Gender and lung cancer

Documento de consenso sobre tabaquismo y riesgo vascular

Consensus statement on smoking and vascular risk About 22% of the Spanish population are daily smokers. Men are more likely to smoke than women. In Spain, women between 15-25 years of age smoke as much or more than men. Every smoker should be assessed for: physical dependence on nicotine (Fagerström test), social and psychological dependence (Glover Nilsson test), level of motivation to quit (Richmond test), probability of therapy success (Henri-Mondor and Michael-Fiore tests), and stage of behavioral change development (Prochaska and DiClementi). Advice on smoking cessation is highly cost-effective and should always be provided. Smoking is an enhancer of cardiovascular risk because it acts as a pathogen agent in the development of arteriosclerosis and is associated with ischemic heart disease, stroke, and peripheral artery disease. Smoking increases the risk of chronic lung diseases (COPD) and is related to cancers of the lung, female genitalia, larynx, oropharynx, bladder, mouth, esophagus, liver and biliary tract, and stomach, among others. Combined oral contraceptives should be avoided in women smokers older than 35 years of age due to the risk of thromboembolism. In smoking cessation, the involvement of physicians, nurses, psychologists, etc. is important, and their multidisciplinary collaboration is needed. Effective pharmacological treatments for smoking cessation are available. Combined treatments are recommended when smoker's dependence is high. For individuals who are unable to quit smoking, a strategy based on tobacco damage management with a total switch to smokeless products could be a less dangerous alternative for their health than continuing to smoke.

Gender Differences in Oxidative Stress in Relation to Cancer Susceptibility and Survival

Genetic, developmental, biochemical, and environmental variables interact intricately to produce sex differences. The significance of sex differences in cancer susceptibility is being clarified by numerous studies. Epidemiological research and cancer registries have revealed over the past few years that there are definite sex variations in cancer incidence, progression, and survival. However, oxidative stress and mitochondrial dysfunction also have a significant impact on the response to treatment of neoplastic diseases. Young women may be more protected from cancer than men because most of the proteins implicated in the regulation of redox state and mitochondrial function are under the control of sexual hormones. In this review, we describe how sexual hormones control the activity of antioxidant enzymes and mitochondria, as well as how they affect several neoplastic diseases. The molecular pathways that underlie the gender-related discrepancies in cancer that have been identified may be better understood, which may lead to more effective precision medicine and vital information on treatment options for both males and females with neoplastic illnesses.

Addressing Gender Disparities in Lung Cancer Screening Eligibility: USPSTF versus PLCOm2012 Criteria

BACKGROUND

Lung cancer is the leading cause of cancer death in women in the United States. Prospective randomized lung screening trials suggest a greater lung cancer mortality benefit from screening women compared to men.

RESEARCH QUESTION

Do the United States Preventative Services Task Force (USPSTF) lung screening guidelines that are based solely on age and smoking history contribute to gender disparities in eligibility, and if so, does the use of the PLCOm2012 risk prediction model that is based on 11 predictors of lung cancer reduce gender disparities?

STUDY DESIGN AND METHODS

This retrospective analysis of 883 lung cancer cases in the Chicago Race Eligibility for Screening Cohort (CREST) determined the sensitivity of USPSTF versus PLCOm2012 eligibility criteria, stratified by gender. For comparisons to the USPSTF 2013and the recently published USPSTF 2021(released March 9^th, 2021) eligibility criteria, the PLCOm2012 model was used with risk thresholds of ≥1.7%/6y and >1.0%/6y, respectively.

RESULTS

The sensitivities for screening by the USPSTF 2013were 46.7% for women and 64.6% for men (p=0.003) and by the USPSTF 2021were 56.8% and 71.8%, respectively (p=0.02). In contrast, the PLCOm2012 ≥1.7%/6y sensitivities were 64.6% and 70.4%, respectively, and the PLCOm2012 ≥1.0%/6y sensitivities were 77.4% and 82.4%, respectively. The PLCOm2012 differences in sensitivity using ≥1.7%/6y and ≥1.0%/6y thresholds between women and men were nonsignificant (both p=0.07). Compared to men, women were more likely to be ineligible by the USPSTF 2021criteria because their smoking exposures were <20 pack-years (22.8% vs 14.8%, OR_{Women vs Men} 1.70, 95% CI 1.19-2.44; p=0.002) and 27% of these ineligible women were eligible by the PLCOm2012 >1.0%/6y criteria.

INTERPRETATION

Although the USPSTF 2021eligibility criteria are more sensitive than the USPSTF 2013guidelines, there remains gender disparities in eligibility. Adding the PLCOm2012 risk prediction model to the USPSTF guidelines would improve sensitivity and attenuate gender disparities.

The role of gender in non-small cell lung cancer: a narrative review

The role of gender in the development, treatment and prognosis of thoracic malignancies has been underappreciated and understudied. While most research has been grounded in tobacco-related malignancies, the incidence of non-smoking related lung cancer is on the rise and disproportionately affecting women. Recent research studies have unveiled critical differences between men and women with regard to risk factors, timeliness of diagnosis, incongruent screening practices, molecular and genetic mechanisms, as well as response to treatment and survival. These studies also highlight the increasingly recognized need for targeted therapies that account for variations in the response and complications as a function of gender. Similarly, screening recommendations continue to evolve as the role of gender is starting to be ellucidated. As women have been underrepresented in clinical trials until recently, the data regarding optimal care and outcomes is still lagging behind. Understanding the underlying similarities and differences between men and women is paramount to providing adequate care and prognostication to patients of either gender. This review provides an overview of the critical role that gender plays in the care of patients with non-small cell lung cancer and other thoracic malignancies, with an emphasis on the need for increased awareness and further research to continue elucidating these disparities.

