Molecular changes in smoking-related lung cancer

First-Generation Epidermal Growth Factor Receptor Inhibitors Plus Antiangiogenic Drugs Versus Third-Generation Epidermal Growth Factor Receptor Inhibitors in Advanced Non-Small-Cell Lung Cancer: A Meta-Analysis

PURPOSE

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) revolutionized the therapeutic landscape of non-small-cell lung cancer (NSCLC). However, despite significant survival improvement, the emergence of resistance mechanisms represents a common event. In this meta-analysis, we compared the efficacy and safety of third-generation EGFR-TKIs, the current standard of care, to first-generation EGFR-TKIs with antiangiogenic drugs for the first-line treatment of NSCLC harboring EGFR mutations.

MATERIALS AND METHODS

Randomized controlled clinical trials (RCTs) reporting survival data published before September 1, 2022, were searched through the MEDLINE databases (PubMed), the Cochrane Database of Systematic Reviews, and Central Register of Controlled Trials (Wiley). Progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and grade 3 or higher treatment-related adverse events (≥3 TRAEs) data were analyzed.

RESULTS

Twelve RCTs were included in our meta-analysis, with a total of 3,565 patients. We observed that third-generation EGFR-TKIs and first-generation EGFR-TKIs combined with antiangiogenic drugs provided a similar OS benefit over first-generation EGFR-TKIs in any of the subgroups. However, we indirectly observed a greater PFS benefit of third-generation EGFR-TKIs over first-generation EGFR-TKIs in females, never-smokers, in patients harboring exon 19 deletions, and in those with brain metastasis, as compared with using first-generation EGFR-TKIs plus antiangiogenic drugs. The ORR did not differ between the combination strategy and third-generation EGFR-TKIs. Finally, the risk of developing grade ≥3 TRAEs was higher using the combination of first-generation EGFR-TKIs and antiangiogenic drugs over first-generation EGFR-TKIs than third-generation EGFR-TKIs over first-generation EGFR-TKIs.

CONCLUSION

This meta-analysis suggests that the combination strategy may provide an alternative to third-generation EGFR-TKIs, but more data are needed to determine the predictive clinicopathologic characteristics that can influence the treatment choice. Until then, third-generation EGFR-TKIs still represent the first choice in advanced NSCLC harboring EGFR mutations.

Effect of benzo(a)pyrene on oxidative stress and inflammatory mediators in astrocytes and HIV-infected macrophages

BACKGROUND

Benzo(a)pyrene (BaP), an important polycyclic aromatic hydrocarbons (PAH) component of cigarette/tobacco smoking, is known to cause adverse health effects and is responsible for various life-threatening conditions including cancer. However, it is not yet clear whether BaP contributes to the macrophage- and astrocyte-mediated inflammatory response.

METHODS

We examined the acute (up to 72 h) effects of BaP on the expression of antioxidant enzymes (AOEs), cytokines/chemokines, and cytochromes P450 (CYP) enzymes in astrocytic cell lines, SVGA, and chronically HIV-infected U1 macrophage. The treated cells were examined for mRNA, protein levels of CYPs, AOEs superoxide dismutase-1 (SOD1) and catalase (CAT), cytokines/chemokines, using Western blot, multiplex ELISA, and reactive oxygen species (ROS) by flow cytometry analysis.

RESULTS

Upon acute exposure, BaP (1 μM) showed a significant increase in the mRNA levels of CYPs (CYP1A1 and CYP1B1), and pro-inflammatory cytokine IL-1β in SVGA cells following BaP for 24, 48, and 72h. In addition, we observed a significant increase in the mRNA levels of SOD1 and CAT at 24h of BaP treatment. In contrast, BaP did not exert any change in the protein expression of AOEs and CYP enzymes. In U1 cells, however, we noticed an interesting increase in the levels of MCP-1 as well as a modest increase in TNFα, IL-8 and IL-1β levels observed at 72 h of BaP treatment but could not reach to statistically significant level.

