The consequences of the unregulated cigarette

Molecular mechanisms underlying the regulation of tumour suppressor genes in lung cancer

Tumour suppressor genes play a cardinal role in the development of a large array of human cancers, including lung cancer, which is one of the most frequently diagnosed cancers worldwide. Therefore, extensive studies have been committed to deciphering the underlying mechanisms of alterations of tumour suppressor genes in governing tumourigenesis, as well as resistance to cancer therapies. In spite of the encouraging clinical outcomes demonstrated by lung cancer patients on initial treatment, the subsequent unresponsiveness to first-line treatments manifested by virtually all the patients is inherently a contentious issue. In light of the aforementioned concerns, this review compiles the current knowledge on the molecular mechanisms of some of the tumour suppressor genes implicated in lung cancer that are either frequently mutated and/or are located on the chromosomal arms having high LOH rates (1p, 3p, 9p, 10q, 13q, and 17p). Our study identifies specific genomic loci prone to LOH, revealing a recurrent pattern in lung cancer cases. These loci, including 3p14.2 (FHIT), 9p21.3 (p16INK4a), 10q23 (PTEN), 17p13 (TP53), exhibit a higher susceptibility to LOH due to environmental factors such as exposure to DNA-damaging agents (carcinogens in cigarette smoke) and genetic factors such as chromosomal instability, genetic mutations, DNA replication errors, and genetic predisposition. Furthermore, this review summarizes the current treatment landscape and advancements for lung cancers, including the challenges and endeavours to overcome it. This review envisages inspired researchers to embark on a journey of discovery to add to the list of what was known in hopes of prompting the development of effective therapeutic strategies for lung cancer.

The predictive value of the change of the number of pixels under different CT value intervals in the CT-occult central lung squamous cell carcinoma and squamous epithelial precancerous lesions

BACKGROUND

Due to the fact that the CT-occult central lung squamous cell carcinoma and squamous epithelial precancerous lesions. (CT-occult CLSCC and SEPL) cannot be detected by lung CT screening, early and timely diagnosis of central lung cancer becomes very difficult, which directly affects the prognosis of patients.

METHODS

We retrospectively review medical records of patients at the Zhejiang Cancer Hospital and enrolled 41 patients with the CT-occult CLSCC and SEPL and 48 patients without the CT-occult CLSCC and SEPL. We compare the clinical characteristics, imaging features and Changes in the number of pixels under different CT value intervals of patients with and without the CT-occult CLSCC and SEPL and we perform univariate and multivariate logistic regression analysis to explore independent factors for the CT-occult CLSCC and SEPL in the patients.

RESULTS

We demonstrate that pack-years ≥ 20 (OR: 3.848, 95% CI: 1.086 ~ 13.633), the number of pixels change of CT value in interval [-850 ~ -750HU] (OR: 5.302, 95% CI: 1.122 ~ 25.057) and in interval [-900 ~ -850HU] (OR: 3.478, 95% CI: 1.167 ~ 10.365) are independently associated with the CT-occult CLSCC and SEPL in the patients. Ultimately, the logistic model obtained is statistically significant (p < 0.05) and an area under the ROC curve is 0.776 (95% CI: 0.682-0.870). The sensitivity of this model is 90.2% and the specificity is 52.1%.

CONCLUSION

The results of this study indicate that in the CT value range [-950 ~ -750HU], when the total number of lung pixels tend to increase towards the region with high CT value, the probability of the occurrence of CT-occult CLSCC and SEPL lesions also increases. Meanwhile, these results have guiding significance for the further study of radiomic.

The incidence and patterns of lung cancers in Sri Lanka from 2001 to 2010: Analysis of national cancer registry data

OBJECTIVES

Epidemiological studies carried out on lung cancer have shown varying incidence patterns in Asia. We aimed to examine the trends in lung cancer incidence and patterns in Sri Lanka.

METHODS

All newly diagnosed lung cancer patients in Sri Lanka during 2001-2010 included in the National Cancer Registry were analysed. Trends in incidence were analysed using the Joinpoint regression software.

RESULTS

A total of 8482 lung cancer patients (males = 6831, 80.5%, mean age: 60.2 years) were analysed. The WHO age-standardised incidence rate (ASR) has increased from 3.77 per 100,000 in 2001 (95% confidence interval [95% CI]: 3.47-4.07) to 5.74 per 100,000 in 2010 (95% CI: 5.38-6.09; a 1.52-fold increase (p < 0.05 for trend), with an estimated annual percentage change (EAPC) of 5.4 (95% CI: 3.9-7.0). The proportional increase in incidence was higher for females [ASR: 1.2 to 2.3, EAPC = 6.8(95% CI: 4.0-9.7)] than males [ASR: 6.6 to 9.55, EAPC = 5.2(95% CI: 3.8-6.6)] and with similar patterns.

