Interactions between household air pollution and GWAS-identified lung cancer susceptibility markers in the Female Lung Cancer Consortium in Asia (FLCCA)

Interaction between polygenic risk score and reproductive factors in relation to lung cancer risk among Singaporean Chinese women

OBJECTIVES

Studies have shown that reproductive factors can influence hormone levels in females, potentially affecting the risk of developing lung cancer. However, it remains unclear whether this association is modified by genetic variants.

STUDY DESIGN

Age-matched case-control study.

METHODS

Reproductive factors included menopausal status, age at menopause, hormone use, hysterectomy and oophorectomy. Odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between reproductive factors and lung cancer risk were estimated using a multivariable conditional logistic regression model. A polygenic risk score (PRS) was calculated using a clumping plus thresholding approach. Gene-environment interactions between reproductive factors and PRS on lung cancer risk were evaluated.

RESULTS

Our analysis included a total of 2910 female participants (1455 cases and 1455 controls). Compared to women with no surgical history, those who had undergone hysterectomy (OR = 1.41, 95 % CI = 1.10-1.82) or oophorectomy (OR = 1.52, 95% CI = 1.15-2.02) were associated with an increased risk of lung cancer. A PRS for lung cancer derived from 7 genetic variants showed a linear association with lung cancer risk (Ptrend < 0.001). After adjusting for false discovery rate (FDR), we found a borderline non-significant interaction between hormone use and PRS on lung cancer risk (Pinteraction-FDR = 0.05).

CONCLUSIONS

Women with a history of hysterectomy or oophorectomy had a higher risk of lung cancer compared to those without such surgical history, highlighting the need for targeted prevention strategies in this high-risk population. No significant effect modification by the lung cancer PRS was observed in the associations between reproductive factors and lung cancer risk. Larger prospective studies are warranted to validate these findings.

Genetic Ancestry and Lung Cancer in Latin American Patients: A Crucial Step for Understanding a Diverse Population

Lung cancer is the second leading cause of cancer-related deaths in Latin America. While incidence and mortality rates are higher in other populations, the ``Hispanic paradox'' observed in US Hispanics reflects a lower mortality rate for mortality from non-small cell lung cancer (NSCLC) despite socioeconomic disparities, which may be related to epigenetic and cultural factors. Genetic studies have identified single nucleotide polymorphisms associated with ancestry as key contributors to lung cancer risk and outcomes, emphasizing the importance of genomic insights for early detection and personalized treatments. This narrative review explores the impact of genetic ancestry on lung cancer in Hispanic/Latino populations. We searched MEDLINE and Google Scholar for "((SNP) OR (germline) OR (variant)) AND (lung cancer) AND ((Hispanic) OR (Latin))," focusing on Latin American studies. We included articles published up to December 2024. Specific variation in genes such as XRCC1, CYP1A1, CYP1A2, SEMA3B, PADPRP, and mEPHX have been associated with increased lung cancer risk. Lung cancer incidence and prognosis vary significantly among Hispanics due to their diverse genetic ancestry. Understanding ancestry-specific genetic variations may help personalize treatment and improve outcomes for this population.

Association of rs401681 (C > T) and rs402710 (C > T) polymorphisms in the CLPTM1L region with risk of lung cancer: a systematic review and meta-analysis

Although many genome-wide association studies (GWAS) have confirmed the negative associations between rs401681[T] / rs402710[T] in the Cleft lip and cleft palate transmembrane protein 1 (CLPTM1L) region and lung cancer (LC) susceptibility in Caucasian and Asian populations, some other studies haven't found these negative associations. The purpose of this study is to clarify the associations between them and LC, as well as the differences in these associations between patients of different ethnicities (Caucasians and Asians), LC subtypes and smoking status. Relevant literatures published before July 7, 2023 in PubMed, EMbase, Web of Science, MEDLINE were searched through the Internet. Statistical analysis of data was performed in Revman 5.3, including drawing forest plots, funnel plots and so on. Sensitivity and publication bias were performed in Stata 14.0. TSA software was performed for the trial sequential analysis (TSA) tests to assess the stability of the results. Registration number: CRD42023407890. A total of 41 literatures (containing 44 studies: 16 studies in Caucasians and 28 studies in Asians) were included in this meta-analysis, including 126476 LC patients and 191648 healthy controls. The results showed that the T allele variants of rs401681 and rs402710 were negatively associated with the risk of LC (rs401681[T]: [OR] = 0.87, 95% CI [0.86, 0.88]; rs402710[T]: [OR] = 0.88, 95% CI [0.86, 0.89]), and the negative associations were stronger in Caucasians than in Asians (Subgroup differences: I2 > 50%). In LC subtypes, the rs401681[T] was negatively associated with the risk of Non-small-cell lung carcinoma (NSCLC), Lung adenocarcinoma (LUAD) and Lung squamous cell carcinoma (LUSC) (P < 0.05), and these negative associations were stronger in Caucasians than in Asians (Subgroup differences: I2 > 50%). The rs402710[T] was negatively associated with the risk of NSCLC, LUAD and LUSC (P < 0.05), and these negative associations in Caucasians were the same as in Asians (Subgroup differences: I2 < 50%). The rs401681[T] was negatively associated with the risk of LC in both smokers and non-smokers (P < 0.05), and the negative association for smokers equals to that of non-smokers (Subgroup differences: P = 0.25, I2 = 24.2%). In LC subtypes, the rs401681[T] was negatively associated with the risks of NSCLC and LUAD in both Caucasian smokers and Asian non-smokers (P < 0.05). The rs402710[T] was negatively associated with the risk of LC in both smokers and non-smokers (P < 0.05), and there was no difference in the strength of this negative risk association between them in Caucasians (Subgroup differences: I2 = 0%). In Asians, this negative association was found to be predominantly among smokers ([OR] = 0.80, 95%CI [0.65, 0.99]). In LC subtypes, the rs402710[T]was negatively associated with the risk of NSCLC in non-smokers, and this negative association was found to be predominantly among non-smokers in Asians ([OR] = 0.75, 95%CI [0.60, 0.94]). The T allele variants of rs401681 and rs402710 are both negatively associated with the risk of developing LC, NSCLC (LUAD, LUSC) in the Caucasian and Asian populations, and the negative associations with the risk of LC are higher in Caucasians. Smoking is an important risk factor for inducing the rs401681 and rs402710 variants and causes LC development in both populations. Other factors like non-smoking are mainly responsible for inducing the development of NSCLC in Asians, and is concentrated in LUAD among Asian non-smoking women.

