Genetic analysis of microsomal epoxide hydrolase gene and its association with lung cancer risk

The human microsomal epoxide hydrolase (EH) gene contains polymorphic alleles, which may be linked to increased risk for tobacco-related lung cancer. The purpose of this study is to screen new polymorphisms and determine whether these polymorphisms can be used to predict individual susceptibility to lung cancer. The polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis was used to screen for polymorphisms in the coding region of the EH gene. Eleven polymorphisms, including previously reported polymorphisms, were identified and the prevalence of these variants was assessed in at least 50 healthy Caucasians and African-Americans. Among the 11 polymorphisms, the prevalence of the amino acid-changing EH polymorphisms in codons 43, 113 and 139 was examined in 182 Caucasian incident cases with primary lung cancer, as well as in 365 frequency-matched controls to examine the role of EH polymorphisms in lung cancer risk. A significant increase in lung cancer risk was observed for predicted high EH activity genotypes (odds ratio (OR) 2.3, 95% confidence interval (CI) 1.2-4.3) as compared with low EH activity genotypes. This association was more pronounced among patients with lung adenocarcinoma (OR 4.7, 95% CI 1.7-13.1). These results suggest that the EH polymorphism plays an important role in lung cancer risk and is linked to tobacco smoke exposure.

Moving to the routine management of pre symptomatic lung cancer

Lung cancer is the world's leading cause of cancer death. Since progress in the treatment of this cancer has been exceedingly slow, the upswing in tobacco consumption in many sectors becomes even more tragic. One area for cautious optimism is the recent pilot reports of improved early lung cancer detection using new spiral CT techniques from institutions in Japan and New York. The prospect of improved early detection in a major cancer raises a number of public health concerns and highlights the importance of critical validation of this proposed new tool. From experience with early detection-based management of other cancers, it is evident that the entire process of detection, case validation, intervention, monitoring and public education needs to be carefully developed. The International Association for the Study of Lung Cancer has worked with the National Cancer Institute over the last decade to nurture interest and expertise in conducting population-based management of early lung cancer. A distillation of this process up to the current time is reviewed in this manuscript.

Expression of early lung cancer detection marker: hnRNP-A2/B1 and its relation to microsatellite alteration in non-small cell lung cancer

We have reported that a mouse monoclonal antibody, 703D4, which recognizes heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP-A2/B1) can frequently detect lung cancer in exfoliated sputum epithelial cells 1-2 years earlier than routine chest X-ray or sputum cytomorphology. We along with others have shown that microsatellite alteration (MA) at selected loci can be recognized in sputum cells prior to clinical lung cancer. The present study was undertaken to determine how frequently the expression of hnRNP-A2/B1 message is associated with neoplastic clonal expansion as shown by MA in 41 cases of non-small cell lung cancer (NSCLC). We used Northern blotting to evaluate hnRNP-A2/B1 mRNA expression in lung tumor and remote noninvolved lung. We evaluated microsatellite instability (i.e. shifts; MI) or loss of heterozygosity (LOH) with a panel of 13 microsatellite markers at loci identified previously as susceptible in NSCLC. Of the 41 tumors, 25 (61%) over-expressed hnRNP-A2/B1 and 33 (80%) demonstrated MA in at least one of 13 loci (58% in at least two loci). The association between MA (one locus) and the overexpression of hnRNP-A2/B1 is statistically significant (P=0.0082), and those lung tumors with MA at two or more loci were significantly more likely to over-express hnRNP-A2/B1 mRNA (P=0.004). MA of loci on 3p were the only MA statistically associated with hnRNP-A2/B1 message overexpression (P=0.001). We conclude that lung tumor cells undergoing clonal expansion frequently upregulate hnRNP-A2/B1.

Loss of heterogeneous ribonucleoprotein A(2)/B(1) expression in thyroid neoplasms

OBJECTIVE

To determine whether a difference exists in the immunohistochemical expression of heterogeneous ribonucleoprotein (hnRNP) A(2)/B(1) between benign and malignant thyroid lesions and to assess whether a gradient of expression could be found in normal thyroid, adenomas, and thyroid malignant tumors.

METHODS

Formalin-fixed, paraffin-embedded archival tissues from 32 cases (8 nodular goiters, 8 follicular adenomas, 8 follicular carcinomas, and 8 papillary carcinomas) were immunostained with monoclonal antibody 703D4, directed against hnRNP A(2)/B(1), applied at a concentration of 10 microg/mL. The streptavidin-biotin peroxidase method was used to label bound monoclonal antibody. Positivity was independently scored by two pathologists, who used a three-tiered scale.

RESULTS

The benign thyroid tissues, including the hyperplastic and adenomatous lesions, demonstrated 3+ granular cytoplasmic staining for hnRNP A(2)/B(1), except in two cases (one nodular goiter and one follicular adenoma) in which 2+ staining intensity was noted. In contrast, the papillary and follicular carcinomas failed to stain with the antibody, except in two cases that showed weak (1+) staining.

CONCLUSION

hnRNP A(2)/B(1) immunostaining appears to distinguish benign from malignant thyroid lesions. Loss of hnRNP A(2)/B(1) expression seems to be a characteristic feature of thyroid malignant lesions.

Lung cancer: chemoprevention and intermediate effect markers

Even after smoking cessation, genetic damage in the airways epithelium may lead to focal progression of lung carcinogenesis. Some centres now report as many new lung cancer cases among former smokers as among current smokers. Chemoprevention is a potential approach to diminish the progression of pre-clinical genetic damage. The most intensively studied lung cancer chemoprevention agents are the retinoids, including vitamin A and its synthetic analogues and precursors. While effective in suppressing lung carcinogenesis in animal models, retinoids have failed to inhibit carcinogenesis in human chemoprevention trials with premalignant end-points (sputum atypia, bronchial metaplasia). In trials with lung cancer end-points, administration of retinoids either was ineffective or, in the case of beta-carotene, led to greater lung cancer incidence and mortality. In view of these findings, markers of specific retinoid effect (i.e., levels of RAR-beta) become less relevant. Other markers of genetic instability and proliferation may be useful for both early detection and potentially as intermediate-effect markers for new chemoprevention trials. Cytological atypia, bronchial metaplasia, protein (hnRNP A2/B1) overexpression, ras oncogene activation and tumour-suppressor gene deletion, genomic instability (loss of heterozygosity, microsatellite alterations), abnormal methylation, helical CT detection of atypical adenomatous hyperplasia and fluorescent bronchoscopic detection of angiogenic squamous dysplasia offer great promise for molecular diagnosis of lung cancer far in advance of clinical presentation. These end-points can now be evaluated as monitors of response to chemoprevention as potential intermediate-effect markers.

