Epidemiology of lung cancer: looking to the future

Genetic susceptibility according to three metabolic pathways in cancers of the lung and bladder and in myeloid leukemias in nonsmokers

BACKGROUND

We chose a set of candidate single nucleotide polymorphisms (SNPs) to investigate gene-environment interactions in three types of cancer that have been related to air pollution (lung, bladder and myeloid leukemia).

PATIENTS AND METHODS

The study has been conducted as a nested case-control study within the European Prospective Investigation into Cancer and Nutrition cohort (409 cancer cases and 757 matched controls). We included never and ex-smokers. SNPs were in genes involved in oxidative stress, phase I metabolizing genes, phase II metabolizing genes and methylenetetrahydrofolate reductase (MTHFR).

RESULTS

The most notable findings are: GSTM1 deletion and bladder cancer risk [odds ratio (OR) = 1.60; 95% confidence interval 1.00-2.56]; CYP1A1 and leukemia (2.22, 1.33-3.70; heterozygotes); CYP1B1 and leukemia (0.47, 0.27-0.84; homozygotes); MnSOD and leukemia (1.91, 1.08-3.38; homozygotes) and NQO1 and lung cancer (8.03, 1.73-37.3; homozygotes). Other statistically significant associations were found in subgroups defined by smoking habits (never or ex-smokers), environmental tobacco smoke or gender, with no obvious pattern. When gene variants were organized according to the three main pathways, the emerging picture was of a strong involvement of combined phase I enzymes in leukemia, with an OR of 5 (1.63-15.4) for those having three or more variant alleles. The association was considerably stronger for leukemias arising before the age of 55.

Spectral karyotyping detects chromosome damage in bronchial cells of smokers and patients with cancer

RATIONALE

Lung cancer is a multistep process that is preceded and often accompanied by molecular cytogenetic lesions in benign bronchial epithelium, the precise character, extent and timing of which are not well defined.

OBJECTIVES

In this study we comprehensively defined molecular cytogenetic changes in bronchial cells that may precede lung carcinoma using spectral karyotyping (SKY).

METHODS

SKY was applied to cultured benign bronchial cells from 43 high-risk smokers without carcinoma, 14 patients with concurrent lung carcinoma, and 14 never-smoker healthy volunteers.

MEASUREMENTS AND MAIN RESULTS

The proportion of cells displaying numeric or structural anomalies/total number of metaphase cells was calculated for each case and was referred to as the chromosomal abnormality index. Mean chromosomal abnormality indices were 15.8, 10.1, and 0.7% for patients with cancer, high-risk smokers, and never-smokers, respectively. Clonal abnormalities were found in 17 (40%) of the high-risk smokers without carcinoma and 7 (50%) of the patients with carcinoma, but in none of 14 (0%) never-smokers. Chromosomal gains observed by SKY were confirmed in interphase cultured cells or paraffin sections of biopsy specimens by fluorescence in situ hybridization in 11 of 13 cases for which appropriate probes were available. In 6 of 57 high-risk patients or those with carcinoma, identical clonal abnormalities were dispersed at multiple bronchial sites and were admixed with nonclonal cells.

CONCLUSIONS

Clonal and single-cell chromosomal abnormalities are frequent in benign bronchial epithelium during lung carcinogenesis, indicating that chromosomal missegregation and other chromosomal rearrangements occur before overt malignancy.

Interplay between mutagen sensitivity and epidemiological factors in modulatinglung cancer risk

Few studies have assessed mutagen sensitivity and lung cancer (LC) risk associations in the context of multiple epidemiological risk factors. We evaluated mutagen sensitivity as a susceptibility marker and explored the interplay of the genetic marker and multiple epidemiologic risk factors in modulating LC risk. This largest case-control study included 977 newly diagnosed LC patients and 977 controls, matched by age, gender, ethnicity and smoking status. Cases exhibited significantly higher mutagen sensitivity than controls in bleomycin (0.76 vs. 0.62 breaks/cell, p < 0.001) and benzo[a]pyrene diol epoxide (BPDE) assays (0.70 vs. 0.61 breaks/cell, p < 0.001). Mutagen sensitivity also exhibited dose-response relationship with LC risk in quartile analysis (p for trend <0.001). In smokers, history of emphysema, absence of hay fever history, LC in first-degree relatives, belomycin sensitivity, and high pack-year were identified to be the top 5 significant risk factors in a stepwise logistic regression model (odds ratios (ORs) of 2.69, 1.91, 1.84, 1.73 and 1.67, respectively). Analyses of joint effects of risk factors showed that compared to the reference group, subjects with no exposure to any of the aforementioned risk factors, the ORs for exposure to 1, 2, 3, 4, 5 or more of the risk factors were 1.56, 2.39, 3.75, 6.74 and 17.39, respectively (p for trend <0.001). This study strongly supports mutagen sensitivity as a predisposition factor for LC and demonstrates the importance of assessing multiple risk factors to comprehensively assess LC risk. This new integrative approach should facilitate identification of high-risk subgroups and has important implications in LC prevention.