[Research Progress of Comprehensive Follow-up Management Strategy on the Natural History of Simultaneous, Persistent Multiple Pulmonary Ground-glass Nodules]

The development and change patterns as well as the disease course management of multiple ground-glass nodules (GGNs) in the lungs are currently hotspots and difficulties in clinical lung cancer research. Understanding the latest advancements in the natural history of multiple GGNs is crucial for grasping the disease variation patterns and formulating management strategies. Meanwhile, utilizing advanced methods such as intelligent follow-up management platforms makes the long-term standardized management of GGNs possible. Therefore, this article provides an overview of the latest research advancements on the natural history of multiple GGNs and new experience in GGNs management.
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Differences in the risk association of TERT-CLPTM1L rs4975616 (A>G) with lung cancer between Caucasian and Asian populations: A meta-analysis

BACKGROUND

Although the G allele variant of TERT-CLPTM1L rs4975616 has been confirmed to be negatively associated to the risk of lung cancer (LC), some other studies haven't found this negative association. The purpose of this study is to clarify the association of the rs4975616 with the risk of developing LC and the differences of this association among patients with different ethnicities (Caucasians and Asians), different subtypes of LC, and different smoking status.

METHODS

Relevant literatures published before July 20, 2023 in PubMed, EMbase, Web of Science, MEDLINE databases were searched through the Internet. Statistical analysis of data was performed in Revman5.3, including drawing forest plots, funnel plots and so on. Sensitivity and publication bias were performed in Stata 14.0. The stability of the results was assessed using Test Sequence Analysis (TSA) software. Registration number: CRD42024568348.

RESULTS

The G allele variant of rs4975616 was negatively associated with the risk of LC ([OR] = 0.86, 95%CI [0.84, 0.88]), and that this negative association was present in both Caucasians ([OR] = 0.85, 95%CI [0.83, 0.87]) and Asians ([OR] = 0.91, 95%CI [0.86, 0.95]), and the strength of the negative association was higher in Caucasians than in Asians (subgroup differences: P = 0.02, I2 = 80.3%). Across LC subtypes, rs4975616[G] was negatively associated with the risk of NSCLC (LUAD, LUSC) in both Caucasians and Asians (P<0.05) and the strength of the association with NSCLC (LUAD) was higher in Caucasians than in Asians (Subgroup differences: I2>50%). In Caucasians, rs4975616[G] was negatively associated with the risk of LC in both smokers and non-smokers (P<0.05), and the strength of the association did not differ between smokers and non-smokers (Subgroup differences: P = 0.18, I2 = 45.0%). In Asians, rs4975616[G] was mainly negatively associated with the risk of LC in smokers (P<0.05) but not in non-smokers ([OR] = 0.97, 95%CI [0.78, 1.20]). Comparisons between the two populations showed that the strength of this negative association was higher in Caucasian non-smokers than in Asian non-smokers (Subgroup differences: P = 0.04, I2 = 75.3%), whereas the strength of this negative association was the same for Caucasian smokers as for Asian smokers (Subgroup differences: P = 0.42, I2 = 0%). Among the different LC subtypes, rs4975616[G] was negatively associated with the risk of NSCLC (LUAD) incidence in both Asian smokers and Caucasian non-smokers (P<0.05), whereas it was not associated with the risk of NSCLC development in Asian non-smokers (P>0.05). Comparisons between the two populations showed that the strength of the association was higher in Caucasian non-smokers than in Asian non-smokers (Subgroup differences: I2>50%).

CONCLUSION

The G allele variant of rs4975616 is negatively associated with the risk of LC and NSCLC (LUAD, LUSC). Compared with Asians, Caucasians are more likely to have a higher risk of LC and NSCLC (LUAD) due to the rs4975616 variant. In Caucasians, smoking and other factors like non-smoking contribute to rs4975616 variations leading to LC, and other factors like non-smoking also induce rs4975616 variations leading to NSCLC (LUAD). In Asians, smoking is the major risk factor for the induction of rs4975616 variations leading to LC and NSCLC(LUAD).

Lung cancer in patients who have never smoked - an emerging disease

Lung cancer is the most common cause of cancer-related deaths globally. Although smoking-related lung cancers continue to account for the majority of diagnoses, smoking rates have been decreasing for several decades. Lung cancer in individuals who have never smoked (LCINS) is estimated to be the fifth most common cause of cancer-related deaths worldwide in 2023, preferentially occurring in women and Asian populations. As smoking rates continue to decline, understanding the aetiology and features of this disease, which necessitate unique diagnostic and treatment paradigms, will be imperative. New data have provided important insights into the molecular and genomic characteristics of LCINS, which are distinct from those of smoking-associated lung cancers and directly affect treatment decisions and outcomes. Herein, we review the emerging data regarding the aetiology and features of LCINS, particularly the genetic and environmental underpinnings of this disease as well as their implications for treatment. In addition, we outline the unique diagnostic and therapeutic paradigms of LCINS and discuss future directions in identifying individuals at high risk of this disease for potential screening efforts.