Polymorphisms of the DNA repair gene XRCC1 and lung cancer risk

We explored the association between polymorphisms of the DNA repair gene XRCC1 (codons 194, 280, and 399) and lung cancer risk in a case-control study nested within a cohort of tin miners. Cases were those diagnosed with lung cancer over 6 years of follow-up (n = 108). Two controls, matched on age and sex, were selected for each case by incidence density sampling. Of the three polymorphisms, only the XRCC1 Arg280His allele was associated with increased lung cancer risk (odds ratio, 1.8; 95% confidence interval, 1.0-3.4) after adjustment for radon and tobacco exposure. In addition, individuals with the variant Arg280His allele who were alcohol drinkers seemed to be at higher risk for lung cancer compared with those with the homozygous wild-type genotype. Conversely, individuals with the variant Arg194Trp allele who were alcohol drinkers seemed to be at lower risk for lung cancer compared with those with the homozygous wild-type genotype. Polymorphisms of XRCC1 appear to influence risk of lung cancer and may modify risk attributable to environmental exposures.

Microsatellite instability at AAAG repeat sequences in respiratory tract cancers

We surveyed the occurrence of novel alleles at microsatellite sequences in non-small cell lung cancers (NSCLC) using 61 tetranucleotide repeat markers. The presence of at least one new allele, consistent with microsatellite instability (MSI), was observed in 26 of 61 (43%) markers involving 30 of 47 (64%) NSCLC. Twelve of the 26 markers detected new alleles in 2 or more tumors and 11 of these 12 markers contained an AAAG repeat sequence. Using this panel of 12 markers, MSI was detected in 24 of 47 (51%) NSCLC and 10 of 18 (56%) head and neck cancers but was only observed in 8 of 38 (21%) bladder cancers and 3 of 25 (12%) kidney cancers. Our results suggested that about 50% of respiratory tract cancers exhibited microsatellite instability predominantly at AAAG sequences. This distinct type of instability was termed EMAST for elevated microsatellite alterations at selected tetranucleotide repeats. The identification of markers with EMAST should have potential application for the molecular detection of respiratory tract cancers.

Considerations in developing successful, population-based molecular screening and prevention of lung cancer

The current mortality rate for lung cancer exceeds 85%, as it has for the last 3 decades. This statistic reflects the utility of the major diagnostic tool that has been used during this period to diagnose lung cancer: the chest X-ray. The overwhelming majority of new cases of lung cancer that are detected with chest X-rays involve individuals who already have regional or distant metastatic disease. Because the systemic treatment of this disease has not improved greatly, patients with metastatic disease rarely are cured. This article reviews the issues involved with the development of sputum-based cellular diagnostics for early stage lung cancer. The biomarker, heterogeneous nuclear ribonucleoprotein A2/B1, is the lead marker for this approach. It has been used in several studies in independent cohorts that have suggested that its overexpression in bronchial epithelial cells is associated highly with the development of lung cancer. This marker is detectable 1 year or more prior to the detection of lung cancer by chest X-ray. Finding this early airway-confined phase of lung cancer may allow for the evolution of new management approaches for very early stage lung cancer. Research activities, such aerosolized chemoprevention, are discussed.

The early detection of occult lung cancer

These sputum tests offer great promise in determining a molecular diagnosis of lung cancer far in advance of clinical presentation. Any or all of these tests could be incorporated into the routine management of individuals at risk for developing primary or second primary lung cancer; however, several issues must be considered before these tests are ready for clinical application. First, test performance characteristics must be confirmed in prospective trials. For several of these tests, those trials are currently underway. Second, management and intervention strategies appropriate to the stage at which lung cancer is diagnosed must be developed. The ability to detect lung cancer at the stage of clonal expansion, well in advance of malignant invasion of the basement membrane, suggests that noninvasive, chemoprevention might be appropriate in such cases. Preliminary studies of chemopreventive agents are now underway at the National Cancer Institute. Several of these agents could be delivered by inhaler to place a maximum dose directly on the transformed epithelium. Clinical trials are needed that evaluate combined diagnostic and therapeutic approaches for their impact on the incidence of clinical lung cancer. Finally, the larger public health issues of cost and accessibility of lung cancer screening must be considered before these advances in sputum and helical CT screening can reach their potential.

Serum carotenoids are associated with increased lung cancer risk among alcohol drinkers, but not among non-drinkers in a cohort of tin miners

To examine the association between pre-diagnostic serum carotenoid levels and lung cancer risk and the effects of alcohol intake on the carotenoid-lung cancer relationship, we conducted a case-control study in an occupational cohort from the Yunnan Tin Corporation in China. During 6 years of follow-up, 339 cases of confirmed lung cancer were diagnosed. Among these cases, those who donated pre-diagnostic blood (n = 108) were eligible for this study. For each case, two individuals alive and free of cancer at the time of case diagnosis, matched on age, sex, and date of blood collection, were selected as controls. Serum beta-carotene (odds ratios (ORs) for tertiles: 1, 1.3, 2.0) and beta-cryptoxanthin (ORs for tertiles: 1, 1.8, 2.9) levels were positively associated with lung cancer risk after adjustment for tobacco use and radon exposure. Among alcohol drinkers, higher serum carotenoid levels were significantly associated with increased lung cancer risk (alpha-carotene OR 2.2, 95% confidence interval (CI) 1.1-4.4, beta-carotene OR 7.6, 95% CI 3.1-18.6, lutein/zeaxanthin OR 2.3, 95% CI 1.2-6.6 and beta-cryptoxanthin OR 7.6, 95% CI 2.7-21.5). Conversely, risk estimates among non-drinkers suggest a possible protective association for higher carotenoid levels.

Serum tocopherols, selenium and lung cancer risk among tin miners in China

OBJECTIVE

To evaluate the association of prediagnostic serum antioxidants and lung cancer risk we conducted a case-control study nested in an occupational cohort of tin miners.

METHODS

Male workers free of cancer enrolled in the cohort. During up to 6 years of follow-up, 339 lung cancer cases were diagnosed and, among these cases, those who donated blood prospectively (n = 108) were eligible for this study. For each case, two controls alive and free of cancer at the time of case diagnosis were matched on age and date of blood collection.

RESULTS

Overall, we observed no association between serum alpha-tocopherol, gamma-tocopherol or selenium levels and lung cancer risk. However, a significant gradient of decreasing lung cancer risk with increasing serum alpha-tocopherol was apparent for men less than 60 years old (odds ratio by tertile: 1.0, 0.9, 0.2; trend p = 0.002). Alpha-tocopherol was also protective in men who reported no alcohol drinking (OR by tertile: 1.0, 0.6, 0.3; trend p = 0.008).

CONCLUSION

Although there were no significant overall associations between prospectively collected serum alpha-tocopherol, gamma-tocopherol or selenium and incidence of lung cancer, results from this study suggest that higher alpha-tocopherol levels may be protective in men less than 60 years old and in those who do not drink alcohol.