The molecular basis of gender disparities in smoking lung cancer patients

AIMS

Gender disparities exist in smoking-related lung cancer epidemiology, but the molecular basis has not been explored so far. We aimed at identifying genes with gender-bias expression pattern in smoking lung cancer patients for understanding the molecular basis of gender bias in smokers using meta-analysis of microarray gene expression data.

MATERIALS AND METHODS

Transcriptome of around 1100 samples from 13 studies were used in the meta-analysis to identify 'Lung Cancer genes specific to Female-Smokers' (LCFS) and 'Lung Cancer genes specific to Male-Smokers' (LCMS). The expression profiles of these genes were validated with an independent microarray report and TCGA-RNA-sequencing data. The molecular interactions, pathway, and other functional annotations were portrayed for the key genes identified.

KEY FINDINGS

We identified 1159 gender-biased genes in smoking lung cancer patients. Of these, 400 and 474 genes showed differential expression in cancerous compared to normal lung of women (LCFS) and men (LCMS), respectively. While many up-regulated LCFS were involved in 'immune responses' including T-cell activation, leukocyte cell-cell adhesion, the LCMS were mainly involved in 'positive regulation of gene expression', signaling pathways including RAS, VEGF, insulin-receptor signaling, and 'cell cycle'.

SIGNIFICANCE

The strategic-method identified genes, particularly, SNX20, GIMAP6, MTMR2, FAM171B, IDH1, MOBP, FBXO17, LPXN and WIPF1, which were consistently differentially expressed in at least 4 studies, and in agreement with RNA-Seq data. Exploring their functions could be beneficial to the gender-based diagnosis, prognosis, and treatment of lung cancer in smokers. The current meta-analysis supports existing knowledge of sexual-dimorphism of immune responses in cancer.

Estrogen receptor-alpha isoforms are the main estrogen receptors expressed in non-small cell lung carcinoma

The expression profile of estrogen receptors (ER) in Non-Small Cell Lung Carcinoma (NSCLC) remains contradictory. Here we investigated protein and transcriptome expression of ERα wild type and variants. Tissue Micro-Arrays of 200 cases of NSCLC (paired tumor/non-tumor) were assayed by immunohistochemistry using a panel of ERα antibodies targeting different epitopes (HC20, 6F11, 1D5, ERα36 and ERα17p). ERβ epitopes were also examined for comparison. In parallel we conducted a probe-set mapping (Affymetrix HGU133 plus 2 chip) meta-analysis of 12 NSCLC tumor public transcriptomic studies (1418 cases) and 39 NSCLC cell lines. Finally, we have investigated early transcriptional effects of 17β-estradiol, 17β-estradiol-BSA, tamoxifen and their combination in two NSCLC cell lines (A549, H520). ERα transcript and protein detection in NSCLC specimens and cell lines suggests that extranuclear ERα variants, like ERα36, prevail, while wild-type ERα66 is minimally expressed. In non-tumor lung, the wild-type ERα66 is quasi-absent. The combined evaluation of ERα isoform staining intensity and subcellular localization with sex, can discriminate NSCLC subtypes and normal lung. Overall ERα transcription decreases in NSCLC. ERα expression is sex-related in non-tumor tissue, but in NSCLC it is exclusively correlating with tumor histologic subtype. ERα isoform protein expression is higher than ERβ. ERα isoforms are functional and display specific early transcriptional effects following steroid treatment. In conclusion, our data show a wide extranuclear ERα-variant expression in normal lung and NSCLC that is not reported by routine pathology ER evaluation criteria, limited in the nuclear wild type receptor.

Different inhibitory potential of sex hormones on NNK detoxification in vitro: A possible explanation for gender-specific lung cancer risk

Smoking women are probably at a higher risk to develop lung cancer than men. Different explanations exist for these findings, a gender-specific impairment of tobacco carcinogen metabolism being one of them. In this study, we examined the inhibition of NNK reduction to NNAL, the first and most important detoxication step of this tobacco-specific carcinogen. It is mediated by different carbonyl reductases of the SDR (CBR1 and 11βHSD1) and AKR (AKR1B10, AKR1C1, AKR1C2 and AKR1C4) superfamilies. Inhibition constants of NNK reduction were determined with male (testosterone) and female (estradiol, progesterone) sex hormones and the contraceptives ethinylestradiol and drospirenone in A549 cells and with purified enzymes. Female sex hormones turned out to be stronger inhibitors than testosterone. The gestagen progesterone and its synthetic derivative drospirenone are the strongest inhibitors with Ki-values similar to hormone levels in pregnant women or women using hormonal contraceptives. Therefore, pregnancy or hormonal contraception may commit these women as high risk groups. The results of this study support the hypothesis that women bear a higher lung cancer risk when smoking because of female sex hormones acting as inhibitors of NNK detoxication.