CONCLUSIONS

Overall, these results suggest that BaP contributes in part to macrophage and astrocyte-mediated neuroinflammation by mainly inducing IL-1β and MCP-1 production, which is likely to occur with the involvement of CYP and/or oxidative stress pathways.

Addition of bevacizumab to erlotinib as first-line treatment of patients with EGFR-mutated advanced nonsquamous non-small cell lung cancer. The BEVERLY multicenter randomized phase III trial

INTRODUCTION

Adding bevacizumab to erlotinib prolonged PFS of patients with EGFR-mutated advanced NSCLC in the Japanese JO25567 trial, but limited data were available in non-Asian patients. BEVERLY is an Italian, multicenter, randomized phase III investigating the addition of bevacizumab to erlotinib as first-line treatment of advanced EGFR-mutated NSCLC.

METHODS

Eligible patients were randomized 1:1 to erlotinib plus bevacizumab or erlotinib alone. Investigator-assessed PFS (IA-PFS) and blinded-independent centrally-reviewed PFS (BICR-PFS) were co-primary endpoints. With 80% power in detecting a 0.60 HR and 2-sided α error 0.05, 126 events out of 160 patients were needed. The trial was registered as NCT02633189 and EudraCT 2015-002235-17.

RESULTS

From Apr 11, 2016 to Feb 27, 2019, 160 pts were randomized to erlotinib+bevacizumab (80) or erlotinib alone (80). At a median follow-up of 36.3 months, median IA-PFS was 15.4 months (95%CI:12.2-18.6) with erlotinib+bevacizumab and 9.6 months (95%CI:8.2-10.6) with erlotinib (HR 0.66; 95%CI: 0.47-0.92). BICR-PFS analysis confirmed this result. A statistically significant interaction with treatment effect was found for smoking habit (P=0.0323), PFS prolongation being clinically significant only among current or previous smokers. Hypertension (grade≥3: 24% vs 5%), skin rash (grade≥3: 31% vs 14%), thromboembolic events (any grade: 11% vs 4%), and proteinuria (any grade: 23% vs 6%) were more frequent with the combination.

CONCLUSION

The addition of bevacizumab to first-line erlotinib prolonged PFS in Italian patients with EGFR-mutated NSCLC; toxicity was increased with the combination but without unexpected safety issues.

New insights into the association between AXIN2 148 C/T, 1365 C/T, and rs4791171 A/G variants and cancer risk

BACKGROUND

Many epidemiological studies have investigated association of AXIN2 variants on overall cancer risks; however, the available results remain inconsistent.

METHODS

An updated analysis was conducted to ascertain a more accurate estimation of the correlation between AXIN2 148 C/T, 1365 C/T, and rs4791171 A/G polymorphisms and cancer risk. We also used in silico tools to assess the effect of AXIN2 expression on cancer susceptibility and overall survival time.

RESULTS

A total of 4281 cases and 3955 control participants were studied. The overall results indicated that AXIN2 148 C/T variant was associated with cancer risk (allelic contrast: OR = 0.88, 95% CI 0.77-0.99, P heterogeneity = 0.004; dominant model: OR = 0.82, 95% CI 0.69-0.96, P heterogeneity = 0.022), especially for lung and prostate adenocarcinoma. Similar results were observed in 1365 C/T polymorphism (OR = 0.71, 95% CI 0.61-0.98, P heterogeneity = 0.873; dominant model: OR = 0.66, 95% CI 0.47-0.94, P heterogeneity = 0.775). Moreover, in subgroup analysis by ethnicity, similar findings were obtained for Asian and Caucasian populations. Results from in silico tools suggested that AXIN2 expressions in lung adenocarcinoma were lower than that in normal group.

CONCLUSIONS

Our findings indicated that AXIN2 148 C/T and 1365 C/T variants may be associated with decreased cancer susceptibility.

Unfavorable clinical implications of peripheral blood CD44+ and CD54+ lymphocytes in patients with lung cancer undergoing chemotherapy

BACKGROUND

There is an unmet need for identification of additional prognostic markers for lung cancer. The aim of this study was to identify novel clinical and immunological predictors of prognosis in lung cancer patients.