Advances in sputum analysis for screening and early detection of lung cancer

BACKGROUND

Screening for lung cancer using currently available techniques is not effective in reducing mortality from the disease.

METHODS

Archived sputum specimens and clinical data linking specimens to lung cancer outcomes from prior screening programs have been reexamined to evaluate altered gene expressing, including specific oncogene activation and tumor suppressor gene deletion, as well as genomic instability and abnormal methylation.

RESULTS

Several of these tests allow determination of a molecular diagnosis of cancer years before clinical presentation.

CONCLUSIONS

These sputum tests provide an impetus to reconsider screening for lung cancer. Prospective trials are required to confirm test performance characteristics, and management and intervention strategies must be developed that are appropriate to the stage at which lung cancer is diagnosed.

Efficacy of two sputum collection techniques in patients with air flow obstruction

OBJECTIVE

To compare the efficacy of two sputum collection techniques in patients with chronic obstructive pulmonary disease (COPD) in order to diagnose dysplasia or neoplasia.

STUDY DESIGN

This was a crossover study design comparing induced sputum with sputum collected at home. One hundred seven patients with COPD were enrolled. Fifty-six were randomized to collect induced sputum first followed by sputum collection at home. Fifty-one randomly assigned patients collected the sputum in reverse order.

RESULTS

The second sputum collection technique for both random assignments gave the greatest yield of adequate sputum. There was no significant difference in efficacy between the collection of the two sputum collection techniques in the presence of the learning (period) effect.

CONCLUSION

Sputum collection is equally efficacious by the induced method and the home collection method. A learning effect was responsible for the increased yield of sputum abnormalities in the second collection session. Sputum collection at home may facilitate the amount of dysplasic and neoplastic bronchial epithelial changes in heavy smokers with COPD.

Docosahexaenoic acid and smoking-related chronic obstructive pulmonary disease. The Atherosclerosis Risk in Communities Study Investigators

If the inflammatory response to inhalation of cigarette smoke causes chronic obstructive pulmonary disease (COPD), suppression of that natural response might be beneficial. We hypothesized that a smoker's risk of developing COPD is inversely related to physiologic levels of two fatty acids that have antiinflammatory properties: eicosapentaenoic acid (EPA, C20:5) and docosahexaenoic acid (DHA, C22:6). The proportion of each fatty acid in plasma lipids was measured in 2,349 current or former smokers. COPD was identified and defined by clinical symptoms and/or spirometry. After adjustment for smoking exposure and other possible confounders, the prevalence odds of COPD were inversely related to the DHA (but not to the EPA) content of plasma lipid components in most of the models. For example, as compared with the first quartile of the DHA distribution, the prevalence odds ratios (ORs) for chronic bronchitis were 0.98, 0.88, and 0.69 for the second, third, and fourth quartiles, respectively (p for linear trend = 0.09). The corresponding ORs for COPD as defined spirometrically, were 0.65, 0.51, and 0.48 (p < 0. 001). Among 543 current heavy smokers, adjusted mean values of FEV1 (lowest to highest DHA quartile) were 2,706, 2,785, 2,801, and 2,854 ml. DHA may have a role in preventing or treating COPD and other chronic inflammatory conditions of the lung. Pilot testing of that hypothesis in experimental models seems warranted.

Demographic and anthropometric correlates of maximum inspiratory pressure: The Atherosclerosis Risk in Communities Study

Maximum inspiratory pressure (MIP), an indicator of inspiratory muscle strength, is reported on 13,005 African-American and white participants from the Atherosclerosis Risk in Communities Study. Sex-specific associations between MIP and age, anthropometric measures, physical activity, health status, smoking status, and education level are presented. In this cohort of subjects 47 to 68 yr of age, MIP decreased 0.93 cm H2O (p </= 0.0001) in women and 1.2 cm H2O (p </= 0.0001) in men for each 1-yr increase in age. In both sexes, after adjusting for age, the associations between MIP and current body weight, weight at 25 yr of age, waist girth, body mass index, and calf girth were statistically significant and nonlinear (convex quadratic). MIP was positively associated with standing height in both sexes after controlling for age (p </= 0.03). The age-adjusted association between MIP and sitting height was nonlinear in men and linear in women. MIP was also associated (positively) with education level, health status, physical activity, and (negatively) cigarette smoking. The study was not designed to evaluate associations with race, but data patterns suggest the absence of a race effect on MIP.

Prospective detection of preclinical lung cancer: results from two studies of heterogeneous nuclear ribonucleoprotein A2/B1 overexpression

The United States lung cancer epidemic has not yet been controlled by present prevention and treatment strategies. Overexpression of a Mr 31,000 protein, heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1, had shown promise as a marker of lung cancer. In a pilot study of archived preneoplastic sputum specimens, hnRNP A2/B1 overexpression more accurately detected preclinical lung cancer than standard cytomorphology. In separate, ongoing prospective studies, sputum is collected annually from stage I resected non-small cell lung cancer patients at high risk of developing a second primary lung cancer and Yunnan tin miners at high risk of primary lung cancer. After the first year of follow-up, preclinical detection of lung cancer by routine cytology was compared with hnRNP A2/B1 overexpression as measured by quantitative densitometry of immunostained slides. Up-regulation of hnRNP A2/B1 in sputum specimens accurately predicted the outcome in 32 of 40 primary lung cancer and control patients within 12 months, whereas cytological change suggestive of lung cancer was found in only 1 patient. In the primary lung cancer study, overexpressed hnRNP A2/B1 accurately predicted the outcome in 69 of 94 primary lung cancer and control miners, whereas only 10 with primary lung cancer were diagnosed cytologically. These two prospective studies accurately predicted that 67 and 69% of those with hnRNP A2/B1 up-regulation in their sputum would develop lung cancer in the first year of follow-up, compared with background lung cancer risks of 2.2 and 0.9% (35- and 76-fold increase, respectively). Using sputum cells to monitor hnRNP A2/B1 expression may greatly improve the accuracy of preclinical lung cancer detection.

Risk factors and early detection of lung cancer in a cohort of Chinese tin miners

PURPOSE

To examine risk factors and establish a biologic specimen and data bank for the study of early markers of lung cancer.

METHODS

We designed a dynamic cohort using an ongoing lung cancer screening program among radon- and arsenic-exposed tin miners in Yunnan China. Through the first four years of the study, 8,346 miners aged 40 years and older with over 10 years of occupational exposure have been enrolled, risk factors have been assessed, annual sputum and chest radiographs have been obtained, and numerous biologic specimens have been collected.

RESULTS

A total of 243 new lung cancer cases have been identified through 1995. Radon and arsenic exposures are the predominant risk factors, but lung cancer risk is also associated with chronic bronchitis and silicosis, as well as a number of exposure to tobacco smoke, including early age of first use, duration, and cumulative exposure. Tumor and sputum samples are being examined for early markers of lung cancer.

