Sex-related differences in bronchial epithelial changes associated with tobacco smoking

The role of climate change in food security; empirical evidence over Punjab regions, Pakistan

Climate change is bringing drastic changes to the food availability, accessibility, quality, and stability in the world. Pakistan heavily relies on production of wheat for food security. This study investigates the role of climate change on food security over Punjab regions, Pakistan, from 1979-2020. The study utilized the total production of wheat to measure food security. Moreover, the study utilized mean, maximum, minimum temperature, wind speed, and rainfall as a measurement of climate change. This study utilized auto-regressive distributed lag (ARDL) bound test cointegration approach to test the long-run cointegration, while ARDL model is applied to investigate the short-run relationship among modeled variables. This study adopted Augmented Dicky Fuller (ADF) and Phillips Parron (PP) test to check the stationarity of the data. Moreover, the study ensures reliability and validity of the model by utilizing Breusch-Godfrey serial correlation, Breusch-Pagan-Godfry HSK, and Ramsey RESET test. This study found that wheat cultivated area (0.46*), total irrigated area (2.67***), total un-irrigated area (1.93***), and total area sown ([1.0809**) have a positive and significant long-run impact on food production in all regions of Punjab Pakistan. However, while average, the maximum and minimum temperature is negatively and significantly associated with food production in all regions of Punjab (- 1.07**; - 3.33***; - 1.84**), except northern Punjab, where maximum temperature affects positively food production Punjab. Rainfall negatively and significantly affects food production in northern (- 0.34**) and central and southern (- 0.13***) Punjab. Furthermore, wind speed negatively affects food production in all regions of Punjab (- 0.22**; - 0.21*; - 0.11**), except northern Punjab. This study implies that government should develop policies to increase irrigation facilities and loan facilities to increase the total area sown that will help to increase wheat yield and ensure food security. Moreover, the government should devise policies for large-scale plantations to minimize climate change impacts. The study also suggests new improved varieties of the wheat crop that can survive and flourish in the presence of adverse climatic changes, high temperature, and high wind speed.

The promises and challenges of early non-small cell lung cancer detection: patient perceptions, low-dose CT screening, bronchoscopy and biomarkers

Lung cancer survival statistics are sobering with survival ranking among the poorest of all cancers despite the addition of targeted therapies and immunotherapies. However, improvements in tools for early detection hold promise. The Nederlands–Leuvens Longkanker Screenings Onderzoek (NELSON) trial recently corroborated the findings from the previous National Lung Screening Trial low‐dose Computerised Tomography (NLST) screening trial in reducing lung cancer mortality. Biomarker research and development is increasing at pace as the molecular life histories of lung cancers become further unravelled. Low‐dose CT screening (LDCT) is effective but targets only those at the highest risk and is burdensome on healthcare. An optimally designed CT screening programme at best will only detect a low proportion of overall lung cancers as only those at very high‐risk meet screening criteria. Biomarkers that help risk stratify suitable patients for LDCT screening, and those that assist in determining which LDCT detected nodules are likely to represent malignant disease are needed. Some biomarkers have been proposed as standalone lung cancer diagnosis tools. Bronchoscopy technology is improving, with better capacity to identify and obtain samples from early lung cancers. Clinicians need to be aware of each early lung cancer detection method’s inherent limitations. We anticipate that the future of early lung cancer diagnosis will involve a synergistic, multimodal approach, combining several early detection methods.

Lung cancer in women in 21th century

Lung cancer is the first cause of death from malignant disease. The distressing epidemiological data show the increasing female to male incidence ratio for this tumor. A high incidence of lung cancer in never smokers with importance of environmental agents makes a problem among women. Adenocarcinoma (ADC) is noted in women with increasing rate and ethnic background impacts female lung cancer with differences in the incidence of genetic aberrations. The conception of different hormonal status is taken into consideration as potential explanation of variant cancer biology and clinical manifestation in women and men. The impact of 17-β-estradiol, estrogen receptors, aromatase expression, pituitary sex hormones receptors in carcinogenesis with relation between estrogens and genetic aberrations are investigated. The response to newest therapies among female is also different than in men. This overview summarizes currently available evidence on the specificity of female lung cancer and presents the direction of necessary studies.

Comparison of autofluorescence and white-light bronchoscopies performed with the Evis Lucera Spectrum for the detection of bronchial cancers: a meta-analysis

Background

Many recent studies have reported that autofluorescence bronchoscopy (AFB) has a superior sensitivity and decreased specificity in the diagnosis of bronchial cancers when compared with white-light bronchoscopy (WLB). We specifically analyzed the diagnostic performances of autofluorescence imaging video bronchoscopy (AFI) performed with the Evis Lucera Spectrum from Olympus, which is a relatively novel approach in detecting and delineating bronchial cancers, and compared it to the older WLB method.

Methods

We searched the PubMed, Embase, Web of Science, and CNKI databases from inception to July 12^th, 2018 for trials in which patients were diagnosed with lung cancer via concurrent or combined use of AFI and WLB. The included studies were required to have a histologic diagnosis as the gold standard comparison, and a sufficient amount of data was extracted to assess the diagnostic capacity. A 2×2 table was constructed, and the area under the receiver-operating characteristic curve (AUC) of AFI and WLB was estimated by using a stochastic model for diagnostic meta-analysis using STATA software.

Results

A total of 10 articles were eligible for the meta analysis, comprising 1,830 patients with complete data included in the analysis. AFI showed a superior sensitivity of 0.92 (95% CI, 0.88-0.95) over WLB's 0.70 (95% CI, 0.58-0.80) with P<0.01, and a comparable specificity of 0.67 (95% CI, 0.51-0.80) compared with WLB's 0.78 (95% CI, 0.68-0.86) with P=0.056. Egger's test P value (0.225) demonstrated that there was no publication bias.

Conclusions

Our research showed that in the evaluation of bronchial cancers, AFI was superior to conventional WLB. With its higher sensitivity, AFI could be valuable for avoiding misdiagnosis.

DNA repair as an emerging target for COPD-lung cancer overlap

Cigarette smoking is the leading cause of lung cancer and chronic obstructive pulmonary disease (COPD). Many of the detrimental effects of cigarette smoke have been attributed to the development of DNA damage, either directly from chemicals contained in cigarette smoke or as a product of cigarette smoke-induced inflammation and oxidative stress. In this review, we discuss the environmental, epidemiological, and physiological links between COPD and lung cancer and the likely role of DNA damage and repair in COPD and lung cancer development. We explore alterations in DNA damage repair by DNA repair proteins and pathways. We discuss emerging data supporting a key role for the DNA repair protein, xeroderma pigmentosum group C (XPC), in cigarette smoke-induced COPD and early lung cancer development. Understanding the interplay between cigarette smoke, DNA damage repair, COPD, and lung cancer may lead to prognostic tools and new, potentially targetable, pathways for lung cancer prevention and treatment.