METHODS

Lymphocyte subsets CD3+, CD4+, CD8+, CD4+/8+, CD25+, CD69+, CD44+ and CD54+ were quantified in peripheral blood using flow cytometry, for 203 newly diagnosed lung cancer patients and 120 healthy controls.

RESULTS

The levels of CD3+, CD4+, CD8+, CD4+/CD8+ and CD69+ lymphocytes were significantly lower in patients with lung cancer compared with the healthy control group, while CD54+ and CD44+ lymphocytes were significantly higher. In stage III/IV patients with lymph node metastasis or distant metastasis, the levels of CD44+ and CD54+ lymphocytes were significantly increased compared with patients with stage I/II disease (p<0.05). The levels of CD44+ and CD54+ lymphocytes markedly reduced after chemotherapy, and follow-up analysis indicated that patients found without increase of CD44+ and CD54+ lymphocytes after chemotherapy had survival advantages. Independent predictors of survival in lung cancer patients included clinical stage (hazard ratio [HR] = 2.791; 95% confidence interval [95% CI], 1.42-3.54, p<0.001), CD44+ lymphocytes (HR = 1.282; 95% CI, 1.02-1.49, p = 0.002) and CD54+ lymphocytes (HR = 1.475; 95% CI, 1.22-1.73, p = 0.003). Elevated levels of CD44+ and CD54+ lymphocytes correlated with poor prognosis in lung cancer patients.

CONCLUSIONS

Peripheral blood lymphocyte subsets in patients with lung cancer are different from those in healthy people, and circulating CD44+ and CD54+ lymphocytes seem to be a promising criterion to predict survival in lung cancer patients undergoing chemotherapy.

Smoking and Male Infertility: An Evidence-Based Review

Many studies have reported that the contents of cigarette smoke negatively affect sperm parameters, seminal plasma, and various other fertility factors. Nevertheless, the actual effect of smoking on male fertility is not clear. The effect of smoking on semen parameters is based on the well-established biological finding that smoking increases the presence of reactive oxygen species, thereby resulting in oxidative stress (OS). OS has devastating effects on sperm parameters, such as viability and morphology, and impairs sperm function, hence reducing male fertility. However, not all studies have come to the same conclusions. This review sheds light upon the arguable association between smoking and male fertility and also assesses the impact of non-smoking routes of tobacco consumption on male infertility. It also highlights the evidence that links smoking with male infertility, including newly emerging genetic and epigenetic data, and discusses the clinical implications thereof.

Low dose nicotine attenuates Aβ neurotoxicity through activation early growth response gene 1 pathway

Epidemiological studies indicate that smoking is negatively correlated with the incidence and development of Alzheimer's disease (AD). Nicotine was reported to be the active factor. However, the detailed mechanisms still remain to be fully elucidated. Early growth response gene 1 (EGR-1) plays important roles in several important biological processes such as promoting cell growth, differentiation, anti oxidative stress, and apoptosis, but few in the pathogenesis of AD. In the present study, we show that nicotine can activate the MAPK/ERK/EGR-1 signaling pathway partially through α7 nAChR. In addition, the up-regulation of EGR-1 by nicotine can also increase the phosphorylation of CyclinD1 which contributes to the attenuation of amyloid-β (Aβ(25-35)) -induced neurotoxicity. Although nicotine and Aβ(25-35) can activate EGR-1, the expression of EGR-1 is down-regulated following treatment with nicotine and Aβ(25-35). This study demonstrates that low dose nicotine attenuates Aβ(25-35)-induced neurotoxicity in vitro and in vivo through activating EGR-1 pathway.

