The significance of estrogen receptor beta in 301 surgically treated non-small cell lung cancers

Genes Co-Expressed with ESR2 Influence Clinical Outcomes in Cancer Patients: TCGA Data Analysis

ERβ has been assigned a tumor suppressor role in many cancer types. However, as conflicting findings emerge, ERβ's tissue-specific expression and functional role have remained elusive. There remains a notable gap in compact and comprehensive analyses of ESR2 mRNA expression levels across diverse tumor types coupled with an exploration of its potential gene network. In this study, we aim to address these gaps by presenting a comprehensive analysis of ESR2 transcriptomic data. We distinguished cancer types with significant changes in ESR2 expression levels compared to corresponding healthy tissue and concluded that ESR2 influences patient survival. Gene Set Enrichment Analysis (GSEA) distinguished molecular pathways affected by ESR2, including oxidative phosphorylation and epithelial-mesenchymal transition. Finally, we investigated genes displaying similar expression patterns as ESR2 in tumor tissues, identifying potential co-expressed genes that may exert a synergistic effect on clinical outcomes, with significant results, including the expression of ACIN1, SYNE2, TNFRSF13C, and MDM4. Collectively, our results highlight the significant influence of ESR2 mRNA expression on the transcriptomic landscape and the overall metabolism of cancerous cells across various tumor types.

Aiming to Improve Equity in Lung Health: Sex and Gender

Sex and gender impact risk factors, presentations of, and response to therapy in lung diseases such as chronic obstructive pulmonary disease, asthma, lung cancer, interstitial lung disease, and obstructive sleep apnea. Many physicians lack training in the impact of sex and gender on lung disease, resulting in diagnostic delays. Scales and indices taught in the health care system are largely validated in male populations, thereby limiting their application to females. For transgender and lesbian, gay, bisexual, transgender, and questioning + patients, high rates of bias in health care may limit patients' willingness to seek health care.

Management of pulmonary nodules in women with pregnant intention: A review with perspective

The process for the management of pulmonary nodules in women with pregnant intention remains a challenge. There was a certain proportion of targeted female patients with high-risk lung cancer, and anxiety for suspicious lung cancer in early stage also exists. A comprehensive review of hereditary of lung cancer, effects of sexual hormone on lung cancer, natural history of pulmonary nodules, and computed tomography imaging with radiation exposure based on PubMed search was completed. The heredity of lung cancer and effects of sexual hormone on lung cancer are not the decisive factors, and the natural history of pulmonary nodules and the radiation exposure of imaging should be the main concerns. The management of incidental pulmonary nodules in young women with pregnant intention is an intricate and indecisive problem we have to encounter. The balance between the natural history of pulmonary nodules and the radiation exposure of imaging should be weighed.

The Impact of Estrogen Receptor Expression on Mutational Status in the Evolution of Non-Small Cell Lung Cancer

BACKGROUND

The role of estrogen receptor (ER) status in the carcinogenesis of lung cancer and its impact on prognosis remain unclear.

MATERIALS AND METHODS

We previously reported a prospective, multicenter, molecular epidemiology study (Japan Molecular Epidemiology for Lung Cancer Study [JME]). We examined the relationship of ER status with reproductive and hormonal factors, mutational profile, and survival using JME study data. Patients were enrolled between July 2012 and December 2013, with follow-up until November, 2017.

RESULTS

Among 441 ever- and 435 never-smokers, ER expression was observed in 46.4% and 53.5%, respectively (P = .022). Hormone use and reproductive history of female patients were not associated with ER status. Mutations in EGFR (P = .003), TP53 (P = .007), and CTNNB1 (P = .027) were significantly associated with ER expression. Multivariate analysis showed that mutations in EGFR (P = .032) and CTNNB1 (P = .026) were significantly associated with ER expression, whereas TP53 mutations exhibited a trend toward significance (P = .059). Relapse-free survival (RFS) was longer in all the patients with ER-positive tumors than those with ER-negative tumors (P = .021). RFS and overall survival were longer (P = .024, P = .011, respectively) in the stage I patients with ER-positive tumors than those with ER-negative tumors.

CONCLUSION

ERβ expression is positively associated with EGFR mutations and negatively with TP53 and CTNNB1 mutations. ER-positive tumors can be associated with better prognosis of the patients, suggesting that ER expression with coexisting EGFR mutations and wild-type TP53 contribute to the biology of non-small cell lung cancer.

Expression patterns and clinical significance of estrogen receptor in non-small cell lung cancer

BACKGROUND

Lung cancer death remains the highest among all malignancies. Gender differences show women have an increased cancer incidence while men have worse outcomes. These observations identified that some lung carcinomas express estrogen receptors (ER). This is a promising target as antiestrogen drugs can reduce tumors and improve survival. However, there is a limited understanding of ER distribution and its clinical significance to properly design antiestrogen drug clinical trials. Thus, we comprehensively analyzed ERα and ERβ expression patterns by gender, cancer cell type, and receptor location in lung cancer.

METHODS

We conducted a systematic review using the PubMed database from all-time through October 2022, using MeSH terms with the keywords "lung cancer," "estrogen receptor," and "immunohistochemistry." We identified 120 studies with 21 reports being evaluated based on our inclusion criteria.

RESULTS

We examined 4874 lung cancers from 5011 patients. ERβ is the predominant form of ER expressed, mainly found in the nucleus. The ERβ positivity rate is 51.5% in males versus 55.5% in females and was not statistically different. In contrast, ERα is predominately extranuclear in location, and ERα expression varies by gender. Males had a positivity rate of 31% versus 26.6% in females, which is statistically different. ERα is associated with a worse prognosis in some studies, while it had no effect in others. Overall, ERβ was associated with a better prognosis.

CONCLUSION

We characterized ER expression patterns in 4874 lung cancers. Over 50% expressed ERβ with equal rates in both sexes and was associated with a better prognosis. ERα expression was slightly higher in males (31%) than females (26.6%) and was associated with a poor prognosis. Our findings suggest estrogen signaling may be a promising drug target in lung cancer.

ERβ overexpression may not be a direct prognostic factor in patients with NSCLC: A meta-analysis

BACKGROUND

Overall survival of non-small cell lung cancer (NSCLC) patients remains disappointingly low. The estrogen receptor (ER) was considered a promising therapeutic target for NSCLC. Numerous studies have linked expression of ERβ to lung cancer outcome. However, results are conflicting regarding the association of ERβ with surviving lung cancer.

METHOD

The aim of this meta-analysis was to evaluate the prognostic aspect of ERβ expression on survival among NSCLC patients. We performed a final analysis of prognostic value of overexpression ERβ on 3500 patients from 18 evaluable studies (from January 1, 2000 to May 1, 2021). The reference category is specified as low ERβ expression levels. Summarized hazard ratios were calculated.

