Differential expression of biomarkers in lung adenocarcinoma: a comparative study between smokers and never-smokers

A Functional Genomics Review of Non-Small-Cell Lung Cancer in Never Smokers

There is currently a dearth of information regarding lung cancer in never smokers (LCINS). Additionally, there is a difference in somatic mutations, tumour mutational burden, and chromosomal aberrations between smokers and never smokers (NS), insinuating a different disease entity in LCINS. A better understanding of actionable driver alterations prevalent in LCINS and the genomic landscape will contribute to identifying new molecular targets of relevance for NS that will drastically improve outcomes. Differences in treatment outcomes between NS and smokers, as well as sexes, with NSCLC suggest unique tumour characteristics. Epidermal growth factor receptor (EGFR) tyrosine kinase mutations and echinoderm microtubule-associated protein-like 4 anaplastic lymphoma kinase (EML4-ALK) gene rearrangements are more common in NS and have been associated with chemotherapy resistance. Moreover, NS are less likely to benefit from immune mediators including PD-L1. Unravelling the genomic and epigenomic underpinnings of LCINS will aid in the development of not only novel targeted therapies but also more refined approaches. This review encompasses driver genes and pathways involved in the pathogenesis of LCINS and a deeper exploration of the genomic landscape and tumour microenvironment. We highlight the dire need to define the genetic and environmental aspects entailing the development of lung cancer in NS.

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.

Association between Air Pollution and Squamous Cell Lung Cancer in South-Eastern Poland

Air pollution is closely associated with the development of respiratory illness. The aim of the present study was to assess the relationship between long-term exposure to PM2.5, PM10, NO₂, and SO₂ pollution and the incidence of lung cancer in the squamous subtype in south-eastern Poland from the years 2004 to 2014. We collected data of 4237 patients with squamous cell lung cancer and the level of selected pollutants. To investigate the relationship between the level of concentrations of pollutants and the place of residence of patients with lung cancer in the squamous subtype, proprietary pollution maps were applied to the places of residence of patients. To analyze the data, the risk ratio was used as well as a number of statistical methods, i.e., the pollution model, inverse distance weighted interpolation, PCA, and ordered response model. Cancer in women and in men seems to depend in particular on the simultaneous inhalation of NO₂ and PM10 (variable NO₂PM10) and of NO₂ and SO₂ (variable NO₂ SO₂), respectively. Nitrogen dioxide exercises a synergistic leading effect, which once composed with the other elements it becomes more persistent in explaining higher odds in the appearance of cancers and could constitute the main cause of squamous cancer.

The crucial roles of long noncoding RNA SNHGs in lung cancer

Lung cancer is one of the most common malignant tumors with growing morbidity and mortality worldwide. Several treatments are used to manage lung cancer, including surgery, radiotherapy and chemotherapy, as well as molecular-targeted therapy. However, the current measures are still far from satisfactory. Therefore, the current research should focus on exploring the molecular mechanism and then finding an effective treatment. Interestingly, we and others have embarked on a line of investigations focused on the mechanism of lung cancer. Specifically, lncRNA small nucleolar RNA host gene has been shown to be associated with biological characteristics and therapeutic resistance of lung cancer. In addition, small nucleolar RNA host genes may be used as diagnostic biomarker in the future. Herein, we will provide a brief review demonstrating the importance of small nucleolar RNA host genes in lung cancer, especially non-small cell lung cancer. Although lncRNA has shown a crucial role in tumor-related research, a large number of studies are needed to validate its clinical application in the future.

Characteristics of Women with Lung Adenocarcinoma in the World Trade Center Environmental Health Center

The destruction of the World Trade Center towers on 11 September 2001 exposed local residents, workers, and individuals in the area (Survivors) to dust and fumes that included known and suspected carcinogens. Given the potential for inhalation of toxic substances and the long latency after exposure, the incidence of lung cancer is expected to increase in WTC-exposed individuals. We describe the characteristics of women WTC Survivors with lung adenocarcinoma who were enrolled in the WTC Environmental Health Center (WTC EHC) between May 2002 and July 2021. A total of 173 women in WTC EHC had a diagnosis of any type of lung cancer, representing 10% of all cancers in women. Most of the lung cancers (87%) were non-small cell carcinomas, with adenocarcinoma (77%) being the most common subtype. Nearly half (46%) of these patients were exposed to dust clouds on 11 September 2001. Race and ethnicity varied by smoking status, as follows: 44% of Asian women compared with 29% of non-Hispanic White women were never-smokers (p < 0.001). There was no significant difference between the pathologic characteristics of adenocarcinomas between never and ever smokers. We also summarize EGFR, ALK, KRAS, ROS-1 and BRAF mutation status stratified by smoking, race and ethnicity. The identification of a relatively high proportion of women never-smokers with lung cancer warrants further investigation into the role of WTC dust exposure.

Implications of the Immune Landscape in COPD and Lung Cancer: Smoking Versus Other Causes

Cigarette smoking is reported in about one third of adults worldwide. A strong relationship between cigarette smoke exposure and chronic obstructive pulmonary disease (COPD) as well as lung cancer has been proven. However, about 15% of lung cancer cases, and between one fourth and one third of COPD cases, occur in never-smokers. The effects of cigarette smoke on the innate as well as the adaptive immune system have been widely investigated. It is assumed that certain immunologic features contribute to lung cancer and COPD development in the absence of smoking as the major risk factor. In this article, we review different immunological aspects of lung cancer and COPD with a special focus on non-smoking related risk factors.

Comprehensive targeting of resistance to inhibition of RTK signaling pathways by using glucocorticoids

Inhibition of RTK pathways in cancer triggers an adaptive response that promotes therapeutic resistance. Because the adaptive response is multifaceted, the optimal approach to blunting it remains undetermined. TNF upregulation is a biologically significant response to EGFR inhibition in NSCLC. Here, we compared a specific TNF inhibitor (etanercept) to thalidomide and prednisone, two drugs that block TNF and also other inflammatory pathways. Prednisone is significantly more effective in suppressing EGFR inhibition-induced inflammatory signals. Remarkably, prednisone induces a shutdown of bypass RTK signaling and inhibits key resistance signals such as STAT3, YAP and TNF-NF-κB. Combined with EGFR inhibition, prednisone is significantly superior to etanercept or thalidomide in durably suppressing tumor growth in multiple mouse models, indicating that a broad suppression of adaptive signals is more effective than blocking a single component. We identify prednisone as a drug that can effectively inhibit adaptive resistance with acceptable toxicity in NSCLC and other cancers.