The polymorphism of CYP2E1 Rsa I/Pst I gene and susceptibility to respiratory system cancer: a systematic review and meta-analysis of 34 studies

The purpose of this articles is to determine whether the cytochrome P450 2E1 (CYP2E1) Rsa I/Pst I gene polymorphism is correlated with respiratory system cancers. Respiratory system cancers included lung cancer, laryngeal cancer, nasopharyngeal cancer, and cancers of other respiratory organs, which are the most common malignant tumors worldwide; the significant relationship between CYP2E1 Rsa I/Pst I gene polymorphism and some respiratory system cancer have been reported, but results of some other studies are controversial. The pooled odds ratio (OR) with 95% confidence interval (CI) was calculated to assess the association. PubMed, EMBASE, Cochrane Library Databases, China National Knowledge Infrastructure, and Wanfang Database (up to July 20, 2014) were searched for all case-control studies those mainly studied the relationship between CYP2E1 Rsa I/Pst I gene polymorphism and the susceptibility of respiratory system cancer. A total of 332 articles were collected, among which 34 studies that involved 7028 cases and 9822 controls fulfilled the inclusion criteria after being assessed by 2 reviewers. When stratified by cancer site, the C2/C2 polymorphism could increase the risk of nasopharyngeal cancer under the homozygote model (C2C2 vs C1C1: OR = 1.85, 95% CI = 1.20-2.85, P = 0.005) and recessive model (C2C2 vs C1C2/C1C1: OR = 1.89, 95% CI = 1.23-2.89, P = 0.003). Protection effect was found in lung cancer in heterozygote model (C1C2 vs C1C1: OR = 0.82, 95% CI = 0.74-0.91, P < 0.001), dominant model (C1C2/C2C2 vs C1C1: OR = 0.83, 95% CI = 0.76-0.90, P < 0.001), and allele contrast model (C2 vs C1: OR = 0.85, 95% CI = 0.73-1.00, P = 0.045). With regard to ethnicity subgroup analysis, there was significant association in Asian population in heterozygote model (C1C2 vs C1C1: OR = 0.85, 95% CI = 0.78-0.94, P = 0.001), dominant model (C1C2/C2C2 vs C1C1: OR = 0.88, 95% CI = 0.81-0.95, P = 0.001), and recessive model (C2C2 vs C1C2/C1C1: OR = 1.25, 95% CI = 1.01-1.53, P = 0.036). CYP2E1 Rsa I/Pst I gene polymorphism may reduce the risk of respiratory system cancer. Furthermore, significant association was also found in Asian populations.

Elevated levels of preoperative circulating CD44⁺ lymphocytes and neutrophils predict poor survival for non-small cell lung cancer patients

BACKGROUND

Certain circulating cells have been shown to predict the clinical outcome of several cancers. The objective of this study was to identify clinical, hematological and immunological predictors of prognosis in non-small cell lung cancer (NSCLC) patients.

METHODS

A retrospective study on a prevalent cohort of 225 NSCLC patients hospitalized at the Zhejiang Province Cancer Hospital (ZPCH) was conducted from August 1, 2006 to April 15, 2008. Circulating lymphocytes were measured by flow cytometry. WBC count and classification in peripheral blood were measured with a Coulter counter. We calculated the proportion of patients surviving after first hospital admission and hazard ratios (HR) using the Cox proportional hazards model.

RESULTS

Elevated levels of preoperative circulating CD44(+) lymphocytes, WBCs and neutrophils indicated low cumulative survival. Clinical stage (HR: 2.292; 95% confidence interval (CI): 1.34-3.91, P=0.002), neutrophils (HR: 1.877; 95% CI: 1.34-2.62, P<0.001) and CD44(+) lymphocytes (HR: 1.018; 95% CI: 1.00-1.03, P=0.002) are independent predictors of survival in NSCLC patients, respectively. Elevated levels of CD44(+) lymphocytes and neutrophils correlated with distant metastasis and prognosis in NSCLC patients with stage III/IV, respectively.

CONCLUSIONS

CD44(+) lymphocytes along with neutrophils could serve as an independent prognostic marker for NSCLC patients.