RESULTS

Our study showed that the pooled hazard ratios of ERβ overexpression for overall survival in NSCLC was 0.81 (95% confidence interval (CI): 0.64-1.02, P = 0.07) by univariate analysis and 1.06 (95% CI: 0.83-1.36, P = 0.63) by multivariate analysis. Pooled hazard ratio by univariate analysis in Asian studies was 0.73 (95%CI: 0.59-0.89, P = 0.002). Pooled hazard ratio by univariate analysis was 0.75 (95% CI: 0.61-0.93, P = 0.009) from seven studies reported for nuclear ERβ. No significant results were found in subgroups by multivariate analysis. No significant results were found in studies outside Asia or in studies reported for cytoplasmic ERβ.

CONCLUSION

Our results suggested that expression of ERβ might not be a direct prognostic factor for NSCLC patients. More detailed prospective studies are needed to identify direct prognostic factors in these patients.

Targeting Nuclear Receptors in Lung Cancer—Novel Therapeutic Prospects

Lung cancer, the second most commonly diagnosed cancer, is the major cause of fatalities worldwide for both men and women, with an estimated 2.2 million new incidences and 1.8 million deaths, according to GLOBOCAN 2020. Although various risk factors for lung cancer pathogenesis have been reported, controlling smoking alone has a significant value as a preventive measure. In spite of decades of extensive research, mechanistic cues and targets need to be profoundly explored to develop potential diagnostics, treatments, and reliable therapies for this disease. Nuclear receptors (NRs) function as transcription factors that control diverse biological processes such as cell growth, differentiation, development, and metabolism. The aberrant expression of NRs has been involved in a variety of disorders, including cancer. Deregulation of distinct NRs in lung cancer has been associated with numerous events, including mutations, epigenetic modifications, and different signaling cascades. Substantial efforts have been made to develop several small molecules as agonists or antagonists directed to target specific NRs for inhibiting tumor cell growth, migration, and invasion and inducing apoptosis in lung cancer, which makes NRs promising candidates for reliable lung cancer therapeutics. The current work focuses on the importance of various NRs in the development and progression of lung cancer and highlights the different small molecules (e.g., agonist or antagonist) that influence NR expression, with the goal of establishing them as viable therapeutics to combat lung cancer.

Targeting Estrogens and Various Estrogen-Related Receptors against Non-Small Cell Lung Cancers: A Perspective

Non-small cell lung cancers (NSCLCs) account for ~85% of lung cancer cases worldwide. Mammalian lungs are exposed to both endogenous and exogenous estrogens. The expression of estrogen receptors (ERs) in lung cancer cells has evoked the necessity to evaluate the role of estrogens in the disease progression. Estrogens, specifically 17β-estradiol, promote maturation of several tissue types including lungs. Recent epidemiologic data indicate that women have a higher risk of lung adenocarcinoma, a type of NSCLC, when compared to men, independent of smoking status. Besides ERs, pulmonary tissues both in healthy physiology and in NSCLCs also express G-protein-coupled ERs (GPERs), epidermal growth factor receptor (EGFRs), estrogen-related receptors (ERRs) and orphan nuclear receptors. Premenopausal females between the ages of 15 and 50 years synthesize a large contingent of estrogens and are at a greater risk of developing NSCLCs. Estrogen-ER/GPER/EGFR/ERR-mediated activation of various cell signaling molecules regulates NSCLC cell proliferation, survival and apoptosis. This article sheds light on the most recent achievements in the elucidation of sequential biochemical events in estrogen-activated cell signaling pathways involved in NSCLC severity with insight into the mechanism of regulation by ERs/GPERs/EGFRs/ERRs. It further discusses the success of anti-estrogen therapies against NSCLCs.

Protumor role of estrogen receptor expression in oral squamous cell carcinoma cells

OBJECTIVE

Accumulating evidence has demonstrated the protumor role of estrogen receptor (ER)-mediated signaling in multiple cancer types, which is distinct from this signaling in sex steroid-dependent organs. However, its role in oral squamous cell carcinoma (OSCC) remains unclear.

STUDY DESIGN

We assessed the expression of ERα and ERβ in human OSCC tissues by immunohistochemistry and evaluated the expression of both receptors in OSCC cell lines by immunoblotting and flow cytometry. To further assess the contribution of ER-mediated signals to oral cancer progression, proliferation, invasion, and chemosensitivity, cell lines were stimulated with the ER agonist β-estradiol.

RESULTS

Immunohistochemical analysis of OSCC tissues showed that ERβ was present in the cytoplasm and nuclei of OSCC cells. In contrast, ERα was not detected in any of the cases analyzed. Additionally, the proliferation and invasiveness of OSCC cells were significantly elevated following stimulation with β-estradiol. Chemotherapeutic agent-induced apoptosis of cancer cells was attenuated by pretreatment with β-estradiol.

CONCLUSIONS

ER-mediated signaling plays a crucial role in oral cancer progression by facilitating the proliferation, invasion, and chemoresistance of OSCC cells, indicating its potential for developing novel targeted therapies for this type of cancer.

Complex Differential Diagnosis between Primary Breast Cancer and Breast Metastasis from EGFR-Mutated Lung Adenocarcinoma: Case Report and Literature Review

We present a case of a woman with epidermal growth factor receptor (EGFR)-mutated lung adenocarcinoma who received gefitinib for 2 years and obtained a partial response. The patient then developed liver metastasis and a breast lesion, displaying high estrogen receptor (ER) expression and harboring the same EGFR mutation. From the radiological studies, it was not possible to make a differential diagnosis between primary breast cancer and breast metastasis from lung cancer. After the removal of the breast nodule, thanks to the clinical history, radiology, and above all, molecular and immunohistochemical investigations, a diagnosis of breast metastasis from lung adenocarcinoma was made. This case emphasizes the importance of a comprehensive clinical, pathological, and molecular analysis in the differential diagnosis between primary breast cancer and metastases from extramammary tumor to guide adequate treatment decision making.

Upregulation of estrogen receptor beta protein but not mRNA predicts poor prognosis and may be associated with enhanced translation in non-small cell lung cancer: a systematic review and meta-analysis

Background

An increasing number of original studies suggest that estrogen receptor beta (ERβ) expression may be related to non-small cell lung cancer (NSCLC) prognosis; however, the evidence remains inconclusive and conflicting. We aimed to systematically evaluate the expression and prognostic value of ERβ in NSCLC, and to explain the inconsistency between ERβ protein and mRNA level.

Methods

PubMed, Embase, and Web of Science databases were searched for studies (published before October 6, 2020) reporting the prognostic value of ERβ protein expression in NSCLC. The pooled hazard ratios (HRs) with 95% confidence intervals (CIs) for overall survival (OS) were calculated. Transcriptome and survival data of lung adenocarcinoma patients were obtained from public databases for differential expression and survival analyses. Immunohistochemistry (IHC) was performed to examine the ERβ protein expression in 39 NSCLC patients. Western blotting and RT-qPCR were performed to analyze ERβ expression in two paired NSCLC and normal adjacent tissue samples. The effect of methyltransferase-like 13 (METTL3) on ERβ expression was investigated in a lung cancer cell line.