Homozygous deletion of p16INK4a and tobacco carcinogen exposure in nonsmall cell lung cancer

Inactivation of p16(INK4a) in the Rb pathway is among the most common somatic alterations observed in nonsmall cell lung cancers (NSCLCs). While epigenetic inactivation of the p16(INK4a) gene promoter has been shown to be associated with increased tobacco carcinogen exposure, little investigation of any similar association of homozygous deletion or mutation of p16(INK4a) and tobacco use has been completed. In 177 consecutive NSCLCs, we examined the determinants of p16(INK4a) homozygous deletion and mutation, including the pattern of tobacco smoking and asbestos exposure. We observed that p16(INK4a) homozygous deletion occurred at a higher frequency in never smokers as compared to former and current smokers (p = 0.01). This observation suggested that tumors from these patients might be more prone to DNA deletion events; consistent with this, epigenetic silencing of the DNA double-strand break repair genes FancF and BRCA1 was also associated with homozygous deletion of p16(INK4a)(p = 0.002 and p = 0.06, respectively). Finally, mutation of p16(INK4a) was rare and only occurred in patients who were smokers. Hence, the character of somatic alteration in the Rb pathway (deletion, mutation or methylation silencing) in NSCLC is associated with the pattern of tobacco exposure, suggesting that susceptibility to lung cancer is, at least in part, mediated by the biological mechanism that selects for the character of the induced somatic lesion.

The association between the anti-inflammatory protein CC10 and smoking status among participants in a chemoprevention trial

CC10, the secretory product of bronchiolar Clara cells, is infrequently expressed in non-small cell lung cancer (NSCLC), and its overexpression in NSCLC cell lines results in a less malignant phenotype. CC10 levels in bronchoalveolar lavage fluid (BAL) and serum are significantly lower in current smokers than healthy nonsmokers, but the effect of long-term smoking cessation on CC10 is unknown. We measured CC10 in baseline BAL and plasma collected from current (n = 81) and former (n = 23) smokers participating in a chemoprevention trial. Former smokers had significantly higher plasma CC10 levels compared with current smokers [mean, 62.1 ng/mL (95% CI, 43.0-81.2); range, 23.0-175.0 ng/mL for former smokers; and mean, 37.1 ng/mL (95% CI, 29.8-44.4); range, 5.0-171.0 ng/mL for current smokers; P < 0.001]. BAL CC10 levels also trended in the same direction. A significant positive correlation was found between CC10 plasma and BAL levels. After adjustment for age, sex, and pack-years of cigarette consumption, former smokers had 1.70 (95% CI, 1.23-2.36) times higher plasma CC10 levels than current smokers (P < 0.01), whereas former smokers also had nonsignificantly higher baseline BAL CC10 levels compared with current smokers [adjusted mean ratio (95% CI), 1.60 (0.92-2.80), P = 0.094 and 1.35 (0.86-2.10), P = 0.193 for the absolute and normalized BAL CC10, respectively]. These results show that sustained smoking cessation is associated with higher plasma CC10 levels, suggesting that at least some of the damage associated with tobacco smoke may be repaired by long-term smoking cessation.

National survey of non-small cell lung cancer in the United States: epidemiology, pathology and patterns of care

PURPOSE

To determine the epidemiology, pathology and patterns of care for patients with non-small cell lung cancer (NSCLC) in the United States.

METHODS

In 2001 the National Cancer Data Base, under direction of the American College of Surgeons, conducted a patient care evaluation study in 719 hospitals. We collected information on patient demographics and histories, diagnostic and staging methods, pathology, and initial treatment.

RESULTS

Information on 40,909 patients was obtained; 93% were smokers. Slightly more than half were older than 70 years; 58.5% were male and 35% had adenocarcinoma. Comorbid conditions were present in 71.8% and 22% had a prior malignancy. A chest CT scan was performed in 92% of patients and PET scans in 19.3%. Mediastinoscopy was performed in 20.3%. 67.2% of patients had Stage III or IV disease. More of the Hispanic, Asian or Black patients than White had Stage IV disease (p<0.01). Treatment was multimodality in a little over 30% of patients. Surgery alone was primarily utilized for patients in Stage I or II. Choice of treatment correlated more with stage and age than comorbidities.

CONCLUSION

Our results substantiated the pattern of increasing proportions of women with NSCLC and the increasing frequency of adenocarcinoma. Most patients presented with Stage III or IV disease. Ethnic minorities were more likely to present in late stage disease than Whites. Treatment strategies depended more on stage and age than comorbid burden. Older patients were less likely to receive surgery and more likely to be treated with radiation only or have no treatment.

Sulfasalazine suppresses drug resistance and invasiveness of lung adenocarcinoma cells expressing AXL

Metastasis and drug resistance are the major causes of mortality in patients with non-small cell lung cancer (NSCLC). Several receptor tyrosine kinases (RTKs), including AXL, are involved in the progression of NSCLC. The AXL/MER/SKY subfamily is involved in cell adhesion, motility, angiogenesis, and signal transduction and may play a significant role in the invasiveness of cancer cells. Notably, no specific inhibitors of AXL have been described. A series of CL1 sublines with progressive invasiveness established from a patient with NSCLC has been identified that positively correlates with AXL expression and resistance to chemotherapeutic drugs. The ectopic overexpression of AXL results in elevated cell invasiveness and drug resistance. Nuclear factor-kappaB (NF-kappaB) signaling activity is associated with AXL expression and may play an important role in the enhancement of invasiveness and doxorubicin resistance, as shown by using the NF-kappaB inhibitor, sulfasalazine, and IkappaB dominant-negative transfectants. In the current study, sulfasalazine exerted a synergistic anticancer effect with doxorubicin and suppressed cancer cell invasiveness in parallel in CL1 sublines and various AXL-expressing cancer cell lines. Phosphorylation of AXL and other RTKs (ErbB2 and epidermal growth factor receptor) was abolished by sulfasalazine within 15 min, suggesting that the inhibition of NF-kappaB and the kinase activity of RTKs are involved in the pharmacologic effects of sulfasalazine. Our study suggests that AXL is involved in NSCLC metastasis and drug resistance and may therefore provide a molecular basis for RTK-targeted therapy using sulfasalazine to enhance the efficacy of chemotherapy in NSCLC.