CONCLUSIONS

In Sri Lanka, the incidence of lung cancer has shown as increasing trend with a greater proportional rise in females. Although the observed trends could be partly due to better reporting, the greater increase in females who are generally non-smokers is intriguing. Further studies are required to identify reasons for observed incidence trends in lung cancer in Sri Lanka.

Nivolumab treatment in advanced non-small cell lung cancer: real-world long-term outcomes within overall and special populations (the UNIVOC study)

OBJECTIVE

To describe long-term outcomes of patients treated with nivolumab for advanced non-small cell lung cancer (aNSCLC) in everyday clinical practice in France, with a focus on patients aged ⩾80 years, patients with renal impairment and patients with brain metastases.

METHODS

The study included all patients with aNSCLC recorded in the French national hospital database, starting nivolumab in 2015-2016 and followed until December 2018. Patients were stratified by age, the presence of renal impairment and brain metastasis, as documented in the hospital discharge summaries. Information was retrieved on demographics, comorbidities and treatment history at baseline. Time to discontinuation of nivolumab treatment and overall survival were estimated using Kaplan-Meier survival analysis.

RESULTS

Overall, 10,452 patients were included, of whom 514 were octogenarians, 479 had renal impairment and 1800 had brain metastases at baseline. Median duration of nivolumab treatment was 2.8 months in the overall population and in both the octogenarian and renally impaired subgroups, and 2.3 months in patients with brain metastases. Median overall survival in these patient groups was 11.7 months (95% confidence interval: 11.3-12.2), 11.7 months (11.3-12.1), 11.7 months (11.3-12.2) and 9.9 months (9.0-10.9) respectively. Three-year overall survival rates were 19.1% (18.1-20.2) in the overall population, 16.5% (11.6-23.4) in octogenarians, 15.9% (11.8-21.4) in patients with renal impairment and 21.7% (19.4-24.2) in those with brain metastases.

CONCLUSION

This large nationwide retrospective real-life cohort provided narrow estimates of long-term overall survival, which reached 19% at 3 years, consistent with data from phase III trials of nivolumab. Survival rates were comparable in the three special populations of interest and the overall population.

Clinical Characteristics and Prognostic Factors of Lung Cancer in Korea: A Pilot Study of Data from the Korean Nationwide Lung Cancer Registry

Background

Lung cancer is a leading cause of morbidity and mortality worldwide, and the incidence continues to rise. Although many prognostic factors have been identified, the clinical characteristics and outcomes in Korean lung cancer patients are not well defined.

Methods

Of the 23,254 new lung cancer cases registered at the Korea Central Cancer Registry in 2013, total 489 patients from 19 hospitals were abstracted by the Korean Central Cancer Registry. The clinical data retrospectively analyzed, patients were followed up until December 2015.

Results

The median age was 69 years (interquartile range, 60–74 years); 65.4% were male and 62.1% were ever-smokers. Cough was the most common initial symptom (33.5%); 13.1% of patients were asymptomatic. While squamous cell carcinoma was the most common subtype in male patients (37.2%), adenocarcinoma was the most frequent histological type in all patients (48.7%) and females (76.3%). The majority of patients received treatment (76.5%), which included surgery, radiation therapy, and chemotherapy. Older age (hazard ratio [HR], 1.037), lower body mass index (HR, 0.904), ever-smoker (HR, 2.003), small cell lung cancer (HR, 1.627), and distant metastasis (HR, 3.990) were independent predictors of mortality. Patients without symptoms (HR, 0.387) and without treatment (HR, 0.364) were associated with a favorable outcome in multivariate Cox analysis.

Conclusion

Lung cancer in Korea occurs predominantly in elderly patients, with adenocarcinoma being the most frequent subtype. The prognosis was poorer in ever-smokers and older, malnourished, and untreated patients with advanced lung cancer.

Lung cancer incidence trends in California by race/ethnicity, histology, sex, and neighborhood socioeconomic status: An analysis spanning 28 years

OBJECTIVES

Lung cancer incidence trends by histology, sex, race/ethnicity, and neighborhood socioeconomic status (nSES) have not been previously reported. We conducted a population-based study of lung cancer incidence over three peri-censal periods: 1988-1992, 1998-2002, and 2008-2012.