Ethnicity-specific association between TERT rs2736100 (A > C) polymorphism and lung cancer risk: a comprehensive meta-analysis

The rs2736100 (A > C) polymorphism of the second intron of Telomerase reverse transcriptase (TERT) has been confirmed to be closely associated with the risk of Lung cancer (LC), but there is still no unified conclusion on the results of its association with LC. This study included Genome-wide association studies (GWAS) and case-control studies reported so far on this association between TERT rs2736100 polymorphism and LC to clarify such a correlation with LC and the differences in it between different ethnicities and different types of LC. Relevant literatures published before May 7, 2022 on 'TERT rs2736100 polymorphism and LC susceptibility' in PubMed, EMbase, CENTRAL, MEDLINE databases were searched through the Internet, and data were extracted. Statistical analysis of data was performed in Revman5.3 software, including drawing forest diagrams, drawing funnel diagrams and so on. Sensitivity and publication bias analysis were performed in Stata 12.0 software. The C allele of TERT rs2736100 was associated with the risk of LC (Overall population: [OR] = 1.21, 95%CI [1.17, 1.25]; Caucasians: [OR] = 1.11, 95%CI [1.06, 1.17]; Asians: [OR] = 1.26, 95%CI [1.21, 1.30]), and Asians had a higher risk of LC than Caucasians (C vs. A: Caucasians: [OR] = 1.11 /Asians: [OR]) = 1.26). The other gene models also showed similar results. The results of stratified analysis of LC patients showed that the C allele was associated with the risk of Non-small-cell lung carcinoma (NSCLC) and Lung adenocarcinoma (LUAD), and the risk of NSCLC and LUAD in Asians was higher than that in Caucasians. The C allele was associated with the risk of Lung squamous cell carcinoma (LUSC) and Small cell lung carcinoma(SCLC) in Asians but not in Caucasians. NSCLC patients ([OR] = 1.27) had a stronger correlation than SCLC patients ([OR] = 1.03), and LUAD patients ([OR] = 1.32) had a stronger correlation than LUSC patients ([OR] = 1.09).In addition, the C allele of TERT rs2736100 was associated with the risk of LC, NSCLC and LUAD in both smoking groups and non-smoking groups, and the risk of LC in non-smokers of different ethnic groups was higher than that in smokers. In the Asians, non-smoking women were more at risk of developing LUAD. The C allele of TERT rs2736100 is a risk factor for LC, NSCLC, and LUAD in different ethnic groups, and the Asian population is at a more common risk. The C allele is a risk factor for LUSC and SCLC in Asians but not in Caucasians. And smoking is not the most critical factor that causes variation in TERT rs2736100 to increase the risk of most LC (NSCLC, LUAD). Therefore, LC is a multi-etiological disease caused by a combination of genetic, environmental and lifestyle factors.

Where there are fumes, there may be lung cancer: a systematic review on the association between exposure to cooking fumes and the risk of lung cancer in never-smokers

PURPOSE

Lung cancer in never-smokers (LCINS) is the seventh leading cause of cancer, and exposure to cooking fumes has recently emerged as a potential risk factor. This systematic review is the first to summarize and evaluate the relationship between exposure to cooking fumes and the risk of LCINS.

METHODS

This study conducted an online literature search of PubMed, CINAHL, and PsychInfo databases. Inclusion criteria were original research articles published in English, that assessed the relationship between exposure to cooking fumes and the risk of lung cancer between 1 January 2012 and 6 December 2022, and that included never-smokers.

RESULTS

Thirteen case-control studies and three prospective cohort studies, focusing mostly on women with LCINS, met the inclusion criteria. Seven case-control studies reported an association between exposure to cooking oil fumes and an increased risk of LCINS. Two case-control studies found that using a fume extractor was associated with a decreased risk of LCINS. In other case-control studies, coal use was linked to an increased risk of LCINS, and participants who did not use a ventilator in their kitchens had a higher risk for LCINS. Poor ventilation [Adjusted Hazard Ratio (AHR) = 1.49; 95% CI: 1.15, 1.95] and poor ventilation in combination with coal use (AHR = 2.03; 95% CI: 1.35, 3.05) were associated with an increased risk for LCINS in one prospective cohort study.

CONCLUSION

The evidence reviewed underscores the need to develop culturally-tailored interventions that improve access to affordable and clean fuel through engaging relevant stakeholders.

Genetic differences between smokers and never-smokers with lung cancer

Smoking is a major risk factor for lung cancer, therefore lung cancer epidemiological trends reflect the past trends of cigarette smoking to a great extent. The geographic patterns in mortality closely follow those in incidence. Although lung cancer is strongly associated with cigarette smoking, only about 15% of smokers get lung cancer, and also some never-smokers develop this malignancy. Although less frequent, lung cancer in never smokers is the seventh leading cause of cancer deaths in both sexes worldwide. Lung cancer in smokers and never-smokers differs in many aspects: in histological types, environmental factors representing a risk, and in genes associated with this disease. In this review, we will focus on the genetic differences between lung cancer in smokers versus never-smokers: gene expression, germ-line polymorphisms, gene mutations, as well as ethnic and gender differences. Finally, treatment options for smokers and never-smokers will be briefly reviewed.

Etiology of lung cancer: Evidence from epidemiologic studies

Lung cancer is one of the leading causes of cancer incidence and mortality worldwide. While smoking, radon, air pollution, as well as occupational exposure to asbestos, diesel fumes, arsenic, beryllium, cadmium, chromium, nickel, and silica are well-established risk factors, many lung cancer cases cannot be explained by these known risk factors. Over the last two decades the incidence of adenocarcinoma has risen, and it now surpasses squamous cell carcinoma as the most common histologic subtype. This increase warrants new efforts to identify additional risk factors for specific lung cancer subtypes as well as a comprehensive review of current evidence from epidemiologic studies to inform future studies. Given the myriad exposures individuals experience in real-world settings, it is essential to investigate mixture effects from complex exposures and gene-environment interactions in relation to lung cancer and its subtypes.