CONCLUSION

A cohort of occupationally-exposed tin miners with an extensive biologic specimen repository has been successfully established to simultaneously study the etiology and early detection of lung cancer.

A case-cohort study of an early biomarker of lung cancer in a screening cohort of Yunnan tin miners in China

We initiated the present study to evaluate the accuracy of a new epithelial biomarker of early lung cancer. We tested the hypothesis that expression of a tumor-associated antigen by exfoliated sputum epithelial cells has greater accuracy (sensitivity and specificity) for the detection of preclinical, localized lung cancer than do routine clinical detection methods. Monoclonal antibody (MAb) 703D4 recognizes heterogeneous nuclear ribonuclear protein (hnRNP) A2/B1. We compared the accuracy of hnRNP up-regulation with cytology and radiographic screening for lung cancer detection in miners who were highly exposed to tobacco smoke, radon, and arsenic in southwestern China. The results showed that MAb 703D4 detection of hnRNP expression by sputum epithelial cells had greater accuracy for the detection of lung cancer than did routine screening methods, particularly for early (localized) disease. Among 57 cases and 76 noncases at the first screening, overall MAb detection of hnRNP was more sensitive (74 versus 21% for cytology and 42% for chest x-ray) but had lower specificity (70 versus 100% for cytology and 90% for chest x-ray) than standard methods. Recognizing hnRNP up-regulation resulted in detection of approximately one-third more early cases than did the combination of X-ray and cytology. Detection of hnRNP A2/B1 expression appears to be a good initial screening test for lung carcinogenesis, as it identified 74% of those who developed subsequent clinical lung cancer. Future studies might separate individuals with high lung cancer risk by MAb detection, confirming the positives with markers having greater specificity (e.g., clinical studies that become positive later in the morphological progression).

New approaches to the integrated management of early lung cancer

We have briefly surveyed some the developments in the field of molecular diagnostics that provide a basis for cautious optimism about progress in population-based early lung cancer screening. The sound lung cancer management strategies that were formulated several decades ago failed in clinical trials because the necessary tools to implement the strategies were not yet available. Technology is beginning to emerge that makes population-based screening achievable. This same technology may be used to define a comprehensive marker panel including the most informative markers from the long list of candidate markers. Validation studies will define more clearly the strengths and limitations of new molecular diagnostics and provide leads for further research attention. The clinical community can expedite this process if these validation efforts are aggressively pursued. Parallel developments are clearly needed in refining the range of therapeutic intervention for early cancer management. The success of both diagnostic and intervention tools is interwoven in the ultimate goal of reducing lung cancer mortality. This article is an invitation to think expansively about new approaches to cancer care that integrate the fruits of our hard-learned lessons.

High frequency of K-ras codon 12 mutations in bronchoalveolar lavage fluid of patients at high risk for second primary lung cancer

A high frequency of K-ras mutations may indicate preneoplastic changes in the bronchial epithelium as a result of genotoxic injury. With the use of sensitive detection techniques, we report a higher prevalence of K-ras mutations in bronchoalveolar lavage than has been reported previously for lung cancer. A PCR/ligase chain reaction technique was used to determine K-ras codon 12 mutations in a group of 52 bronchoalveolar lavage specimens from patients at risk of a second lung cancer. Of the specimens examined, 84% contained at least one mutation in K-ras codon 12, corroborated by an allele-specific hybridization method. These results suggest that point mutations in K-ras codon 12 are widespread in the bronchial epithelium. Based on these preliminary findings, further evaluation of this efficient sensitive assay to monitor K-ras status should be conducted in larger clinical cohorts where clinical outcomes will ultimately be available. Such a trial will define the utility of K-ras codon 12 mutation status as a marker of lung cancer.

Clinical detection of lung cancer progression markers

Lung cancer is the leading cause of cancer-related deaths in western countries. The prognosis for patients with lung cancer depends primarily on the stage of the tumor at the time of clinical diagnosis. New understanding of tumor biology has turned attention away from detection of clinical lung cancer, usually metastatic at presentation, toward recognition of genetic and protein markers which precede malignancy. Mutations of four types of genes contribute to the process of epithelial carcinogenesis by modifying control of cell growth. Examples of three of these changes have been detected in pre-malignant sputum, and validated in subsequent tumor. We have identified gene products (tumor associated and differentiation protein antigens), mutations of k-ras and p53, and microsatellite alterations as potential markers of subsequent malignancy. We consider the morphologic progression seen in archived sputum cells as the paradigm of neoplastic development in the lung. Although the NCl collaborative trials had shown that this progression is not recognized sufficiently often (sensitive) to be useful for lung cancer screening, this progression may be used to assess the timing of gene and peptide markers of carcinogenesis. Previous work has shown that at the time Johns Hopkins Lung Project sputum cells express moderately atypical metaplasia, 53% (8/15) of sputum specimens expressed common (codon 12) k-ras or (codons 273 or 281) p53 mutations. Other investigators have reported that earlier morphologic changes (metaplasia) accompany 3p and 9p losses of heterozygosity. These observations suggest that 3p and 9p loss likely precede k-ras or p53 mutations. Our preliminary data demonstrate that over-expression of a 31 kD tumor associated antigen recently purified, sequenced, and identified as heterogeneous nuclear ribonucleoprotein (hnRNP) A2 (with cross reactivity to splice variant B1), is expressed in most lung cancer cases before any morphologic abnormality. Comparison of the accuracy of this marker with sputum cytology will determine its value for early lung cancer detection. Preliminary evidence confirms this marker greatly improves the accuracy of standard sputum cytology for detection of lung carcinogenesis. Clinical intervention trials must be undertaken to determine whether modulation of hnRNP overexpression is useful as an intermediate endpoint for chemoprevention.

Safe separation of sputum cells from mucoid glycoprotein

OBJECTIVE

To compare the safety and efficacy of homogenizing sputum with deoxyribonuclease I (DNAse I), dithiothreitol (DTT), N-acetyl-L-cysteine, sodium EDTA and trypsin against standard mechanical blending to provide mucus-free, single-cell suspensions for quantitative analysis.

STUDY DESIGN

Clinical sputum specimens or cultured human bronchogenic carcinoma cells were preserved in 2% polyethylene glycol/50% ethanol, divided into aliquots, counted and stained (Papanicolaou and avidin-biotin complex immunostained) at baseline. Cells of each aliquot were separated from mucus by the standard physical blending method or by chemical or enzymatic mucus liquefaction. After staining, washing and resuspending in the original volume of polyethylene glycol/ethanol mixture, aliquots were again counted and stained.

RESULTS

Cell counts, Papanicolaou staining and immunostaining showed that homogenization of induced, preserved sputum with 0.5 mM DTT is safe and provides mucus-free monolayers for immunocytochemistry and single-cell suspensions for flow cytometry. Mucolysis with 0.5 mM DTT resulted in a significant (16%) increase in cells available. In contrast, mechanical blending resulted in up to a 24% reduction in specimen cellularity.