Identification of the SOX2 Interactome by BioID Reveals EP300 as a Mediator of SOX2-dependent Squamous Differentiation and Lung Squamous Cell Carcinoma Growth

Lung cancer is the leading cause of cancer mortality worldwide, with squamous cell carcinoma (SQCC) being the second most common form. SQCCs are thought to originate in bronchial basal cells through an injury response to smoking, which results in this stem cell population committing to hyperplastic squamous rather than mucinous and ciliated fates. Copy number gains in SOX2 in the region of 3q26-28 occur in 94% of SQCCs, and appear to act both early and late in disease progression by stabilizing the initial squamous injury response in stem cells and promoting growth of invasive carcinoma. Thus, anti-SOX2 targeting strategies could help treat early and/or advanced disease. Because SOX2 itself is not readily druggable, we sought to characterize SOX2 binding partners, with the hope of identifying new strategies to indirectly interfere with SOX2 activity. We now report the first use of proximity-dependent biotin labeling (BioID) to characterize the SOX2 interactome in vivo We identified 82 high confidence SOX2-interacting partners. An interaction with the coactivator EP300 was subsequently validated in both basal cells and SQCCs, and we demonstrate that EP300 is necessary for SOX2 activity in basal cells, including for induction of the squamous fate. We also report that EP300 copy number gains are common in SQCCs and that growth of lung cancer cell lines with 3q gains, including SQCC cells, is dependent on EP300. Finally, we show that EP300 inhibitors can be combined with other targeted therapeutics to achieve more effective growth suppression. Our work supports the use of BioID to identify interacting protein partners of nondruggable oncoproteins such as SOX2, as an effective strategy to discover biologically relevant, druggable targets.

SOX2 and PI3K Cooperate to Induce and Stabilize a Squamous-Committed Stem Cell Injury State during Lung Squamous Cell Carcinoma Pathogenesis

Although cancers are considered stem cell diseases, mechanisms involving stem cell alterations are poorly understood. Squamous cell carcinoma (SQCC) is the second most common lung cancer, and its pathogenesis appears to hinge on changes in the stem cell behavior of basal cells in the bronchial airways. Basal cells are normally quiescent and differentiate into mucociliary epithelia. Smoking triggers a hyperproliferative response resulting in progressive premalignant epithelial changes ranging from squamous metaplasia to dysplasia. These changes can regress naturally, even with chronic smoking. However, for unknown reasons, dysplasias have higher progression rates than earlier stages. We used primary human tracheobronchial basal cells to investigate how copy number gains in SOX2 and PIK3CA at 3q26-28, which co-occur in dysplasia and are observed in 94% of SQCCs, may promote progression. We find that SOX2 cooperates with PI3K signaling, which is activated by smoking, to initiate the squamous injury response in basal cells. This response involves SOX9 repression, and, accordingly, SOX2 and PI3K signaling levels are high during dysplasia, while SOX9 is not expressed. By contrast, during regeneration of mucociliary epithelia, PI3K signaling is low and basal cells transiently enter a SOX2LoSOX9Hi state, with SOX9 promoting proliferation and preventing squamous differentiation. Transient reduction in SOX2 is necessary for ciliogenesis, although SOX2 expression later rises and drives mucinous differentiation, as SOX9 levels decline. Frequent coamplification of SOX2 and PIK3CA in dysplasia may, thus, promote progression by locking basal cells in a SOX2HiSOX9Lo state with active PI3K signaling, which sustains the squamous injury response while precluding normal mucociliary differentiation. Surprisingly, we find that, although later in invasive carcinoma SOX9 is generally expressed at low levels, its expression is higher in a subset of SQCCs with less squamous identity and worse clinical outcome. We propose that early pathogenesis of most SQCCs involves stabilization of the squamous injury state in stem cells through copy number gains at 3q, with the pro-proliferative activity of SOX9 possibly being exploited in a subset of SQCCs in later stages.

Low Prevalence of High-Grade Lesions Detected With Autofluorescence Bronchoscopy in the Setting of Lung Cancer Screening in the Pan-Canadian Lung Cancer Screening Study

BACKGROUND

Lung cancer screening with low-dose CT (LDCT) scan has been demonstrated to reduce lung cancer mortality. Preliminary reports suggested that up to 20% of lung cancers may be CT scan occult but detectable by autofluorescence bronchoscopy (AFB). We evaluated the prevalence of CT scan occult, invasive, and high-grade preinvasive lesions in high-risk participants undergoing screening for lung cancer.

METHODS

The first 1,300 participants from seven centers in the Pan-Canadian Early Detection of Lung Cancer Study who had ≥ 2% lung cancer risk over 5 years were invited to have an AFB in addition to a LDCT scan. We determined the prevalence of CT scan and AFB abnormalities and analyzed the association between selected predictor variables and preinvasive lesions plus invasive cancer.

RESULTS

A total of 776 endobronchial biopsies were performed in 333 of 1,300 (25.6%) participants. Dysplastic or higher-grade lesions were detected in 5.3% of the participants (n = 68; mild dysplasia: n = 36, moderate dysplasia: n = 25, severe dysplasia: n = 3, carcinoma in situ [CIS]: n = 1, and carcinoma: n = 4). Only one typical carcinoid tumor and one CIS lesion were detected by AFB alone, for a rate of CT scan occult cancer of 0.15% (95% CI, 0.0%-0.6%). Fifty-six prevalence lung cancers were detected by LDCT scan (4.3%). The only independent risk factors for finding of dysplasia or CIS on AFB were smoking duration (OR, 1.05; 95% CI, 1.02-1.07) and FEV₁ percent predicted (OR, 0.99; 95% CI, 0.98-0.99).

CONCLUSIONS

The addition of AFB to LDCT scan in a high lung cancer risk cohort detected too few CT occult cancers (0.15%) to justify its incorporation into a lung cancer screening program.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00751660; URL: www.clinicaltrials.gov.

Aberrant gene methylation and bronchial dysplasia in high risk lung cancer patients

INTRODUCTION

The risk for lung cancer is incremented in high degree dysplasia (HGD) and in subjects with hypermethylation of multiple genes. We sought to establish the association between them, as well as to analyze the DNA aberrant methylation in sputum and in bronchial washings (BW).

METHODS

Cross sectional study of high risk patients for lung cancer in whom induced sputum and autofluorescence bronchoscopy were performed. The molecular analysis was determined on DAPK1, RASSF1A and p16 genes using Methylation-specific PCR.