Tobacco Smoking and Lung Cancer: Perception-changing facts

Tobacco smoking remains the most established cause of lung carcinogenesis and other disease processes. Over the last 50 years, tobacco refinement and the introduction of filters have brought a change in histology, and now adenocarcinoma has become the most prevalent subtype. Over the last decade, smoking also has emerged as a strong prognostic and predictive patient characteristic along with other variables. This article briefly reviews scientific facts about tobacco, and the process and molecular pathways involved in lung carcinogenesis in smokers and never-smokers. The evidence from randomised trials about tobacco smoking's impact on lung cancer outcomes is also reviewed.

DNA repair genes polymorphism and lung cancer risk with the emphasis to sex differences

Polymorphisms in nucleotide and base excision repair genes are associated with the variability in the risk of developing lung cancer. In the present study, we investigated the polymorphisms of following selected DNA repair genes: XPC (Lys939Gln), XPD (Lys751Gln), hOGG1 (Ser326Cys) and XRCC1 (Arg399Gln), and the risks they present towards the development of lung cancer with the emphasis to gender differences within the Slovak population. We analyzed 761 individuals comprising 382 patients with diagnosed lung cancer and 379 healthy controls. Genotypes were determined by polymerase chain reaction/restriction fragment length polymorphism method. We found out statistically significant increased risk for lung cancer development between genders. Female carrying XPC Gln/Gln, XPC Lys/Gln+Gln/Gln and XRCC1 Arg/Gln, XRCC1 Arg/Gln+Gln/Gln genotypes had significantly increased risk of lung cancer corresponding to OR = 2.06; p = 0.04, OR = 1.66; p = 0.04 and OR = 1.62; p = 0.04, OR = 1.69; p = 0.02 respectively. In total, significantly increased risk of developing lung cancer was found in the following combinations of genotypes: XPD Lys/Gln+XPC Lys/Lys (OR = 1.62; p = 0.04), XRCC1 Gln/Gln+hOGG1 Ser/Ser (OR = 2.14; p = 0.02). After stratification for genders, the following combinations of genotype were found to be significant in male: XPD Lys/Gln+XPC Lys/Lys (OR = 1.87; p = 0.03), XRCC1 Arg/Gln+XPC Lys/Lys (OR = 4.52; p = 0.0007), XRCC1 Arg/Gln+XPC Lys/Gln (OR = 5.44; p < 0.0001). In female, different combinations of the following genotypes were found to be significant: XRCC1 Arg/Gln+hOGG1 Ser/Ser (OR = 1.98; p = 0.04), XRCC1 Gln/Gln+hOGG1 Ser/Ser (OR = 3.75; p = 0.02), XRCC1 Arg/Gln+XPC Lys/Gln (OR = 2.40; p = 0.04), XRCC1 Arg/Gln+XPC Gln/Gln (OR = 3.03; p = 0.04). We found out decreased cancer risk in genotype combinations between female patients and healthy controls: XPD Lys/Lys+XPC Lys/Gln (OR = 0.45; p = 0.02), XPD Lys/Gln+XPC Lys/Lys (OR = 0.32; p = 0.005), XPD Lys/Gln+XPC Lys/Gln (OR = 0.48; p = 0.02). Our results did not show any difference between pooled smokers and non-smokers in observed gene polymorphisms in the association to the lung cancer risk. However, gender stratification indicated the possible effect of heterozygous constitution of hOGG1 gene (Ser/Cys) on lung cancer risk in female non-smokers (OR = 0.20; p = 0.01) and heterozygous constitution of XPC gene (Lys/Gln) in male smokers (OR = 2.70; p = 0.01).

An omics strategy for discovering pulmonary biomarkers potentially relevant to the evaluation of tobacco products

Smoking is known to cause serious lung diseases including chronic bronchitis, chronic obstructive lung disease, obstruction of small airways, emphysema and cancer. Tobacco smoke is a complex chemical aerosol containing at least 8000 chemical constituents, either tobacco derived or added by tobacco product manufacturers. Identification of all of the toxic agents in tobacco smoke is challenging, and efforts to understand the mechanisms by which tobacco use causes disease will be informed by new biomarkers of exposure and harm. In 2009, President Obama signed into law the Family Smoking Prevention and Tobacco Control Act granting the US FDA the authority to regulate tobacco products to protect public health. This perspective article presents the background, rationale and strategy for using omics technologies to develop new biomarkers, which may be of interest to the FDA when implementing the Family Smoking Prevention and Tobacco Control Act.