Short- and long-term survival outcomes among never smokers who developed lung cancer

BACKGROUND

Lung cancer is the leading cause of cancer death in the US. While an extensive literature exists detailing lung cancer risk factors and mortality among patients with a history of tobacco use, the data are more limited among individuals who have never smoked. The purpose of this investigation is to compare survival rates between the two groups and evaluate potential risk factors among never smokers.

METHODS

This retrospective study included 3380 smokers and 334 never smokers who were diagnosed with lung cancer at Stony Brook University Hospital between 2003 and 2016. 1-, 3-, 5- and 10-year survival outcomes, stratified by smoking status, were compared and Kaplan-Meier curves for overall survival are provided. Cox Proportional Hazard models were used to evaluate factors influencing survival among never smokers.

RESULTS

Never smokers with lung cancer were more likely to be female, be diagnosed with adenocarcinoma histology, and had fewer comorbidities than lung cancer patients who smoked. Although 60% of patients were diagnosed at a later stage of disease development, regardless of smoking status, overall short- and long-term survival was significantly higher among never smokers compared to those with a history of tobacco use. In addition to age and stage at diagnosis, a history of diabetes was found to be a significant prognostic factor for decreased survival among never smokers (HR=3.15, 95% CI (1.74, 5.71)).

CONCLUSIONS

Data from the present investigation suggest that, regardless of smoking status, approximately three of every five lung cancer patients are diagnosed at a later stage, and that both short- and long-term survival outcomes are significantly better among never smokers compared to those with a history of tobacco use. Additional studies are required to validate these findings and better explain the mechanistic drivers for the improved outcomes among never smokers.

Polymorphisms of Antigen-Presenting Machinery Genes in Non-Small Cell Lung Cancer: Different Impact on Disease Risk and Clinical Parameters in Smokers and Never-Smokers

Lung cancer is strongly associated with cigarette smoking; nevertheless some never-smokers develop cancer. Immune eradication of cancer cells is dependent on polymorphisms of HLA class I molecules and antigen-processing machinery (APM) components. We have already published highly significant associations of single nucleotide polymorphisms (SNPs) of the ERAP1 gene with non-small cell lung cancer (NSCLC) in Chinese, but not in Polish populations. However, the smoking status of participants was not known in the previous study. Here, we compared the distribution of APM polymorphic variants in larger cohorts of Polish patients with NSCLC and controls, stratified according to their smoking status. We found significant but opposite associations in never-smokers and in smokers of all tested SNPs (rs26653, rs2287987, rs30187, and rs27044) but one (rs26618) in ERAP1. No significant associations were seen in other genes. Haplotype analysis indicated that the distribution of many ERAP1/2 haplotypes is opposite, depending on smoking status. Additionally, haplotypic combination of low activity ERAP1 and the lack of an active form of ERAP2 seems to favor the disease in never-smokers. We also revealed interesting associations of some APM polymorphisms with: age at diagnosis (ERAP1 rs26653), disease stage (ERAP1 rs27044, PSMB9 rs17587), overall survival (ERAP1 rs30187), and response to chemotherapy (ERAP1 rs27044). The results presented here may suggest the important role for ERAP1 in the anti-cancer response, which is different in smokers versus never-smokers, depending to some extent on the presence of ERAP2, and affecting NSCLC clinical course.

Cigarette smoke preparations, not electronic nicotine delivery system preparations, induce features of lung disease in a 3D lung repeat-dose model

Cigarette smoking is a risk factor for several lung diseases, including chronic obstructive pulmonary disease, cardiovascular disease, and lung cancer. The potential health effects of chronic use of electronic nicotine delivery systems (ENDS) is unclear. This study utilized fully differentiated primary normal human bronchial epithelial (NHBE) cultures in a repeat-dose exposure to evaluate and compare the effect of combustible cigarette and ENDS preparations. We show that 1-h daily exposure of NHBE cultures over a 10-day period to combustible cigarette whole smoke-conditioned media (WS-CM) increased expression of oxidative stress markers, cell proliferation, airway remodeling, and cellular transformation markers and decreased mucociliary function including ion channel function and airway surface liquid. Conversely, aerosol conditioned media (ACM) from ENDS with similar nicotine concentration (equivalent-nicotine units) as WS-CM and nicotine alone had no effect on those parameters. In conclusion, primary NHBE cultures in a repeat-dose exposure system represent a good model to assess the features of lung disease. This study also reveals that cigarette and ENDS preparations differentially elicit several key endpoints, some of which are potential biomarkers for lung cancer or chronic obstructive pulmonary disease (COPD).

Non-small cell lung cancer in never- and ever-smokers: Is it the same disease?

OBJECTIVES

To investigate differences in presentation, pathology, and outcomes after resection of non-small cell lung cancer (NSCLC) in never-smokers versus ever-smokers.

METHODS

From January 2006 to July 2016, 172 never-smokers and 1376 ever-smokers with NSCLC underwent pulmonary resection. The 2 cohorts were matched on patient characteristics, histopathological cancer cell type, and pathological stage group using a weighted balancing score, and overall survival and cancer recurrence were compared by pathological stage. Random forests for survival was used to identify granular cancer characteristics with different survival and cancer recurrence importance between groups.