Results

Meta-analysis of 23 studies with a total of 3744 patients demonstrated that high protein expression of overall ERβ and cytoplasmic ERβ indicated poor OS (HR: 1.05, 95% CI: 1.00 to 1.10; HR: 1.48, 95% CI: 1.13 to 1.95) in NSCLC. For lung adenocarcinoma especially, high protein expression of both overall/cytoplasmic ERβ and nuclear ERβ suggested poor OS (HR: 1.54, 95% CI: 1.05 to 2.25; HR: 1.36, 95% CI: 1.03 to 1.80). Bioinformatics analysis indicated the expression of ERβ mRNA was not associated with the prognosis of lung adenocarcinoma. Analysis of public databases showed that ERβ mRNA is not highly expressed in tumor tissues, however, IHC results revealed that ERβ protein is highly expressed in NSCLC tissues. We validated this inconsistency in ERβ expression in paired tumors and normal adjacent tissues from patients. Moreover, METTL3 knockdown in the A549 cell line downregulated ERβ protein expression but not ERβ mRNA expression.

Conclusions

Our study elucidated the inconsistency between ERβ protein and mRNA expression levels and their prognostic values. The results indicated that METTL3-driven enhanced translation in NSCLC may cause this inconsistency.

The smoking estrogens - a potential synergy between estradiol and benzo(a)pyrene

According to recent statistics, Lung Cancer (LC) is one of the most frequently diagnosed tumor types, representing nearly 12% of all global cancer cases. Moreover, in recent years, an increased mortality rate and incidence of this cancer were observed, especially among nonsmokers. Lung cancer patients are often characterized by poor prognosis and low survival rates, which encourages the scientific community to investigate the biochemical and molecular processes leading to the development of this malignancy. Furthermore, the mechanisms of LC formation and progression are not yet fully elucidated due to their high complexity, as well as a multitude of environmental, genetic, and molecular factors involved. Even though LC's association with exposure to cigarette smoke is indisputable, current research provides evidence that the development of this cancer can also be affected by the presence of estrogens and their interaction with several tobacco smoke components. Hence, the main goal of this brief review was to investigate reports of a possible synergy between 17β estradiol (E2), the most biologically active estrogen, and benzo(a)pyrene (BaP), a strongly carcinogenic compound produced as a result of incomplete tobacco combustion. The literature sources demonstrate a possible carcinogenic synergy between estrogens, especially E2, and BaP, a toxic tobacco smoke component. Therefeore, the combined effect of disturbed estrogen production in cancer cells, as well as the molecular influence exerted by BaP, could explain the increased aggressiveness and rate of LC development. Summarizing, the synergistic effect of these risk factors is an interesting area of further research.

Expression and clinical implications of estrogen receptors in thoracic malignancies: a narrative review

Thoracic malignancies represent a significant global health burden with incidence and mortality increasing year by year. Thoracic cancer prognosis and treatment options depend on several factors, including the type and size of the tumor, its location, and the overall health status of patients. Gender represents an important prognostic variable in thoracic malignancies. One of the greatest biological differences between women and men is the presence of female sex hormones, and an increasing number of studies suggest that estrogens may play either a causative or a protective role in thoracic malignancies. Over the past 60 years since the discovery of the first nuclear estrogen receptor (ER) isoform α and the almost 20 years since the discovery of the second estrogen receptor, ERβ, different mechanisms governing estrogen action have been identified and characterized. This literature review reports the published data regarding the expression and function of ERs in different thoracic malignancies and discuss sex disparity in clinical outcomes. From this analysis emerges that further efforts are warranted to better elucidate the role of sex hormones in thoracic malignancies, and to reduce disparities in care between genders. Understanding the mechanisms by which gender-related differences can affect and interfere with the onset and evolution of thoracic malignancies and impact on response to therapies could help to improve the knowledge needed to develop increasingly personalized and targeted treatments.

Prognostic value of ESR2 expression on adjuvant chemotherapy in completely resected NSCLC

Background

Prognostic biomarker, which can inform the treatment outcome of adjuvant chemotherapy (ACT) after complete resection of early-stage non-small cell lung cancer (NSCLC), is urgently needed for the personalized treatment of these patients.

Patients and methods

The prognostic value of gene expression of the estrogen receptor (ER) on the effect of ACT in completely resected NSCLC was investigated in the present study. Two independent datasets from Gene Expression Omnibus (GEO) with a total of 309 patients were included in this study. The prognostic value of ER gene expression on ACT’s efficacy was evaluated by survival analysis and Cox hazards models.

Results

We found a consistent and significant prognostic value of ERβ (ESR2) expression for ACT’s efficacy in completely resected NSCLC in both of the two independent cohorts. After multivariate adjustment, a significant survival benefit of ACT was observed in patients with low expression of ESR2, with a hazard ratio (HR) of 0.19 (95%CI 0.05–0.82, p = 0.026) in the discovery cohort and an HR of 0.27 (95%CI 0.10–0.76, p = 0.012) in the validation group. No significant benefit of ACT in the subgroup of patients with high expression of ESR2 was observed, with an HR of 0.80 (95%CI 0.31–2.09, p = 0.644) in the discovery cohort and an HR of 1.05 (95%CI 0.48–2.29, p = 0.896) in the validation group.

Conclusion

A significant survival benefit from ACT was observed in patients with low ESR2 expression. No significant survival benefit was observed in patients with high ESR2 expression. Detection of ESR2 expression in NSCLC may help personalize its treatment after complete resection.

An examination of two dichotomies: Women with lung cancer and living with lung cancer as a chronic disease

Lung cancer remains the leading cause of cancer death globally, yet with many recent advances in the diagnosis and treatment of lung cancer, the face of the disease is shifting. Historically, lung cancer is often thought of as a predominantly male disease with more than twice as many men as women being diagnosed worldwide-mostly due to the influence of smoking as the leading risk factor. However, lung cancer is also the second leading cause of cancer death in women and there is a growing population of young women who have never smoked and are being diagnosed. The past decade has seen groundbreaking innovations in both the early detection and treatment of lung cancer. In this new era, survival rates are beginning to increase and many of those diagnosed are finding themselves in a new situation-living long term with a deadly cancer. Here, we review pertinent aspects of women and lung cancer as well as the concept of living with lung cancer as a chronic disease to give a new perspective on the changing face of lung cancer treatment and care.

The prevalence and prognostic significance of estrogen receptor beta expression in non-small cell lung cancer

Background

Estrogen receptor beta (ERβ) is the predominant estrogen receptor (ER) expressed in non-small cell lung cancer (NSCLC); however, due to methodological disparities among prior studies, the prognostic value of ERβ expression in NSCLC remains unclear. Our objective was to apply improved detection and analysis techniques to assess the prognostic value of ERβ expression in NSCLC.

Methods

A tissue microarray (TMA) was used which contained resected and biopsy specimens from 299 patients diagnosed at a single center with stages I-IV NSCLC. Sections of this array were stained using high-sensitivity fluorescence immunohistochemistry, with the well-validated PPG5/10 monoclonal antibody. Digital images of the stained array slides were analyzed using software-based image analysis, which reported ERβ expression as a continuous variable in different subcellular domains.