RESULTS

A total of 128 patients were enrolled in the study. Dysplasia lesions were found in 79 patients (61.7%) and high grade dysplasia in 20 (15.6%). Ninety eight patients out of 128 underwent molecular analysis. Methylation was observed in bronchial secretions (sputum or BW) in 60 patients (61.2%), 51 of them (52%) for DAPK1, in 20 (20.4%) for p16 and in three (3.1%) for RASSF1A. Methylated genes only found in sputum accounted for 38.3% and only in BW in 41.7%, and in both 20.0%. In the 11.2% of the patients studied, HGD and a hypermethylated gene were present, while for the 55.1% of the sample only one of both was detected and for the rest of the subjects (33.6%), none of the risk factors were observed.

CONCLUSIONS

Our data determines DNA aberrant methylation panel in bronchial secretions is present in a 61.2% and HGD is found in 15.6%. Although both parameters have previously been identified as risk factors for lung cancer, the current study does not find a significative association between them. The study also highlights the importance of BW as a complementary sample to induced sputum when analyzing gene aberrant methylation.

G-protein coupled receptor family C, group 5, member A (GPRC5A) expression is decreased in the adjacent field and normal bronchial epithelia of patients with chronic obstructive pulmonary disease and non-small-cell lung cancer

INTRODUCTION

Understanding oncogenes and tumor suppressor genes expression patterns is essential for characterizing lung cancer pathogenesis. We have previously demonstrated that mGprc5a/hGPRC5A is a lung-specific tumor suppressor evidenced by inflammation-mediated tumorigenesis in Gprc5a-knockout mice. The implication of GPRC5A in human lung cancer pathogenesis, including that associated with inflammatory chronic obstructive pulmonary disease (COPD), a risk factor for the malignancy, remains elusive.

METHODS

We sought to examine GPRC5A immunohistochemical expression in histologically normal bronchial epithelia (NBE) from lung disease-free never- and ever-smokers (n = 13 and n = 18, respectively), from COPD patients with (n = 26) and without cancer (n = 24) and in non-small cell lung cancers (NSCLCs) (n = 474). Quantitative assessment of GPRC5A transcript expression in airways (n = 6), adjacent NBEs (n = 29) and corresponding tumors (n = 6) from 6 NSCLC patients was also performed.

RESULTS

GPRC5A immunohistochemical expression was significantly lower in tumors compared to uninvolved NBE (p < 0.0001) and was positively associated with adenocarcinoma histology (p < 0.001). GPRC5A airway expression was highest in lung disease-free NBE, decreased and intermediate in NBE of cancer-free COPD patients (p = 0.004) and further attenuated and lowest in epithelia of COPD patients with adenocarcinoma and SCC (p < 0.0001). Furthermore, GPRC5A mRNA was significantly decreased in NSCLCs and corre sponding NBE compared to uninvolved normal lung (p = 0.03).

CONCLUSIONS

Our findings highlight decreased GPRC5A expression in the field cancerization of NSCLC, including that associated with lung inflammation. Assessment of the use of GPRC5A expression as a risk factor for NSCLC development in COPD patients is warranted.

Preinvasive lesions of the bronchus

It has been proposed that invasive carcinoma of the bronchus develops through a transition from preinvasive lesions to overt malignancy. Newer diagnostic technologies have provided a more sensitive way to diagnose preinvasive lesions and a better understanding of the prevalence of such lesions. The natural history of preinvasive lesions has not been well defined; however, there is evidence that high-grade lesions are at a higher risk of progression to carcinoma. Molecular alterations have been described in preinvasive lesions and may help better predict which lesions will progress. Several noninvasive techniques are available for the treatment of high-grade lesions.

Natural history of bronchial preinvasive lesions

Preinvasive bronchial lesions defined as dysplasia and carcinoma in situ (CIS) have been considered as precursors of squamous cell carcinoma of the lung. The risk and rate of progression of preinvasive lesions to invasive squamous cell carcinoma as well as the mechanism of progression or regression are incompletely understood. While the evidence for the multistage, stepwise progression model is weak with relatively few documented lesions that progress through various grades of dysplasia to CIS and then to invasive carcinoma, the concept of field carcinogenesis is strongly supported. The presence of high-grade dysplasia or CIS is a risk marker for lung cancer both in the central airways and peripheral lung. Genetic alterations such as loss of heterozygosity in chromosome 3p or chromosomal aneusomy as well as host factors such as the inflammatory load and levels of anti-inflammatory proteins in the lung influence the progression or regression of preinvasive lesions. CIS is different than severe dysplasia at the molecular level and has different clinical outcome. Molecular analysis of dysplastic lesions that progress to CIS or invasive cancer and rare lesions that progress rapidly from hyperplasia or metaplasia to CIS or invasive cancer will shed light on the key molecular determinants driving development to an invasive phenotype versus those associated with tobacco smoke damage.

Preinvasive lesions of the bronchus

Preinvasive lesions are considered the precursors of squamous cell carcinoma of the bronchus. Treatment at the preinvasive stage, before the potential for metastasis, may improve survival from squamous cell carcinoma. An understanding of the natural history and outcome of preinvasive lesions is essential for the accurate interpretation studies of their treatment, and decisions regarding the management of individual lesions. The natural history of preinvasive lesions has only been reported in a small number of highly selected patients and uses different inclusion criteria, treatment criteria. and time-periods of follow-up, making it difficult to draw definitive conclusions. High-grade preinvasive lesions carry a risk of progression to carcinoma but most patients have multiple lesions and a significant probability of developing new lesions over time. Distinguishing lesions with malignant potential, the targets for therapy, from those that will regress or remain indolent is difficult. The American College of Chest Physicians guidelines recommend bronchoscopic follow-up of severe dysplasia and carcinoma-in situ. This review of the evidence regarding the natural history and outcome of preinvasive lesions supports this view, but also shows that further studies in individuals at risk for lung cancer are necessary before guidelines for the management of preinvasive lesions can be developed.