Sex hormones reduce NNK detoxification through inhibition of short-chain dehydrogenases/reductases and aldo-keto reductases in vitro

Carbonyl reduction is an important metabolic pathway for endogenous and xenobiotic substances. The tobacco specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK, nicotine-derived nitrosamine ketone) is classified as carcinogenic to humans (IARC, Group 1) and considered to play the most important role in tobacco-related lung carcinogenesis. Detoxification of NNK through carbonyl reduction is catalyzed by members of the AKR- and the SDR-superfamilies which include AKR1B10, AKR1C1, AKR1C2, AKR1C4, 11β-HSD1 and CBR1. Because some reductases are also involved in steroid metabolism, five different hormones were tested for their inhibitory effect on NNK carbonyl reduction. Two of those hormones were estrogens (estradiol and ethinylestradiol), another two hormones belong to the gestagen group (progesterone and drospirenone) and the last tested hormone was an androgen (testosterone). Furthermore, one of the estrogens (ethinylestradiol) and one of the gestagens (drospirenone) are synthetic hormones, used as hormonal contraceptives. Five of six NNK reducing enzymes (AKR1B10, AKR1C1, AKR1C2, AKR1C4 and 11β-HSD1) were significantly inhibited by the tested sex hormones. Only NNK reduction catalyzed by CBR1 was not significantly impaired. In the case of the other five reductases, gestagens had remarkably stronger inhibitory effects at a concentration of 25 μM (progesterone: 66-88% inhibition; drospirenone: 26-87% inhibition) in comparison to estrogens (estradiol: 17-51% inhibition; ethinylestradiol: 14-79% inhibition) and androgens (14-78% inhibition). Moreover, in most cases the synthetic hormones showed a greater ability to inhibit NNK reduction than the physiologic derivatives. These results demonstrate that male and female sex hormones have different inhibitory potentials, thus indicating that there is a varying detoxification capacity of NNK in men and women which could result in a different risk for developing lung cancer.

A potential role for estrogen in cigarette smoke-induced microRNA alterations and lung cancer

Alteration in the expression of microRNAs (miRNAs) is associated with oncogenesis and cancer progression. In this review we aim to suggest that elevated levels of estrogens and their metabolites inside the lungs as a result of cigarette smoke exposure can cause widespread repression of miRNA and contribute to lung tumor development. Anti-estrogenic compounds, such as the components of cruciferous vegetables, can attenuate this effect and potentially reduce the risk of lung cancer (LC) among smokers.

Lung cancer in women, a different disease: survival differences by sex in Turkey

PURPOSE

In this study, we aimed to evaluate the effects of sex-based non-small cell lung cancer (NSCLC) varieties on survival rates.

MATERIALS AND METHODS

A retrospective study was performed in patients with NSCLC who were diagnosed by histological methods between the years 2000 and 2010. A chi-square test was used to compare variables. Overall survival (OS) was estimated by the Kaplan-Meier method.

RESULTS

Of the 844 patients, 117 (13.9%) were women and 727 (86.1%) were men. Adenocarcinoma was more common in women than in men (p<0.0001). There were more women non-smokers than men (p<0.0001). There was no statistically significant difference in ECOG PS, weight loss>10%, stage, LDH, albumin and treatment between women and men. Women younger than 65 years (17.0 vs 12.0 months; p=0.03), who had adenocarcinoma histology (15.0 vs 10.0 months; p=0.006) and who had a hemoglobin level≥12 g/dL (18.0 vs 12.0 months; p=0.01) were found to have a better median OS rate than men. Median OS rates were found to be 13.0 months in females and 12.0 months in males (p=0.14). Among metastatic patients, the median OS was 11.0 months in females and 8.0 months in males (p=0.005). Among stage IIIB and stage IV patients who had first line platinum-based chemotherapy, the median OS was 17.0 months in women and 11.0 months in men (p=0.002). The response rate of chemotherapy was higher in women than in men (p=0.03).

CONCLUSIONS

In our study, we found that survival duration is longer and chemotherapy response is better in women with NSCLC who do not have anemia or comorbidities and who are mostly non-smokers with adenocarcinomas. Further studies regarding the causes of these differences may provide clarity on this subject.

Human papillomavirus infection and risk of lung cancer in never-smokers and women: an 'adaptive' meta-analysis

OBJECTIVES:

The incidence of lung cancer in Koreans is increasing in women and in both men and women with a never-smoking history. Human papillomavirus (HPV) infection has been suggested as a modifiable risk factor of lung cancer in never-smokers and women (LCNSW). This systematic review (SR) aimed to evaluate an association between HPV infection and lung cancer risk in LCNSW.

METHODS:

Based on a prior SR and some expert reviews, we identified refereed, cited, or related articles using the PubMed and Scopus databases. All case-control studies that reported the odds ratio of HPV infection in LCNSW were selected. An estimate of the summary odds ratio (SOR) with 95% confidence intervals (CI) was calculated.

RESULTS:

A total of four case-control studies were included. The fixed-effect model was applied because of homogeneity (I-squared=0.0%). The SORs in women and in never-smokers were 5.32 (95% CI, 1.75 to 16.17) and 4.78 (2.25 to 10.15) respectively.

CONCLUSIONS:

These results showed a significant effect of HPV infection in LCNSW. It is evident that developing a preventive plan against LCNSW may be necessary.

Do smoking habits differ between women and men in contemporary Western populations? Evidence from half a million people in the UK Biobank study

OBJECTIVES

Several studies have shown that smoking may confer a greater excess risk for chronic diseases in women compared with men. The reasons for this excess risk of smoking in women are unclear, yet sex differences in smoking habits may play a role. We, thus, characterised sex differences in smoking habits in a contemporary Western population.

DESIGN

Cross-sectional population-based study.

SETTING

UK Biobank Resource.

PARTICIPANTS

499,797 (54% women) individuals with data on smoking habits.

MAIN OUTCOME MEASURES

Women-to-men prevalence ratios in smoking status, and the women-minus-men mean difference in age at smoking initiation, number of cigarettes smoked daily and age at smoking cessation in 5-year birth cohort bands.

RESULTS

The women-to-men ever-smoking ratio ranged from 0.57 in the oldest to 0.87 in the youngest birth cohort. In the oldest cohort, born 1935-1939, women started smoking 1.9 years (95% CI 1.7 to 2.1) later than did men, but in those born after 1959 there was no difference in the age at initiation. The oldest women smoked 5.3 (95% CI 4.7 to 5.9) cigarettes per day fewer than did the oldest men, compared with 2.0 (95% CI 1.7 to 2.3) fewer cigarettes smoked per day in the youngest, born 1965-1969. Among quitters, women born before 1945 were, on average, 1.5 years older than their male contemporaries, but this differential was 1 year or less among people born after 1949.