RESULTS

In never-smokers, the prevalence of NSCLC was more frequent in women than in men (63% [n = 109] vs 45% [n = 63]). Compared with ever-smokers, never-smokers had less upper-lobe disease (53% [n = 91] vs 62% [n = 855]) and more adenocarcinoma (88% [n = 151] vs 62% [n = 845]). Postoperative complications were similar. Never-smokers had a lower prevalence of non-lung cancer deaths than ever-smokers (13% vs 23% at 5 years; P = .006). Among matched pairs, never-smokers had better overall survival at 5 years in pathological stage I (96% vs 78%), but worse survival in stage II (54% vs 78%). Tumor size, N category, and histopathological cell type were more important drivers of mortality and cancer recurrence in never-smokers than in ever-smokers.

CONCLUSIONS

NSCLC in never-smokers affects women more than men and presents with different anatomic and histopathological distributions. Matched never-smokers have better or equivalent outcomes than ever-smokers in pathological stage I cancer, but are less likely to survive and to be cured of cancer as tumor burden increases. These findings suggest that there might be unique tumor or host behaviors differentially impacting survival of never- and ever-smoking patients with NSCLC.

Epidermal growth factor receptor first generation tyrosine-kinase inhibitors

The epidermal growth factor receptor (EGFR) oncogene was positioned as an attractive target for drug development in non-small cell lung cancer (NSCLC). Gefitinib and erlotinib were the first two reversible inhibitors of the EGFR kinase. The discovery of EGFR kinase domain-activating mutations that significantly correlated with a high likelihood of response to EGFR tyrosine-kinase inhibitors (TKIs) allowed to design studies to test these drugs as potential first-line therapies. In the same way, the feasibility of personalized medicine was established in patients with advanced NSCLC. Currently in the field of NSCLC with EGFR mutation have developed second and even third generation TKIs that would be gaining the positioning in the treatment of this subset population of NSCLC. In spite of this, without the knowledge that EGFR first generation TKIs have provided, we would not have gotten so far. We will review step by step how it was forged the exciting history of the subpopulation of lung cancer with EGFR mutated, through the various clinical trials performed with first generation TKIs that changed the focus, the future of NSCLC as well as survival of these patients.

Synthesis and preliminary evaluation of 18F-icotinib for EGFR-targeted PET imaging of lung cancer

Epidermal growth factor receptor (EGFR) has emerged as an attracting target in the field of imaging and treatment for non-small cell lung cancer (NSCLC). Radiolabeled EGFR-tyrosine kinase inhibitors (EGFR-TKIs) specifically targeting EGFR are deemed as promising probes for the imaging of NSCLC. This study aimed to label icotinib (one kind of EGFR-TKI) with ¹⁸F through click reaction to develop a new EGFR-targeting PET probe-¹⁸F-icotinib. ¹⁸F-icotinib was obtained in 44.81% decay-corrected yield in 100 min synthesis time with 34 GBq/μmol specific activity and >99% radiochemical purity at the end of synthesis. The identity of the product was confirmed by co-injection with ¹⁸F-icotinib and ¹⁹F-icotinib. The Log P was 1.28 ± 0.04 (n = 6). The tracer displayed excellent stability after incubation for 4 h in vitro. ¹⁸F-icotinib showed satisfying binding ability to A549 NSCLC cells, which could be inhibited by icotinib. PET imaging studies demonstrated a specific uptake of the radiotracer (0.90 ± 0.24% ID/g) in A549 tumor-bearing mice, while lower uptake was observed in heart, lung and spleen at 1.5 h post injection. Inmunohistochemical staining confirmed that the A549 tumor was EGFR-positive. Therefore, we considered that ¹⁸F-icotinib was a highly promising compound for EGFR-based tumor PET imaging.

ICRP Publication 131: Stem Cell Biology with Respect to Carcinogenesis Aspects of Radiological Protection

This report provides a review of stem cells/progenitor cells and their responses to ionising radiation in relation to issues relevant to stochastic effects of radiation that form a major part of the International Commission on Radiological Protection's system of radiological protection. Current information on stem cell characteristics, maintenance and renewal, evolution with age, location in stem cell 'niches', and radiosensitivity to acute and protracted exposures is presented in a series of substantial reviews as annexes concerning haematopoietic tissue, mammary gland, thyroid, digestive tract, lung, skin, and bone. This foundation of knowledge of stem cells is used in the main text of the report to provide a biological insight into issues such as the linear-no-threshold (LNT) model, cancer risk among tissues, dose-rate effects, and changes in the risk of radiation carcinogenesis by age at exposure and attained age. Knowledge of the biology and associated radiation biology of stem cells and progenitor cells is more developed in tissues that renew fairly rapidly, such as haematopoietic tissue, intestinal mucosa, and epidermis, although all the tissues considered here possess stem cell populations. Important features of stem cell maintenance, renewal, and response are the microenvironmental signals operating in the niche residence, for which a well-defined spatial location has been identified in some tissues. The identity of the target cell for carcinogenesis continues to point to the more primitive stem cell population that is mostly quiescent, and hence able to accumulate the protracted sequence of mutations necessary to result in malignancy. In addition, there is some potential for daughter progenitor cells to be target cells in particular cases, such as in haematopoietic tissue and in skin. Several biological processes could contribute to protecting stem cells from mutation accumulation: (a) accurate DNA repair; (b) rapidly induced death of injured stem cells; (c) retention of the DNA parental template strand during divisions in some tissue systems, so that mutations are passed to the daughter differentiating cells and not retained in the parental cell; and (d) stem cell competition, whereby undamaged stem cells outcompete damaged stem cells for residence in the niche. DNA repair mainly occurs within a few days of irradiation, while stem cell competition requires weeks or many months depending on the tissue type. The aforementioned processes may contribute to the differences in carcinogenic radiation risk values between tissues, and may help to explain why a rapidly replicating tissue such as small intestine is less prone to such risk. The processes also provide a mechanistic insight relevant to the LNT model, and the relative and absolute risk models. The radiobiological knowledge also provides a scientific insight into discussions of the dose and dose-rate effectiveness factor currently used in radiological protection guidelines. In addition, the biological information contributes potential reasons for the age-dependent sensitivity to radiation carcinogenesis, including the effects of in-utero exposure.