Results

There were no differences in ERβ expression between male and female patients. High expression of ERβ was not a prognostic factor, but was significantly associated with stage IV disease in both tumor and stroma (P<0.001). In multivariable analysis, a high nuclear/cytoplasmic (N/C) ratio of ERβ expression was significantly associated with shorter overall survival, based on expression in the tumor [hazard ratio (HR): 1.65; 95% confidence interval (CI): 1.25-2.19; P<0.001] and in the stroma (HR: 1.57; 95% CI: 1.16-2.12; P=0.003).

Conclusions

These results suggest that subcellular localization of ERβ, but not absolute expression, is a prognostic factor in NSCLC.

Somatic profile in lung cancers is associated to reproductive factors in never-smokers women: Results from the IFCT-1002 BioCAST study

BACKGROUND

Lung cancer in women is on the rise, with a higher proportion occurring in lifelong never-smokers. Lung cancer in never-smokers (LCINS) exhibits a high frequency of driver oncogene alterations. In this study, we aimed to investigate whether exposure to reproductive factors in women with LCINS may modulate the molecular pattern.

METHODS

All newly diagnosed LCINSs were included in a prospective, observational study (IFCT-1002 BioCAST). Each patient responded to a questionnaire including reproductive factors. Biomarker test results were also collected.

RESULTS

Two hundred and sixty women were included in this analysis, and 166 alterations were characterized. EGFR mutation frequency proved greater among patients with late menarche (74% in age>14 vs. 40% and 41% for 12-14 and ≤12 years, respectively; P=0.020) and tended to decrease with increasingly late age at menopause. In multivariate analysis, EGFR mutation frequency increased by 23% per increment of 1 year of age at menarche (P=0.048), and by 9% for each year at age at first birth (P=0.035). ALK alteration frequency was greater in women with high parity (50% in≥5 vs. 12% and 7% for 1-4 and nulliparity, respectively; P=0.021).

CONCLUSION

In a cohort of women LCINSs, female hormonal factors appear to impact molecular pattern.

Influence of Estrogen on the NSCLC Microenvironment: A Comprehensive Picture and Clinical Implications

Lung cancer mortality represents the leading cause of cancer related deaths in the United States and worldwide. Almost half of these deaths occur in female patients, making lung cancer the most common cause of cancer mortality in women with a higher annual mortality rate than breast, uterine, and ovarian cancers combined. The distinct epidemiological, histological and biological presentation of non-small cell lung cancer (NSCLC) in women combined with extensive preclinical data have demonstrated that the female sex hormone β-estradiol (E2) plays an important role in NSCLC tumorigenesis, prognosis, and treatment response. Estrogen receptors are widely expressed on stromal and immune cells, and estrogen-linked signaling pathways are known to be involved in regulating the response of both the innate and adaptive immune system. Immune evasion has been recognized as a “hallmark” of cancer and immunotherapy has re-defined standard of care treatment for NSCLC. Despite these advancements, the low response rates observed in patients treated with immune checkpoint inhibitors has led to a search for mediators of immunosuppression and ways to augment the action of these agents. We focus on emerging data describing sex differences that modulate immunotherapy efficacy in NSCLC, immunosuppressive properties of E2 that lead to a pro-tumor microenvironment (TME), and the translational potential of altering the immune microenvironment by targeting the estrogen signaling pathway. E2-induced modulation affects multiple cell types within the TME, including cancer-associated fibroblasts, tumor infiltrating myeloid cells, and tumor infiltrating lymphocytes, all of which interplay with lung tumor cells via E2 and estrogen receptor engagement, ultimately shaping the TME that may, in part, be responsible for the sex-based disparities observed in NSCLC. An improved understanding of the role of the estrogen pathway in NSCLC anti-cancer immunity may lead to novel therapeutic approaches for altering the TME to improve the efficacy of immunotherapy agents.

Inhibiting Pathways Predicted From a Steroid Hormone Gene Signature Yields Synergistic Antitumor Effects in NSCLC

INTRODUCTION

Mounting evidence supports a role for estrogen signaling in NSCLC progression. We previously reported a seven-gene signature that predicts prognosis in estrogen receptor β positive (ERβ+) NSCLC. The signature defines a network comprised of ER and human EGFR-2/3 (HER2/HER3) signaling.

METHODS

We tested the efficacy of combining the pan-HER inhibitor, dacomitinib, with the estrogen antagonist, fulvestrant, in ERβ+ NSCLC models with differing genotypes. We assessed the potency of this combination on xenograft growth and survival of host mice, and the ability to reverse the gene signature associated with poor outcome.

RESULTS

Synergy was observed between dacomitinib and fulvestrant in three human ERβ+ NSCLC models: 201T (wild-type EGFR), A549 (KRAS mutant), and HCC827 (EGFR 19 deletion) with combination indices of 0.1-0.6. The combination, but not single agents, completely reversed the gene signature associated with poor prognosis in a mechanism that is largely mediated by activator protein 1 downregulation. In vivo, the combination also induced tumor regression and reversed the gene signature. In HCC827 xenografts treated with the combination, survival of mice was prolonged after therapy discontinuation, tumors that recurred were less aggressive, and two mechanisms of HER inhibitor resistance involving c-Met activation and PTEN loss were blocked.

CONCLUSIONS

The combination of an ER blocker and a pan-HER inhibitor provides synergistic efficacy in different models of ERβ+ NSCLC. Our data support the use of this combination clinically, considering its ability to induce potent antitumor effects and produce a gene signature that predicts better clinical outcomes.

The estrogen pathway as a modulator of response to immunotherapy

Lung cancer is the leading cause of cancer deaths worldwide, with a 5-year survival rate of about 18%. Thus, there is a great need for novel therapeutic approaches to treat non-small-cell lung cancer (NSCLC). Immune checkpoint inhibitors (ICIs) have improved outcomes for a subset of patients, especially those with high programmed death-ligand 1 expression and/or high tumor mutational burden, but have failed in the majority of patients. Increasing evidence suggests that the estrogen signaling pathway may be a therapeutic target in metastatic NSCLC and that the estrogen pathway may play a role in sex-based responses to ICIs. This report will review the epidemiologic, preclinical and clinical data on the estrogen pathway in NSCLC, its implications in sex-based responses to ICIs and the potential use of antiestrogen therapy in combination with ICIs.

Sex specific function of epithelial STAT3 signaling in pathogenesis of K-ras mutant lung cancer

Lung adenocarcinomas (LUADs) with mutations in the K-ras oncogene display dismal prognosis. Proinflammatory and immunomodulatory events that drive development of K-ras mutant LUAD are poorly understood. Here, we develop a lung epithelial specific K-ras mutant/Stat3 conditional knockout (LR/Stat3^Δ/Δ) mouse model. Epithelial Stat3 deletion results in intriguing sex-associated discrepancies; K-ras mutant tumors are decreased in female LR/Stat3^Δ/Δ mice whereas tumor burdens are increased in males. RNA-sequencing and tumor microenvironment (TME) analysis demonstrate increased anti-tumor immune responses following Stat3 deletion in females and, conversely, elevated pro-tumor immune pathways in males. While IL-6 blockade in male LR/Stat3^Δ/Δ mice reduces lung tumorigenesis, inhibition of estrogen receptor signaling in female mice augments K-ras mutant oncogenesis and reprograms lung TME toward a pro-tumor phenotype. Our data underscore a critical sex-specific role for epithelial Stat3 signaling in K-ras mutant LUAD, thus paving the way for developing personalized (e.g. sex-based) immunotherapeutic strategies for this fatal disease.