CONCLUSIONS

Differences in smoking behaviour between women and men have decreased over time. Even past differentials are unlikely to explain the increased susceptibility to smoking-related chronic disease in women compared with men that has previously been observed. Future studies are required to determine whether sex differences in the physiological and biological effects of smoking are responsible for the differential impact of smoking on health in women and men.

Women are more susceptible than men to oxidative stress and chromosome damage caused by polycyclic aromatic hydrocarbons exposure

Exposure to environmental polycyclic aromatic hydrocarbons (PAHs) has been associated with increased risk of cancer, but evidence for gender differences in this association is limited. The aim of this study was to examine the gender differences in PAHs caused early genotoxic effects such as oxidative stress and chromosome damage, which are potential carcinogenic etiology of PAHs. A total of 478 nonsmoking workers (272 men and 206 women) from a coke oven plant were recruited. We determined 16 environmental PAHs in their workplaces, and measured concentrations of 12 urinary PAH metabolites (OH-PAHs), plasma benzo[a]pyrene-r-7,t-8,t-9,c-10-tetrahydotetrol-albumin (BPDE-Alb) adducts, urinary 8-hydroxydeoxyguanosine (8-OHdG) and 8-iso-prostaglandin-F2α (8-iso-PGF2α), and micronucleus frequencies in lymphocytes in all subjects. It showed that, women working at the office, adjacent to the coke oven, and on the bottom or side of the coke oven displayed significantly higher levels of urinary 8-OHdG and 8-iso-PGF2α, and lymphocytic micronucleus frequencies compared with men working at above areas, respectively (all P < 0.05). These gender differences remain significant after adjusted for potential confounders and urinary ΣOH-PAHs or plasma BPDE-Alb adducts. A significant interaction existed between gender and BPDE-Alb adducts on increasing micronucleus frequencies (Pinteraction  < 0.001). We further stratified all workers by the tertiles of urinary ΣOH-PAHs or plasma BPDE-Alb adducts, and the above gender differences were more evident in the median- and high-exposure groups (all P < 0.05). In conclusion, women were more susceptible than men to oxidative stress and chromosome damage induced by PAHs, which may add potential evidence underlying gender differences in PAH exposure-related lung cacinogenesis.

The many faces of tobacco use among women

Smoking is still considered to be mainly a male problem. However, it is estimated that there are approximately 250 million women worldwide who smoke cigarettes and millions more women who use smokeless tobacco products. This article addresses the many facets of tobacco use among women. The aim of the paper is to increase recognition among clinicians and researchers of the specific characteristics of female tobacco use. Together with providing epidemiological data on the distribution of tobacco use among women and data from population-based analyses on sociocultural factors that influence it, the article presents tobacco use during pregnancy as a particularly important public health problem. Further, the article points out sex-related differences (ie, physiological, psychological, or behavioral) between male and female tobacco use. A special focus is on the important role of ovarian hormones. Adverse effects of tobacco use to women and their children as well as tobacco-related morbidities and comorbidities are presented, and women's greater susceptibility to tobacco constituents as compared to men is stressed. Awareness of these differences can contribute to improvement of the effectiveness of smoking cessation programs addressed both to the specific female population and to an individual smoking woman.

Sex as an independent prognostic factor in a population-based non-small cell lung cancer cohort

BACKGROUND

Males with non-small cell lung cancer (NSCLC) tend to experience worse outcomes, as do those with nonadenocarcinoma histology; however, the independent effects of these factors remain unclear.

OBJECTIVE

To evaluate the independent effect of sex and histology on mortality in a population of patients with NSCLC.

METHODS

All patients with NSCLC in Manitoba from 1985 to 2004 were identified from the Manitoba Cancer Registry. Treatment data were extracted from the Manitoba Health administrative databases and linked to the registry. Cox regression analysis was used to determine the independent effect of sex on survival.

RESULTS

A total of 10,908 patients (6665 male, 4243 female) with NSCLC were identified. Females had a median overall survival of 9.4 months versus 6.8 months for males (P<0.001). The adjusted HR for death for males compared with females was 1.13 (95% CI 1.04 to 1.23; P=0.004). Sex modified the effect of surgical treatment on survival (HR 1.26 [95% CI 1.13 to 1.40]; P<0.001). Adenocarcinoma histology modified the effect of sex on survival (HR 1.36 [95% CI 1.24 to 1.50]; P<0.001) when treatment was accounted for.

CONCLUSION

Females experienced a significantly better survival rate than males independent of treatment, age, year of diagnosis and histology. This was greatest in surgically treated patients and in those with adenocarcinoma.

NSCLC subtype prediction using cytologic fluid specimens from needle aspiration biopsies

This study evaluated the diagnostic usefulness of tumor marker concentrations in cytologic fluids (CF) for subtyping non-small cell lung cancer (NSCLC) and assessed the relationship between fluorine-18-fluorodeoxyglucose ((18)F-FDG) uptake with serum and CF tumor marker levels. This prospective study included 88 patients diagnosed with adenocarcinoma or squamous cell carcinoma (SCC). Cytokeratin-19 fragment (CYFRA 21-1), carcinoembryonic antigen (CEA), and squamous cell carcinoma antigen (SCCA) concentrations in the CF samples were correlated with serum tumor marker concentrations, (18)F-FDG uptake, and NSCLC subtype. Fifty-eight patients were diagnosed with adenocarcinoma. Multivariate analysis revealed higher CF and serum SCCA levels; smoking status predicted SCC from adenocarcinoma. CF SCCA showed the highest accuracy (83%) in distinguishing between SCC and adenocarcinoma. CF samples obtained during routine needle aspiration biopsy procedure contain tumor marker levels sufficient to distinguish between SCC and adenocarcinoma; CF SCCA had the highest diagnostic accuracy.