Application Value of PET/CT and MRI in the Diagnosis and Treatment of Patients With Synchronous Multiple Pulmonary Ground-Glass Nodules

Background

Synchronous multiple ground-glass nodules (SMGGNs) in synchronous multiple lung cancers are associated with specific imaging findings. It is difficult to distinguish whether multiple nodules are primary tumors or metastatic lesions in the lungs. The need for PET/CT and contrast-enhanced brain MRI for these patients remains unclear. This study investigated the necessity of these two imaging examinations for SMGGN patients by means of retrospective analysis.

Methods

SMGGN patients who were diagnosed and treated in our hospital from October 2017 to May 2020 and underwent whole-body PET/CT(Cranial excepted) and/or contrast-enhanced brain MRI+DWI were enrolled in this study. We analyzed the imaging and clinical characteristics of these patients to evaluate SMGGN patients’ need to undergo whole-body PET/CT and brain MRI examination.

Results

A total of 87 SMGGN patients were enrolled. 51 patients underwent whole-body PET/CT examinations and did not show signs of primary tumors in other organs, metastatic foci in other organs, or metastasis to surrounding lymph nodes. 87 patients underwent whole-brain MRI, which did not reveal brain metastases but did detect an old cerebral infarction in 23 patients and a new cerebral infarction in one patient. 87 patients underwent surgical treatment in which 219 nodules were removed. All nodules were diagnosed as adenocarcinoma or atypical adenomatous hyperplasia. No lymph node metastasis was noted.

Conclusion

For SMGGN patients, PET/CT and enhanced cranial MRI are unnecessary for SMGGNs patients, but from the perspective of perioperative patient safety, preoperative MRI+DWI examination is recommended for SMGGNs patients.

Lung cancer risk in never-smokers: An overview of environmental and genetic factors

Lung cancer is the leading cause of cancer-related mortality globally, accounting for 1.8 million deaths in 2020. While the vast majority are caused by tobacco smoking, 15%-25% of all lung cancer cases occur in lifelong never-smokers. The International Agency for Research on Cancer (IARC) has classified multiple agents with sufficient evidence for lung carcinogenesis in humans, which include tobacco smoking, as well as several environmental exposures such as radon, second-hand tobacco smoke, outdoor air pollution, household combustion of coal and several occupational hazards. However, the IARC evaluation had not been stratified based on smoking status, and notably lung cancer in never-smokers (LCINS) has different epidemiological, clinicopathologic and molecular characteristics from lung cancer in ever-smokers. Among several risk factors proposed for the development of LCINS, environmental factors have the most available evidence for their association with LCINS and their roles cannot be overemphasized. Additionally, while initial genetic studies largely focused on lung cancer as a whole, recent studies have also identified genetic risk factors for LCINS. This article presents an overview of several environmental factors associated with LCINS, and some of the emerging evidence for genetic factors associated with LCINS. An increased understanding of the risk factors associated with LCINS not only helps to evaluate a never-smoker's personal risk for lung cancer, but also has important public health implications for the prevention and early detection of the disease. Conclusive evidence on causal associations could inform longer-term policy reform in a range of areas including occupational health and safety, urban design, energy use and particle emissions, and the importance of considering the impacts of second-hand smoke in tobacco control policy.

Air Pollution, Genetic Factors and the Risk of Lung Cancer: A Prospective Study in the UK Biobank

Rationale: Both genetic and environmental factors contribute to lung cancer, but the degree to which air pollution modifies the impact of genetic susceptibility on lung cancer remains unknown. Objectives: To investigate whether air pollution and genetic factors jointly contribute to incident lung cancer. Methods: We analyzed data from 455,974 participants (53% women) without previous cancer at baseline in the UK Biobank. The concentrations of particulate matter (PM_2.5, PM_coarse and PM₁₀), nitrogen dioxide (NO₂), and nitrogen oxides (NO_x) were estimated by land-use regression models, and the association between air pollutants and incident lung cancer was investigated using a Cox proportional hazard model. Furthermore, we constructed a polygenic risk score and evaluated whether air pollutants modified the effect of genetic susceptibility on the development of lung cancer. Measurements and Main Results: The results showed significant associations between the risk of lung cancer and PM_2.5 (hazard ratio [HR]: 1.63, 95% confidence interval [CI]: 1.33-2.01; per 5 μg/m³), PM₁₀ (1.53, 1.20-1.96; per 10 μg/m³), NO₂ (1.10, 1.05-1.15; per 10 μg/m³), and NO_x (1.13, 1.07-1.18; per 20 μg/m³). There were additive interactions between air pollutants and the genetic risk. Compared with participants with low genetic risk and low air pollution, those with high air pollution and high genetic risk had the highest risk of lung cancer (PM_2.5: HR: 1.71, 95% CI:1.45-2.02; PM₁₀: 1.77, 1.50-2.10; NO₂: 1.77, 1.42-2.22; NO_x: 1.67, 1.43-1.95). Conclusion: Long-term exposure to air pollution may increase the risk of lung cancer, especially in those with high genetic risk.