CONCLUSION

Homogenization with low-concentration DTT will probably facilitate the exploration of sputum for protein and gene markers of carcino genesis.

Rapid decline in FEV1. A new risk factor for coronary heart disease mortality

Coronary heart disease (CHD) is the leading cause of mortality in the United States. The present cohort study was conducted to determine whether rate of FEV1 loss independently predicts CHD mortality in apparently healthy men. White male Baltimore Longitudinal Study of Aging (BLSA) participants without CHD underwent clinical evaluation at 2-yr intervals; 883 had satisfactory pulmonary and lipid studies and returned for a least one visit. Cases were BLSA subjects without CHD on entry who died a "coronary death" (death from acute myocardial infarction, sudden death, or congestive heart failure in the presence of coronary artery disease). Forced expiratory maneuvers followed American Thoracic Society guidelines. Serum cholesterol, blood pressure, cigarette smoking, and body mass index were obtained from the BLSA database. There were 79 CHD deaths and 804 survivors during an average follow-up of 17.4 yr. After adjustment for age, initial FEV1% predicted, smoking status, hypertension, and cholesterol, a time-dependent proportional hazards model showed that cardiac mortality, but not all causes of mortality, generally increased with increasing quintile of FEV1 decline for the entire cohort (relative risk [RR] 2.92-5.13) and separately for the subset of never-smokers. Thus, excess CHD mortality follows a large decline in FEV1, independent of the initial FEV1% predicted, cigarette smoking, and other common CHD risk factors.

The early detection of second primary lung cancers by sputum immunostaining. LCEWDG Investigators. Lung Cancer Early Detection Group

STUDY OBJECTIVE

To determine whether monoclonal antibody (Mab) detection of tumor-associated antigen expressed on sputum epithelial cells precedes clinical presentation of second primary lung cancer. DESIGN SETTING/PARTICIPANTS: Eleven oncology centers collaborate in the accrual of 1,000 patients with stage I non-small cell lung cancer (NSCLC) who had undergone resection. The Mabs examined in this study (624H12, 703D4) detect two promising oncofetal/differentiation markers (ie, a difucosylated Lewis X and a 31-Kd glycoprotein antigen).

INTERVENTIONS

Induced sputum specimens are evaluated for quality, then are Papanicolaou and immunostained by independent central laboratories at enrollment and annually thereafter. The predictive value of Mab markers is compared with routine morphologic study for detection of second primary lung cancer during an anticipated 3 years of accrual and 1 year of follow-up.

MEASUREMENTS AND RESULTS

Five hundred eighty of an anticipated 1,000 patients have been accrued on schedule. Patients are primarily white (88.6%), former smokers (75.9%), men (55.6%), with a median age of 66.7, and joined the study at an average of 3.7 years following resection of a stage 1 NSCLC (34.4% squamous, 43.6% adenocarcinoma). Central laboratories found less dysplasia and more unsatisfactory specimens (27.3%) than do the accrual institution laboratories. Immunostaining identifies more suspicious cells than does morphologic study. However, only two second primary lung cancers (eight total deaths) have occurred to date.

CONCLUSIONS

Halfway through the accrual, we describe the study design and preliminary observations. This study illustrates rational selection of carcinogenesis markers by linkage of marker expression on preneoplastic specimens with subsequent expression on tumor tissue.

Microsatellite alterations as clonal markers for the detection of human cancer

Microsatellite instability has been reported to be an important feature of tumors from hereditary nonpolyposis colorectal carcinoma (HNPCC) patients. The recent discovery of genetic instability in small cell lung carcinoma, a neoplasm not associated with HNPCC, led us to investigate the possible presence of microsatellite alterations in other tumor types. We examined 52 microsatellite repeat sequences in the DNA of normal and tumor pairs from 100 head and neck, bladder, and lung cancer patients by the polymerase chain reaction. Although alterations were rare in dinucleotide repeats, larger (tri- or tetranucleotide) repeats were found to be more prone to expansion or deletion. We screened 100 tumors with a panel of nine tri- and tetranucleotide repeat markers and identified 26 (26%) that displayed alterations in at least one locus. This observation prompted us to examine the possibility of using microsatellite alterations as markers to detect clonal tumor-derived cell populations in pathologic samples. The identical microsatellite alterations detected in the primary tumors were successfully identified in corresponding urine, sputum, and surgical margins from affected patients. This study demonstrates that appropriately selected microsatellite loci are commonly altered in many cancers and can serve as clonal markers for their detection.

Does dietary vitamin A protect against airway obstruction? The Atherosclerosis Risk in Communities (ARIC) Study Investigators

A recent report based on data from the first National Health and Nutrition Examination Survey suggested that low intake of vitamin A may be associated with a greater risk of airway obstruction. We attempted to replicate these findings in a population-based sample of middle-aged adults (n = 15,743) who participated in the baseline examination of the Atherosclerosis Risk in Communities (ARIC) Study. Vitamin A intake was estimated from a 66-item food frequency questionnaire, and the presence of airway obstruction was determined by spirometry. Although airway obstruction was associated in ARIC with well-established risk factors such as age, sex, and smoking, there was little evidence for a role of vitamin A. With only one exception, vitamin A intake was unrelated to airway obstruction in all smoking categories using either categorical or continuous measures of lung function (FEV1, FVC, FEV1/FVC). Only among current smokers in the upper tertile of lifetime cigarette smoking (> 41 pack-years) was the odds ratio of having airway obstruction for the lowest quartile of vitamin A intake compared with the highest quartile elevated (1.7 [95% confidence interval 1.1 to 2.7]). Despite some biological plausibility that vitamin A intake may prevent obstructive lung disease, the inability to demonstrate association in a larger population study, with better estimation of usual dietary intake, casts doubt on the existence of causal relationship.

Dietary n-3 polyunsaturated fatty acids and smoking-related chronic obstructive pulmonary disease. Atherosclerosis Risk in Communities Study Investigators

BACKGROUND

Fish contain n-3 polyunsaturated fatty acids, principally eicosapentaenoic acid and docosahexaenoic acid, which are known to interfere with the body's inflammatory response and may be of benefit in chronic inflammatory conditions.

METHODS

We studied the relation between the dietary intake of n-3 fatty acids and chronic obstructive pulmonary disease (COPD) in 8960 current or former smokers participating in a population-based study of atherosclerosis. Intake of fatty acids was estimated with a dietary questionnaire. The presence of COPD was assessed by a questionnaire on respiratory symptoms and by spirometry. Three case definitions of COPD were used: symptoms of chronic bronchitis (667 subjects), physician-diagnosed emphysema reported by the subject (185 subjects), and spirometrically detected COPD (197 subjects).