A randomized phase II chemoprevention trial of 13-CIS retinoic acid with or without alpha tocopherol or observation in subjects at high risk for lung cancer

No chemoprevention strategies have been proven effective for lung cancer. We evaluated the effect of 13-cis retinoic acid (13-cis RA), with or without alpha tocopherol, as a lung cancer chemoprevention agent in a phase II randomized controlled clinical trial of adult subjects at high risk for lung cancer as defined by the presence of sputum atypia, history of smoking, and airflow obstruction, or a prior surgically cured nonsmall cell lung cancer (disease free, >3 years). Subjects were randomly assigned to receive either 13-cis RA, 13-cis RA plus alpha tocopherol (13-cis RA/alpha toco) or observation for 12 months. Outcome measures are derived from histologic evaluation of bronchial biopsy specimens obtained by bronchoscopy at baseline and follow-up. The primary outcome measure is treatment "failure" defined as histologic progression (any increase in the maximum histologic score) or failure to return for follow-up bronchoscopy. Seventy-five subjects were randomized (27/22/26 to observations/13-cis RA/13-cis RA/alpha toco); 59 completed the trial; 55 had both baseline and follow-up bronchoscopy. The risk of treatment failure was 55.6% (15 of 27) and 50% (24 of 48) in the observation and combined (13 cis RA plus 13 cis RA/alpha toco) treatment arms, respectively (odds ratio adjusted for baseline histology, 0.97; 95% confidence interval, 0.36-2.66; P = 0.95). Among subjects with complete histology data, maximum histology score in the observation arm increased by 0.37 units and by 0.03 units in the treated arms (difference adjusted for baseline, -0.18; 95% confidence interval, -1.16 to 0.81; P = 0.72). Similar (nonsignificant) results were observed for treatment effects on endobronchial proliferation as assessed by Ki-67 immunolabeling. Twelve-month treatment with 13-cis RA produced nonsignificant changes in bronchial histology, consistent with results in other trials. Agents advancing to phase III randomized trials should produce greater histologic changes. The addition of alpha tocopherol did not affect toxicity.

Lung cancer and chronic obstructive pulmonary disease: needs and opportunities for integrated research

Lung cancer and chronic obstructive pulmonary disease (COPD) are leading causes of morbidity and mortality in the United States and worldwide. They share a common environmental risk factor in cigarette smoke exposure and a genetic predisposition represented by the incidence of these diseases in only a fraction of smokers. The presence of COPD increases the risk of lung cancer up to 4.5-fold. To investigate commonalities in disease mechanisms and perspectives for disease chemoprevention, the National Heart, Lung, and Blood Institute (NHLBI) and the National Cancer Institute (NCI) held a workshop. The participants identified four research objectives: 1) clarify common epidemiological characteristics of lung cancer and COPD; 2) identify shared genetic and epigenetic risk factors; 3) identify and validate biomarkers, molecular signatures, and imaging-derived measurements of each disease; and 4) determine common and disparate pathogenetic mechanisms. These objectives should be reached via four research approaches: 1) identify, publicize, and enable the evaluation and analysis of existing datasets and repositories of biospecimens; 2) obtain phenotypic and outcome data and biospecimens from large studies of subjects with and/or at risk for COPD and lung cancer; 3) develop and use animal and other preclinical models to investigate pathogenetic links between the diseases; and 4) conduct early-phase clinical trials of potential chemopreventive agents. To foster much needed research interactions, two final recommendations were made by the participants: 1) incorporate baseline phenotyping and outcome measures for both diseases in future longitudinal studies of each disease and 2) expand collaborative efforts between the NCI and NHLBI.

Confocal fluorescence microendoscopy of bronchial epithelium

Confocal microendoscopy permits the acquisition of high-resolution real-time confocal images of bronchial mucosa via the instrument channel of an endoscope. We report here on the construction and validation of a confocal fluorescence microendoscope and its use to acquire images of bronchial epithelium in vivo. Our objective is to develop an imaging method that can distinguish preneoplastic lesions from normal epithelium to enable us to study the natural history of these lesions and the efficacy of chemopreventive agents without biopsy removal of the lesion that can introduce a spontaneous regression bias. The instrument employs a laser-scanning engine and bronchoscope-compatible confocal probe consisting of a fiber-optic image guide and a graded-index objective lens. We assessed the potential of topical application of physiological pH cresyl violet (CV) as a fluorescence contrast-enhancing agent for the visualization of tissue morphology. Images acquired ex vivo with the confocal microendoscope were first compared with a bench-top confocal fluorescence microscope and conventional histology. Confocal images from five sites topically stained with CV were then acquired in vivo from high-risk smokers and compared to hematoxylin and eosin stained sections of biopsies taken from the same site. Sufficient contrast in the confocal imagery was obtained to identify cells in the bronchial epithelium. However, further improvements in the miniature objective lens are required to provide sufficient axial resolution for accurate classification of preneoplastic lesions.

Autofluorescence bronchoscopy in volunteer asymptomatic smokers

We assess the sensitivity of autofluorescence bronchoscopy (AFB) compared to that of white light bronchoscopy (WLB) for identification of pre-invasive neoplastic changes of bronchial mucosa in asymptomatic heavy smokers. WLB was performed using a standard flexible fibre-optic bronchoscope, and AFB carried out using the Xillix LIFE Lung((R)) system. Positive AFB images were indicated in the bronchial tree from 51 of the 93 subjects in the study. Biopsies showed epithelial abnormalities in 27 (15 metaplasia, 12 inflammatory changes) of these. WLB showed abnormality in 1 subject but with no pathological changes revealed by cyto-histology. Therefore, the sensitivity of AFB to metaplasia was 75% compared to zero for WLB. AFB yields positive predictive values for metaplastic and overall mucosal changes of 29.4% and 52.9%, respectively. In summary, over 16% of asymptomatic smokers had metaplastic changes in their bronchial mucosa, and AFB proved more sensitive in revealing early changes than WLB.

Lung cancer preneoplasia

From histological and biological perspectives, lung cancer is a complex neoplasm. Although the sequential preneoplastic changes have been defined for centrally arising squamous carcinomas of the lung, they have been poorly documented for the other major forms of lung cancers, including small cell lung carcinoma and adenocarcinomas. There are three main morphologic forms of preneoplastic lesions recognized in the lung: squamous dysplasias, atypical adenomatous hyperplasia, and diffuse idiopathic pulmonary neuroendocrine cell hyperplasia. However, these lesions account for the development of only a subset of lung cancers. Several studies have provided information regarding the molecular characterization of lung preneoplastic changes, especially for squamous cell carcinoma. These molecular changes have been detected in the histologically normal and abnormal respiratory epithelium of smokers. Two different molecular pathways have been detected in lung adenocarcinoma pathogenesis: smoking-associated activation of RAS signaling, and nonsmoking-associated activation of EGFR signaling; the latter is detected in histologically normal respiratory epithelium.

Molecular predictive factors for progression of high-grade preinvasive bronchial lesions

RATIONALE

The outcome of precancerous bronchial lesions is not well known, and their management is subject to controversy. Many molecular alterations are present in preinvasive lesions, but none has been assessed to predict the evolution of the lesions.

OBJECTIVES

To analyze the outcome of high-grade precancerous lesions according to their molecular profile.