TERT Gene rs2736100 and rs2736098 Polymorphisms are Associated with Increased Cancer Risk: A Meta-Analysis

Abnormal telomerase activity plays a key role in the development of carcinogenesis. The variants rs2736100 and rs2736098 of the telomerase reverse transcriptase (TERT) gene, which encodes the telomerase catalytic subunit, are associated with the risk of different types of cancers. However, the results remain controversy. We conducted a meta-analysis to more precisely assess this association. We comprehensively searched the PubMed and Web of Science databases up to June 1, 2020, and retrieved a total of 103 studies in 82 articles, including 89,320 cases and 121,654 controls. Among these studies, 69 published studies including 75,274 cases and 10,3248 controls were focused on rs2736100, and 34 published studies including 14,046 cases and 18,362 controls were focused on rs2736098. The results showed a strong association between variant rs2736100 and cancer risk in all populations. (G vs. T: OR 1.18, 95% CI 1.12-1.24; TG+GG vs. TT: OR 1.23, 95% CI 1.15-1.31; GG vs. TG+TT: OR 1.25, 95% CI 1.16-1.36); the variant rs2736098 was associated with cancer risk in all populations as well (A vs. G: OR 1.13, 95% CI 1.05-1.22; GA+AA vs. GG: OR 1.15, 95% CI 1.04-1.27; AA vs. GA+GG: OR 1.22, 95% CI 1.10-1.38). Stratified analysis based on the cancer type indicated that rs2736100 was associated with an increased risk of thyroid cancer, bladder cancer, lung cancer, glioma, and myeloproliferative neoplasms. rs2736098 only increased the risk of bladder cancer and lung cancer. Moreover, the TERT variants rs2736100 and rs2736098 were associated with a decreased risk of breast cancer and colorectal cancer. The variants rs2736098 and rs2736100 located in 5p15.33 around TERT were associated with increased cancer risk in all populations. These two variants had bidirectional effects in different tumors.

Sub-multiplicative interaction between polygenic risk score and household coal use in relation to lung adenocarcinoma among never-smoking women in Asia

We previously identified 10 lung adenocarcinoma susceptibility loci in a genome-wide association study (GWAS) conducted in the Female Lung Cancer Consortium in Asia (FLCCA), the largest genomic study of lung cancer among never-smoking women to date. Furthermore, household coal use for cooking and heating has been linked to lung cancer in Asia, especially in Xuanwei, China. We investigated the potential interaction between genetic susceptibility and coal use in FLCCA. We analyzed GWAS-data from Taiwan, Shanghai, and Shenyang (1472 cases; 1497 controls), as well as a separate study conducted in Xuanwei (152 cases; 522 controls) for additional analyses. We summarized genetic susceptibility using a polygenic risk score (PRS), which was the weighted sum of the risk-alleles from the 10 previously identified loci. We estimated associations between a PRS, coal use (ever/never), and lung adenocarcinoma with multivariable logistic regression models, and evaluated potential gene-environment interactions using likelihood ratio tests. There was a strong association between continuous PRS and lung adenocarcinoma among never coal users (Odds Ratio (OR) = 1.69 (95% Confidence Interval (CI) = 1.53, 1.87), p=1 × 10-26). This effect was attenuated among ever coal users (OR = 1.24 (95% CI: 1.03, 1.50), p = 0.02, p-interaction = 6 × 10-3). We observed similar attenuation among coal users from Xuanwei. Our study provides evidence that genetic susceptibility to lung adenocarcinoma among never-smoking Asian women is weaker among coal users. These results suggest that lung cancer pathogenesis may differ, at least partially, depending on exposure to coal combustion products. Notably, these novel findings are among the few instances of sub-multiplicative gene-environment interactions in the cancer literature.

Impact of Gene-Environment Interactions on Cancer Development

Several epidemiological and experimental studies have demonstrated that many human diseases are not only caused by specific genetic and environmental factors but also by gene-environment interactions. Although it has been widely reported that genetic polymorphisms play a critical role in human susceptibility to cancer and other chronic disease conditions, many single nucleotide polymorphisms (SNPs) are caused by somatic mutations resulting from human exposure to environmental stressors. Scientific evidence suggests that the etiology of many chronic illnesses is caused by the joint effect between genetics and the environment. Research has also pointed out that the interactions of environmental factors with specific allelic variants highly modulate the susceptibility to diseases. Hence, many scientific discoveries on gene-environment interactions have elucidated the impact of their combined effect on the incidence and/or prevalence rate of human diseases. In this review, we provide an overview of the nature of gene-environment interactions, and discuss their role in human cancers, with special emphases on lung, colorectal, bladder, breast, ovarian, and prostate cancers.

Long non-coding RNA AGER-1 inhibits colorectal cancer progression through sponging miR-182

OBJECTIVE

Abundant evidence has illustrated that long non-coding RNA (lncRNA) plays a vital role in the regulation of tumor development and progression. Ectopic expression of a novel lncRNA, termed lnc-AGER-1, has been discovered in cancers, and this lncRNA was reported to exert an anti-tumor effect. However, its biological mechanism remains unelucidated in colorectal cancer.

METHODS

A total of 159 paired colorectal cancer specimens and adjacent tissues was applied to detect the expression of lnc-AGER-1 by the quantitative Real-time PCR (qRT-PCR), and a series of functional assays was executed to uncover the role of this lncRNA on colorectal cancer.

RESULTS

We found that the expression of lnc-AGER-1 in the tumor tissues was significantly down-regulated, while compared with adjacent normal tissues (0.0115 ± 0.0718 vs. 0.0347 ± 0.157; P < 0.0001). Also, lnc-AGER-1 was observably associated with clinical T status (r = -0.184, P = 0.024). Patients with advanced T status exerted a significantly lower level of lnc-AGER-1 than those with early T status (20.0% vs. 40.7%, P = 0.021). Over-expression of lnc-AGER-1 inhibited cell proliferation and migration efficiency, and induced cell cycle arrest at the G0/G1 phase, and promoted cell apoptosis. Further research proved that lnc-AGER-1 altered the expression of its neighbor gene, AGER, through acting as a competing endogenous RNA for miR-182 in colorectal cancer.

CONCLUSION

lnc-AGER-1 has a suppressive role in colorectal cancer development via modulating AGER, which may serve as a target for colorectal cancer diagnosis and treatment.

Daily cooking duration and its joint effects with genetic polymorphisms on lung cancer incidence: Results from a Chinese prospective cohort study

OBJECTIVES

In this study, we conducted a prospective cohort study to investigate the joint effects of daily cooking duration with single nucleotide polymorphisms (SNPs) on lung cancer incidence.