Changing trends in the distribution of the histologic types of lung cancer: a review of 4,439 cases

Lung cancer is the second most common cancer and the leading cause of cancer death in both men and women. The purpose of the study is to explore the distribution of the 4 major histologic types of lung carcinoma and the incidence of lung cancer with reference to all other sites of cancer. The clinical and histopathologic data of 4,439 patients with lung carcinoma between January 1980 and December 2003 were reviewed. Adenocarcinoma has become the most frequent histologic type in men and women (36.8% and 46.5%, respectively), followed by squamous cell carcinoma (31.6% and 25.4%, respectively). The incidence of large cell (undifferentiated) carcinoma in men and women is 18.0% and 9.9%, respectively. The incidence of small cell carcinoma in men and women is 13.7% and 18.3%, respectively. In addition, analysis of our data indicates that lung cancer rate is decreasing, relative to all other primary cancer sites. The results of this study suggest that the incidence of lung cancer has decreased in comparison with other sources of cancer in southern Texas. This observation is consistent with the current national trends. In addition, there are significant changes in the distribution of the major histologic types of lung cancer. The results of this study may portend important changes in the selection of targeted therapy and patient management.

The California Tobacco Control Program's effect on adult smokers: (1) Smoking cessation

OBJECTIVES

To estimate national population trends in long-term smoking cessation by age group and to compare cessation rates in California (CA) with those of two comparison groups of states.

SETTING

Retrospective smoking history of a population sample from the US: from CA, with a comprehensive tobacco-control programme since 1989 with the goal of denormalising tobacco use; from New York and New Jersey (NY & NJ), with similar high cigarette prices but no comprehensive programme; and from the tobacco-growing states (TGS), with low cigarette prices, no tobacco-control programme and social norms relatively supportive of tobacco use.

PARTICIPANTS

Respondents to the Current Population Survey-Tobacco Use Supplements (1992-2002; n = 57 918 non-Hispanic white ever-smokers).

MAIN OUTCOME MEASURES

The proportion of recent ever-smokers attaining long-term abstinence (quit > or = 1 year) and the successful-quit ratio (the proportion of all ever-smokers abstinent > or = 1 year).

RESULTS

Nationally, long-term cessation rates increased by 25% from the 1980s to the 1990s, averaging 3.4% per year in the 1990s. Cessation increased for all age groups, and by > 40% (p<0.001) among smokers aged 20-34 years. For smokers aged < 50 years, higher cigarette prices were associated with higher quitting rates. For smokers aged < 35 years, quitting rates in CA were higher than in either comparison group (p<0.05). Half of the ever-smokers had quit smoking by age 44 years in CA, 47 years in NY & NJ, and by age 54 years in TGS.

CONCLUSION

Successful smoking cessation increased by 25% during the 1990s in the US. Comprehensive tobacco-control programmes were associated with greater cessation success than were with high cigarette prices alone, although both effects were limited to younger adults.

Decline in respiratory symptoms in service workers five months after a public smoking ban

OBJECTIVE

To evaluate the effect of a total ban on smoking indoors in restaurants and other hospitality business premises in Norway, on respiratory symptoms among workers in the industry.

METHODS

Phone interviews with 1525 employees in the hospitality business were conducted immediately before the enacting of the law. In a follow-up study five months later, 906 of the workers from the baseline sample participated. Questions were asked on demographic variables, passive smoking exposure, personal smoking, attitudes towards the law, and five respiratory symptoms. Change in symptom prevalence was analysed with McNemar's test and with analysis of variance (ANOVA) for repeated measures.

RESULTS

The prevalence of all five symptoms declined after the ban; for morning cough from 20.6% to 16.2% (p < 0.01); for daytime cough from 23.2% to 20.9%; for phlegm cough from 15.3% to 11.8% (p < 0.05); for dyspnoea from 19.2% to 13.0% (p < 0.01); and for wheezing from 9.0% to 7.8%. ANOVA showed that the largest decline in symptom prevalence was seen among workers who themselves gave up smoking, and subjects with a positive attitude towards the law before it took effect.

CONCLUSION

A significant decrease in respiratory symptoms among service industry workers was found five months after the enacting of a public smoking ban.

Genetic polymorphisms of the epidermal growth factor and related receptor in non-small cell lung cancer--a review of the literature

Worldwide, approximately 1.3 billion individuals are current smokers, and smoking is the second major cause of death. Currently, lung cancer is the most common type of cancer in Europe, and the third in the U.S. Until now, cytotoxic chemotherapy has had a limited impact on survival in metastatic non-small cell lung cancer (NSCLC). The central role of epidermal growth factor (EGF) and its receptor (EGFR) in lung carcinogenesis is well recognized. Genetic polymorphisms are variants in individual genomes that may be responsible for different functional molecular roles and contribute to variability in drug pharmacokinetic and pharmacodynamic processes. Herein, we review the literature on EGF and EGFR functions and activities, particularly the current role of their functional polymorphisms as related to NSCLC.

Targeting the epigenome for the treatment of thoracic malignancies

Despite considerable efforts to improve the diagnosis and treatment of lung cancer, this disease remains the leading cause of cancer-related mortality worldwide. Recent elucidation of epigenetic regulation of gene expression during malignant transformation, together with the identification of agents that modulate DNA methylation and histone acetylation, provide new opportunities for the treatment and prevention of lung cancer via chromatin remodeling mechanisms. Further analysis of molecular response in tumor tissues following exposure to chromatin remodeling agents may enable us to identify novel mechanisms pertaining to lung cancer epigenetics, and design more efficacious regimens.