Proinflammatory and immunomodulatory events that drive development of K-ras mutant lung adenocarcinoma (LUAD) are poorly understood. Here they develop a lung epithelial specific K-ras mutant/Stat3 conditional knockout mouse model and show a sex-specific role for epithelial Stat3 signaling in K-ras-mutant LUAD.

Cytoplasmic expression of estrogen receptor β may predict poor outcome of EGFR-TKI therapy in metastatic lung adenocarcinoma

There is growing evidence that estrogen receptors (ER) are expressed in lung cancer cells, and are able to interact with the epidermal growth factor receptor (EGFR) signaling pathway. However, data on the association between cytoplasmic ER expression and the response to EGFR-tyrosine kinase inhibitors (TKI) treatment are limited. The aim of the present study was to investigate the associations between ERα/ERβ expression and EGFR mutational status and response to TKI treatment in metastatic lung adenocarcinoma. A retrospective study of 126 consecutive patients with lung adenocarcinoma who were diagnosed with stage IV disease and had received EGFR-TKI treatment was conducted. ER expression was detected by immunohistochemistry. EGFR and GTPase KRas (KRAS) mutational statuses were evaluated by denaturing high performance liquid chromatography and PCR-restriction fragment length polymorphism, respectively. In the overall cohort of 126 lung adenocarcinoma samples analyzed, ERα expression in the nucleus of tumor cells was identified in 17 (18.9%) patients, whereas ERβ expression was identified in the nucleus (22/126, 17.5%) and cytoplasm (17/126, 13.5%). The nuclear expression of ERβ was positively associated with the degree of tumor differentiation (P=0.010). EGFR-sensitizing mutations were significantly associated with improved objective response rates (ORR), disease control rates (DCR), median progression-free survival (mPFS) and median overall survival (mOS) (P<0.001; P<0.001; P=0.003; and P=0.026, respectively). Patients with cytoplasmic ERβ expression exhibited non-significant poorer ORR, DCR, mPFS and mOS compared with patients without cytoplasmic ERβ expression (P=0.082; P=0.106; P=0.084; and P=0.119, respectively). However, the significant decrease of ORR, DCR and mPFS was observed in patients with coexisting cytoplasmic ERβ expression and EGFR-sensitizing mutations (P=0.030; P=0.009; and P=0.018, respectively) in comparison with the subgroup with EGFR sensitizing mutations but negative expression of cytoplasmic ERβ. A trend towards shorter mOS was also observed in patients with coexisting cytoplasmic ERβ expression and EGFR-sensitizing mutations (P=0.071). No KRAS mutations were identified in patients with cytoplasmic ERβ expression. Subsequent to adjusting for sex, smoking status and EGFR mutation status, the Cox repression analysis indicated that cytoplasmic expression of ERβ was a negative independent predictor for mPFS in the whole patient cohort (HR=1.870; 95% confidence interval 1.058–3.305; P=0.031). Cytoplasmic ERβ expression was negatively correlated with the efficacy of EGFR-TKI treatment for metastatic lung adenocarcinoma, particularly for patients with coexisting cytoplasmic ERβ expression and EGFR-sensitizing mutations. Cytoplasmic ERβ may be a promising marker to predict the outcome of EGFR-TKI treatment.

Preclinical Evidence for Combined Use of Aromatase Inhibitors and NSAIDs as Preventive Agents of Tobacco-Induced Lung Cancer

INTRODUCTION

A hormonal role in NSCLC development is well documented. We previously showed that the aromatase inhibitor (AI) anastrozole decreased development of tobacco carcinogen-induced lung tumors in a murine lung cancer prevention model and that aromatase and estrogen receptor were expressed in pulmonary inflammatory cells.

METHODS

We utilized a tobacco carcinogen-induced lung tumor mouse model by treatment with 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK), to determine whether an AI combined with nonsteroidal anti-inflammatory drugs results in greater lung tumor prevention effects compared to single-agent treatment.

RESULTS

Combination of anastrozole (0.1 mg/kg/d) with aspirin (25 mg/kg/d) after NNK exposure resulted in significantly fewer and smaller lung tumors than did single-agent treatments and was accompanied by maximum decreases in circulating β-estradiol (E2) and interleukin-6, tumor-infiltrating macrophages, and tumoral Ki67, phospho-mitogen-activated protein kinase, phospho-signal transducer and activator of transcription 3, and interleukin-17A expression. Preneoplasia arising after combination treatment showed the lowest Sox-2 expression, suggesting an inhibitory effect on proliferative capacity in the airways by blocking both E2 and inflammation. Anastrozole combined with ibuprofen instead of aspirin also showed enhanced antitumor effects. Moreover, male mice treated with NNK that received E2 in their drinking water showed greater levels of pulmonary macrophages and inflammatory markers than did the control, confirming an E2 effect on inflammation in the microenvironment.

CONCLUSIONS

Our results suggest a benefit to joint targeting of the estrogen and inflammatory pathways for NSCLC prevention. Combining AIs with nonsteroidal anti-inflammatory drugs reduces circulating E2, proinflammatory cytokines, and macrophage recruitment in the lung microenvironment after tobacco exposure. This strategy could be particularly effective in women who have underlying pulmonary inflammatory diseases.

Estrogen, Estrogen Receptor and Lung Cancer

Estrogen has been postulated as a contributor for lung cancer development and progression. We reviewed the current knowledge about the expression and prognostic implications of the estrogen receptors (ER) in lung cancer, the effect and signaling pathway of estrogen on lung cancer, the hormone replacement therapy and lung cancer risk and survival, the mechanistic relationship between the ER and the epidermal growth factor receptor (EGFR), and the relevant clinical trials combining the ER antagonist and the EGFR antagonist, to investigate the role of estrogen in lung cancer. Estrogen and its receptor have the potential to become a prognosticator and a therapeutic target in lung cancer. On the other hand, tobacco smoking aggravates the effect of estrogen and endocrine disruptive chemicals from the environment targeting ER may well contribute to the lung carcinogenesis. They have gradually become important issues in the course of preventive medicine.