MATERIALS AND METHODS

A total of 33,868 individuals recruited in 2013 from Dongfeng-Tongji cohort study were included in our research, in which 5178 participants were genotyped. Daily cooking duration was accessed by questionnaire, and the incident lung cancer cases were confirmed. Fifteen lung cancer related SNPs were selected according to the previous reports. We used the multiple Cox regression models to evaluate the separate and joint effects of daily cooking duration and SNPs on lung cancer incidence.

RESULTS

Each 1-h increase in daily cooking duration was associated with a 17% elevated risk of lung cancer incidence [hazard ratio (HR) (95%CI) = 1.17(1.03, 1.33)]. Specifically, subjects with daily cooking duration >2 h/day had a 2.05-fold increased incident risk of lung cancer than those without cooking [HR(95%CI) = 2.05(1.20, 3.53)] (P_trend = 0.011). The rs2395185 and rs3817963, both located at 6p21.32, were significantly associated with lung cancer incidence. Compared with no cooking subjects with rs2395185GG or rs3817963TT genotype, subjects with daily cooking >2 h/day and carrying rs2395185GT + TT genotypes had a 2.48-fold increased risk of lung cancer [HR(95%CI) = 2.48(1.03, 5.97)], and there were significant joint effects of rs3817963TC + CC with daily cooking 1-2 and >2 h/day [HR(95%CI) = 2.23(1.07, 4.64) and 2.22(1.05, 4.68), respectively].

CONCLUSIONS

Longer daily cooking duration, especially daily cooking >2 h/day, was associated with increased risk of lung cancer. There were significant joint effects of rs2395185 and rs3817963 with daily cooking duration on lung cancer incidence. This study offered a new indicator of cooking related pollution exposure and added new evidence for the joint effects of environment and genetic factors on lung cancer incidence.

Synchronous multiple lung cancers presenting as multifocal pure ground glass nodules: are whole-body positron emission tomography/computed tomography and brain enhanced magnetic resonance imaging necessary?

Background

Multifocal ground glass nodules (GGNs) represent a special radiological pattern indicative of synchronous multiple lung cancers (SMLCs), especially adenocarcinoma. However, the necessity of performing whole-body positron emission tomography/computed tomography (PET-CT) scanning and brain enhanced magnetic resonance imaging (MRI) as a staging workup for multifocal pure GGN (pGGN) patients remains unclear. The purpose of this study was to determine the utility of these two imaging scans for patients with multifocal pGGNs.

Methods

This retrospective study was reviewed and approved by the ethics committee of the Cancer Hospital of the Chinese Academy of Medical Sciences. The study cohort was retrospectively selected from patients with multifocal pGGNs who underwent whole-body PET-CT examinations and/or brain enhanced MRIs between January 2010 and February 2019 at our institution. The additional value of the two exams for detecting nodal and distant metastases was evaluated.

Results

In total, 73 patients (male-to-female ratio, 20:53; median age, 57 years) with multifocal pGGNs who underwent whole-body PET-CT (55 patients) and/or brain enhanced MRI (25 patients) were enrolled. No clearly metastatic lesions were detected. Among the enrolled patients, 53 (128 pGGNs) underwent complete surgical resection. All pGGNs were adenocarcinomas and/or preneoplasias, and no lymph node metastases were found on final pathology. Whole-body PET-CT and brain enhanced MRI added no definite benefit compared with chest CT alone before surgery.

Conclusions

Whole-body PET-CT scans and brain enhanced MRIs are not necessary for patients with multifocal pGGNs.

Major histocompatibility complex class II molecule in non-small cell lung cancer diagnosis, prognosis and treatment

Lung cancer is one of the commonest cancers in the world. More than 70% of lung cancer patients are diagnosed with non-small cell lung cancer (NSCLC). Major histocompatibility complex class II (MHC class II), an important component in antigen presenting process, usually expresses on professional antigen presenting cells (APCs), and it can be induced by interferon-γ (IFN-γ). MHC class II can be expressed by NSCLC cells. In NSCLC patients, the expression of MHC class II can be correlated with the outcome of anti-programmed death-1 (anti-PD-1) therapy. This review summarizes MHC class II expression in NSCLC and the correlation between MHC class II and NSCLC diagnosis, prognosis and therapy.

Genetic variants in SLC22A3 contribute to the susceptibility to colorectal cancer

Previous a genome-wide association study (GWAS) of colorectal cancer in Japanese population has identified a risk region at the chromosome 6q26-q27 associated with colorectal cancer risk. However, the causal gene at this locus remained unclear. In our study, we enrolled a total of 14 candidate functional single nucleotide polymorphisms (SNPs) at 6q26-q27 (318 kb), and then genotyped them by TaqMan method in a Chinese population including 1,147 colorectal cancer cases and 1,203 controls. Among that, 5 SNPs were identified statistical association with colorectal cancer risk by logistic regression analysis. Of which, SNP rs420038 G > A in SLC22A3 was related to decreased risk of colorectal cancer (adjusted odds ratio (OR) = 0.79, 95% confidence interval (CI) = 0.67-0.94, p = 0.007), and also associated with lower expression of SLC22A3 (p = 0.040) using expression quantitative trait loci (eQTL) analysis. Moreover, by the luciferase assays, we found that compared to the G allele of rs420038, the A allele could suppress the activity of the promoter in SLC22A3. Furthermore, the expression of SLC22A3 was significantly higher in colorectal cancer tissues than that in paired normal tissues (p < 0.001). Meanwhile, the phenotypes of proliferation, migration, invasion, cell cycle and apoptosis of colorectal cancer cell were significantly affected by SLC22A3 in vitro. Our results revealed a novel susceptible locus, rs420038 in SLC22A3, which may be involved in colorectal cancer development and progression.