RESULTS

After control for pack-years of smoking, age, sex, race, height, weight, energy intake, and educational level, the combined intake of eicosapentaenoic acid and docosahexaenoic acid was inversely related to the risk of COPD in a quantity-dependent fashion. The adjusted odds ratio for the highest quartile of intake as compared with the lowest quartile was 0.66 for chronic bronchitis (95 percent confidence interval, 0.52 to 0.85; P < 0.001 for linear trend across the range of intake values), 0.31 for physician-diagnosed emphysema (95 percent confidence interval, 0.18 to 0.52; P for linear trend, 0.003), and 0.50 for spirometrically detected COPD (95 percent confidence interval, 0.32 to 0.79; P for linear trend, 0.007).

CONCLUSIONS

A high dietary intake of n-3 fatty acids may protect cigarette smokers against COPD.

Cytometric validation of immunocytochemical observations in developing lung cancer

Video-enhanced optical microscopy objectively confirms that immunocytochemical biomarker supplementation of routine cytology permits separation of (1) "pre"-cancer epithelial cells from JHLP screened individuals who subsequently developed lung cancer from (2) similarly atypical epithelial cells from JHLP participants who did not. The establishment of a bank of sputum cytology specimens along with a data respository of 5-yr follow-up and clinical outcome had permitted banked specimens to be immunostained and scored against a gold standard of subsequent histologic lung cancer. A highly skilled cytopathologist, interpreting immunostained screening sputum specimens and blinded to the clinical outcome, originally was able to correctly predict clinical outcome with 88.7% accuracy compared to this "gold standard" (Tockman et al., J Clin Oncol 1988;6:1685-1693). This study presents an independent confirmation of that earlier immunocytochemical classification through feature extraction of digitally recorded, transmission optical microscope video images of immunostained, moderately atypical sputum cells from the original slides.

Effects of smoking and occupational exposures on pulmonary function impairment in Italian shipyard workers

We examined the association of job title and duration of employment with the smoking-adjusted prevalences of chronic bronchitis, obstruction, restriction, and mixed pulmonary function impairment in 657 white male shipyard workers aged 20 to 60 years. Logistic regression was used to compute odds ratios (OR) and confidence intervals (CI) for risk of chronic bronchitis and pulmonary function impairment. Compared to employment for less than 20 years, employment for more than 20 years was independently associated with chronic bronchitis (OR = 2.0; 95% CI: 1.2-3.5), restriction (OR = 2.6; CI: 1.4-4.6), and mixed impairment (OR = 2.5; 95% CI: 1.1-5.5). Compared to metal-workers, which was the lowest exposure job category, four job categories were independently associated with restriction: gas welders (OR = 3.6; 95% CI: 1.5-8.9), arc welders (OR = 4.1; 95% CI: 1.5-11.4), masons (OR = 6.2; 95% CI: 1.0-39.0), and insulators (OR = 8.0; 95% CI: 1.8-35.2). These results suggest that exposure to pulmonary toxic agents in the shipyard environment can lead to both parenchymal inflammation (restriction) and airways inflammation (obstruction).

Biomarkers of carcinogen exposure and cancer risk in a coke plant

To evaluate the association between an indicator of carcinogen exposure (peripheral blood leukocyte DNA adducts of polycyclic aromatic hydrocarbons) and an early indicator of neoplastic transformation (sputum epithelial cell membrane antigens binding by monoclonal antibodies against small cell lung cancer and against nonsmall cell lung cancer), a survey of 350 coke-oven workers and 100 unexposed workers was planned. This paper reports a pilot investigation on a subgroup of 23 coke-oven workers and 8 unexposed controls. A "gas regulator" worker with positive tumor antigen binding was identified. Results show that smokers, subjects with decreased pulmonary function (forced expiratory volume in 1 sec/forced vital capacity% < 80), and those with morphological dysplasia of sputum cells have higher levels of DNA adducts. The gas regulators showed the highest values for adducts; however, no significant difference of adduct levels was found between the coke-oven group and unexposed controls.

Considerations in bringing a cancer biomarker to clinical application

Specific challenges face our application of emerging biomarkers to early lung cancer detection. These challenges might be considered frontiers to be bridged between established biomedical disciplines, requiring expertise often beyond the range of individual investigators. Cross-disciplinary research already has led to new appreciation of the mechanisms which underlie the phenotypic expression of the transformed cell and places within our grasp the tools which might lead to successful early lung cancer detection. Prior to the successful application of newly described markers, further cross-disciplinary research must (a) refine the selection of biologically appropriate markers, (b) validate such markers against acknowledged disease end points, (c) establish quantitative criteria for marker presence/absence, and (d) confirm marker predictive value in prospective population trials.

Pulmonary function and respiratory symptoms in wildland firefighters

We studied cross-seasonal changes in pulmonary function and respiratory symptoms in 52 wildland firefighters in Northern California. The mean cross-seasonal change in forced expiratory volume in 1 second (FEV1) was -1.2% (95% confidence interval [CI] -0.5%, -2.0%) with a corresponding mean change in forced expiratory volume (FVC) of -0.3% (95% CI 0.4%, -1.0%). Decreases in FEV1 and FVC were most strongly associated with hours of recent fire-fighting activity (P = .002 and .01, respectively). When the study group was divided into three categories based on recent fire-fighting activity, firefighters in the high activity category (mean +/- SE, 73 +/- 7 hours of fire-fighting in previous week) had a -2.9% (130 mL) change in FEV1 and a -1.9% (102 mL) change in forced vital capacity (FVC). There was a significant cross-seasonal increase in most respiratory symptoms evaluated. Several symptoms (eye irritation, nose irritation, and wheezing) were associated with recent fire-fighting. These findings suggest that wildland firefighters experience a small cross-seasonal decline in pulmonary function and an increase in several respiratory symptoms. Research is under way to identify the fire conditions and specific components of exposure that produce pulmonary irritants, and to examine the potential reversibility of acute pulmonary change.

Serum retinol and airway obstruction

The relation of serum retinol and carotenoids to airway obstruction was investigated in a population-based study. Respiratory symptoms and the pulmonary function of 83 white males were assessed in 1979 5 years after their blood had been drawn. Airway obstruction in 1979, defined as a forced expiratory volume in 1 second which was equal to or less than 75% of the forced vital capacity, was associated with a decreased 1974 level of serum retinol.