Lung Cancer in Never Smokers

Lung cancer is predominantly associated with cigarette smoking; however, a substantial minority of patients with the disease have never smoked. In the US it is estimated there are 17,000-26,000 annual deaths from lung cancer in never smokers, which as a separate entity would be the seventh leading cause of cancer mortality. Controversy surrounds the question of whether or not the incidence of lung cancer in never-smokers is increasing, with more data to support this observation in Asia. There are several factors associated with an increased risk of developing lung cancer in never smokers including second hand smoke, indoor air pollution, occupational exposures, and genetic susceptibility among others. Adenocarcinoma is the most common histology of lung cancer in never smokers and in comparison to lung cancer in smokers appears less complex with a higher likelihood to have targetable driver mutations.

Molecular profiles of non-small cell lung cancers in cigarette smoking and never-smoking patients

PURPOSE

Molecular features of non-small cell lung cancer (NSCLC) in never-smokers are not well recognized. We assessed the expression of genes potentially related to lung cancer etiology in smoking vs. never-smoking NSCLC patients.

METHODS

We assayed frozen tumor samples from surgically resected 31 never-smoking and 54 clinically pair-matched smoking NSCLC patients, and from corresponding normal lung tissue from 27 and 43 patients, respectively. Expression of 21 genes, including cell membrane kinases, sex hormone receptors, transcription factors, growth factors and others was assessed by reverse transcription - quantitative PCR.

RESULTS

Expression of 5 genes was significantly higher in tumors of non-smokers vs. smokers: CSF1R (p<0.0001), RRAD (p<0.0001), PR (p=0.0004), TGFBR2 (p=0.0027) and EPHB6 (p=0.0033). Expression of AKR1B10 (p<0.0001), CDKN2A (p<0.0001), CHRNA6 (p<0.0001), SOX9 (p<0.0001), survivin (p<0.0001) and ER2 (p=0.002) was significantly higher in tumors compared to normal lung tissue. Expression of AR (p<0.0001), EPHB6 (p<0.0001), PR (p<0.0001), TGFBR2 (p<0.0001), TGFBR3 (p<0.0001), ER1 (p=0.0006) and DLG1 (p=0.0016) was significantly lower in tumors than in normal lung tissue. Expression of IGF2 was higher in tumors than in healthy lung tissue in never-smokers (p=0.003), and expression of AHR (p<0.0001), CSF1R (p<0.0001) and RRAD (p<0.0001) was lower in tumors than in healthy lung tissue in smokers.

CONCLUSION

Expression of several genes in NSCLC is strongly related to smoking history. Lower expression of PR and higher expression of ER2 in tumors suggests a possibility of hormonal therapeutic intervention in selected NSCLC patients. Distinct molecular features of NSCLC in never-smokers, e.g. CHRNA6 upregulation, may prompt new treatment strategies.

Lung carcinoma signaling pathways activated by smoking

Lung cancer is the leading cause of cancer death in men and women worldwide, with over a million deaths annually. Tobacco smoke is the major etiologic risk factor for lung cancer in current or previous smokers and has been strongly related to certain types of lung cancer, such as small cell lung carcinoma and squamous cell lung carcinoma. In recent years, there has been an increased incidence of lung adenocarcinoma. This change is strongly associated with changes in smoking behavior and cigarette design. Carcinogens present in tobacco products and their intermediate metabolites can activate multiple signaling pathways that contribute to lung cancer carcinogenesis. In this review, we summarize the smoking-activated signaling pathways involved in lung cancer.

Serum cotinine and prognosis in breast cancer

Various studies have suggested that women who smoke have a worse prognosis if they develop breast cancer. Cotinine levels have been measured in sera from 511 patients with stage I and II breast cancer diagnosed between 1975 and 1980, all of whom had complete follow-up. Although the known prognostic factors, axillary nodal status, tumour size and grade were found to be significant, there was no relationship between serum cotinine and metastasis-free survival. A point estimate of serum cotinine was not found to be a determinant of survival in women with early breast cancer.

Targeted therapies for lung cancer: clinical experience and novel agents

Although lung cancer remains the leading cancer killer in the United States, recently a number of developments indicate future clinical benefit. These include evidence that computed tomography-based screening decreases lung cancer mortality, the use of stereotactic radiation for early-stage tumors, the development of molecular methods to predict chemotherapy sensitivity, and genome-wide expression and mutation analysis data that have uncovered oncogene "addictions" as important therapeutic targets. Perhaps the most significant advance in the treatment of this challenging disease is the introduction of molecularly targeted therapies, a term that currently includes monoclonal antibodies and small-molecule tyrosine kinase inhibitors. The development of effective targeted therapeutics requires knowledge of the genes and pathways involved and how they relate to the biologic behavior of lung cancer. Drugs targeting the epidermal growth factor receptor, anaplastic lymphoma kinase, and vascular endothelial growth factor are now U.S. Food and Drug Administration approved for the treatment of advanced non-small cell lung cancer. These agents are generally better tolerated than conventional chemotherapy and show dramatic efficacy when their use is coupled with a clear understanding of clinical data, mechanism, patient selection, drug interactions, and toxicities. Integrating genome-wide tumor analysis with drug- and targeted agent-responsive phenotypes will provide a wealth of new possibilities for lung cancer-targeted therapeutics. Ongoing research efforts in these areas as well as a discussion of emerging targeted agents being evaluated in clinical trials are the subjects of this review.

Non-small cell lung cancer in never-smokers: a new disease entity?

Non-small cell lung cancer (NSCLC) in never-smokers is an increasing entity. It seems that it has a different pathogenesis, at least in some cases, making it more sensitive to targeted therapies. Two promising targets have so far been identified. This article gives an overview on the biologic background and latest developments in the treatment of this particular entity.