Lung cancer incidence in never smokers

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Lung carcinoma in African Americans

Lung carcinoma is the most commonly diagnosed cancer and the leading cause of cancer deaths in the US. It accounts for 12% of all cancers diagnosed worldwide, making it the most common malignancy, other than nonmelanoma skin cancer. A new focus has emerged involving the role of race and ethnicity in lung carcinoma. Current health statistics data demonstrate striking disparities, which are most evident between African American patients and their white counterparts. This disparity is greatest among male patients, where statistically significant differences are seen not only in lung cancer incidence and risk, but also in survival and treatment outcomes. Several hypotheses that attempt to explain this disparity include genetic, cultural and socioeconomic differences, in addition to differences in tobacco use and exposure. Current evidence does not clearly identify the reasons for this observed disparity, or the role the aforementioned factors play in the development and overall outcomes of people with lung cancer in these populations. This disease continues to pose a considerable public health burden and more research is needed to improve understanding of the disparity of lung carcinoma statistics among African Americans. This review summarizes the existing body of knowledge regarding lung carcinoma in African Americans and attempts to identify promising areas for future investigation and intervention.

Lung cancer risk prediction: a tool for early detection

Although 45% of men and 39% of women will be diagnosed with cancer in their lifetime, it is difficult to predict which individuals will be affected. For some cancers, substantial progress in individual risk estimation has already been made. However, relatively few models have been developed to predict lung cancer risk beyond effects of age and smoking. This paper reviews published models for lung cancer risk prediction, discusses their potential contribution to clinical and research settings and suggests improvements to the risk modeling strategy for lung cancer. The sensitivity and specificity of existing cancer risk models is less than optimal. Improvement in individual risk prediction is important for selection of individuals for prevention or early detection interventions. In addition to smoking, factors related to occupational exposure, personal medical history and family history of cancer can add to the predictive power. A good risk prediction model is one that can identify a small fraction of the population in which a large proportion of the disease cases will occur. In the future, genetic and other biological markers are likely to be useful, although they will require rigorous evaluation. Validation is essential to establish the predictive effect and for ongoing monitoring of the model's continued relevance.

Common Genetic Variation in TP53 Is Associated with Lung Cancer Risk and Prognosis in African Americans and Somatic Mutations in Lung Tumors

Lung cancer is primarily caused by tobacco smoking, but susceptibility is likely modified by common genetic variation. In response to many forms of cellular stress, including DNA damage, the p53 protein functions to induce cell cycle arrest, DNA repair, senescence, or apoptosis. We hypothesized that common TP53 haplotypes modulate pathways of lung carcinogenesis and lung cancer susceptibility or prognosis. To investigate our hypothesis, 14 polymorphisms in TP53, including haplotype tagging and coding single nucleotide polymorphisms, were genotyped in two studies from the greater Baltimore, Maryland area. One study is a case-control study and the second is a case-only study for which TP53 mutational spectra data are available. African Americans with Pro-T-A-G-G haplotypes of the combined TP53 polymorphisms TP53_01 (rs1042522), TP53_65 (rs9895829), TP53_66 (rs2909430), TP53_16 (rs1625895), and TP53_11 (rs12951053) had both an increased risk for lung cancer (odds ratio, 2.32; 95% confidence interval, 1.18-4.57) and a worsened lung cancer prognosis (hazards ratio, 2.38; 95% confidence interval, 1.38-4.10) compared with those with Arg-T-A-G-T haplotypes. No associations of TP53 polymorphisms with lung cancer were observed in Caucasians. In the case-only study, several polymorphisms in TP53 and TP53 haplotypes, overlapping regions of TP53 associated with risk and prognosis in African Americans, were associated with increased odds of somatic TP53 mutation in lung tumors in Caucasians. In conclusion, common genetic variation in TP53 could modulate lung cancer pathways, as suggested by the association with lung cancer in African Americans and somatic TP53 mutation frequency in lung tumors.

Dietary intake of fruit and vegetable and lung cancer risk: a case–control study in Harbin, northeast China

BACKGROUND

We studied the relationship between dietary intake of vegetables and fruit and lung cancer risk in Harbin, Heilongjiang province, northeast China, an area with a very high baseline risk of lung cancer in both sexes.

PATIENTS AND METHODS

We used data from a case-control study, conducted from 1987 to 1990, among 218 cases with incident, histologically confirmed lung cancer and 436 controls admitted to the same hospitals as cases with non-neoplastic, non-lung diseases unrelated to smoking and other potential risk factors for lung cancer.

RESULTS

Compared with the lowest tertile of intake of vegetables, fruit or both, the multivariate odds ratios (ORs) for the highest tertile of intake were 0.39 [95% confidence interval (CI) 0.25-0.62], 0.73 (95% CI 0.48-1.11) and 0.40 (95% CI 0.25-0.63), respectively. In particular, high intake of Chinese cabbage (OR = 0.53), chives (OR = 0 .54), carrots (OR = 0.51) and celery (OR = 0.40) was inversely associated with lung cancer. The OR was more than six-fold elevated for smokers reporting low intake of vegetables, and more than four-fold elevated for smokers reporting low intake of fruit, as compared with never smokers reporting high intake of these items.

CONCLUSION

In agreement with previous studies, we found an inverse relation between vegetable and fruit intake and lung cancer risk in both strata of current and never smokers.