Biological monitoring of fire fighters: sister chromatid exchange and polycyclic aromatic hydrocarbon-DNA adducts in peripheral blood cells

Fire fighters are exposed to potentially carcinogenic combustion and pyrolysis products during the course of their work. The present study was designed to test 43 fire fighters and matched controls for DNA damage which might be related to occupational carcinogen exposures. Using peripheral blood lymphocytes, we examined (a) baseline sister chromatid exchange (SCE) frequency and (b) SCE induction by in vitro mutagenic challenge with mitomycin C. Using nucleated peripheral blood cells, we examined (c) polycyclic aromatic hydrocarbon-DNA adduct levels by assessing benzo(a)pyrene diol epoxide (BPDE)-DNA antigenicity. Exposures were determined from histories of fire-fighting activity. The presence of confounding factors (e.g., tobacco smoking, charcoal-broiled food consumption, etc.) was determined by questionnaire. Plasma cotinine levels were measured to assess recent exposures to tobacco smoke. White fire fighters exhibited a significantly higher risk for the presence of detectable BPDE-DNA antigenicity than white controls (odds ratio, 3.4; 95% confidence interval, 1.08-10.5 after adjustment). Consumption of charcoal-broiled food less than 3 times a month was associated with a smaller proportion of individuals exhibiting measurable (positive) BPDE-DNA antigenicity, while consumption of broiled food greater than 3 times a month did not affect the proportion of positive individuals. Daily alcohol consumption was associated with a larger proportion of individuals exhibiting positive BPDE-DNA antigenicity, (P = 0.07). Tobacco smoking and charcoal-broiled food consumption, but not fire fighting, were associated with increased levels of baseline SCE. Sensitivity to SCE induced by mitomycin C in cultured peripheral lymphocytes was similar in fire fighter and control groups. However, sensitivity of individual fire fighters to mitomycin C-induced SCE was correlated with number of fires fought in the previous 24 h.

Respiratory risk factors and mortality: longitudinal studies in Washington County, Maryland

Risk factors for temporal changes in chronic respiratory disease mortality were evaluated from two studies conducted in Washington County, Maryland. The first examined the mortality of a private census population (greater than 35,000 whites) enumerated in 1963 over two subsequent time periods by age, sex, and initial smoking status. The second examined the 10-yr mortality of a subset of the 1963 census (884 men who had undergone spirometry). We observed a fall in age-adjusted mortality from all causes and from arteriosclerotic heart disease (ASHD), but an increase in COPD mortality. However, the increase in these chronic pulmonary deaths is essentially confined to persons who were smoking cigarettes at the beginning of the study period. Furthermore, while smokers showed an increased mortality risk for all causes, the excess mortality risk did not fall uniformly across cigarette smokers. It is a major observation of this study that all-cause and cardiovascular (as well as pulmonary) mortality are significantly more often found among subjects with ventilatory impairment (independent of smoking status). Reasons for the association of ASHD mortality with impaired forced expiration are discussed. Thus, men at increased risk for three (ASHD, lung cancer, COPD) of the five leading causes of death (three of eight for women) may be identified by spirometry. Perhaps it is time that this test was more generally applied.

Sex and race differences in the development of lung function

The second National Health and Nutrition Examination Survey (1976 to 1980) provided spirometric examinations for a nationwide sample of individuals 6 to 24 yr of age. We analyzed spirometric data on 1,963 healthy, nonsmoking blacks and whites to examine sex and race differences in FVC, FEV1, FEV3, PEF, Vmax50, Vmax75, and mid-maximal expiratory flow (MMEF). The population was divided into three age groups: children (6 to 11), teens (males 12 to 20, females 12 to 17), and young adults (males 21 to 24, females 18 to 24). Controlling for sex, age, standing height, and body mass index, blacks had consistently lower levels of lung function for most measures. The inclusion of sitting height explained part of this reduction. Controlling for lung size using FVC as a surrogate, the performance of blacks on other spirometry measures was equal to whites in all age groups. Males tended to outperform females with the same anthropometric characteristics before the inclusion of FVC as a predictor variable. However, after controlling for lung size (FVC), female performance exceeded that of males. The higher female performance is particularly noticeable in the later flow measures. Both anatomic and physiologic factors may account for these findings.

Analysis of spirometric data from a national sample of healthy 6- to 24-year-olds (NHANES II)

The second National Health and Nutrition Examination Survey (NHANES II) incorporated spirometric examinations for a nationwide sample of individuals 6 to 24 yr of age. We analyzed spirometric data on 1,963 healthy, nonsmoking black and white subjects to derive prediction equations for FVC, FEV1, FEV3, PEF, Vmax50, Vmax75, and MMEF. The population was divided into three groups: children (6 to 11 yr of age); teens (males 12 to 20, females 12 to 17 yr of age); and young adults (males 21 to 24, females 18 to 24 yr of age). Using regression analysis, standing height appeared to be the most important predictor of pulmonary function across the entire age group, with the importance of the age variable decreasing in older ages. Controlling for other variables, blacks exhibited consistently lower respiratory function for most measures. This difference increased with age. Male FVC exceeded female FVC after 8 to 9 yr of age; however, female MMEF and Vmax50 performance equaled or exceeded males until approximately 13 yr of age. Males tended to outperform females with the same anthropometric characteristics in all age groups, except in the height range of 130 to 160 cm, where female flows and volumes were superior. Percentile growth curves were also developed to track lung development in clinical practice.

Sensitive and specific monoclonal antibody recognition of human lung cancer antigen on preserved sputum cells: a new approach to early lung cancer detection

Murine monoclonal antibodies (Mabs) to a glycolipid antigen of small-cell (SCC) and a protein antigen of non-small-cell lung cancer (NSCC) were applied to preserved sputum specimens from individuals who participated in The Johns Hopkins Lung Project (JHLP). In that study, undertaken in 1973 to evaluate the efficacy of sputum cytology screening, half of the high-risk participants (5,226 men, greater than or equal to 45 years of age, currently smoking greater than or equal to 1 pack of cigarettes per day) were randomly assigned to produce specimens for cytopathological analysis. During regular screenings over the next 5 to 8 years, 626 (12%) showed moderate (or greater) atypia. Sixty-nine of these (26 who progressed to cancer, 43 who did not) were randomly selected for a blinded improved Mab immunostaining protocol in the present study. Satisfactory specimens with morphologic atypia immunostained positively in 14 of the 22 patients who eventually progressed to cancer (sensitivity 64%), and were nonreactive in 35 of the 40 patients who did not progress to lung cancer (specificity 88%). Review of the true positive specimens (14/22 atypias) showed that they were collected 24 months in advance of diagnosis. In contrast, the 8/22 false negative atypias (failure to stain) showed that they were collected for an average of 57 months preceding the diagnosis of cancer. Subsequent specimens (average, 26 months before cancer) from participants who were originally considered "false negative" did stain positively improving sensitivity to 91% among specimens collected for an average of 2 years in advance of the clinical appearance of lung cancer. Specificity remained at 88%. Recognition of neoplastic antigen expression 2 years in advance of clinical cancer may be a valuable intermediate end point in studies of lung cancer prevention, detection, and therapy.