Adenylosuccinate synthetase 1 gene is a novel target of deletion in lung adenocarcinoma

Tobacco smoke consists of numerous carcinogens whose effect on lung tumor development includes the induction of mutations in key genes as well as the induction of chromosome instability (CIN). Consequently, carcinogen-induced mouse lung adenocarcinomas (LAC) display many more recurrent site- and chromosome-specific changes in DNA copy number compared with noninduced LAC. Here we identified the Adenylosuccinate synthetase 1 (Adss1) gene located on distal chromosome 12q as a focus of bi-allelic or homozygous deletion (HD) in LAC. HDs of Adss1 were detected in 10 out of 84 carcinogen-induced mouse primary LAC and mouse LAC cell lines. In only four of these cases did the deletions affect either Siva1 or Inverted-formin 2 (Inf2), which immediately flank the Adss1 locus, indicating that Adss1 is a selective target of deletion in LAC. Losses of Adss1 not meeting the quantitative threshold of HD were detected in 36 out of 84 (42.9%) of the mouse tumors and cell lines. A similar frequency of ADSS1 deletion was observed in human LAC cell lines, suggesting relevance in human lung cancer. Adss1 losses were also found to be significantly associated with a more extensive CIN phenotype in the primary mouse tumors. These results implicate ADSS1 inactivation as a novel somatic alteration in lung carcinogenesis, and suggest that its selective deletion in LAC may be triggered by CIN.

The selenium analog of the chemopreventive compound S,S'-(1,4-phenylenebis[1,2-ethanediyl])bisisothiourea is a remarkable inducer of apoptosis and inhibitor of cell growth in human non-small cell lung cancer

Lung cancer continues to be the leading cause of cancer deaths throughout the world and conventional therapy remains largely unsuccessful. Although, chemoprevention is a plausible alternative approach to curb the lung cancer epidemic, clinically there are no effective chemopreventive agents. Thus, development of novel compounds that can target cellular and molecular pathways involved in the multistep carcinogenesis process is urgently needed. Previous studies have suggested that substitution of sulfur by selenium in established cancer chemopreventive agents may result in more effective analogs. Thus in the present study we selected the chemopreventive agent S,S'-(1,4-phenylenebis[1,2-ethanediyl])bisisothiourea (PBIT), also known to inhibit inducible nitric oxide synthase (iNOS), synthesized its selenium analog (Se-PBIT) and compared both compounds in preclinical model systems using non-small cell lung cancer (NSCLC) cell lines (NCI-H460 and A549); NSCLC is the most common histologic type of all lung cancer cases. Se-PBIT was found to be superior to PBIT as an inducer of apoptosis and inhibitor of cell growth. Se-PBIT arrested cell cycles at G1 and G2-M stage in both A549 and H460 cell lines. Although both compounds are weakly but equally effective inhibitors of iNOS protein expression and activity, only Se-PBIT significantly enhanced the levels of p53, p38, p27 and p21 protein expression, reduced levels of phospholipase A2 (PLA2) but had no effect on cyclooxygenase-2 (COX-2) protein levels; such molecular targets are involved in cell growth inhibition, induction of apoptosis and cell cycle regulation. The results indicate that Se-PBIT altered molecular targets that are involved in the development of human lung cancer. Although, the mechanisms that can fully account for these effects remain to be determined, the results are encouraging to further evaluate the chemopreventive efficacy of Se-PBIT against the development of NSCLC in a well-defined animal model.

The NER proteins are differentially expressed in ever smokers and in never smokers with lung adenocarcinoma

BACKGROUND

The expression levels of excision repair cross-complementation group 1 (ERCC1), replication protein A (RPA) and xeroderma pigmentosum group F (XPF) nucleotide excision repair proteins may be important in the response to platin-based therapy in lung cancer patients. It is not known whether ERCC1, RPA and XPF expression levels differ between ever smokers (ES) and never smokers (NS).

PATIENTS AND METHODS

ERCC1, RPA and XPF expression levels were immunohistochemically evaluated in 125 patients with resected lung adenocarcinoma (AC) and carefully reviewed smoking status.

RESULTS

ERCC1 was correlated with XPF (P = 0.001), but not with RPA (P = 0.11). In the univariate analysis, ERCC1 and XPF levels were higher in NS compared with ES (P = 0.004 and P = 0.003, respectively). In the multivariate analysis, the smoking status was predictive of the ERCC1 level [odds ratio (OR) 2.5, 95% confidence interval (CI) 1.03-6.2] after adjustment for variables linked to the smoking status, including age and the presence of bronchioloalveolar (BAC) features. The smoking status was also predictive of both RPA (OR 6.7, 95% CI 1.5-33.3) and XPF levels (OR 12.5, 95% CI 2.9-50) after adjusting for age, sex and BAC features.

CONCLUSION

In patients with resected lung AC, ERCC1, RPA and XPF expression levels are higher in NS compared with ES.

Predictive value of telomerase reverse transcriptase expression in patients with high risk superficial bladder cancer treated with adjuvant BCG immunotherapy

PURPOSE

We conducted a prospective study to determine whether expression of telomerase reverse transcriptase (hTERT) is associated with recurrence-free-survival (RFS) or development of invasive disease in patients with high risk superficial bladder cancer (SBC) that received adjuvant BCG immunotherapy.

METHODS

Thirty patients with high-grade T1 tumors were evaluated. Pre-BCG TURBT and post-BCG specimens were analyzed for hTERT nucleolar expression by immunohistochemistry.

RESULTS

Post-BCG hTERT expression was statistically significantly lower than pre-BCG hTERT expression. Pre-BCG hTERT nucleolar staining in more than 75% of cells was associated with worse RFS (9 months vs. not yet reached, P = 0.05), while post-BCG hTERT nucleolar staining in more than 50% of the cells was associated with worse RFS (6 months vs. not yet reached, P = 0.001) and development of invasive disease. In multivariate analysis, post-BCG hTERT expression was independently associated with RFS and development of invasive disease.

CONCLUSIONS

Immunohistochemical evaluation of hTERT may help define a subset of high risk SBC patients that will eventually fail BCG and may therefore benefit from early salvage cystectomy.