METHODS

Twenty-three severe dysplasia and 31 carcinoma in situ (CIS) lesions in 37 patients were monitored using repeated autofluorescence bronchoscopy over a 12-year period. Microdissection and polymerase chain reaction analysis were performed on paraffin tissue sections to assess loss of heterozygosity (LOH) and microsatellite instability on chromosome 3p, 5q, and 9p. Histology and molecular status at baseline were compared between 7 lesions that became invasive, 11 that relapsed after treatment, 17 that were eradicated with local treatment, and 19 that spontaneously regressed.

MEASUREMENTS AND MAIN RESULTS

Ninety-four percent of lesions that progressed or relapsed were CIS at baseline, whereas 79% of spontaneously regressing lesions were severe dysplasia (P < 0.0001). 3p and 9p LOH was more frequent in CIS than in severe dysplasia (P = 0.03). In the whole group of lesions as well as in the CIS group, 3p LOH was strongly associated with progression (P < 0.0001 and P = 0.02, respectively). Microsatellite instability was not associated with the outcome of the lesions. A therapeutic strategy based on the presence of 3p or 9p LOH would have led to overtreatment of six lesions but would have missed only 1 among the 18 progressing lesions.

CONCLUSIONS

Baseline histology and 3p LOH analysis appear to be useful in predicting the outcome of high-grade precancerous lesions.

Glutathione S-transferase genotypes modify lung function decline in the general population: SAPALDIA cohort study

Background

Understanding the environmental and genetic risk factors of accelerated lung function decline in the general population is a first step in a prevention strategy against the worldwide increasing respiratory pathology of chronic obstructive pulmonary disease (COPD). Deficiency in antioxidative and detoxifying Glutathione S-transferase (GST) gene has been associated with poorer lung function in children, smokers and patients with respiratory diseases. In the present study, we assessed whether low activity variants in GST genes are also associated with accelerated lung function decline in the general adult population.

Methods

We examined with multiple regression analysis the association of polymorphisms in GSTM1, GSTT1 and GSTP1 genes with annual decline in FEV1, FVC, and FEF_25–75 during 11 years of follow-up in 4686 subjects of the prospective SAPALDIA cohort representative of the Swiss general population. Effect modification by smoking, gender, bronchial hyperresponisveness and age was studied.

Results

The associations of GST genotypes with FEV1, FVC, and FEF_25–75 were comparable in direction, but most consistent for FEV1. GSTT1 homozygous gene deletion alone or in combination with GSTM1 homozygous gene deletion was associated with excess decline in FEV1 in men, but not women, irrespective of smoking status. The additional mean annual decline in FEV1 in men with GSTT1 and concurrent GSTM1 gene deletion was -8.3 ml/yr (95% confidence interval: -12.6 to -3.9) relative to men without these gene deletions. The GSTT1 effect on the FEV1 decline comparable to the observed difference in FEV1 decline between never and persistent smoking men. Effect modification by gender was statistically significant.

Conclusion

Our results suggest that genetic GSTT1 deficiency is a prevalent and strong determinant of accelerated lung function decline in the male general population.

Biomarkers to assess the utility of potential reduced exposure tobacco products

To date, we have no valid biomarkers that serve as proxies for tobacco-related disease to test potential reduced exposure products. This paper represents the deliberations of four workgroups that focused on four tobacco-related heath outcomes: Cancer, nonmalignant pulmonary disease, cardiovascular disease, and fetal toxicity. The goal of these workgroups was to identify biomarkers that offer some promise as measures of exposure or toxicity and ultimately may serve as indicators for future disease risk. Recommendations were based on the relationship of the biomarker to what is known about mechanisms of tobacco-related pathogenesis, the extent to which the biomarker differs among smokers and nonsmokers, and the sensitivity of the biomarker to changes in smoking status. Other promising biomarkers were discussed. No existing biomarkers have been demonstrated to be predictive of tobacco-related disease, which highlights the importance and urgency of conducting research in this area.

Biomarkers to assess the utility of potential reduced exposure tobacco products

To date, we have no valid biomarkers that serve as proxies for tobacco-related disease to test potential reduced exposure products. This paper represents the deliberations of four workgroups that focused on four tobacco-related heath outcomes: Cancer, nonmalignant pulmonary disease, cardiovascular disease, and fetal toxicity. The goal of these workgroups was to identify biomarkers that offer some promise as measures of exposure or toxicity and ultimately may serve as indicators for future disease risk. Recommendations were based on the relationship of the biomarker to what is known about mechanisms of tobacco-related pathogenesis, the extent to which the biomarker differs among smokers and nonsmokers, and the sensitivity of the biomarker to changes in smoking status. Other promising biomarkers were discussed. No existing biomarkers have been demonstrated to be predictive of tobacco-related disease, which highlights the importance and urgency of conducting research in this area.

Prevalence of COPD in Women Compared to Men Around the Time of Diagnosis of Primary Lung Cancer

PURPOSES

COPD is a well-known independent risk factor that is associated with primary lung cancer. There is, however, a striking paucity of women in studies demonstrating this association. The purpose of this study was to compare the prevalence of COPD as determined by pulmonary function tests (PFTs) between women and men at around the time of lung cancer diagnosis.

METHODS

We retrospectively reviewed patients with newly diagnosed primary lung cancer who had undergone PFTs prior to their treatment. The diagnosis of airflow obstruction was made according to American Thoracic Society guidelines. Comparisons of the prevalence of COPD between men and women were performed using univariate and multivariate logistic regression analysis.

RESULTS

Of the 294 patients in the study, 151 patients (51.4%) were men and 143 patient (48.6%) were women. Of the men, 110 patients (72.8%) had COPD compared with 75 patients (52.5%) among the women. This represented a significantly lower prevalence of COPD in women than in men (odds ratio [OR], 0.41; 95% confidence interval [CI], 0.25 to 0.67; p = 0.0003). When adjusted for age and smoking status, a sustained lower prevalence of COPD was noted in women compared to men (OR, 0.44; 95% CI, 0.26 to 0.74; p = 0.002). In a subset of 256 smokers, there remained a lower prevalence of COPD in women compared to men (OR, 0.45; 95% CI, 0.27 to 0.77; p = 0.003). Adjusted analysis to control for age and number of pack-years of smoking in this subset again showed a sustained reduction in the OR for women presenting with COPD (OR, 0.48; 95% CI, 0.28 to 0.83; p = 0.009).

CONCLUSIONS

When COPD was examined as an end point among patients who had newly diagnosed lung cancer, a significantly higher proportion of women had normal PFT results. Gender-based differences on PFT results should be considered during the screening of lung cancer, because the stratification of high-risk patients based on the presence of COPD may miss a significant proportion of women with lung cancer.