MATERIALS AND METHODS

We abstracted lung cancer cases from the California Cancer Registry and used US Census and American Community Survey data to develop multidimensional nSES indices for each census period. We calculated nSES tertile-specific incidence rates and rate ratios for each peri-censal period and used incidence rate ratios (IRR) to assess changes in rates from 1988 to 1992 to 1998-2002 and 2008-2012.

RESULTS

There were a total of 231,205 lung cancer cases. Males: Among males, incidence rates of lung cancer decreased over time, all race/ethnicities, and all nSES tertiles, with larger declines among males in higher nSES areas. Rates either declined or were stable for adenocarcinoma, with larger declines for other histologic subtypes. Females: Among females, declines in incidence rates of lung cancer were more pronounced for females in higher nSES areas, but diverged more so than for males, with variations by histology and race/ethnicity. Incidence rates of adenocarcinoma increased over time among all females, with greater increase among females in low nSES areas.

CONCLUSIONS

Our findings demonstrate differences in incidence trends over three decades by histology, gender, race/ethnicity, and nSES. While incidence rates consistently declined over time for males, there were greater declines in incidence for high nSES populations. In contrast, among females, there was evidence of increases in lung cancer incidence among low SES API females, and for adenocarcinoma.

Epidemiology of Lung Cancer in Korea: Recent Trends

Lung cancer causes the most cancer deaths in Korea. Although the smoking rate has begun to decrease, the prevalence of lung cancer is still increasing. We reviewed the national lung cancer registry data and the data published about lung cancer in Korea. In 2012, the crude incidence rate of lung cancer was 43.9 per 100,000. The age-standardized mortality rate of lung cancer was 19.8 per 100,000. The 5-year relative survival rate for lung cancer was 11.3% from 1993 to 1995 and increased to 21.9% in the period from 2008 to 2012. Lung cancer occurring in never-smokers was estimated to increase in Korea. Adenocarcinoma is steadily increasing in both women and men and has replaced squamous cell carcinoma as the most common type of lung cancer in Korea. In patients with adenocarcinoma, the frequency of EGFR mutations was 43% (range, 20%–56%), while that of the EMK4-ALK gene was less than 5%.

Histological subtypes of lung cancer in Chinese women from 2000 to 2012

BACKGROUND

The aim of the study was to characterize the histological and epidemiological features of lung cancer in Chinese women.

METHODS

Demographic and histological information on female lung cancer cases identified during 1 January 2000 through 31 December 2012 from the Cancer Hospital of the Chinese Academy of Medical Sciences were collected. The International Classification of Diseases for Oncology system was used to classify the histological subtypes. Relative frequencies (RF) were estimated for major histological subtypes and compared by the years of diagnosis and birth, and among residential areas. Statistical differences were tested for RFs in the time periods with a trend test and with Pearson Chi square tests for distribution.

RESULTS

Of 7070 female Chinese lung cancer cases, the major histological subtypes were adenocarcinoma (ADC) 65.79%; squamous cell carcinoma (SCC) 10.21%; small cell cancer 8.12%; large cell carcinoma, 2.79%; and adeno-squamous carcinoma (ASC), 2.19%. ADC increased, with RFs from 46.72% in the cases identified in 2000-2002 to 76.49% in 2011-2012 (Z = 16.998, P < 0.0001); SCC decreased from 15.69% to 5.97% (Z = -8.750, P < 0.0001). Compared to the cases identified in 2000-2006, the age-adjusted RFs of ADC in 2007-2012 consistently increased in all study areas.

CONCLUSION

The significant increase of ADC of the lung in Chinese women suggests that a persistently strong exposure to potential carcinogens in the Chinese population should be further and fully investigated.

International trends in lung cancer incidence by histological subtype: adenocarcinoma stabilizing in men but still increasing in women

OBJECTIVES

Trends in overall lung cancer incidence in different countries reflect the maturity of the smoking epidemic. Further understanding of the underlying causes for trends over time can be gained by assessing the trends by sex and histological subtype. We provide a temporal analysis of lung cancer incidence in 12 populations (11 countries), with a focus on cohort-specific trends for the main histological subtypes (squamous cell carcinomas (SCC), adenocarcinomas (AdC), and small cell carcinoma).

MATERIAL AND METHODS

We restrict the analysis to population-based registry data of sufficient quality to provide meaningful interpretation, using data in Europe, North America and Oceania, extracted from successive Cancer Incidence in Five Continents Volumes. Poorly specified morphologies were reallocated to a specified grouping on a population, 5-year period and age group basis.