EGFR Inhibition in the Treatment of Non-Small Cell Lung Cancer

Epidermal growth factor receptor (EGFR) inhibitors have introduced the concept of targeted therapy to the treatment of non-small cell lung cancer (NSCLC). These agents appear most effective in patients with tumors that are highly dependent on EGFR signaling pathways, a population that disproportionately includes females, nonsmokers, individuals of East Asian origin, and patients with adenocarcinoma histology. Currently available EGFR-inhibiting drugs include the tyrosine kinase inhibitors (TKIs) erlotinib, gefitinib, and lapatinib, which are administered orally and interfere with the intracellular tyrosine kinase domain, and the monoclonal antibodies (mAbs) cetuximab and panitumumab, which are administered intravenously and interfere with extracellular ligand binding. While the use of EGFR TKIs as monotherapy prolongs survival in metastatic NSCLC, they have demonstrated no benefit when added to conventional, cytotoxic chemotherapy. In contrast, the anti-EGFR mAb cetuximab appears most effective when combined with chemotherapy or radiation. Despite dramatic initial responses to treatment in some cases, NSCLC eventually becomes resistant to EGFR inhibition. Possible mechanisms include secondary mutations that interfere with drug binding, oncogenic pathways driven by other receptor tyrosine kinases, and independent activity of downstream signaling molecules. Efforts to overcome such resistance include irreversibly binding EGFR TKIs, multi-targeted TKIs, and combinations with chemotherapy, radiation, and other targeted therapies.

Differential ErbB receptor expression and intracellular signaling activity in lung adenocarcinomas and squamous cell carcinomas

EGFR (ErbB1) and ErbB2 receptors stimulate several intracellular signaling pathways in non-small-cell lung cancer (NSCLC). Adenocarcinomas (AC) and squamous cell carcinomas (SCC) are NSCLC subtypes with distinct clinico-pathological features, and responses to ErbB-targeted inhibitors treatment. To evaluate the causes of these differences, tissue microarrays with samples from NSCLC patients (189 AC and 56 SCC) were used to study EGFR and ErbB2 expression and phospho-activation of ERK1/2, AKT, STAT3 and SRC ErbB-mediators by immunohistochemistry and Western blot, and EGFR and ErbB2 gene amplification by FISH. EGFR expression was higher in SCC than in AC (P<0.001), while ErbB2 showed similar low levels. Phosphorylated (p) ERK, pAKT, pSTAT3 and pSRC levels were prevalent in AC (P< or =0.002). EGFR levels and signaling mediators activation were differentially associated with each of the pathologies. Whereas in AC the expression and amplification of EGFR were linked to AKT activation (P< or =0.050), in SCC its expression was correlated with pSTAT3 (P=0.024). In addition, pSTAT3 was correlated with pERK and pAKT only in AC (P< or =0.045). Biomarker levels were also differentially associated with the clinico-pathologic variables. In AC, EGFR and pSRC increasing scores correlated with female sex and the smoking habit (P< or =0.008), while ErbB2 amplification increased with advanced age and tumor stage (P< or =0.047), and pERK1/2 and pSTAT3 levels correlated with early tumor stage (P< or =0.045). In SCC, EGFR amplification was stronger in younger patients (P=0.013), pERK1/2 in the older ones (P=0.050), and pSTAT3 amplification was stronger in women (P=0.001). These data support that AC and SCC lung tumors are distinct entities at the molecular level, and that their signaling status in combination with their clinico-pathologic variables may be considered for differential targeted therapies.

Mitogen-activated protein kinase activation in lung adenocarcinoma: a comparative study between ever smokers and never smokers

PURPOSE

There are major differences affecting genes in adenocarcinomas in ever and never smokers. However, data on whether mitogen-activated protein kinase (MAPK) activation state differs according to smoking status are limited.

EXPERIMENTAL DESIGN

Expression of activated extracellular signal-regulated kinases, c-Jun NH(2)-terminal kinases, and P38 enzymes (pP38) were evaluated by means of immunohistochemistry in 188 chemonaïve patients with surgically resected lung adenocarcinoma. Cell viability of the lung adenocarcinoma cell line HCC827 was studied after treatment with cisplatin or the P38 MAPK inhibitor SB 203580.

RESULTS

Thirty-seven of 44 never smokers [84%; 95% confidence intervals (95% CI), 70-92%] expressed high pP38 levels compared with 45 of 104 ever smokers (43%; 95% CI, 34-53%; P < 0.0001). The proportion of never smokers expressing high c-Jun NH(2)-terminal kinase levels (72%; 95% CI, 57-83%) was greater than that of ever smokers (53%; 95% CI, 44-62%; P = 0.03). The proportion of ever smokers expressing high extracellular signal-regulated kinase levels (51%; 95% CI, 42-59%) was similar to that of never smokers (57%; 95% CI, 42-71%; P = 0.47). Never smokers were 10.5 times (95% CI, 3.5-31.5) more likely to express high pP38 levels after adjustment for variables linked to smoking status, including age, sex, and histologic subtype. None of the activated MAPKs predicted for overall survival. Cell viability of HCC827 was significantly reduced after exposure to SB203580 alone or when combined with cisplatin.

CONCLUSIONS

Life-long nonsmoking is associated with high activated P38 levels in patients with lung adenocarcinoma. Activated P38 can contribute to the viability of adenocarcinoma cells in never smokers, but is not predictive for overall survival.