Inhibition of lung tumor development by berry extracts in mice exposed to cigarette smoke

Cigarette smoke (CS) and dietary factors play a major role in cancer epidemiology. At the same time, however, the diet is the richest source of anticancer agents. Berries possess a broad array of health protective properties and were found to attenuate the yield of tumors induced by individual carcinogens in the rodent digestive tract and mammary gland but failed to prevent lung tumors induced by typical CS components in mice. We exposed whole-body Swiss ICR mice to mainstream CS, starting at birth and continuing daily for 4 months. Aqueous extracts of black chokeberry and strawberry were given as the only source of drinking water, starting after weaning and continuing for 7 months, thus mimicking an intervention in current smokers. In the absence of berries, CS caused a loss of body weight, induced early cytogenetical damage in circulating erythrocytes and histopathological alterations in lung (emphysema, blood vessel proliferation, alveolar epithelial hyperplasia and adenomas), liver (parenchymal degeneration) and urinary bladder (epithelial hyperplasia). Both berry extracts inhibited the CS-related body weight loss, cytogenetical damage, liver degeneration, pulmonary emphysema and lung adenomas. Protective effects were more pronounced in female mice, which may be ascribed to modulation by berry components of the metabolism of estrogens implicated in lung carcinogenesis. Interestingly, both the carcinogen and the chemopreventive agents tested are complex mixtures that contain a multitude of components working through composite mechanisms.

Differential role of estrogen receptor beta in early versus metastatic non-small cell lung cancer

Although women have an increased susceptibility to lung cancer, they also have a favorable clinical outcome. This may in part be due to female specific genetic and hormonal factors. In the present study, expression of ER-beta was investigated by immunohistochemistry using tissue samples from two cohorts: non-small cell lung cancer (NSCLC) diagnosed in 1999 in Manitoba and advanced NSCLC patients from the NCIC-CTG BR.18 trial. In the Manitoba cohort assessable tissue samples available in 79 patients (32 females and 47 males) and the majority (75%) had early stage disease. Fifty-one percent of patients expressed high levels of ER-beta (defined by ≥60, the median immunohistochemistry score) and its expression was comparable in males and females. The 3-year overall survival of the group was 53% and males had significantly worse survival compared to females (HR=2.37, 95%CI 1.15–4.91, P=0.02). Higher ER-beta 1 expression was associated with better survival in both univariate (HR=0.41, 95%CI 0.21–0.80, P=0.009) and in multivariate (HR=0.37, 95%CI 0.18–0.77, P=0.008) analysis. In the NCIC-CTG cohort that were more often later stage, assessable tissue samples from 48 cases were available however higher ER beta 1 expression correlated with poorer survival (HR= 1.94, 95%CI 1.01–3.75 P=0.047). These results suggest a differential impact of ER-beta 1 expression on clinical outcome by disease stage, that needs to be explored further and may explain contradictory observations reported in the literature.

Gender is a risk factor for lung cancer

Results of epidemiological studies suggest that, after one controls for the number of cigarettes smoked, women have a three times higher risk of getting lung cancer than men. Although the mechanism(s) explaining this gender-dependent difference in lung cancer risk is not known, it is thought that endocrine factors may play an important role. Normal human bronchial epithelial cells contain estrogen receptors and synthesize 17β-estradiol (E(2)) and estrone (E(1)), which can undergo further metabolism into the catechol estrogens, 4-hydroxyestradiol (4-OHE(2)) and 4-hydroxyestrone (4-OHE(1)), respectively. Catechol estrogens are formed from E(2) by the actions of cytochrome p450 1B1 (CYP1B1). CYP1B1 is present in normal human bronchial epithelial) cells, and its activity is increased by cigarette smoking. Both 4-OHE(1) and 4-OHE(2) are mutagenic and carcinogenic and may exert their biological effects by inducing DNA adducts in cancer-related genes, including the tumor suppressor gene p53 and the proto-oncogene K-ras. Women with lung cancer have a different p53 mutational spectrum and a higher frequency of K-ras mutations than do men with lung cancer. Both clinical and basic research studies support the hypothesis that E(2) and cigarette smoking are cofactors in lung carcinogenesis in women. More specifically, cigarette smoke stimulates metabolism of E(2) into the genotoxic metabolites, 4-OHE(1) and 4-OHE(2,) which interact with DNA in cancer-related genes, including the tumor suppressor gene, p53, and the proto-oncogene K-ras, two genes frequently mutated in patients with lung cancer. E(2) may stimulate cellular proliferation and enhance tumor growth.

No evidence of sex-related survival disparities among head and neck cancer patients receiving similar multidisciplinary care: a matched-pair analysis

PURPOSE

It is unknown whether there are survival disparities between men and women with squamous cell carcinoma of the head and neck (SCCHN), although some data suggest that men have worse outcomes. We conducted a matched-pair study that controlled for several potentially confounding prognostic variables to assess whether a survival advantage exists for female compared with male SCCHN patients receiving similar care.

EXPERIMENTAL DESIGN

We selected 286 female patients and 286 matched male patients from within a prospective epidemiologic study on 1,654 patients with incident SCCHN evaluated and treated at a single large multidisciplinary cancer center. Matching variables included age (±10 y), race/ethnicity, smoking status (never versus ever), tumor site (oral cavity versus oropharynx versus larynx versus hypopharynx), tumor classification (T(1-2) versus T(3-4)), nodal status (negative versus positive), and treatment (surgery, radiation therapy, surgery and radiation therapy, surgery and chemotherapy, chemoradiotherapy, or surgery and chemoradiotherapy).