Oncogenic role of JC virus in lung cancer

The JC virus (JCV) infects a large proportion of the population world wide and can cause progressive multifocal leucoencephalopathy in the context of immunodeficiency. Recent reports provide evidence that it may also be oncogenic. Here, JCV was examined by targeting its T-antigen in lung carcinomas (n=103) and normal lung tissues (n=18) by nested-PCR followed by Southern blot, real-time PCR, immunohistochemistry, in situ hybridization and in situ PCR. Additionally, expression of Ki-67, caspase-3, beta-catenin, p53, and Rb was analysed by immunohistochemistry on tissue microarrays of lung carcinomas. Copy numbers of JCV were compared with clinicopathological features. Normal lung tissue was positive significantly less frequently, and contained a lower copy number of JCV than lung carcinomas (p<0.05), and copies were lower in lung adenocarcinomas than in squamous, small or large cell carcinomas (p<0.05). In situ PCR and immunolabelling revealed JCV positivity in the nuclei of lung carcinoma cells. The JCV copy number correlated closely with sex, and expression of Ki-67 and membrane beta-catenin (p<0.05), but not with age, tumour size, pleural invasion, lymph node metastasis, expression of caspase-3, cytoplasmic beta-catenin, p53 or Rb, prognosis, smoking or cancer family history (p>0.05). Age and UICC staging were independent prognostic factors for lung carcinoma patients. These data suggest that JCV may be involved in lung carcinogenesis, especially in tumour types other than adenocarcinoma. Lung carcinomas with higher JCV copy numbers display high proliferation and down-regulation of cell adhesion mediated by membrane beta-catenin.

Revisit of 1997 TNM Staging System—Survival Analysis of 1112 Lung Cancer Patients in Taiwan

BACKGROUND

There is neither a nation-wide nor a large-scale, multi-institutional lung cancer database available for stage-by-stage survival analysis in Taiwan at present.

METHODS

Using the data element provided by the International Association for the Study of Lung Cancer, the Taiwan Lung Cancer Society initiated a project to include native lung cancer patients into a global database. A total of 1112 Taiwan lung cancer patients treated in 7 medical centers were enrolled.

RESULTS

In small cell lung cancer, patients with ipsilateral pleural effusion had a survival between those with locoregional disease alone and those with distant metastasis; however, the difference was not statistically significant (P = 0.204). In non-small cell lung cancer, tumor size had significant survival influence for patients as a whole (P < 0.001) but it did not support the further division of stage IA according to tumor size (P = 0.122). The survival was compatible in stage IIIB and IV patients and therefore, the survival impact of pleural effusion cannot be determined. In patients with pIIIA-N2 disease, those who had station 8 nodal metastasis had inferior survival (P = 0.020) and station 5 superior survival (P = 0.010). In patients with distant metastasis, bone, liver, or distant lymph node metastasis predicted an inferior survival (all P values < 0.05).

CONCLUSIONS

The present study provides for comparison in this area a stage-by-stage reference for the survival of lung cancer patients. Some factors other than current TNM descriptors need to be further investigated in constructing the next version of the staging system.

[Lung cancer in women: a different entity?]

Lung cancer is becoming a real epidemic in developed countries and one of the main causes of cancer death in women. Although it is controversial to state, it is probable that women are more susceptible to lung cancer than men. Molecular and genetic epidemiology studies are underway to prove this statement. Several biological factors, such as family history, histopathology, response to treatment and the prognosis for lung cancer in women have a bearing on the case. While these are not completely clear or consensual, there is a need for wide-ranging prospective studies which compare the differences between males and females. Until now, there has only been one area in which gender could impact on the therapeutic management of lung cancer: the role of gefitinib and erlotinib in inhibiting the epidermal growth factor receptors, since these products are clearly of more benefit to female non-smokers. Given that women have a better lung cancer prognosis, it is recommended that future research protocols include stratification on gender. Prevention of lung cancer in both women and men is a priority public health concern. A mandatory aim of this is the fight against smoking, the largest aetiological factor of lung cancer.

Bayesian spatio-temporal analysis of joint patterns of male and female lung cancer risks in Yorkshire (UK)

Recent advances in disease mapping have focused first on including the time dimension, thus giving rise to spatio-temporal analysis of the variation of disease risk and, secondly, on carrying out joint analysis of two diseases that share common environmental risk factors and are, therefore, related. Here, we try to combine both issues and present a joint analysis of the spatio-temporal variation of the risks of two related diseases processes-male and female lung cancer incidence-in a region of England. To do so, we use a Bayesian hierarchical model that splits the risk of disease into two spatio-temporal components: a shared component and a specific component that calibrates the differential between the two diseases.

Description and implementation of a quality control program in an imaging-based clinical trial

RATIONALE AND OBJECTIVES

The American College of Radiology Imaging Network is participating in the National Lung Screening Trial, a large, multicenter, randomized controlled trial, comparing multidetector helical computed tomography (MDCT) versus chest radiography (CXR) in screening for lung cancer. Because the threshold for detection of disease is an inherent function of image quality, and consistent image quality is necessary to track changes in suspicious findings, our purpose was to develop an image quality control (QC) program across all clinical sites for both modalities.

MATERIALS AND METHODS

The primary goals of the QC program include standardization of imaging protocols, certification of imaging equipment, and ongoing, periodic evaluation of the equipment calibration and image quality. Minimum standards for equipment and standardized cross-platform acquisition protocols are achieved via radiologist and physicist attestation forms and web-distributed technique charts, respectively. Imaging equipment performance standards are implemented through an initial machine certification process that includes equipment calibration. Ongoing assessment of equipment performance and calibration, as well as adherence to established imaging protocols. is accomplished via periodic submission of calibration records and phantom images. Participant-specific image acquisition parameters are entered into a web-based centralized database and variations from established protocols are automatically flagged for review. Participant radiation dose can be estimated from the image acquisition parameters applied to the imaging equipment calibration measurements. A radiologist visual review committee also evaluates participant images for diagnostic quality. Data are collected from 23 independent centers, representing 14 models of MDCT scanners from four manufacturers, and CXR systems that include film-screen, computed radiography, and direct digital radiography systems.