Bituminous coal combustion and Xuan Wei Lung cancer: a review of the epidemiology, intervention, carcinogens, and carcinogenesis

Indoor air pollution from bituminous coal combustion has been linked to the extremely high lung cancer rates of nonsmoking women in Xuan Wei County, Yunnan Province, China. Venting the smoke outdoors by installing chimneys was found to be effective at reducing the lung cancer risk in a cohort study of 21,232 farmers in central Xuan Wei. However, the lung cancer mortality rates in all 1.2 million residents of Xuan Wei have been increasing dramatically over the last four decades. It was higher than that in Yunnan Province and China overall, with significant heterogeneities in the geographic patterns of Xuan Wei. Intervention measures targeting certain types of coal or certain carcinogenic components in coal smoke need to be explored. To inform targeted intervention policies, it is essential to pinpoint the specific substance (particulate matter, organic extract, PAHs, free radicals, crystalline silica, and inorganic matter) that might account for the carcinogenicity of bituminous coal smoke. Exploring the underlying carcinogenesis mechanisms would also contribute to the intervention and control of the lung cancer epidemic in Xuan Wei, China. Here we review the suspected carcinogens and carcinogenesis mechanisms and discuss future research directions towards a better understanding of the etiology of lung cancer in Xuan Wei, China.

The Relationship Between Population Attributable Fraction and Heritability in Genetic Studies

Population attributable fraction (PAF) has been widely used to quantify the proportion of disease risk in a population that can be attributed to risk factors in epidemiological studies. However, the use of PAF has been limited in assessing the contribution of genetic variants. Most notably, the PAF estimate is typically much larger than other commonly used measures, such as heritability, thereby raising the concern that PAF may overestimate the genetic contribution. In this paper, we show that PAF is a one-to-one function of heritability, and explain why PAF is larger than heritability. Further, we present an estimation procedure based on the summary statistics from genome-wide association studies (GWAS) to estimate the PAF of multiple correlated genetic variants for a binary outcome. Currently available estimation procedures only apply to a single variant or to multiple genetic variants that are independent from each other. Our simulation studies verified the relationship between PAF and heritability, and showed that the proposed estimation procedure for these two measures performed well. Finally, we applied the proposed method to the published data of two lung cancer GWAS to estimate the PAF and heritability of several newly identified variants. Our results demonstrate that the PAF estimate is a useful measure of the genetic contribution to the development of the disease. We hope this paper serves as an advocate for a wider use of PAF in genetic studies.

The Correlation of Visfatin and Its Gene Polymorphism with Non-Small Cell Lung Cancer

Objective: To investigate the protein expression of visfatin and its gene polymorphism in non-small cell lung cancer (NSCLC) patients. Methods: The plasma level of visfatin was detected by enzyme-linked immunosorbent assay, and the genotypes rs59744560, rs9770242, and rs61330082 in the visfatin gene were detected by gene sequencing. Result: This study revealed that plasma levels of visfatin in NSCLC patients were significantly higher than the levels in healthy people (p < 0.01). The high level of plasma visfatin was found to be significantly correlated with TNM stage (p < 0.05). No mutations were detected in rs59744560 and rs9770242 loci. Three genotypes (CC, CT, and TT) were detected in rs61330082 locus, and the differences in the frequency distribution of these genotypes were significant in the two groups (p < 0.05). Central obesity and the CC genotype were independent risk factors in the pathogenesis of NSCLC (p < 0.05). Conclusion: The plasma visfatin level in NSCLC patients significantly increased, and high plasma visfatin levels were correlated with tumor stage. Gene polymorphism was found in the visfatin gene rs61330082 locus. The CC genotype might increase the risk for patients suffering from NSCLC, while the CT genotype, TT genotype, and T allele may reduce the risk of NSCLC. The rs61330082 locus can be used as genetic markers of high-risk populations.

Secure genome-wide association analysis using multiparty computation

Most sequenced genomes are currently stored in strict access-controlled repositories. Free access to these data could improve the power of genome-wide association studies (GWAS) to identify disease-causing genetic variants and aid the discovery of new drug targets. However, concerns over genetic data privacy may deter individuals from contributing their genomes to scientific studies and could prevent researchers from sharing data with the scientific community. Although cryptographic techniques for secure data analysis exist, none scales to computationally intensive analyses, such as GWAS. Here we describe a protocol for large-scale genome-wide analysis that facilitates quality control and population stratification correction in 9K, 13K, and 23K individuals while maintaining the confidentiality of underlying genotypes and phenotypes. We show the protocol could feasibly scale to a million individuals. This approach may help to make currently restricted data available to the scientific community and could potentially enable secure genome crowdsourcing, allowing individuals to contribute their genomes to a study without compromising their privacy.

A Decade of GWAS Results in Lung Cancer

Genome-wide association studies (GWAS) were successful to identify genetic factors robustly associated with lung cancer. This review aims to synthesize the literature in this field and accelerate the translation of GWAS discoveries into results that are closer to clinical applications. A chronologic presentation of published GWAS on lung cancer susceptibility, survival, and response to treatment is presented. The most important results are tabulated to provide a concise overview in one read. GWAS have reported 45 lung cancer susceptibility loci with varying strength of evidence and highlighted suspected causal genes at each locus. Some genetic risk loci have been refined to more homogeneous subgroups of lung cancer patients in terms of histologic subtypes, smoking status, gender, and ethnicity. Overall, these discoveries are an important step for future development of new therapeutic targets and biomarkers to personalize and improve the quality of care for patients. GWAS results are on the edge of offering new tools for targeted screening in high-risk individuals, but more research is needed if GWAS are to pay off the investment. Complementary genomic datasets and functional studies are needed to refine the underlying molecular mechanisms of lung cancer preliminarily revealed by GWAS and reach results that are medically actionable. Cancer Epidemiol Biomarkers Prev; 27(4); 363-79. ©2018 AACRSee all articles in this CEBP Focus section, "Genome-Wide Association Studies in Cancer."