RESULTS

Matched-pair and log-rank analyses showed no significant differences between women and men in recurrence-free, disease-specific, or overall survival. When the analysis was restricted to individual sites (oral cavity, oropharynx, or larynx/hypopharynx), there was also no evidence of a disparity in survival associated with sex.

CONCLUSIONS

We conclude that there is no evidence to suggest that a survival advantage exists for women as compared with men with SCCHN receiving similar multidisciplinary directed care at a tertiary cancer center.

Beta-carotene affects gene expression in lungs of male and female Bcmo1 (-/-) mice in opposite directions

Molecular mechanisms triggered by high dietary beta-carotene (BC) intake in lung are largely unknown. We performed microarray gene expression analysis on lung tissue of BC supplemented beta-carotene 15,15′-monooxygenase 1 knockout (Bcmo1^−/−) mice, which are—like humans—able to accumulate BC. Our main observation was that the genes were regulated in an opposite direction in male and female Bcmo1^−/− mice by BC. The steroid biosynthetic pathway was overrepresented in BC-supplemented male Bcmo1^−/− mice. Testosterone levels were higher after BC supplementation only in Bcmo1^−/− mice, which had, unlike wild-type (Bcmo1^+/+) mice, large variations. We hypothesize that BC possibly affects hormone synthesis or metabolism. Since sex hormones influence lung cancer risk, these data might contribute to an explanation for the previously found increased lung cancer risk after BC supplementation (ATBC and CARET studies). Moreover, effects of BC may depend on the presence of frequent human BCMO1 polymorphisms, since these effects were not found in wild-type mice.

Menopausal hormone therapy and risk of lung cancer-Systematic review and meta-analysis

OBJECTIVES

Lung cancer rates increase among women in many regions of the world. To explore whether menopausal hormone therapy (MHT) plays a role.

METHODS

We conducted a systematic search of the literature and performed meta-analyses of cohort studies (C), case-control studies (CC), randomized controlled trials (RCTs), and cancer registry studies (CR) to analyse the impact of estrogen therapy (ET), estrogen/progestin therapy (EPT) and any hormone therapy (HT) on lung cancer risks. We explored associations between ever-use of therapies and risks, analysed annual changes of risk, and the impact of therapies on histological subtypes. We calculated summary odds ratios, relative risks, 95% confidence intervals (CI; fixed-effects model), and assessed heterogeneity across studies. Eighteen studies were eligible (9 CC, 4 C, 3 RCT, 2 CR).

RESULTS

We found a significant increase of risk - 76.2% - in non-smoking women with adenocarcinoma (CI 1.072-2.898) reporting ever-use of HT. Estrogen plus progestin therapy does not change the risk; however, the pooled analysis of 2 RCTs points at an increased risk (RR 1.359; CI 1.031-1.791). Our further results should be interpreted with caution as significances were found in analyses only when smoking and non-smoking women, various hormone regimens, or histological subtypes, respectively, were pooled.

CONCLUSIONS

Dedicated studies designed to more adequately delineate the role of MHT are necessary to substantiate whether use of MHT is a risk factor for this or other types of lung cancer.

Hormone replacement therapy and survival in lung cancer in postmenopausal women in a rural population

BACKGROUND

Hormone replacement therapy (HRT) may play a role in the development of lung cancer and subsequent survival. Results from studies exploring these issues are inconsistent. A retrospective study in a rural population was conducted to determine whether a history of HRT use is associated with survival of postmenopausal women with lung cancer.

METHODS

A retrospective medical chart review of 648 postmenopausal women, diagnosed with a first primary lung cancer between 1995 and 2005, was conducted in a regional hospital in Paducah, Kentucky. History of HRT use was collected. Log-rank test and multivariate Cox regression analysis were performed to examine the effects of HRT on survival.

RESULTS

The median survival for women with a history of HRT use was 16.4 months, compared with 10.5 months for women without a history of HRT use. However, this difference in survival was not statistically significant (hazard ratio, 1.09; 95% confidence interval, 0.82-1.44). Women with a history of HRT use were younger on average (64.3 years) at diagnosis than women without a history of HRT use (69.5 years, P<.01). Cigarette smoking was adversely associated with survival (P=.03), as were age (P<.01) and TNM stage (P<.01).

CONCLUSIONS

In contrast to previous studies, within this population, a history of HRT use in postmenopausal lung cancer patients was not associated with decreased survival. Because most of the published studies on this issue are retrospective, the discrepant findings reflect the complexity of the role of HRT use in the survival of lung cancer patients.

The quality and strength of evidence for etiology: example of carpal tunnel syndrome

PURPOSE

The purpose of this investigation was to evaluate the quality and strength of scientific evidence supporting an etiologic relationship between a disease and a proposed risk factor using a scoring system based on the Bradford Hill criteria for causal association.

METHODS

A quantitative score based on the Bradford Hill criteria (qBHs) was used to evaluate 117 articles presenting original data regarding the etiology of carpal tunnel syndrome: 33 (28%) that evaluated biological (structural or genetic) risk factors, 51 (44%) that evaluated occupational (environment or activity-related) risk factors, and 33 (28%) that evaluated both types of risk factors.