Adenomatous polyposis coli-mediated accumulation of abasic DNA lesions lead to cigarette smoke condensate-induced neoplastic transformation of normal breast epithelial cells

Adenomatous polyposis coli (APC) is a multifunctional protein having diverse cellular functions including cell migration, cell-cell adhesion, cell cycle control, chromosomal segregation, and apoptosis. Recently, we found a new role of APC in base excision repair (BER) and showed that it interacts with DNA polymerase β and 5'-flap endonuclease 1 and interferes in BER. Previously, we have also reported that cigarette smoke condensate (CSC) increases expression of APC and enhances the growth of normal human breast epithelial (MCF10A) cells in vitro. In the present study, using APC overexpression and knockdown systems, we have examined the molecular mechanisms by which CSC and its major component, Benzo[α]pyrene, enhances APC-mediated accumulation of abasic DNA lesions, which is cytotoxic and mutagenic in nature, leading to enhanced neoplastic transformation of MCF10A cells in an orthotopic xenograft model.

Impact of smoking and smoking cessation on outcomes in bladder cancer patients treated with radical cystectomy

BACKGROUND

Cigarette smoking is the best-established risk factor for urothelial carcinoma development.

OBJECTIVE

To elucidate the association of pretreatment smoking status, cumulative exposure, and time since smoking cessation on outcomes of patients with urothelial carcinoma of the bladder (UCB) treated with radical cystectomy (RC).

DESIGN, SETTING, AND PARTICIPANTS

We retrospectively collected clinicopathologic and smoking variables, including smoking status, number of cigarettes per day (CPD), duration in years, and time since smoking cessation, for 1506 patients treated with RC for UCB. Lifetime cumulative smoking exposure was categorized as light short-term (≤20 CPD for ≤20 yr), light long-term (≤20 CPD for >20 yr), heavy short-term (>20 CPD for ≤20 yr), and heavy long-term (>20 CPD for >20 yr).

INTERVENTION

RC and bilateral lymph node (LN) dissection without neoadjuvant chemotherapy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Logistic regression and competing risk analyses assessed the association of smoking with disease recurrence, cancer-specific mortality, and overall mortality.

RESULTS AND LIMITATIONS

There was no difference in clinicopathologic factors between patients who had never smoked (20%), former smokers (46%), and current smokers (34%). Smoking status was associated with the cumulative incidence of disease recurrence (p=0.004) and cancer-specific mortality (p=0.016) in univariable analyses and with disease recurrence in multivariable analysis (p=0.02); current smokers had the highest cumulative incidences. Among ever smokers, cumulative smoking exposure was associated with advanced tumor stages (p<0.001), LN metastasis (p=0.002), disease recurrence (p<0.001), cancer-specific mortality (p=0.001), and overall mortality (p=0.037) in multivariable analyses that adjusted for standard characteristics; heavy long-term smokers had the worst outcomes, followed by light long-term, heavy short-term, and light short-term smokers. Smoking cessation ≥10 yr mitigated the risk of disease recurrence (hazard ratio [HR]: 0.44; p<0.001), cancer-specific mortality (HR: 0.42; p<0.001), and overall mortality (HR: 0.69; p=0.012) in multivariable analyses. The study is limited by its retrospective nature.

CONCLUSIONS

Smoking is associated with worse prognosis after RC for UCB. This association seems to be dose-dependent, and its effects are mitigated by >10 yr smoking cessation. Health care practitioners should counsel smokers regarding the detrimental effects of smoking and the benefits of smoking cessation on UCB etiology and prognosis.

