously been robustly associated with age-related traits or are potentially functional. Meta-analysis was used to pool within-study genotypic effects of the associations between the polymorphisms and four measures of physical capability: grip strength, timed walk or get up and go, chair rises and standing balance.

RESULTS

Few important associations were observed among the several tests. We found evidence that rs2665802 in GH1 was associated with inability to balance for 5 s (pooled odds ratio per minor allele = 0.90, 95% CI: 0.82-0.98, p-value = 0.01, n = 10,748), after adjusting for age and sex. We found no evidence for other associations between the polymorphisms and physical capability traits.

CONCLUSION

Our findings do not provide evidence for a substantial influence of these common polymorphisms in the GH/IGF axis on objectively measured physical capability levels in older adults.

Novel genetic variants in the chromosome 5p15.33 region associate with lung cancer risk

Chromosome 5p15.33 has been identified by genome-wide association studies as one of the regions that associate with lung cancer risk. A few single-nucleotide polymorphisms (SNPs) in the telomerase reverse transcriptase (TERT) and cleft lip and palate transmembrane 1-like (CLPTM1L) genes located in this region have shown consistent associations. We performed dense genotyping of SNPs in this region to refine the previously reported association signals for lung cancer risk. Two hundred and fifteen SNPs were genotyped on an Illumina iSelect panel, in a hospital-based case-control study of 1681 lung cancer cases and 1235 unaffected controls. Association was tested using unconditional logistic regression, while adjusting for age, sex and pack-years smoked. Furthermore, since many of the SNPs were in linkage disequilibrium (LD), haplotype blocks were constructed, from which tagging SNPs at an r(2) threshold of ≥0.95 were included in a stepwise forward selection logistic regression model. Of the 215 SNPs, 69 were significant at P < 0.05 in univariate analysis; of these, 35 SNPs meeting the r(2) threshold were included in the multiple logistic regression model. Two SNPs, rs370348 (odds ratio = 0.76, P = 1.6 × 10(-6)) and rs4975538 (odds ratio = 1.18, P = 0.005), significantly associated with risk in the overall sample. Among ever smokers, rs4975615 (odds ratio = 0.75, P = 1.2 × 10(-4)) and rs4975538 (odds ratio = 1.26, P = 0.002) were significant, whereas among never-smokers, rs451360 (odds ratio = 0.62, P = 7.6 × 10(-5)) was significant. We refined the consistent association signal in this region, allowing for the considerable LD between SNPs and identified four novel SNPs that were independently and significantly associated with lung cancer risk. Results of these analyses strongly suggest effects on risk from several loci in the TERT/CLPTM1L region.

Absence of association of a single-nucleotide polymorphism in the TERT-CLPTM1L locus with age-related phenotypes in a large multicohort study: the HALCyon programme

Several age-related traits are associated with shorter telomeres, the structures that cap the end of linear chromosomes. A common polymorphism near the telomere maintenance gene TERT has been associated with several cancers, but relationships with other aging traits such as physical capability have not been reported. As part of the Healthy Ageing across the Life Course (HALCyon) collaborative research programme, men and women aged between 44 and 90 years from nine UK cohorts were genotyped for the single-nucleotide polymorphism (SNP) rs401681. We then investigated relationships between the SNP and 30 age-related phenotypes, including cognitive and physical capability, blood lipid levels and lung function, pooling within-study genotypic effects in meta-analyses. No significant associations were found between the SNP and any of the cognitive performance tests (e.g. pooled beta per T allele for word recall z-score = 0.02, 95% CI: -0.01 to 0.04, P-value = 0.12, n = 18,737), physical performance tests (e.g. pooled beta for grip strength = -0.02, 95% CI: -0.045 to 0.006, P-value = 0.14, n = 11,711), blood pressure, lung function or blood test measures. Similarly, no differences in observations were found when considering follow-up measures of cognitive or physical performance after adjusting for its measure at an earlier assessment. The lack of associations between SNP rs401681 and a wide range of age-related phenotypes investigated in this large multicohort study suggests that while this SNP may be associated with cancer, it is not an important contributor to other markers of aging.