RESULTS

Widespread imaging protocol variation in extant clinical practice-as well as variability in equipment technology, image acquisition parameters, manufacturer terminology, and user interface-have required careful standardization as a prerequisite to trial participation and ongoing image QC. Acceptable ranges for image acquisition parameters have been refined to accommodate continuously evolving equipment platforms and the scope of participant size and body habitus.

CONCLUSION

Standardization of imaging protocols is a critical component of image-based clinical trials, predicated on ongoing dialogue between sites and a centralized review committee.

Mouse lung CYP1A1 catalyzes the metabolic activation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) carcinogenesis is initiated by N(2)-hydroxylation, mediated by several cytochromes P450, including CYP1A1. However, the role of CYP1A1 in PhIP metabolic activation in vivo is unclear. In this study, Cyp1a1-null and wild-type (WT) mice were used to investigate the potential role of CYP1A1 in PhIP metabolic activation in vivo. PhIP N(2)-hydroxylation was actively catalyzed by lung homogenates of WT mice, at a rate of 14.9 +/- 5.0 pmol/min/g tissue, but <1 pmol/min/g tissue in stomach and small intestine, and almost undetectable in mammary gland and colon. PhIP N(2)-hydroxylation catalyzed by lung homogenates of Cyp1a1-null mice was approximately 10-fold lower than that of WT mice. In contrast, PhIP N(2)-hydroxylation activity in lung homogenates of Cyp1a2-null versus WT mice was not decreased. Pretreatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin increased lung Cyp1a1 mRNA and lung homogenate PhIP N(2)-hydroxylase activity approximately 50-fold in WT mice, where the activity was substantially inhibited (70%) by monoclonal antibodies against CYP1A1. In vivo, 30 min after oral treatment with PhIP, PhIP levels in lung were similar to those in liver. After a single dose of 0.1 mg/kg [(14)C]PhIP, lung PhIP-DNA adduct levels in Cyp1a1-null mice, but not in Cyp1a2-null mice, were significantly lower (P = 0.0028) than in WT mice. These results reveal that mouse lung has basal and inducible PhIP N(2)-hydroxylase activity predominantly catalyzed by CYP1A1. Because of the high inducibility of human CYP1A1, especially in cigarette smokers, the role of lung CYP1A1 in PhIP carcinogenesis should be considered. (237 words).

Asbestos Surveillance Program Aachen (ASPA): initial results from baseline screening for lung cancer in asbestos-exposed high-risk individuals using low-dose multidetector-row CT

The purpose of this study was to assess the prevalence of lung cancer in a high-risk asbestos-exposed cohort using low-dose MDCT. Of a population of 5,389 former power-plant workers, 316 were characterized as individuals at highest risk for lung cancer according to a lung-cancer risk model including age, asbestos exposure and smoking habits. Of these 316, 187 (mean age: 66.6 years) individuals were included in a prospective trial. Mean asbestos exposure time was 29.65 years and 89% were smokers. Screening was performed on a 16-slice MDCT (Siemens) with low-dose technique (10/20 mAs(eff.); 1 mm/0.5 mm increment). In addition to soft copy PACS reading analysis on a workstation with a dedicated lung analysis software (LungCARE; Siemens) was performed. One strongly suspicious mass and eight cases of histologically proven lung cancer were found plus 491 additional pulmonary nodules (average volume: 40.72 ml, average diameter 4.62 mm). Asbestos-related changes (pleural plaques, fibrosis) were visible in 80 individuals. Lung cancer screening in this high-risk cohort showed a prevalence of lung cancer of 4.28% (8/187) at baseline screening with an additional large number of indeterminate pulmonary nodules. Low-dose MDCT proved to be feasible in this highly selected population.

Physical activity and lung cancer risk in the European Prospective Investigation into Cancer and Nutrition Cohort

Research conducted predominantly in male populations on physical activity and lung cancer has yielded inconsistent results. We examined this relationship among 416,277 men and women from the European Prospective Investigation into Cancer and Nutrition (EPIC). Detailed information on recent recreational, household and occupational physical activity, smoking habits and diet was assessed at baseline between 1992 and 2000. Relative risks (RR) were estimated using Cox regression. During 6.3 years of follow-up we identified 607 men and 476 women with incident lung cancer. We did not observe an inverse association between recent occupational, recreational or household physical activity and lung cancer risk in either males or females. However, we found some reduction in lung cancer risk associated with sports in males (adjusted RR = 0.71; 95% confidence interval 0.50-0.98; highest tertile vs. inactive group), cycling (RR = 0.73; 0.54-0.99) in females and non-occupational vigorous physical activity. For occupational physical activity, lung cancer risk was increased for unemployed men (adjusted RR = 1.57; 1.20-2.05) and men with standing occupations (RR = 1.35; 1.02-1.79) compared with sitting professions. There was no evidence of heterogeneity of physical activity associations across countries, or across any of the considered cofactors. For some histologic subtypes suggestive sex-specific reductions, limited by subgroup sizes, were observed, especially with vigorous physical activity. In total, our study shows no consistent protective associations of physical activity with lung cancer risk. It can be assumed that the elevated risks found for occupational physical activity are not produced mechanistically by physical activity itself but rather reflect exposure to occupation-related lung cancer risk factors.

Long-term survival differences for bronchiolo-alveolar carcinoma patients with ipsilateral intrapulmonary metastasis at diagnosis

BACKGROUND

It has been suggested that the current staging system does not accurately reflect survival outcomes for advanced bronchiolo-alveolar carcinoma (BAC) patients.

METHODS

We conducted a case-only analysis of US Surveillance, Epidemiology, and End Results (SEER) data (1998-2002). Overall survival (OS) and lung cancer-specific survival (LCSS) univariate analyses were conducted using the Kaplan-Meier method. Multivariate survival analyses were performed using Cox proportional hazards ratios.