Current status of research and treatment for non-small cell lung cancer in never-smoking females

Lung cancer is the leading cause of cancer-related deaths worldwide with over 1 million deaths each year. The overall prognosis of lung cancer patients remains unsatisfactory, with a 5-year overall survival rate of less than 15%. Although most lung cancers are a result of smoking, approximately 25% of lung cancer cases worldwide are not attributable to tobacco use. Notably, more than half of the lung cancer cases in women occur in non-smokers. Among non-small-cell lung cancer (NSCLC) cases, cigarette-smokers have a greater association with squamous cell carcinoma than adenocarcinoma, which is more common in non-smokers. These findings imply that specific molecular and pathological features may associate with lung adenocarcinoma arising in non-smoker female patients. Over the past decade, whole genome sequencing and other '-omics' technologies led to the discovery of pathogenic mutations that drive tumor cell formation. These technological developments may enable tailored patient treatments throughout the course of their disease, potentially leading to improved patient outcomes. Some clinical and laboratory studies have shown success outcomes using epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKI) in patients with EGFR mutations and ALK rearrangements, respectively. In fact, these 2 mutations are predominantly present in female non-smokers with adenocarcinoma. Immunotherapy has also recently emerged as a major therapeutic modality in NSCLC. In this review, we summarize the current understanding of NSCLC biology and new therapeutic molecular targets, focusing on the pathogenesis of non-smoker female NSCLC patients.

Exploring estrogenic activity in lung cancer

It is well known that a connection between xenobiotics inhalation, especially tobacco combustion and Lung Cancer development is strongly significant and indisputable. However, recent studies provide evidence indicating that another factors such as, estrogens are also involved in lung carcinoma biology and metabolism. Although the status of estrogen receptors (ER), in both cancerous and healthy lung tissue has been well documented, there is still inconclusive data with respect of which isoform of the receptor is present in the lungs. However according to several studies, ERβ appears to be predominant form. Apart from ERs, estrogens can work through a recently discovered G-coupled estrogen receptor. Binding with both types of the receptors causes a signal, which leads to i.e. enhanced cell proliferation. There are many published reports which suggest that estrogen can be synthesized in situ in lung cancer. Some disturbances in the activity and expression levels of enzymes involved in estrogen synthesis were proved. This suggests that increased amounts of sex-steroid hormones can affect cells biology and be the reason of the accelerated development and pathogenesis of lung cancer. There also exist phenomena which associate estrogenic metabolism and tobacco combustion and its carcinogenic influence on the lungs. Compounds present in cigarette smoke induce the activity of CYP1B1, the enzyme responsible for estrogenic metabolism and synthesis of their cateholic derivatives. These structures during their redox cycle are able to release reactive oxygen species or form DNA adduct, which generally leads to destruction of genetic material. This process may explain the synergistic effect of smoking and estrogens on estrogen-dependent lung cancer development.

Expression of PAM50 Genes in Lung Cancer: Evidence that Interactions between Hormone Receptors and HER2/HER3 Contribute to Poor Outcome

Non–small cell lung cancers (NSCLCs) frequently express estrogen receptor (ER) β, and estrogen signaling is active in many lung tumors. We investigated the ability of genes contained in the prediction analysis of microarray 50 (PAM50) breast cancer risk predictor gene signature to provide prognostic information in NSCLC. Supervised principal component analysis of mRNA expression data was used to evaluate the ability of the PAM50 panel to provide prognostic information in a stage I NSCLC cohort, in an all-stage NSCLC cohort, and in The Cancer Genome Atlas data. Immunohistochemistry was used to determine status of ERβ and other proteins in lung tumor tissue. Associations with prognosis were observed in the stage I cohort. Cross-validation identified seven genes that, when analyzed together, consistently showed survival associations. In pathway analysis, the seven-gene panel described one network containing the ER and progesterone receptor, as well as human epidermal growth factor receptor (HER)2/HER3 and neuregulin-1. NSCLC cases also showed a significant association between ERβ and HER2 protein expression. Cases positive for HER2 expression were more likely to express HER3, and ERβ-positive cases were less likely to be both HER2 and HER3 negative. Prognostic ability of genes in the PAM50 panel was verified in an ERβ-positive cohort representing all NSCLC stages. In The Cancer Genome Atlas data sets, the PAM50 gene set was prognostic in both adenocarcinoma and squamous cell carcinoma, whereas the seven-gene panel was prognostic only in squamous cell carcinoma. Genes in the PAM50 panel, including those linking ER and HER2, identify lung cancer patients at risk for poor outcome, especially among ERβ-positive cases and squamous cell carcinoma.

The prognostic significance of estrogen receptor β in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the fifth most common cancer in the world. Although multimodal and targeted therapy is now used in therapeutic procedures, the survival of patients with HNSCC has remained unchanged over the last 30 years. A number of studies have demonstrated that the increased expression of intranuclear ERβ in breast, lung and colon cancer is a favorable prognostic marker associated with higher survival rates. However, the clinical significance of sex hormone receptors in HNSCC remains unclear. The current study aimed to assess the expression of ERβ in HNSCC immunohistochemically and investigate any possible association between ERβ expression, and clinical and histopathological factors, disease recurrence and patient survival. The present study included 174 patients (165 males and 9 females) with a median age of 60.8 years (range, 39–79) with HNSCC who were primary surgically treated between January 2000 and December 2006. Immunohistochemical reactions for ERβ demonstrated that 73 patients (42%) exhibited positive ERβ expression. Distribution of ERβ status among different head and neck subsites indicated that >40% of all negative cases were located in laryngeal primaries, while incidence of other sublocalization within positive cases was similar and comparable (P=0.04). Furthermore, a correlation was observed between ERβ immunopositivity and the survival of patients, with respect to the primary tumor site. Patients with ERβ positive oropharyngeal cancer had a survival rate of 35.3% at 5-years compared with 25% for patients with negative expression. However, ERβ status was not significantly correlated with any other clinical or histopathological parameter. After an average follow-up time of 38.5 months (range, 3–60 months), 54 patients (31.1%) had succumbed to disease recurrence while 50 (28.7%) succumbed to other causes. In conclusion, ERβ positivity indicates improved survival of patients with oropharyngeal cancer. Further research is required in order to implement novel therapeutic strategies.

ICRP Publication 131: Stem Cell Biology with Respect to Carcinogenesis Aspects of Radiological Protection