Acute damage by naphthalene triggers expression of the neuroendocrine marker PGP9.5 in airway epithelial cells

Protein Gene Product 9.5 (PGP9.5) is highly expressed in nervous tissue. Recently PGP9.5 expression has been found to be upregulated in the pulmonary epithelium of smokers and in non-small cell lung cancer, suggesting that it also plays a role in carcinogen-inflicted lung epithelial injury and carcinogenesis. We investigated the expression of PGP9.5 in mice in response to two prominent carcinogens found in tobacco smoke: Naphthalene and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). By immunostaining, we found that PGP9.5 protein was highly expressed throughout the airway epithelium in the days immediately following a single injection of naphthalene. In contrast, PGP9.5 was exclusively confined to neurons and neuroendocrine cells in the control and NNK-exposed lungs. Furthermore, we investigated the expression of PGP9.5 mRNA in the lungs by quantitative RT-PCR (qPCR). PGP9.5 mRNA expression was highly upregulated in the days immediately following naphthalene injection and gradually returning to that of control mice 5 days after naphthalene injection. In contrast, exposure to NNK did not result in a significant increase in PGP9.5 mRNA 10 weeks after exposure. No increased expression of two other neuroendocrine markers was found in the non-neuroendocrine epithelial cells after naphthalene exposure. In contrast, immunostaining for the cell cycle regulator p27(Kip1), which has previously been associated with PGP9.5 in lung cancer cells, revealed transient downregulation of p27(Kip1) in naphthalene exposed airways compared to controls, indicating that the rise in PGP9.5 in the airway epithelium is related to downregulation of p27(Kip1). This study is the first to specifically identify the carcinogen naphthalene as an inducer of PGP9.5 expression in non-neuroendocrine epithelium after acute lung injury and further strengthens the accumulating evidence of PGP9.5 as a central player in lung epithelial damage and early carcinogenesis.

Mechanisms of Disease: signal transduction in lung carcinogenesis -- a comparison of smokers and never-smokers

Although smoking has been established as the most important cause of lung cancer, approximately 10% of patients with this malignancy have no history of smoking. The pathogenesis of tobacco-related lung carcinogenesis is becoming well characterized, but the molecular mechanisms of neoplastic transformation in never-smokers have not yet been adequately elucidated. Nevertheless, numerous recent studies have revealed a distinct biological process of malignant transformation with unique epidemiological and clinicopathological characteristics in never-smokers. The molecular pathways involved in the differential pattern of lung oncogenesis according to smoking status, however, remain fairly obscure. Researchers have studied several molecular pathways implicated in lung carcinogenesis in smokers and never-smokers, examining these processes at the genomic, epigenetic and proteomic level. The differential protein expression according to smoking status in critical signal transduction pathways has attracted scientific interest because of the possibilities of therapeutic intervention. In this Review we describe the best-characterized signaling pathways implicated in the transduction of proliferative signals and discuss the activity of these pathways in smokers and never-smokers.

EGFR Tyrosine Kinase Inhibitors in Lung Cancer: An Evolving Story

Drugs that target the epidermal growth factor receptor (EGFR) have had a major impact on the treatment of non-small cell lung cancer (NSCLC). The use of these drugs has also motivated pivotal advances in the understanding of the molecular biology of NSCLC, including the discovery that mutations in EGFR are associated with dramatic and sustained responses to anti-EGFR treatments. This review summarizes the clinical development of EGFR tyrosine kinase inhibitors, the discovery of molecular predictors of response, and the future directions for research in the field.

Epidermal growth factor receptor signaling in adenocarcinomas with bronchioloalveolar components

BACKGROUND

Epidermal growth factor receptor (EGFR) has gained importance in non-small cell lung cancer given impressive responses to agents targeting this molecule, particularly in bronchioloalveolar carcinoma (BAC) and adenocarcinomas, mixed subtype, with BAC components (adeno/BAC). This study assesses EGFR signaling in these tumors.

METHODS

One hundred fifty tumors were classified as BAC or adeno/BAC. Tumor marker expression was determined by immunohistochemistry. Correlations with expression were examined for all tumors (BAC and adeno/BAC), and by BAC and adeno/BAC subset analyses.

RESULTS

Positive immunophenotype was observed in 40.6% of tumors for EGFR, 51.3% for p-AKT, 58.7% for p-ERK, and 28.0% for PTEN, with increased overexpression of EGFR (p = 0.025) and p-AKT (p < 0.0001) in adeno/BAC. Epidermal growth factor receptor immunophenotype was greater in never-smokers (p = 0.008) and correlated with improved overall survival (p = 0.018). On subset analysis, EGFR correlated with improved overall survival (p = 0.05) and disease-free interval (p = 0.044) only in adeno/BAC. Epidermal growth factor receptor independently predicted improved disease-free interval in adeno/BAC (p = 0.03; hazard ratio, 0.47; 95% confidence interval, 0.23 to 0.94).

CONCLUSIONS

Overexpression of EGFR in lung adenocarcinomas with components of BAC histology correlate with never-smoker status and improved overall survival and disease-free interval. Epidermal growth factor receptor immunophenotype may be a useful predictor of clinical outcomes in this tumor subset.

Nicotine and apoptosis

Cigarette smoking is associated with a plethora of different diseases. Nicotine is the addictive component of cigarette but also acts onto cells of the non-neuronal system, including immune effector cells. Although nicotine itself is usually not referred to as a carcinogen, there is ongoing debate whether nicotine functions as a 'tumor enhancer.' By binding to nicotinic acetylcholine receptors, nicotine deregulates essential biological processes like angiogenesis, apoptosis, and cell-mediated immunity. Apoptosis plays critical roles in a wide variety of physiologic processes during fetal development and in adult tissue and is also a fundamental aspect of the biology of malignant diseases. This review provides an overlook how nicotine influences apoptotic processes and is thus directly involved in the etiology of pathological conditions like cancer and obstructive diseases.

Lung cancer in never smokers--a different disease

Although most lung cancers are a result of smoking, approximately 25% of lung cancer cases worldwide are not attributable to tobacco use, accounting for over 300,000 deaths each year. Striking differences in the epidemiological, clinical and molecular characteristics of lung cancers arising in never smokers versus smokers have been identified, suggesting that they are separate entities. This Review summarizes our current knowledge of this unique and poorly understood disease.