RESULTS

2345 incident cases of BAC were analyzed, including 707 patients with stage IIIB or IV BAC. Patients with stage IIIB BAC due to multiple lesions in the same lobe (n=93) had significantly improved median OS (46m) and LCSS (>58m) compared to other stage IIIB BAC patients (n=111; OS=9m, P<0.0001; LCSS=10m, P<0.0001). Among stage IV BAC patients, those with intrapulmonary metastasis (n=278) had significantly improved median OS (13m) and LCSS (15m) compared to those with distant metastasis (n=225; OS=7m, P<0.0001; LCSS=7m, P=0.0001). These survival differences persisted after adjustment for age, gender, ethnicity, and surgical treatment status.

CONCLUSIONS

Among stage IIIB and IV BAC patients, those presenting with ipsilateral intrapulmonary metastasis have improved survival outcomes. Our results add further support for modification to the current staging system for BAC.

Treatment of squamous carcinoma in mice with a vaccine enriched for cells that induce immunity to squamous carcinoma--a new vaccination strategy

We report a new vaccination strategy for squamous cell carcinoma (SCC). The vaccine was prepared by transfer of unfractionated DNA-fragments (25 kb) from squamous carcinoma cells (KLN205, DBA/2 origin (H-2(d))) into LM mouse fibroblasts (C3H/He origin; H-2(k)), a highly immunogenic cell line. To enhance their nonspecific immunogenic properties, the fibroblasts were modified before DNA transfer to secrete IL-2 and to express additional allogeneic MHC class I determinants. As the transferred DNA integrates into the genome of the recipient cells, and is replicated as the cells divide, sufficient DNA to prepare the vaccine could be obtained from as few as 10(7) squamous carcinoma cells (4 mm tumor). Since only a small proportion of the transfected cell-population was expected to have incorporated genes specifying antigens associated with the squamous carcinoma cells (TAA), we devised a novel approach to enrich the vaccine for cells that induce immunity to the SCC. Aliquots of the transfected population were divided into 10 small pools (initial inoculums = 1 x 10(3)). We reasoned that if the starting inoculums were sufficiently small, then the distribution of highly immunogenic and weakly immunogenic cells in each pool would not be the same. Cells from individual pools were allowed to increase in number. A portion of the expanded cell populations were maintained frozen/viable for later recovery. The remaining portions were used to immunize naïve DBA/2 mice. Pools containing greater numbers of immunogenic cells were identified by 2 independent assays. Frozen aliquots of cells from the pool that stimulated immunity to the squamous carcinoma to the greatest extent were recovered and subdivided for additional rounds of immune selection. Enhanced immunity to squamous carcinoma mediated by CD8+ T cells was induced in tumor-bearing mice treated solely by immunization with the enriched cell-population.

B7-H3 and B7-H4 expression in non-small-cell lung cancer

Inhibitory regulatory functions of B7-H3 and B7-H4 regarding T-cell activation have been reported recently. Little is known about the significance of human B7-H3 and B7-H4 expression in non-small-cell lung cancer (NSCLC), and we conducted the present study to address this issue in cell lines and tumor tissue from 70 patients. B7-H3 is over-expressed by all six NSCLC cell lines on both mRNA and protein level. B7-H4 is only transcripted by one cell line in which an alternatively spliced form was discovered. In tumor tissues, expression of B7-H3 and B7-H4 was found both on the cell membrane and in the cytoplasm. Thirty-seven percent of the specimens expressed B7-H3 and 43% B7-H4. The number of T infiltrating lymphoid cells (TILs) in the tumor tissues that expressed B7-H3 or B7-H4 was much lower than those who did not. There was a significant positive relation between the expression of B7-H3 and B7-H4, and high B7-H3 or B7-H4 expression was significantly more common in cases with lymph node metastasis. These observations suggest the contribution of B7-H3 and B7-H4 to immune dysfunction and tumor progression in NSCLC patients. B7-H3 and B7-H4 may be an important target for diagnosis and/or therapy of NSCLC.

Respiratory diseases and Helicobacter pylori infection: is there a link?

Recent studies suggest an epidemiological association between Helicobacter pylori infection and several extra-gastroduodenal pathologies, including cardiovascular, rheumatic, skin and liver diseases. The observed associations might be explained by a role of H. pylori infection in the pathogenesis of certain extra-digestive disorders, as a variety of inflammatory mediators are activated by H. pylori infection. The present review summarizes the current literature, including our own studies, concerning the association between respiratory diseases and H. pylori infection. A small number of epidemiological and serologic case-control studies suggest that patients with chronic obstructive pulmonary disease have an increased seroprevalence of H. pylori. A frequent coexistence of bronchiectasis and H. pylori infection has also been found. Moreover, recent studies have shown an increased prevalence of H. pylori infection in patients with pulmonary tuberculosis and in those with lung cancer. On the other hand, bronchial asthma does not seem to be related to H. pylori infection. At present, there is no definite proof of a causal relationship between H. pylori and respiratory diseases. The primary evidence rests on case-control studies, concerning relatively small numbers of patients. Future studies should be large enough for moderate-sized effects to be assessed or registered reliably. The activation of inflammatory mediators by H. pylori infection might be the pathogenetic mechanism underlying the observed associations. Therefore, the role of genetic predisposition of the infected host, the presence of strain-specific virulence factors and the serum concentration of proinflammatory markers in H. pylori-infected patients with respiratory diseases need further evaluation.