This report provides a review of stem cells/progenitor cells and their responses to ionising radiation in relation to issues relevant to stochastic effects of radiation that form a major part of the International Commission on Radiological Protection's system of radiological protection. Current information on stem cell characteristics, maintenance and renewal, evolution with age, location in stem cell 'niches', and radiosensitivity to acute and protracted exposures is presented in a series of substantial reviews as annexes concerning haematopoietic tissue, mammary gland, thyroid, digestive tract, lung, skin, and bone. This foundation of knowledge of stem cells is used in the main text of the report to provide a biological insight into issues such as the linear-no-threshold (LNT) model, cancer risk among tissues, dose-rate effects, and changes in the risk of radiation carcinogenesis by age at exposure and attained age. Knowledge of the biology and associated radiation biology of stem cells and progenitor cells is more developed in tissues that renew fairly rapidly, such as haematopoietic tissue, intestinal mucosa, and epidermis, although all the tissues considered here possess stem cell populations. Important features of stem cell maintenance, renewal, and response are the microenvironmental signals operating in the niche residence, for which a well-defined spatial location has been identified in some tissues. The identity of the target cell for carcinogenesis continues to point to the more primitive stem cell population that is mostly quiescent, and hence able to accumulate the protracted sequence of mutations necessary to result in malignancy. In addition, there is some potential for daughter progenitor cells to be target cells in particular cases, such as in haematopoietic tissue and in skin. Several biological processes could contribute to protecting stem cells from mutation accumulation: (a) accurate DNA repair; (b) rapidly induced death of injured stem cells; (c) retention of the DNA parental template strand during divisions in some tissue systems, so that mutations are passed to the daughter differentiating cells and not retained in the parental cell; and (d) stem cell competition, whereby undamaged stem cells outcompete damaged stem cells for residence in the niche. DNA repair mainly occurs within a few days of irradiation, while stem cell competition requires weeks or many months depending on the tissue type. The aforementioned processes may contribute to the differences in carcinogenic radiation risk values between tissues, and may help to explain why a rapidly replicating tissue such as small intestine is less prone to such risk. The processes also provide a mechanistic insight relevant to the LNT model, and the relative and absolute risk models. The radiobiological knowledge also provides a scientific insight into discussions of the dose and dose-rate effectiveness factor currently used in radiological protection guidelines. In addition, the biological information contributes potential reasons for the age-dependent sensitivity to radiation carcinogenesis, including the effects of in-utero exposure.

Pre-existing Pulmonary Diseases and Survival in Patients With Stage-dependent Lung Adenocarcinoma: A STROBE-compliant Article

Asthma, chronic obstructive pulmonary disease (COPD), and pulmonary tuberculosis (TB) are common lung diseases associated with lung cancer mortality. This study evaluated sex disparities in pre-existing pulmonary diseases and stage-dependent lung adenocarcinoma survival.Patients newly diagnosed with lung adenocarcinoma between 2003 and 2008 were identified using the National Health Insurance Research Database and Cancer Registry. Cases with lung adenocarcinoma were followed until the end of 2010. Survival curves were estimated by the Kaplan-Meier method. Cox proportional-hazard regression was used to calculate the hazard ratio (HR) of pre-existing asthma, COPD, and/or TB, and to estimate all-cause mortality risk in patients with different stages of lung adenocarcinoma.A total of 14,518 cases were identified with lung adenocarcinoma. Specifically, among men, the HRs for TB were 1.69 (95% confidence interval [CI], 1.10-2.58), 1.48 (95% CI, 1.14-1.93), and 1.27 (95% CI, 1.08-1.49) for individuals with stage I + II, III, and IV diseases, respectively. The HRs for asthma were 1.41 (95% CI, 1.00-1.99) in women with stage I + II and 1.14 (95% CI, 1.04-1.26) in men with stage IV disease. For pulmonary disease combinations in men, the HRs were 1.45 (95% CI, 1.12-1.89) for asthma + COPD + TB, 1.35 (95% CI, 1.12-1.63) for COPD + TB, 1.28 (95% CI, 1.01-1.63) for TB, and 1.15 (95%CI, 1.04-1.27) for asthma + COPD, respectively. For women with stage I + II disease, the HR was 6.94 (95% CI, 2.72-17.71) for asthma + COPD + TB.Coexistence of pre-existing pulmonary diseases increased mortality risk in men with adenocarcinoma. TB is at elevated risk of mortality among men with different stages of adenocarcinoma. Asthmatic women with early-stage adenocarcinoma had increased risk of mortality.

Generation of an estrogen receptor beta-iCre knock-in mouse

A novel knock-in mouse that expresses codon-improved Cre recombinase (iCre) under regulation of the estrogen receptor beta (Esr2) promoter was developed for conditional deletion of genes and for the spatial and/or temporal localization of Esr2 expression. ESR2 is one of two classical nuclear estrogen receptors and displays a spatiotemporal expression pattern and functions that are different from the other estrogen receptor, ESR1. A cassette was constructed that contained iCre, a polyadenylation sequence, and a neomycin selection marker. This construct was used to insert iCre in front of the endogenous start codon of the Esr2 gene of a C57BL/6J embryonic stem cell line via homologous recombination. Resulting Esr2-iCre mice were bred with ROSA26-lacZ and Ai9-RFP reporter mice to visualize cells of functional iCre expression. Strong expression was observed in the ovary, the pituitary, the interstitium of the testes, the head and tail but not body of the epididymis, skeletal muscle, the coagulation gland (anterior prostate), the lung, and the preputial gland. Additional diffuse or patchy expression was observed in the cerebrum, the hypothalamus, the heart, the adrenal gland, the colon, the bladder, and the pads of the paws. Overall, Esr2-iCre mice will serve as a novel line for conditionally ablating genes in Esr2-expressing tissues, identifying novel Esr2-expressing cells, and differentiating the functions of ESR2 and ESR1.

Prognostic value of estrogen receptors mRNA expression in non-small cell lung cancer: A systematic review and meta-analysis

The prognostic value of estrogen receptors (ESR1 and ESR2) mRNA expression in patients with non-small cell lung cancer (NSCLC) remains controversial. Therefore, a systematic review with meta-analysis was conducted. A systematic literature search was conducted in both Pubmed and Embase. Studies that reported association of ESR and survival in NSCLC patients in the form of hazard ratio (HR) and 95% confidence interval (CI) were included. Pooled HR was taken as the effect size to reflect the association. Five eligible articles provided six separate studies for ESR1 and four for ESR2. For ESR1, the pooled HR of overall survival was 0.72 (95% CI 0.41-1.27) by univariate analysis and was 0.33 (95% CI: 0.20-0.53) by multivariate analysis. For ESR2, the pooled HR was 0.95 (95% CI 0.73-1.23) by univariate analysis. Sub-group analysis suggested that the disease stages and cut-off point may explain heterogeneity among studies of ESR1. Results of the meta-analysis revealed a potential benefit of positive ESR1 mRNA expression in survival in patients with NSCLC, especially in those of advanced stage. No statistically significant association was found between ESR2 mRNA expression and NSCLC patients' prognosis.

Correlation between epidermal growth factor receptor mutations and nuclear expression of female hormone receptors in non-small cell lung cancer: a meta-analysis

BACKGROUND

Compared with male, female non-small cell lung cancer (NSCLC) patients have better response when treated with epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs), suggesting a potential association between female hormones and EGFR mutation. However, the results provided by previous studies were inconclusive and controversial. We sought to examine the link between the expression of nuclear female hormone receptors and EGFR mutations in NSCLC.

METHODS

Electronic databases were used to search the relevant articles. The involved hormone receptors included estrogen receptor (ER) and progesterone receptor (PR). The primary endpoint was the occurrence of ER/PR expression and EGFR mutation in NSCLC patients.

RESULTS

Five studies fulfilled the criteria and were included in our analysis. Patients with high ER-β expression had higher positive EGFR mutation than low ER-β patients (44.2% vs. 23.7%), and there was a significant difference between the two groups [odds radio (OR) 3.44, 95% confidence interval (CI): 2.40-4.93, Z=6.72, P<0.001]. However, there is no significant correlation between EGFR mutations and ER-α (when included ER-α3, OR 1.20, 95% CI: 0.62-2.33, Z=0.55, P=0.58; and when included ER-α4, OR 1.18, 95% CI: 0.62-2.25, Z=0.51, P=0.61) or PR (OR 1.29, 95% CI: 0.40-4.10, Z=0.43, P=0.67). No significant publication bias was observed.