RESULTS

In men, lung cancer rates have been declining overall and by subtype, since the beginning of the study period, except for AdC. AdC incidence rates have risen and surpassed those of SCC (historically the most frequent subtype) in the majority of these populations, but started to stabilize during the mid-1980s in North America, Australia and Iceland. In women, AdC has been historically the most frequent subtype and rates continue to increase in most populations studied. Early signs of a decline in AdC can however be observed in Canada, Denmark and Australia among very recent female cohorts, born after 1950.

CONCLUSIONS

The continuing rise in lung cancer among women in many countries reinforces the need for targeted smoking cessation efforts alongside preventive actions.

Topographical study of O(6)-alkylguanine DNA alkyltransferase repair activity and N7-methylguanine levels in resected lung tissue

BACKGROUND

Tobacco specific nitrosamines such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) are genotoxic alkylating agents found within cigarette smoke that induce lung adenocarcinomas in animal models. In humans, adenocarcinomas originate most frequently in the lung periphery. The aim of this study was to determine whether peripheral lung has increased susceptibility to the genotoxic effects of alkylating agents by comparing DNA alkylation damage (N7-methylguanine: N7-meG) and repair (O(6)-alkylguanine DNA alkyltransferase: MGMT) in peripheral relative to central lung tissue.

METHODS

Macroscopically normal lung tissue, resected from patients undergoing surgery for lung cancer, was sampled at equidistant points from central to peripheral lung along a bronchus. N7-meG levels were determined using an immunoslotblot technique and MGMT activity with a [32P]-labelled oligodeoxynucleotide cleavage assay.

RESULTS

A total of 20 subjects were recruited, 12 males and 8 females with a mean age of 68.7±5.8years. There were 14 former and 6 current smokers with a mean smoking exposure of 34.0±18.3packyears. N7-meG (mean 0.75±0.57/10(6)dG, n=65 samples from 14 patients) and MGMT repair (geometric mean 9.57±1.62fmol/μg DNA, n=79 samples from 16 patients) were detected in all samples assayed. MGMT activity increased towards the lung periphery (r=0.28, p=0.023; n=16) with a highly significant association in current (r=0.53, p=0.008; n=6) but not former smokers (r=0.13; p=0.41; n=10). No correlation was seen with N7-meG levels and lung position (r=-0.18; p=0.21; n=14). N7-meG levels were higher in current compared to former smokers reaching significance in two lung positions including peripheral lung (p=0.047).

CONCLUSIONS

The findings in this study do not support the hypothesis that peripheral tissue is more susceptible to the genotoxic effects of alkylating agents than central lung tissue. In addition exposure to cigarette smoke reduced the level of MGMT in central bronchial tissue possibly through increased alkylating agent exposure.

Lung cancer: epidemiology, etiology, and prevention

Lung cancer is the leading cause of cancer death in the United States and around the world. A vast majority of lung cancer deaths are attributable to cigarette smoking, and curbing the rates of cigarette smoking is imperative. Understanding the epidemiology and causal factors of lung cancer can provide additional foundation for disease prevention. This article focuses on modifiable risk factors, including tobacco smoking, occupational carcinogens, diet, and ionizing radiation. It also discusses briefly the molecular and genetic aspects of lung carcinogenesis.

Lung cancer: epidemiology, etiology, and prevention

Lung cancer is the leading cause of cancer death in the United States and around the world. A vast majority of lung cancer deaths are attributable to cigarette smoking, and curbing the rates of cigarette smoking is imperative. Understanding the epidemiology and causal factors of lung cancer can provide additional foundation for disease prevention. This article focuses on modifiable risk factors, including tobacco smoking, occupational carcinogens, diet, and ionizing radiation. It also discusses briefly the molecular and genetic aspects of lung carcinogenesis.

Whose butt is it? tobacco industry research about smokers and cigarette butt waste

Background

Cigarette filters are made of non-biodegradable cellulose acetate. As much as 766 571 metric tons of butts wind up as litter worldwide per year. Numerous proposals have been made to prevent or mitigate cigarette butt pollution, but none has been effective; cigarette butts are consistently found to be the single most collected item in beach clean-ups and litter surveys.

Methods

We searched the Legacy Tobacco Documents Library (http://legacy.library.ucsf.edu) and http://tobaccodocuments.org using a snowball strategy beginning with keywords (eg, ‘filter’, ‘biodegradable’, ‘butts’). Data from approximately 680 documents, dated 1959–2006, were analysed using an interpretive approach.