Impact of smoking and smoking cessation on oncologic outcomes in primary non-muscle-invasive bladder cancer

BACKGROUND

Cigarette smoking is the best-established risk factor for urothelial carcinoma (UC) development, but the impact on oncologic outcomes remains poorly understood.

OBJECTIVE

To analyse the effects of smoking status, cumulative exposure, and time from smoking cessation on the prognosis of patients with primary non-muscle-invasive bladder cancer (NMIBC).

DESIGN, SETTING, AND PARTICIPANTS

We collected smoking data from 2043 patients with primary NMIBC. Smoking variables included smoking status, average number of cigarettes smoked per day (CPD), duration in years, and time since smoking cessation. Lifetime cumulative smoking exposure was categorised as light short term (≤ 19 CPD, ≤ 19.9 yr), light long term (≤ 19 CPD, ≥ 20 yr), heavy short term (≥ 20 CPD, ≤ 19.9 yr) and heavy long term (≥ 20 CPD, ≥ 20 yr). The median follow-up in this retrospective study was 49 mo.

INTERVENTIONS

Transurethral resection of the bladder with or without intravesical instillation therapy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Univariable and multivariable logistic regression and competing risk regression analyses assessed the effects of smoking on outcomes.

RESULTS AND LIMITATIONS

There was no difference in clinicopathologic factors among never (24%), former (47%), and current smokers (29%). Smoking status was associated with the cumulative incidence of disease progression in multivariable analysis (p=0.003); current smokers had the highest cumulative incidences. Among current and former smokers, cumulative smoking exposure was associated with disease recurrence (p<0.001), progression (p<0.001), and overall survival (p<0.001) in multivariable analyses that adjusted for the effects of standard clinicopathologic factors and smoking status; heavy long-term smokers had the worst outcomes, followed by light long-term, heavy short-term, and light short-term smokers. Smoking cessation >10 yr reduced the risk of disease recurrence (hazard ratio [HR]: 0.66; 95% confidence interval [CI], 0.52-0.84; p<0.001) and progression (HR: 0.42; 95% CI, 0.22-0.83; p=0.036) in multivariable analyses. The study is limited by its retrospective nature.

CONCLUSIONS

Smoking status and a higher cumulative smoking exposure are associated with worse prognosis in patients with NMIBC. Smoking cessation >10 yr abrogates this detrimental effect. These findings underscore the need for integrated smoking cessation and prevention programmes in the management of NMIBC patients.

Genetic network and gene set enrichment analysis to identify biomarkers related to cigarette smoking and lung cancer

OBJECTIVES

Cigarette smoking is the most demonstrated risk factor for the development of lung cancer, while the related genetic mechanisms are still unclear.

METHODS

The preprocessed microarray expression dataset was downloaded from Gene Expression Omnibus database. Samples were classified according to the disease state, stage and smoking state. A new computational strategy was applied for the identification and biological interpretation of new candidate genes in lung cancer and smoking by coupling a network-based approach with gene set enrichment analysis.

MEASUREMENTS

Network analysis was performed by pair-wise comparison according to the disease states (tumor or normal), smoking states (current smokers or nonsmokers or former smokers), or the disease stage (stages I-IV). The most activated metabolic pathways were identified by gene set enrichment analysis.

RESULTS

Panels of top ranked gene candidates in smoking or cancer development were identified, including genes involved in cell proliferation and drug metabolism like cytochrome P450 and WW domain containing transcription regulator 1. Semaphorin 5A and protein phosphatase 1F are the common genes represented as major hubs in both the smoking and cancer related network. Six pathways, e.g. cell cycle, DNA replication, RNA transport, protein processing in endoplasmic reticulum, vascular smooth muscle contraction and endocytosis were commonly involved in smoking and lung cancer when comparing the top ten selected pathways.

CONCLUSION

New approach of bioinformatics for biomarker identification and validation can probe into deep genetic relationships between cigarette smoking and lung cancer. Our studies indicate that disease-specific network biomarkers, interaction between genes/proteins, or cross-talking of pathways provide more specific values for the development of precision therapies for lung.