Progression of airway dysplasia and C-reactive protein in smokers at high risk of lung cancer

RATIONALE

Chronic inflammation has been implicated in the development of airway dysplasia and lung cancer. It is unclear whether circulating biomarkers of inflammation could be used to predict progression of airway dysplasia.

OBJECTIVE

We determined whether circulating levels of C-reactive protein (CRP) or other inflammatory biomarkers could predict progression of bronchial dysplasia in smokers over 6 mo.

METHODS

The plasma levels of CRP, interleukins 6 and 8, and monocyte chemoattractant protein 1 were measured at baseline in 65 ex- and current smokers who had at least one site of bronchial dysplasia > 1.2 mm in size. Additional bronchial biopsies were taken after 6 mo from the same sites where dysplastic lesions were discovered at baseline. Progressive dysplastic lesions were defined as worsening of the dysplastic lesion by at least two grades or development of new dysplastic lesions.

RESULTS

Half of the participants developed progressive dysplastic lesions after 6 mo. The baseline CRP levels in these participants were 64% higher than those without progressive disease (p = 0.027). Only one of eight (13%) participants with CRP < or = 0.5 mg/L developed progressive disease, whereas 31 of 57 (54%) participants with CRP > 0.5 mg/L developed progressive disease (p = 0.011). The odds of developing progressive disease were 9.6-fold higher in the latter than in the former group.

CONCLUSION

Plasma CRP, in concert with lung function and pack-years of smoking, appears to have excellent predictive powers in identifying participants with bronchial dyplastic lesions whose lesions progress to more advanced stages of dysplasia.

Increased staining for phospho-Akt, p65/RELA and cIAP-2 in pre-neoplastic human bronchial biopsies

Background

The development of non-small cell lung carcinoma proceeds through a series of well-defined pathological steps before the appearance of invasive lung carcinoma. The molecular changes that correspond with pathology changes are not well defined and identification of the molecular events may provide clues on the progression of intraepithelial neoplasia in the lung, as well as suggest potential targets for chemoprevention. The acquisition of anti-apoptotic signals is critical for the survival of cancer cells but the pathways involved are incompletely characterized in developing intra-epithelial neoplasia (IEN).

Methods

We used immunohistochemistry to determine the presence, relative levels, and localization of proteins that mediate anti-apoptotic pathways in developing human bronchial neoplasia.

Results

Bronchial epithelial protein levels of the phosphorylated (active) form of AKT kinase and the caspase inhibitor cIAP-2 were increased in more advanced grades of bronchial IEN lesions than in normal bronchial epithelium. Additionally, the percentage of biopsies with nuclear localization of p65/RELA in epithelial cells increased with advancing pathology grade, suggesting that NF-κB transcriptional activity was induced more frequently in advanced IEN lesions.

Conclusion

Our results indicate that anti-apoptotic pathways are elevated in bronchial IEN lesions prior to the onset of invasive carcinoma and that targeting these pathways therapeutically may offer promise in prevention of non-small cell lung carcinoma.

Nuclear morphometry as a biomarker for bronchial intraepithelial neoplasia: correlation with genetic damage and cancer development

BACKGROUND

Bronchial carcinomas are preceded by epithelial morphologic changes. The variation in interpretation of these grades of intraepithelial neoplasia makes it difficult to determine its natural history and utility of histopathology as a surrogate endpoint biomarker. The objective of this study was to quantitate morphologic changes of intraepitherlial neoplasia and validate its utility through correlation with histopathology, allelic loss, and cancer development.

METHODS

Quantitative nuclear morphometry was performed on 47 normal bronchial biopsies and 28 invasive cancer to generate a morphometry index (MI) that was applied to 1,096 bronchial biopsies from 230 volunteers who were current smokers (> or =25 pack-years) and 30 patients who had cancer. In a subset of 631 biopsies, MI was correlated with frequency of loss of heterozygosity at nine chromosomal regions (14 polymorphic markers).

RESULTS

A significant correlation was found between MI and allelic loss in six of nine chromosomal regions. As part of patient long-term follow-up, 12 sites that progressed to cancer were identified and had significantly increased MIs relative to nonprogressing sites. Significant overlap in the MIs was found between most grades of intraepithelial neoplasia.

CONCLUSIONS

In chemoprevention trials, nuclear morphometry can supplement histopathology as a Surrogate Endpont Biomarker (SEB) because it is quantitative, collelates well with genetic damage, and may predict cancer development.

A randomized phase IIb trial of pulmicort turbuhaler (budesonide) in people with dysplasia of the bronchial epithelium

PURPOSE

Preclinical studies suggest that inhaled budesonide may be an effective chemopreventive agent for lung cancer. We conducted a phase IIb study to determine the effects of inhaled budesonide in smokers with bronchial dysplasia.

EXPERIMENTAL DESIGN

A total of 112 smokers with more than or equal to one site of bronchial dysplasia > 1.2 mm in size identified by autofluorescence bronchoscopy-directed biopsy was randomly assigned to receive placebo or budesonide (Pulmicort Turbuhaler) 800 microg twice daily inhalation for 6 months. The primary end point was change in the histopathologic grade on repeat biopsy of the same sites at the end of 6 months.

RESULTS

There were no significant differences in the regression or progression rates of bronchial dysplasia between the two groups. There was a statistically significant but modest decrease in p53 and BclII expression in the bronchial biopsies after 6 months of Pulmicort Turbuhaler versus placebo (P = 0.01 and P = 0.001, respectively). There was a small but statistically significant decrease in the proportion of computed tomography-detected lung nodules after Pulmicort Turbuhaler compared with placebo (P = 0.024).

CONCLUSIONS

Our results suggest that in smokers, inhaled budesonide in the dose of 1600 microg daily for 6 months had no effect in regression of bronchial dysplastic lesions or prevention of new lesions. Budesonide treatment resulted in a modest decrease in p53 and BclII protein expression in bronchial biopsies and a slightly higher rate of resolution of computed tomography-detected lung nodules. Whether budesonide truly has an effect in preneoplastic lesions in the peripheral airways and alveoli requires additional investigation.

Practical issues in autofluorescence bronchoscopy with Storz D Light bronchoscope

Practical aspects of Storz Dlight autofluorescence bronchoscopy are presented from a series of 73 patients. 80 biopsies were taken of which 23 had at least moderate dysplasia, including 8 CIS lesions. Causes of false positive fluorescence abnormalities were suction trauma, overlying mucus, depressions in the leading edge of bronchial spurs, and flexion points of spurs. Positive predictive value of a significant fluorescence abnormality was 56%. The highest yield was in those patients with prior ENT malignancy.