RESULTS

The quantitative Bradford Hill scores of 2 independent observers showed very good agreement, supporting the reliability of the instrument. The average qBHs was 12.2 points (moderate association) among biological risk factors compared with 5.2 points (poor association) for occupational risk factors. The highest average qBHs was observed for genetic factors (14.2), race (11.7), and anthropometric measures of the wrist (11.3 points) with all studies finding a moderate causal association. The highest average qBHs among occupational risk factors was observed for activities requiring repetitive hand use (6.5 points among the 30 of 45 articles that reported a causal association), substantial exposure to vibration (6.3 points; 14 of 20 articles), and type of occupation (5.6 points; 38 of 53 articles), with the findings being much less consistent.

CONCLUSIONS

According to a quantitative analysis of published scientific evidence, the etiology of carpal tunnel syndrome is largely structural, genetic, and biological, with environmental and occupational factors such as repetitive hand use playing a minor and more debatable role. Speculative causal theories should be analyzed through a rigorous approach prior to wide adoption.

Nongenomic beta estrogen receptors enhance beta1 adrenergic signaling induced by the nicotine-derived carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone in human small airway epithelial cells

Women are at higher risk for the development of lung adenocarcinoma than men; however, the mechanisms responsible for this are poorly understood. In lung adenocarcinoma cells, the estrogen receptor beta (ERbeta) is the predominating form. We found that 17beta-estradiol enhanced proliferation of the putative cells of origin of lung adenocarcinoma, small airway epithelial cells (HPLD1), in response to the nicotine-derived nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Reverse-phase protein microarrays combined with Western blotting revealed that NNK induced phosphorylation of ERbeta, an effect that involved stimulation of the adrenergic receptors beta1 (beta1AR). In transiently transfected cells, beta1AR coprecipitated with ERbeta, which increased with NNK treatment. ERbeta enhanced NNK-induced cyclic AMP accumulation as well as Galphai-mediated mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) 1/2 activation. Coexpression of beta1AR and ERbeta activated NNK-mediated ERK1/2 cooperatively. ERbeta gene knockdown, as well as coexpression of the dominant negative Ras and Raf, reduced stimulation of ERK1/2 by NNK. Whereas NNK phosphorylated Akt at Thr(308) and Ser(473), ERbeta had no effect on this activity. Luciferase reporter assays showed that, in response to NNK, ERbeta stimulated transcription of serum responsive element (SRE) but had a very small effect on the activity of estrogen responsive element (ERE). Together, the phosphorylation of ERbeta, the dependence on Galphai proteins, the activation of ERK1/2, and the preferential targeting of SRE over the classic ERE pathway support a role for nongenomic ERbeta in the development of smoking-associated lung cancer. This novel cooperation between beta1AR and ERbeta signaling may contribute to the prominence of lung adenocarcinoma in women.

Clinicopathologic characteristics of the EGFR gene mutation in non-small cell lung cancer

BACKGROUND

The authors sought to define clinicopathologic features associated with mutations of the epidermal growth factor receptor (EGFR) gene in non-small cell lung cancer (NSCLC).

METHODS

The authors evaluated surgically resected NSCLC tumors for EGFR (exons 18-21) and KRAS (codons 12-13) mutations and immunohistochemistry (EGFR, phosphorylated-EGFR, and HER2/Neu), and correlated results with clinical outcome and patient and disease features. After their analysis on 159 patients was completed, they selected a second cohort of Asian patients (n = 22) and compared EGFR mutation results to place of birth and immigration to the United States.

RESULTS

Of 159 patients, 14 had EGFR mutations and 18 had KRAS mutations. EGFR mutations were associated with adenocarcinoma (p = 0.002), female gender (p = 0.02), never-smoking (p < 0.0001), Asian ethnicity (p = 0.005), air bronchograms (p = 0.004), and multiple wedge resections (p = 0.03). Although statistical significance was not reached, a higher incidence of synchronous primary cancers (36% versus 17%; p = 0.09) and a smaller median tumor size (11.8 cm versus 24.0 cm; p = 0.24) were seen. There was no difference in disease-free survival; however, median overall survival in patients with EGFR mutations was shorter (3.49 versus 4.29 years; p = 0.85). EGFR mutation did not correlate with immunohistochemistry. In the second cohort of 22 Asian patients, 12 (55%) had the mutation. Of interest, there was no geographic difference in incidence of EGFR mutation. Asian women with the EGFR mutation developed adenocarcinoma at an earlier age than other lung cancer patients.

CONCLUSION

There is a distinct clinical profile for NSCLC patients with the EGFR mutation. However, this mutation does not alter disease-free survival and is likely attributable to an inherited susceptibility instead of an environmental effect.

Lung Cancer in Never Smokers: A Review

Lung cancer is the leading cause of cancer-related death in the United States. Although tobacco smoking accounts for the majority of lung cancer, approximately 10% of patients with lung cancer in the United States are lifelong never smokers. Lung cancer in the never smokers (LCINS) affects women disproportionately more often than men. Only limited data are available on the etiopathogenesis, molecular abnormalities, and prognosis of LCINS. Several etiologic factors have been proposed for the development of LCINS, including exposure to radon, cooking fumes, asbestos, heavy metals, and environmental tobacco smoke, human papillomavirus infection, and inherited genetic susceptibility. However, the relative significance of these individual factors among different ethnic populations in the development of LCINS has not been well-characterized. Adenocarcinoma is the predominant histologic subtype reported with LCINS. Striking differences in response rates and outcomes are seen when patients with advanced non–small-cell lung cancer (NSCLC) who are lifelong never smokers are treated with epidermal growth factor receptor tyrosine kinase (EGFR-TK) inhibitors such as gefitinib or erlotinib compared with the outcomes with these agents in patients with tobacco-associated lung cancer. Interestingly, the activating mutations in the EGFR-TK inhibitors have been reported significantly more frequently in LCINS than in patients with tobacco-related NSCLC. This review will summarize available data on the epidemiology, risk factors, molecular genetics, management options, and outcomes of LCINS.