Smoking, leukocyte count, and ventilatory lung function in working men

Results of a cross-sectional study of ventilatory lung function (VLF) in a group of 307 working men showed that the leukocyte count in peripheral blood is more closely associated with the relative position (percentile) of a person in the frequency distribution of VLF than is smoking intensity. Leukocyte count is significantly (and inversely) correlated with VLF in nonsmokers as well as in smokers. A multiple regression analysis indicated that, after accounting for the effect of height and age, white blood cell (WBC) count explains more of the VLF variance than many other health determinants. Moreover, WBC count is the only variable, apart from height and age, that contributes significantly to the regression. Current smokers with elevated leukocyte count in peripheral blood may constitute a defined high-risk group because they demonstrate more negative regression age coefficients when compared with smokers without elevated WBC or with nonsmokers. Mechanisms that may explain these findings are discussed.

Airways obstruction and the risk for lung cancer

The presence of airways obstruction identify in middle-aged male smokers at increased risk for lung cancer. This hypothesis was tested in a sample of patients with moderate to severe obstruction from the Intermittent Positive Pressure Breathing Trial and a sample of patients with no obstruction to moderate obstruction from the Johns Hopkins Lung Project, all of whom were followed for the development of lung cancer. On follow-up, the risk of developing lung cancer was found to be associated with entry values for age, smoking, and ventilatory status by linear, proportional hazard, and log-linear adjustment techniques. Among cigarette smokers, the presence of airways obstruction was more of an indicator for the subsequent development of lung cancer than was age or the level of smoking. The risk for lung cancer also increased in proportion to the degree of airways obstruction. These data suggest that smokers with ventilatory obstruction are at greater risk for lung cancer than are smokers without obstruction.

Sputum cytopathology: use and potential in monitoring the workplace environment by screening for biological effects of exposure

Sputum cytopathologic monitoring detects squamous cell lung cancers at an extremely early stage (x-ray negative). It holds further potential for preventing disease by detecting epithelial alterations which reflect environmental hazards. The addition of sputum cytology screening to screening by chest x-ray film does not significantly reduce mortality from all types of lung cancer, but preliminary analysis of Johns Hopkins Lung Project data suggests that mortality from squamous cell carcinoma is reduced. Quantitative automated cytopathology systems and biochemical/immunological cell markers enhance understanding of these precursors and offer great promise for increasing capacity, accuracy, and usefulness in cytopathology screening of workers. Cytological specimens collected over years of screening workers considered at risk may be important to eventually understanding development and prevention of major occupational diseases.

Pulmonary function and respiratory symptoms in polyvinylchloride fabrication workers

We performed preshift and postshift spirometry and administered a standardized respiratory symptoms questionnaire to 174 white males currently employed in polyvinylchloride (PVC) fabrication to examine the acute and chronic respiratory effects of work exposure. Although there were no significant differences between the in-plant comparison group and any department with potential exposures, there was evidence for respiratory effects in the combined group of comparison and exposed workers. In the combined group, duration of employment was significantly associated with decrements in adjusted cross-shift ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FVC), preshift FEV1/FVC, and prevalence of chronic cough and chronic phlegm. In nonsmokers, the prevalences of chronic wheeze and chest tightness were high (36.0 and 50.5%, respectively). The age-adjusted prevalence of chronic wheeze in nonsmokers was also elevated 3.54-fold when compared with that in a community study in the literature. We conclude that the cross-sectional design and in-plant comparison group may mask the effects of exposures on the entire plant population, and that employment in this plant is associated with patterns of obstructive air-flow limitation and respiratory symptoms consistent with exposure to pulmonary irritants. These results suggest that possible agents of pulmonary effects in PVC fabrication are not limited to vinyl chloride monomer, PVC dust, and PVC thermal degradation products.

Familial aggregation in chronic obstructive pulmonary disease: use of the loglinear model to analyze intermediate environmental and genetic risk factors

To examine the contribution of environmental and genetic risk factors to familial aggregation in chronic obstructive pulmonary disease (COPD), 325 first-degree (1d) relatives and 56 spouses of 150 COPD patients were compared with 222 1d relatives and 49 spouses of 107 nonpulmonary patient controls for the prevalence of two clinical outcomes: 1) airways obstruction (AO; 1-sec forced expiratory volume less than 68% of forced vital capacity) and 2) chronic bronchitis (CB; cough and sputum for 3+ months per year for 2+ years). The loglinear model was used to study direct and indirect (ie, those mediated by other risk factors) components of familial aggregation. Three risk factors were found to be independently associated with CB and/or AO: alpha 1-antitrypsin deficiency (PiZ allele), personal cigarette smoking, and parental cigarette smoking. Because 1d relatives of COPD patients were more likely to have a PiZ allele, be heavy smokers (1+ packs per day), and be exposed to parental smoking than 1d relatives of controls, these three factors also constitute indirect components of familial aggregation. However, after controlling for the three factors, 1d relatives of COPD patients were more likely to have AO and CB than 1d relatives of controls (direct component). This direct component might have a genetic basis, because no such association was found when spouses instead of 1d relatives were compared. Thus, both shared environmental factors (personal and passive smoking) and shared genetic factors (alpha 1-antitrypsin and a possible direct genetic component) contribute to familial aggregation in COPD. The loglinear model provides a useful tool for analyzing familial aggregation in diseases of multifactorial etiology.

Effects of pulmonary function on mortality

Survivorship data from a 24 year longitudinal study of 874 male volunteers in the Baltimore Longitudinal Study of Aging were used to assess the role of pulmonary function on total mortality. Even when age and smoking were considered, the ratio of forced expiratory volume in 1 sec to its predicted value was significantly associated with mortality from all causes. Individuals with poorer pulmonary function showed greater mortality during the follow-up period of this study. This relationship was also seen among never smokers in this sample, further supporting the hypothesis that impaired pulmonary function is itself a predictor of total mortality and may contribute to a number of disease processes.

Early lung cancer detection: results of the initial (prevalence) radiologic and cytologic screening in the Johns Hopkins study

The Johns Hopkins Lung Project was designed to determine whether the addition of cytologic screening to the radiographic screening of high-risk volunteers could enhance the early detection of asymptomatic lung cancer and whether early therapeutic intervention in detected cases could significantly reduce the mortality from this disease. Male volunteers, 45 yr of age and older, who smoked at least 1 pack of cigarettes per day were recruited from the Baltimore metropolitan area. All of the 10,387 acceptable high-risk volunteers received annual chest radiographic screening. By random assignment, one half received cytologic examination of induced sputum in addition to the roentgenogram. This report describes the results of the initial screening. Compared with usual methods of clinical diagnosis, screening by both roentgenography and cytology identified a greater proportion of the lung cancer cases at an earlier stage. Screening by sputum cytology was found to improve the detection only of squamous cell carcinoma. In the dual-screen group, sputum cytology accounted for 28% of the detected cases, and resulted in 39% additional detection of lung cancer over that achieved by roentgenography. There was no corresponding decrease in prevalence. Lung cancers detected by cytology alone were found at very early stages. Although there has been an increase in average survival, much of this increase, if not all, may have resulted from lead-time and sampling bias.