Lung DNA adducts detected in human smokers are unrelated to typical polyaromatic carcinogens

Several studies have reported the presence of DNA adducts derived from benzo(a)pyrene and other polyaromatics by 32P-postlabeling/TLC by measuring diagonal radioactive zones (DRZs) in lung tissues of human smokers. However, our experimental studies in rodent models, which used modified chromatographic conditions to obtain distinct adduct spots, suggested that cigarette smoke-related lipophilic DNA adducts may not be derived from polycyclic aromatic hydrocarbons (PAHs) or aromatic amines. In the present study, we have performed similar analysis of human lung tissues to study the chemical nature of DNA adducts. Fifty human lung tissues from cancer patients (ages 42-83 years) with active, ex-, or never-smoking status were analyzed for highly lipophilic DNA adducts by nuclease P1- and n-butanol enrichment-mediated 32P-postlabeling assay. All DNA samples yielded low to highly intense adduct DRZs when adducts were resolved by PEI-cellulose TLC in standard high-salt, high-urea solvents. Adduct burden ranged from 6.6 to 2930 per 10(10) nucleotides. However, when adducts were resolved in a different solvent system comprising of high-salt, high-urea in direction 3 and dilute ammonium hydroxide in direction 4, which retained adducts derived from PAHs and aromatic amines on the chromatograms, this yielded no detectable adducts from human lung DNAs. Furthermore, analysis of human lung DNAs mixed with reference adducted DNAs in multisolvent systems confirmed an absence of PAH- and aromatic amine-derived adducts in human smoker lung DNA. To determine the origin of cigarette smoke-associated DNA adducts, calf thymus DNA was incubated with formaldehyde and acetaldehyde, which are known to be present in cigarette smoke in significant quantities. Analysis of purified DNAs by 32P-postlabeling resulted in adduct DRZs in the aldehyde-modified DNAs when adducts were resolved in standard urea-containing solvents, but no adducts were detected when the ammonium hydroxide-based solvent was used, suggesting that even nonpolyaromatic electrophiles can result in adduct DRZs on the chromatograms similar to those from PAH metabolites. Taken together, our data demonstrate that cigarette smoke-associated lung DNA adducts appear on chromatograms as DRZs, consistent with the literature, but they are not related to PAHs and aromatic amines.

Clinical-scale high-throughput analysis of urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine by isotope-dilution liquid chromatography-tandem mass spectrometry with on-line solid-phase extraction

BACKGROUND

Quantification of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) in urine or blood is used to assess and monitor oxidative stress in patients. We describe the use of on-line solid-phase extraction (SPE) and isotope-dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) for automated measurement of urinary 8-oxodGuo.

METHODS

Automated purification of urine was accomplished with a switching valve and an Inertsil ODS-3 column. After the addition of 15N5-labeled 8-oxodGuo as an internal standard, urine samples were analyzed within 10 min without sample purification. This method was applied to measure urinary 8-oxodGuo in a group of healthy persons (32 regular smokers and 35 nonsmokers). Urinary cotinine was also assayed by an isotope-dilution LC-MS/MS method.

RESULTS

The lower limit of detection was 5.7 ng/L on column (2.0 fmol). Inter- and intraday imprecision (CV) was < 5.0%. Mean recovery of 8-oxodGuo in urine was 99%-102%. Mean (SD) urinary concentrations of 8-oxodGuo in smokers [7.26 (3.14) microg/g creatinine] were significantly higher than those in nonsmokers [4.69 (1.70) microg/g creatinine; P < 0.005]. Urinary concentrations of 8-oxodGuo were significantly correlated with concentrations of cotinine in smokers (P < 0.05).

CONCLUSIONS

This on-line SPE LC-MS/MS method is sufficiently sensitive, precise, and rapid to provide high-throughput direct analysis of urinary 8-oxodGuo without compromising quality and validation criteria. This method could be applicable for use in daily clinical practice for assessing oxidative stress in patients.

Patterns of cancer incidence, mortality, and prevalence across five continents: defining priorities to reduce cancer disparities in different geographic regions of the world

Efforts to reduce global cancer disparities begin with an understanding of geographic patterns in cancer incidence, mortality, and prevalence. Using the GLOBOCAN (2002) and Cancer Incidence in Five Continents databases, we describe overall cancer incidence, mortality, and prevalence, age-adjusted temporal trends, and age-specific incidence patterns in selected geographic regions of the world. For the eight most common malignancies-cancers of lung, breast, colon and rectum, stomach, prostate, liver, cervix, and esophagus-the most important risk factors, cancer prevention and control measures are briefly reviewed. In 2002, an estimated 11 million new cancer cases and 7 million cancer deaths were reported worldwide; nearly 25 million persons were living with cancer. Among the eight most common cancers, global disparities in cancer incidence, mortality, and prevalence are evident, likely due to complex interactions of nonmodifiable (ie, genetic susceptibility and aging) and modifiable risk factors (ie, tobacco, infectious agents, diet, and physical activity). Indeed, when risk factors among populations are intertwined with differences in individual behaviors, cultural beliefs and practices, socioeconomic conditions, and health care systems, global cancer disparities are inevitable. For the eight most common cancers, priorities for reducing cancer disparities are discussed.

GFP transgenic mice show dynamics of lung macrophages

The dynamics of tissue macrophages are poorly understood. We have developed a model where only lung macrophages express high levels of enhanced green fluorescent protein (EGFP) and are easily identified and followed by confocal microscopy. The EGFP+ cells had the morphology of macrophages and express CD11c, CD11b, and F4/80, but not NK1.1 or CD3. The F4/80+ EGFP+ cells were found exclusively in the lung and not in lymph nodes, spleen, blood, liver, intestine, or uterus. These EGFP+ cells are phagocytic and can be activated to migrate within the lung in response to LPS stimulation. In this study, we describe a new model system that allows the specific study of macrophages in the lung.