Recent developments in biomarkers for the early detection of lung cancer: perspectives based on publications 2003 to present

PURPOSE OF REVIEW

Given the poor prognosis associated with lung cancer, the ability to diagnose lung cancer in its early stages is considered crucial to achieving decreased lung cancer mortality. Herein, we discuss recent advances in biomarker discovery and evaluation of their potential application in the clinical setting.

RECENT FINDINGS

Novel potential biomarkers have been identified via new techniques including cDNA microarray analysis, comparative genomic hybridization, and proteomics. These factors have been evaluated in various validation studies including tissue microarrays, RT-PCR, and assays of bioactivity. The characterization of these potential biomarkers through analysis of pathways that have been associated with neo-plastic transformation may help to identify the precursor lesions that are associated with subsequent progression to invasive carcinoma. In addition, the past year has also produced intriguing results regarding the detection of biomarkers in easily accessible screening specimens such as sputa, serum, and exhaled breath. Recent advances in these aspects of biomarker identification for the early detection of lung cancer are reviewed.

SUMMARY

Identification of new candidate biomarkers and improved applications of previously detected biomarkers show great promise for the ultimate establishment of practical lung cancer screening. While recent studies engender optimism for the creation of clinically applicable screening tests, the biomarkers that have been identified need larger, follow-up validational studies and further characterization as to their biologic importance.

Key issues in lung cancer chemoprevention trials of new agents

Lung cancer is a major health problem world-wide. Former heavy smokers retain a significant risk for lung cancer after smoking cessation. With a large population of current and former smokers at risk, an alternative cancer control strategy such as chemoprevention needs to be developed to reduce lung cancer mortality especially for smokers who have followed medical advice to give up smoking. Currently, there is no agent that has been shown to be effective in preventing lung cancer. Key issues that need to be addressed in phase II trials of promising chemopreventive agents include selection of high-risk subjects, potential variation in response due to differences in gender and smoking history as well as the choice of surrogate endpoint biomarkers. Sputum biomarkers such as image analysis of sputum cells and detection of aberrant methylation hold promise in identifying those at highest risk for chemopreventive intervention. Autofluorescence bronchoscopy is an effective method to localize dysplastic lesions to evaluate the efficacy of new chemopreventive agents. Novel imaging methods such as confocal micro-endoscopy and spiral CT-directed endoscopic biopsies are under development to evaluate the response of chemopreventive agents on peripheral pre-neoplastic lesions in small airways.

Aberrant methylation of multiple genes in the upper aerodigestive tract epithelium of heavy smokers

An important method for silencing tumor suppressor genes in cancers is by aberrant methylation (referred to as methylation) of CpG islands in gene promoter regions. In lung cancer, methylation of the genes retinoic acid receptor beta-2 (RARbeta-2), CDH13 (H-cadherin), p16(INK4a) (p16), RASSF1A (RAS association domain family I) is frequent. Thus, we investigated methylation of these genes in 4 different types of specimens (oropharyngeal brushes, sputum samples, bronchial brushes and bronchioloalveolar lavage [BAL] samples) of the upper aerodigestive tract epithelium from heavy smokers without evidence of cancer but with morphometric evidence of sputum atypia and compared the frequencies of methylation in the different types of specimens. In addition, we also analyzed sputum samples from 30 never smokers for methylation of these genes. Our major findings are: (i) At least one gene was methylated in one or more specimens from 48% of the smokers. However, methylation was statistically significant less frequently in never smokers compared to smokers. (ii) In general, methylation occurred more frequently in samples from the central airways (sputum, bronchial brushes) compared to the peripheral airways (BAL) and only occasionally in the oropharynx. (iii) RARbeta-2 was the most frequently methylated gene, whereas the frequency of methylation for the other genes was lower. (iv) Data from sputum samples and bronchial brushes were comparable. Our findings suggest that detection of methylation should be investigated as an intermediate marker for lung cancer risk assessment and response to chemopreventive regimens.

Lung cancer screening: a different paradigm

Thoracic computed tomography (CT) is a sensitive method for detecting early lung cancer but has a high false-positive rate and is not sensitive for detecting central preinvasive and microinvasive cancer. Our hypothesis was that automated quantitative image cytometry (AQC) of sputum cells as the first screening method may improve detection rate by identifying individuals at highest risk for lung cancer. A total of 561 volunteer current or former smokers 50 years of age or older, with a smoking history of more than or equal to 30 pack/years, were studied. Among these, 423 were found to have sputum atypia defined as five cells or more with abnormal DNA content using AQC. Noncalcified pulmonary nodules were found in 46% (259/561). Of the 14 detected cancers, 13 were detected in subjects with sputum atypia-nine by CT and four carcinoma in situ/microinvasive cancers by autofluorescence bronchoscopy. One cancer was detected by CT alone. AQC of sputum cells improved the detection rate of lung cancer from 1.8 to 3.1%. CT scan alone would have missed 29% of the cancers. This screening paradigm shift has the additional potential of reducing the number of initial CT scans by at least 25% with further savings in follow-up investigations and treatment.

Women and small cell lung cancer: social characteristics, medical history, management and survival

The literature make it clear that lung cancer in women differs from that in men in several specific aspects. We conducted a retrospective study of the 967 consecutive recorded patients (696 men and 91 women after exclusions) diagnosed with small cell lung cancers (SCLC) between 1981 and 1994 in the Bas-Rhin population-based cancer registry to determine if such particularities could be observed in SCLC. Data included demographic and social characteristics, medical and smoking history, management (diagnosis and treatment), hospitalisation and survival. The end point for survival was 31 December 1998. Women were more frequently single, divorced, or widowed (P=0.007) and lived more often in urban areas (places with more than 10,000 inhabitants) (P=0.017). They differed significantly from men in their tobacco exposure (P=0.0001) and non-smoking rates (P=0.0003) but not in clinical presentation, except for more frequently elevated LDH levels (P=0.02). Bone marrow biopsies were more often performed in men (P=0.004), but management was otherwise comparable. The mean number of hospitalisations (for any reason) was comparable in both sexes but women tended to remain hospitalised longer (P=0.057). Overall survival did not differ, but women older than 70 years died sooner than their male counterparts (P=0.026). Our study confirms that some of gender differences reported in the lung cancer literature exist in SCLC. Sex-related differences in LDH levels have not previously been reported, to our knowledge. North American and European data concerning survival among women and men are discordant. Whether these gender differences are related to a real difference between the sexes or simply to differential exposure to carcinogens remains to be determined.