Long non-coding RNA AGER-1 functionally upregulates the innate immunity gene AGER and approximates its anti-tumor effect in lung cancer

Little is known about long non-coding RNA (lncRNA) related to innate immunity in lung cancer. The advanced glycosylation end-product specific receptor (AGER) belongs to the immunoglobulin superfamily, and currently, is the only innate immune pattern-recognition receptor whose abnormal expression has been detected in lung cancer. We aimed to explore the lncRNA that is related to AGER and test its effect on lung carcinogenesis. We selected one lncRNA whose chromosome location is in close proximity to AGER namely lnc-AGER-1 (defined as lncAGER). The expression of lncAGER was tested in 276 pairs of lung cancer tissues and adjacent lung normal tissues, and its correlation with lung cancer clinical progress was analyzed. A series of assays were further used to assess the biological function of lncAGER on lung cancer development, tumor immunity and autophagy. LncAGER expression was moderately correlated with AGER expression (r = 0.360, P = 2.15 × 10^-18 ) underlying a mechanism that lncAGER upregulates AGER by competitively binding to miRNA-185. LncAGER was significantly down-regulated in 76.4% of lung cancer tissues compared to adjacent normal tissues due to promoter hypermethylation. Over-expression of the lncRNA resulted in significant decreases in proliferation rate, migration ability, colony formation efficiency of lung cancer cells and tumor growth in nude mice. Notably, lncAGER possibly conduced to enhancement of cytotoxic effect of THP1. Additionally, the lncRNA also promoted cell apoptosis by strengthening autophagy. Taken together, these observations suggest that lncAGER has an inhibitory effect on lung cancer development via AGER, which may serve as a target for lung cancer treatment.

Characteristics, survival, and risk factors of Chinese young lung cancer patients: the experience from two institutions

Limited data is available regarding lung cancer in Chinese young adults. This study was aimed to determine the characteristics, survival, and prognostic factors of young lung cancer patients in China. We reviewed demographic and clinical data, and survival information of 420 young patients (20-45 years old) diagnosed with lung cancer in two Chinese hospitals between 2000 and 2013. The results showed that lung cancer occurred more frequently (70%) and affected more males than females (43.8% vs 26.7%) in patients older than 36; whereas, more females were affected under age 35 (16.7% vs 12.8%). Most patients had adenocarcinoma (67.6%) and stage IV disease (72.4%) at presentation. The median survival of all young patients with lung cancer was 44 months (95% CI: 39-49), of which patients with stage I-IIIA disease had a longer survival than those with stage IIIB/IV disease (101 vs 22 months, p < 0.001). No significant difference in survival was found in patients having different histological subtypes or genders. Multivariate analysis revealed that high exposure risk occupations, smoking, family history of lung cancer were risk factors of young lung cancer patients. This study provides an overview of the clinical characteristics, patterns and prognostic factors of young patients with lung cancer in China.

Surviving With Smog and Smoke: Precision Interventions?

Despite continuous efforts of regional governmental agencies, air pollution remains a major threat to public health worldwide. In January 2017, a severe episode of smog similar to the Great Smog of 1952 occurred in London. The longest episode of Chinese haze also developed in Beijing, during which levels of particulate matter < 2.5 μm rose to 500 μg/m³. European smog and Chinese haze are associated with large numbers of premature deaths each year, at 400,000 and 1.2 million, respectively, primarily from respiratory diseases, cerebrovascular diseases, and ischemic heart diseases. In addition to air pollution, some are exposed to other harmful environmental factors, such as secondhand smoke. For countries with large populations of smokers, such as China, India, the United States, and Russia, surviving both smog and smoke is a serious problem. With novel genomic and epigenomic studies revealing air pollution- and smoking-induced mutational signatures and epigenetic editing in diseases such as lung cancer, it has become feasible to develop precision strategies for early intervention in the disease-causing pathways driven by the specific mutations or epigenetic regulations, or both. New therapies guided by gene-drug interactions and genomic biomarkers may also be developed. We discuss both perspectives regarding the urgent need to manage the toxic effects of smog and smoke for the benefit of global health and the novel concept of precision intervention to protect the exposed individuals when exposure to smog and secondhand smoke cannot be voluntarily avoided or easily modified.

Spatial Analysis of Regional Factors and Lung Cancer Mortality in China, 1973-2013

Background: China's lung cancer crude death rate has increased 6.9-fold from 1973 to 2014. During this time, the country experienced extremely rapid economic growth and social change. It is important to understand the effects of risk factors on lung cancer mortality (LCM) for better allocation of limited resources of cancer prevention and control in China.Methods: Using three nationwide mortality surveys from 1973 to 2005, Global Health Data Exchange data in 2013, three nationwide smoking surveys from 1984 to 2013, four population censuses from 1964 to 2000, and other datasets, we have compiled datasets and developed spatial random effect models to assess the association of various area-level-contributing factors on LCM. Spatial scan statistics are used to detect high-risk clusters of LCM.Results: LCM is higher in urban and more industrialized areas (RR = 1.17) compared with those in rural areas. The level of industrial development's effect is higher for men, which accounts for about 70% of all LCM. Smoking is positively associated with regional variation of LCM rates, and the effect is higher for women than for men.Conclusions: The geographic pattern of high LCM in China is different from that of Western countries. LCM is positively associated with higher socioeconomic status, with more urbanized areas at a higher level of industrial development.Impact: There is a need to further explore additional risk in the high-risk clusters. The study is about China, but this situation may happen in other countries experiencing rapid industrialization and other developing countries. Cancer Epidemiol Biomarkers Prev; 26(4); 569-77. ©2017 AACRSee all the articles in this CEBP Focus section, "Geospatial Approaches to Cancer Control and Population Sciences."