Results

The tobacco industry has feared being held responsible for cigarette litter for more than 20 years. Their efforts to avoid this responsibility included developing biodegradable filters, creating anti-litter campaigns, and distributing portable and permanent ashtrays. They concluded that biodegradable filters would probably encourage littering and would not be marketable, and that smokers were defensive about discarding their tobacco butts and not amenable to anti-litter efforts.

Conclusions

Tobacco control and environmental advocates should develop partnerships to compel the industry to take financial and practical responsibility for cigarette butt waste.

The International Epidemiology of Lung Cancer: geographical distribution and secular trends

This review presents the latest available international data for lung cancer incidence, mortality and survival, emphasizing the established causal relationship between smoking and lung cancer. In 2002, it was estimated that 1.35 million people throughout the world were diagnosed with lung cancer, and 1.18 million died of lung cancer-more than for any other type of cancer. There are some key differences in the epidemiology of lung cancer between more developed and less developed countries. In more developed countries, incidence and mortality rates are generally declining among males and are starting to plateau for females, reflecting previous trends in smoking prevalence. In contrast, there are some populations in less developed countries where increasing lung cancer rates are predicted to continue, due to endemic use of tobacco. A higher proportion of lung cancer cases are attributable to nonsmoking causes within less developed countries, particularly among women. Worldwide, the majority of lung cancer patients are diagnosed after the disease has progressed to a more advanced stage. Despite advances in chemotherapy, prognosis for lung cancer patients remains poor, with 5-year relative survival less than 14% among males and less than 18% among females in most countries. Given the increasing incidence of lung cancer in less developed countries and the current lack of effective treatment for advanced lung cancers, these results highlight the need for ongoing global tobacco reform to reduce the international burden of lung cancer.

Changes in cigarette use and nicotine dependence in the United States: evidence from the 2001-2002 wave of the national epidemiologic survey of alcoholism and related conditions

OBJECTIVES

We examined the roles of gender and poverty in cigarette use and nicotine dependence among adults in the United States.

METHODS

Our data were drawn from the 2001-2002 National Epidemiological Survey of Alcoholism and Related Conditions, a nationally representative sample of US adults 18 years and older.

RESULTS

The overall rate of cigarette use declined between 1964 and 2002. Nicotine dependence does not appear to have declined overall, and there is evidence that nicotine dependence has increased among women in recent cohorts. The odds of nicotine dependence among cigarette users appear to have increased significantly in recent cohorts.

CONCLUSIONS

Despite recent declines in cigarette use, the prevalence of nicotine dependence has increased among some groups and has remained steady overall, which may be hampering public health initiatives to reduce cigarette use. Efforts to study or curb cigarette use should therefore take nicotine dependence into account.

Lung cancer in never smokers--a different disease

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

Prospective study of urinary excretion of 7-methylguanine and the risk of lung cancer: Effect modification bymu class glutathione-S-transferases

Nitrosamines are mainly mutagenic through methylation of DNA. 7-Methylguanine (m(7)Gua) is a product of base excision repair and spontaneous depurination of such lesions in DNA and a metabolite from RNA. Associations between urinary excretion of m(7)Gua and risk of lung cancer were examined in a population-based cohort of 25,717 men and 27,972 women aged 50-64 years. During 3-7 years follow-up 260 cases with lung cancer were identified and a subcohort of 263 individuals matched on sex, age and smoking duration was selected for comparison. Urine collected at entry was analyzed for m(7)Gua by HPLC. Effect modification by glutathione-S-transferases GSTM1, GSTM3, GSTT1 and GSTP1 was investigated. We found higher excretion of m(7)Gua among current smokers than among former smokers. The IRR (incidence rate ratio) of lung cancer was 1.20 (95% CI: 1.00-1.43) per doubling of m(7)Gua excretion in unadjusted analysis and 1.12 (95% CI: 0.93-1.35) after adjustment for smoking status, intensity and duration at entry. This association was mainly present among current smokers. Comparing the highest with the lowest tertile of m(7)Gua excretion the IRR of lung cancer was 1.75 (95% CI: 1.04-2.95) irrespective of genotype and 2.75 (95% CI: 1.33-5.81) in subjects with GSTM1 null genotype. If not caused by residual confounding by smoking a possible association between m(7)Gua excretion and lung cancer supports the importance of methylation of guanine. The finding of an association between m(7)Gua excretion and lung cancer risk mainly among current smokers and subjects with GSTM1 null genotype supports causality in this respect.