Smoke exposure, histologic type and geography-related differences in the methylation profiles of non-small cell lung cancer

Aberrant methylation of several known or putative tumor suppressor genes occurs frequently during the pathogenesis of lung cancers. There are major smoke exposure, histology, geography and gender-related changes in non-small cell lung cancer (NSCLC). We investigated smoking-related, histologic, geographic and gender differences in the methylation profiles of resected NSCLCs. We examined 514 cases of NSCLC and 84 corresponding nonmalignant lung tissues from 4 countries (USA, Australia, Japan and Taiwan) for the methylation status of 7 genes known to be frequently methylated in lung cancers [p16, RASSF1A (RAS association domain family 1), APC, RARbeta, CDH13, MGMT and GSTP1]. Multivariate analyses were used for data analysis. Adenocarcinoma was the major histologic type in women and never smokers; analyses that involved smoke exposure and gender were limited to this histology. Our major findings are a) methylation status of any single gene was largely independent of methylation status of other genes; b) the rates of methylation of p16 and APC and the mean Methylation Index (MI), a reflection of the overall methylation status, were significantly higher in ever smokers than in never smokers; c) the mean MI of tumors arising in former smokers was significantly lower than the mean of current smokers; d) the methylation rates of APC, CDH13 and RARbeta were significantly higher in adenocarcinomas than in squamous cell carcinomas; e) methylation rates of MGMT and GSTP1 were significantly higher in the USA and Australian cases than in those from Japan and Taiwan; and (f) no significant gender-related differences in methylation patterns were noted. Our findings demonstrate important smoke exposure, histologic type and geography-related differences in the methylation profiles of NSCLC tumors.

Cigarette smoking, preinvasive bronchial lesions, and autofluorescence bronchoscopy

STUDY OBJECTIVES

Autofluorescence bronchoscopy (AFB), when used as an adjunct to standard white light bronchoscopy (WLB), enhances the bronchoscopist's ability to localize small neoplastic lesions, especially intraepithelial lesions. The current study was undertaken in order to define the population in which the rate of detection is higher using AFB.

DESIGN AND PATIENTS

Two hundred forty-four consecutive patients, who were symptomatic smokers or patients who previously had been treated for lung cancer or head and neck cancers, underwent WLB and AFB. All patients with endoscopic abnormalities underwent biopsies. Data concerning smoking history were prospectively registered.

RESULTS

We report the prevalence of high-grade or invasive lesions at the time of examination. On a lesion-by-lesion analysis, 92 low-grade lesions, 42 high-grade lesions (ie, moderate dysplasia, severe dysplasia, and carcinoma in situ), and 39 invasive carcinomas were diagnosed. There was no effect of age, gender, and age at smoking initiation on the prevalence of preinvasive or invasive lesions. The 10 patients who previously had undergone surgery for lung cancer and exhibited high-grade preinvasive lesions had a history of carcinoma of the epidermoid histologic type (p = 0.01). These 10 patients displayed multiple lesions in the bronchial tree (mean No. of lesions, 1.8 per patient). In current smokers, the prevalence of high-grade or invasive lesions were both related to the number of pack-years smoking had occurred (p = 0.01) and to the duration of smoking (p = 0.01). In contrast, the prevalence of preinvasive lesions in former smokers was related to a history of epidermoid carcinoma.

CONCLUSIONS

AFB should be recommended in patients with a history of epidermoid carcinomas of the lung. Current smokers with a prolonged smoking history appear to comprise a population in which the rate of detection of preneoplastic lesions is high with AFB.

Smoking molecular damage in bronchial epithelium

Our understanding of the molecular pathology of lung cancer is advancing rapidly with several specific genes and chromosomal regions being identified. Lung cancer appears to require many mutations in both dominant and recessive oncogenes to possess malignant phenotypes. Several genetic and epigenetic changes are common to all lung cancer histologic types, while others appear to be cell type specific. However, specific roles of the genes undergoing mutations and the order of cumulative molecular changes that lead to the development of each lung tumor histologic type remain to be fully elucidated. Recent findings of molecular abnormalities in normal appearing and preneoplastic bronchial epithelium from patients with lung cancer and chronic smokers suggest that genetic changes may serve as biomarkers for early diagnosis, risk assessment and monitoring response to chemoprevention.

Innovative molecular and imaging approaches for the detection of lung cancer and its precursor lesions

Current approaches for the therapy of lung cancer, the majority of which being advanced cancers, have failed to impact on long term survival. The key to improvement lies in the combination of early diagnosis and the introduction of novel targeted therapies. In this article we review some of the innovative approaches, both imaging and molecular, that are currently under investigation for early detection. Because lung cancers may arise in the central or peripheral compartments of the lung, newer approaches must target tumours arising in both of these compartments. Specimens available for analysis include sputa and blood. Detection of genetic changes in peripheral blood is a promising avenue being explored by several groups. Molecular techniques discussed include gene mutations, detection of nuclear riboprotein, methylation related silencing of genes and malignancy associated changes. Newer imaging technologies include autofluorescence bronchoscopy, virtual bronchoscopy, optical coherent tomography and confocal microscopy. Although the impact of these new technologies on survival has not been determined, they offer a wide range of exciting new approaches. In time they may completely revamp the present highly conservative and unsuccessful approaches to early diagnosis.

Molecular follow-up of preneoplastic lesions in bronchial epithelium of former Chernobyl clean-up workers

Ionizing radiation is a potent lung carcinogen, but the precise molecular damage associated with it is still unknown. In this study we investigated cancer-related molecular abnormalities including K-ras (codon 12) mutation, p16(INK4A) promoter hypermethylation and microsatellite alterations at seven chromosomal regions in successive biopsies obtained from former Chernobyl cleanup workers in comparison with smokers and nonsmokers who have never had radiation exposure. Our results indicate that prolonged persistence of inhaled radioactive particles is associated with appearance of allelic loss at 3p12, 3p14.2 (FHIT), 3p21, 3p22-24 (hMLH1) and 9p21 (p16INK4A) in bronchial epithelium of former Chernobyl clean-up workers. The prevalence of 3p14.2 allelic loss was associated with decreased expression of the FHIT mRNA in their bronchial epithelium in comparison with control group of smokers. During several years of our monitoring samples of epithelium were collected from the same area of bronchial tree. In epithelium exposed to carcinogens (tobacco smoke and/or radioactivity) the total number of molecular abnormalities was significantly higher in dysplasia and in morphologically normal foci progressed later to dysplasia than in these samples which never showed evidence of such progression. Our findings indicate that extensive cancer-related molecular abnormalities sequentially occur in radiation damaged bronchial epithelium of former Chernobyl clean-up workers.