Correlation between EGFR gene mutation pattern and Akt phosphorylation in pulmonary adenocarcinomas

The detection of gene mutation of epithelial growth factor receptor (EGFR) is important to predict the therapeutic effect of gefitinib. Recently, it was reported that examination of the activation of the downstream protein of EGFR is useful in the same way as the EGFR mutation. Therefore the purpose of the present paper was to determine whether activation of Akt and Erk, which are downstream proteins, and the EGFR gene mutation pattern was correlated. A total of 130 pulmonary adenocarcinomas were studied for the gene mutations of EGFR in exon 19 and 21, and the phosphorylation of Akt and Erk was investigated by immunostaining. The EGFR mutation was detected in 32%, the positivity of p-Akt was 51%, and the rate of p-Erk was 27%. The EGFR mutation-positive cases were the minority in p-Akt-negative cases, and the p-Akt expression was significantly associated with the mutation of EGFR (P=0.0014). In addition, there was a significant correlation between the L858R mutation and the expression of p-Akt (P=0.040). It is suggested that the activation of Akt is dependent on EGFR mutation pattern.

[Tobacco and morphology: pulmonary diseases]

Tobacco is implicated in multisystemic carcinogenesis through more than fifty identified carcinogenic metabolites that produce mutations responsible for alterations in cell cycle, immune response and endocrine regulation. Is one of nine risk factors identified in one third of cancer deaths together with obesity, sedentary, alcohol consumption, sexual promiscuity, drug addiction, and open and closed air contamination. Answering for cardiovascular diseases as the first cause of death in civilized world, tobacco is also pointed as the major factor implicated in the development of COPD (chronic obstructive pulmonary disease), RB-ILD (respiratory bronchiolitis and interstitial lung disease), DIP (desquamative interstitial pneumonia), bronchiolitis and bronchiolocentric interstitial fibrosis, Langerhans cells histiocytosis, eosinophilic pneumonia, sarcoidosis, epidermoid metaplasia in respiratory epithelium and lung cancer. The chronic tobacco induced inflammatory state is the basis for the acquisition of genetic alterations dependent on the tobacco contaminants.

Lung cancer incidence in never smokers

PURPOSE

Lung cancer is a leading cause of cancer death worldwide. Although smoking remains the predominant cause of lung cancer, lung cancer in never smokers is an increasingly prominent public health issue. However, data on this topic, particularly lung cancer incidence rates in never smokers, are limited.

METHODS

We reviewed the existing literature on lung cancer incidence and mortality rates among never smokers and present new data regarding rates in never smokers from the following large, prospective cohorts: Nurses' Health Study; Health Professionals Follow-Up Study; California Teachers Study; Multiethnic Cohort Study; Swedish Lung Cancer Register in the Uppsala/Orebro region; and First National Health and Nutrition Examination Survey Epidemiologic Follow-Up Study.

RESULTS

Truncated age-adjusted incidence rates of lung cancer among never smokers age 40 to 79 years in these six cohorts ranged from 14.4 to 20.8 per 100,000 person-years in women and 4.8 to 13.7 per 100,000 person-years in men, supporting earlier observations that women are more likely than men to have non-smoking-associated lung cancer. The distinct biology of lung cancer in never smokers is apparent in differential responses to epidermal growth factor receptor inhibitors and an increased prevalence of adenocarcinoma histology in never smokers.

CONCLUSION

Lung cancer in never smokers is an important public health issue, and further exploration of its incidence patterns, etiology, and biology is needed.

Immunodetection of human telomerase reverse-transcriptase (hTERT) re-appraised: nucleolin and telomerase cross paths

The involvement of telomerase in cellular immortalization and senescence has often been assessed by means of telomerase expression at the RNA level and quantification of telomerase activity by the telomeric repeat amplification protocol assay. However, these methods either neglected the existence of various telomerase splice variants, or ignored the nonconventional functions of telomerase independent of its ability to elongate and maintain telomere length. Immunodetection of telomerase is now being recognized as a necessary approach to precisely elucidate its roles in oncogenesis and senescence. A few antibodies directed against the catalytic subunit of the human telomerase (hTERT) are currently used but their specificity is not always demonstrated. A survey of the literature showed inconsistencies and led us to comparatively re-evaluate the most frequently used antibodies. Surprisingly, mass spectrometry, two-dimensional gel analysis and immunofluorescent experiments revealed that the most frequently used hTERT immunoprobe, a mouse monoclonal antibody that was claimed to be directed against an hTERT protein epitope, in fact recognizes nucleolin rather than telomerase. Our findings have interesting implications regarding the biology of nucleolin and telomerase in the context of pathophysiological investigations recently carried out.

Smoking History and Epidermal Growth Factor Receptor Expression as Predictors of Survival Benefit from Erlotinib for Patients with Non–Small-Cell Lung Cancer in the National Cancer Institute of Canada Clinical Trials Group Study BR.21

BACKGROUND

Erlotinib is an oral, reversible inhibitor of the HER1/epidermal growth factor receptor (EGFR) tyrosine kinase. A survival advantage for erlotinib compared with placebo was demonstrated in the National Cancer Institute of Canada Clinical Trials Group study BR.21, a randomized double-blind study of 731 patients with advanced-stage non-small-cell lung cancer.

PATIENTS AND METHODS

In this retrospective, exploratory investigation, univariate and multivariate analyses of survival of the 311 patients with available EGFR status by immunohistochemistry and known smoking history were performed to determine which factor might be more important for predicting clinical outcome.

RESULTS

A marginally significant interaction was observed between smoking history and treatment (P = 0.054). The hazard ratios (HRs) were 0.42 among never-smokers and 0.87 for smokers, indicating that erlotinib was beneficial in both subsets but more effective in patients who had never smoked. The HRs for patients with EGFR-positive and EGFR-negative tumors were 0.65 and 0.83, respectively; however, the interaction between EGFR status and treatment was not significant in univariate or multivariate analyses. Patients with EGFR-positive tumors who never smoked had the greatest survival benefit from erlotinib relative to placebo (HR, 0.28; P = 0.0007).

CONCLUSION

These data suggest that never-smokers and patients with EGFR-positive tumors might experience an enhanced benefit from erlotinib compared with placebo but that smoking history might be more predictive of survival benefit than EGFR expression. Subset analyses of ever-smokers revealed significant survival advantages for men and patients with squamous cell histology. Male ever-smokers with squamous cell non-small-cell lung cancer derived a significant survival benefit from erlotinib (HR, 0.66; P = 0.015) despite a very low tumor response rate.