Fetal onset of aberrant gene expression relevant to pulmonary carcinogenesis in lung adenocarcinoma development induced by in utero arsenic exposure

Arsenic is a human pulmonary carcinogen. Our work indicates that in utero arsenic exposure in mice can induce or initiate lung cancer in female offspring. To define early molecular changes, pregnant C3H mice were given 85 ppm arsenic in drinking water from days 8 to 18 of gestation and expression of selected genes in the fetal lung or in lung tumors developing in adults was examined. Transplacental arsenic exposure increased estrogen receptor-alpha (ER-alpha) transcript and protein levels in the female fetal lung. An overexpression of various estrogen-regulated genes also occurred, including trefoil factor-3, anterior gradient-2, and the steroid metabolism genes 17-beta-hydroxysteroid dehydrogenase type 5 and aromatase. The insulin growth factor system, which can be influenced by ER and has been implicated in the pulmonary oncogenic process, was activated in fetal lung after gestational arsenic exposure. In utero arsenic exposure also induced overexpression of alpha-fetoprotein, epidermal growth factor receptor, L-myc, and metallothionein-1 in fetal lung, all of which are associated with lung cancer. Lung adenoma and adenocarcinoma from adult female mice exposed to arsenic in utero showed widespread, intense nuclear ER-alpha expression. In contrast, normal adult lung and diethylnitrosamine-induced lung adenocarcinoma showed little evidence of ER-alpha expression. Thus, transplacental arsenic exposure at a carcinogenic dose produced aberrant estrogen-linked pulmonary gene expression. ER-alpha activation was specifically associated with arsenic-induced lung adenocarcinoma and adenoma but not with nitrosamine-induced lung tumors. These data provide evidence that arsenic-induced aberrant ER signaling could disrupt early life stage genetic programing in the lung leading eventually to lung tumor formation much later in adulthood.

Sex-Specific Survival Advantage with Parathyroid Hormone–Related Protein in Non–Small Cell Lung Carcinoma Patients

PURPOSE

Parathyroid hormone-related protein (PTHrP) is commonly expressed in non-small cell lung carcinomas (NSCLC). Expression of the protein could have implications for progression of the disease because it regulates cancer cell growth, apoptosis, and angiogenesis. However, its relationship with survival has not been evaluated in a large-scale investigation.

EXPERIMENTAL DESIGN

PTHrP expression was assessed in paraffin-embedded tumor samples from 407 patients with NSCLC by immunohistochemistry. A pathologist unaware of the clinical history classified specimens as PTHrP positive or PTHrP negative. The log-rank test was used to compare survivals of PTHrP-positive and PTHrP-negative groups, and Cox regression was used to adjust for additional covariates.

RESULTS

Median survival was 55 versus 22 months (P < 0.001) in female patients with and without tumor PTHrP, respectively. Male survival was 38 months independent of PTHrP status. Stage, histology, age, and smoking history were also associated with increased longevity. PTHrP remained a significant predictor of survival for female patients after controlling for stage, histology, and age.

CONCLUSIONS

In this study, PTHrP expression was associated with a survival advantage in female patients. Additional investigations must be done to ascertain whether the result is reproducible and independent of potential confounding covariates. Sex-dependent effects of PTHrP in lung cancer would open new avenues of research into the role of sex in cancer progression.

Hormone Replacement Therapy Is Associated With Decreased Survival in Women With Lung Cancer

Purpose

Lung cancer is the leading cause of cancer-related death in women. Hormone replacement therapy (HRT) is frequently prescribed to postmenopausal women, but there is little data on its effect on lung cancer. Hence, we conducted a retrospective study to examine the impact of HRT on the natural history of lung cancer.

Methods

We conducted a retrospective chart review of women diagnosed with lung cancer between January 1994 and December 1999. Data collected included age, stage, past history of cancer, smoking history, family history of cancer, HRT use, treatment, and overall survival. The effects of various clinical features on survival were examined using Cox proportional hazards regression models.

Results

Four hundred ninety-eight women (median age, 67 years; range, 31 to 93 years) with lung cancer were included. A history of smoking was present in 429 women (86%), whereas 86 women (17%) had taken HRT. Women with lung cancer who received HRT were younger than women with lung cancer who never received HRT (63 v 68 years old, respectively; P < .0001). Overall survival was significantly higher in patients with no HRT compared with patients who received HRT (79 v 39 months, respectively; hazard ratio = 1.97; 95% CI, 1.14 to 3.39). This effect seemed to be more pronounced in women with a smoking history.

Conclusion

HRT may affect outcomes from lung cancer adversely. Further studies examining the role of HRT use on outcomes from lung cancer, especially in women with a history of smoking, are urgently needed to clarify this important problem.

Molecular epidemiology of lung cancer in female passive smokers

To clarify etiology of lung cancer in nonsmoker females, various studies have been done. Particularly, host factors and environmental tobacco smoking (ETS) of females have been emphasized. However, traditional epidemiological data showed controversial results of sex or gender differences in lung cancer susceptibility and suggest presence of some confounders. One of them is that most of epidemiology studies are based on self-reports for ETS. To prevent misestimate effects of ETS via the self-report, exposure monitoring of ETS is required. On the other hand, focusing on genetic polymorphisms in metabolic enzymes and DNA repair, molecular epidemiological studies have been done in nonsmoker females. Therefore, this review considered: 1. gender differences in lung cancer; 2. effects of passive smoking on lung cancer; 3. exposure monitoring of ETS including genetic risks of lung cancer to clarify etiology of lung cancer in the nonsmoker females with molecular epidemiological discussion.