CONCLUSIONS

High nuclear expression of ER-β, but not ER-α or PR is correlated with EGFR mutations in NSCLC. The underlying mechanism and potential translational relevance warrant further investigation.

Minireview: Familiar Faces in Unfamiliar Places: The Emerging Role of Nuclear Receptors in Lung Cancer

Nuclear hormone receptors (NRs) are a superfamily of 48 transcription factors that are frequently modulated by ligands and control various cancer-relevant cellular pathways, such as differentiation, proliferation, migration, and metabolism. These properties make them excellent therapeutic targets in cancers dependent upon their activity, and as such, 3 NRs, estrogen receptor-α, androgen receptor, and retinoic acid receptor-α (more specifically, the promyelocytic leukemia-retinoic acid receptor-α translocation), have been targeted clinically in breast cancer, prostate cancer, and acute promyelocytic leukemia, respectively. Recently, a number of studies have highlighted a putative role for NRs in nonsmall cell lung cancer (NSCLC), a highly lethal type of lung cancer with relatively few targeted agents. Here, we review the potential roles of selected NRs in NSCLC and offer insights on how NRs may be leveraged in NSCLC to improve patient outcomes.

Sodium Valproate Enhances the Urethane-Induced Lung Adenomas and Suppresses Malignization of Adenomas in Ovariectomized Female Mice

In the present study, the possible effect of sodium valproate (NaVP) on urethane-induced lung tumors in female mice has been evaluated. BALB/c mice (n = 60; 4-6 weeks old, females) were used in the following groups: (1) urethane-treated; (2) urethane-NaVP-treated; (3) only NaVP-treated; (4) control. In the same groups, ovariectomized female mice (n = 60) were investigated. Urethane was given intraperitoneally, with a total dose of 50 mg/mouse. In NaVP-treated mice groups, 0.4% aqueous solution of NaVP was offered to mice ad libitum. The duration of the experiment was 6 months. The number of tumors per mouse in ovariectomized mice and in those treated with urethane and NaVP was significantly higher than in mice treated with urethane only (8.29 ± 0.58 versus 6.0 ± 0.63, p < 0.02). No significant difference in the number of tumors per mouse was revealed while comparing the nonovariectomized urethane- and urethane-NaVP-treated groups (p = 0.13). A significant decrease of adenocarcinoma number in ovariectomized mice treated with a urethane-NaVP as compared with ovariectomized mice treated with urethane only was found (p = 0.031). NaVP together with low estrogen may have a protective effect on the malignization of adenomas in ovariectomized mice.

The Impact of Coexisting Asthma, Chronic Obstructive Pulmonary Disease and Tuberculosis on Survival in Patients with Lung Squamous Cell Carcinoma

BACKGROUND

Pulmonary diseases [asthma, chronic obstructive pulmonary disease (COPD), and tuberculosis (TB)] are associated with lung cancer mortality. However, the relationship between coexisting pulmonary diseases and survival in patients with lung squamous cell carcinoma (SqCC) has not been well defined.

METHODS

Patients newly diagnosed with SqCC between 2003 and 2008 were identified by linking the National Health Insurance Research Database and Taiwan Cancer Registry Database. Cases with SqCC were followed up until death, loss to follow-up, or study end in 2010. Information on health status, date of death and the main causes of death was ascertained from the National Death Registry Database. Cox proportional hazard regression was used to calculate the hazard ratio (HR) of coexisting asthma, COPD and/or TB.

RESULTS

During the study period, a total of 5406 cases with SqCC were enrolled. For all cause-mortality, HRs were 1.08 [95% confidence interval (CI), 0.99-1.18], 1.04 (95% CI, 0.97-1.12), and 1.14 (95% CI, 1.00-1.31) for individuals with asthma, COPD, and TB, respectively. Specifically, among men with coexisting pulmonary diseases, the HRs were 1.56 (95% CI, 1.23-1.97) and 1.11 (95% CI, 1.00-1.24) for individuals with asthma+COPD+TB and asthma+COPD, respectively. Among male patients with stage III SqCC, HRs were 3.41 (95%CI, 1.27-9.17) and 1.65 (95%CI, 1.10-2.47) for individuals with asthma+TB and asthma+COPD+TB, respectively. Among male patients with stage IV SqCC, HRs were 1.40 (95%CI, 1.00-1.97) and 1.25 (95%CI, 1.03-1.52) for individuals with asthma+ COPD+TB and asthma. Among female patients with stage I and II, HR was 0.19 (95%CI, 005-0.77) for individuals with asthma.

CONCLUSIONS

Coexisting pulmonary diseases increased the risk of mortality from SqCC in male patients. For female patients with early stage SqCC, pre-existing asthma decreased mortality. These patients deserve greater attention while undergoing cancer treatment.

Potential therapeutic benefit of combining gefitinib and tamoxifen for treating advanced lung adenocarcinoma

Introduction. Epidermal growth factor receptor (EGFR) mutations are known as oncogene driver mutations and with EGFR mutations exhibit good response to the EGFR tyrosine kinase inhibitor Gefitinib. Some studies have shown that activation of estrogen and estrogen receptor α or β (ERα/β) promote adenocarcinoma. We evaluated the relationship between the two receptors and the potential therapeutic benefit with Gefitinib and Tamoxifen. Methods. We assessed the association between EGFR mutations as well as ERα/β expression/location and overall survival in a cohort of 55 patients with LAC from a single hospital. PC9 (EGFR exon 19 deletion mutant; Gefitinib-vulnerable cells) and A549 (EGFR wild type; Gefitinib-resistant cells) cancer cells were used to evaluate the in vitro therapeutic benefits of combining Gefitinib and Tamoxifen. Results. We found that the cytosolic but not the nuclear expression of ERβ was associated with better OS in LAC tumors but not associated with EGFR mutation. The in vitro study showed that combined Gefitinib and Tamoxifen resulted in increased apoptosis and cytosolic expression of ERβ. In addition, combining both medications resulted in reduced cell growth and increased the cytotoxic effect of Gefitinib. Conclusion. Tamoxifen enhanced advanced LAC cytotoxic effect induced by Gefitinib by arresting ERβ in cytosol.

Impact of coexisting pulmonary diseases on survival of patients with lung adenocarcinoma: a STROBE-compliant article

Asthma, chronic obstructive pulmonary disease (COPD), and pulmonary tuberculosis (TB) are common pulmonary diseases associated with lung cancer. Besides, smoking is more prevalent in Taiwanese men. This study evaluated gender disparities in coexisting pulmonary diseases on survival of patients with lung adenocarcinoma. Patients newly diagnosed with lung cancer between 2003 and 2008 were identified from Taiwan National Health Insurance Research Database. Cases with lung adenocarcinoma were further confirmed using the Cancer Registry Database and followed up until the end of 2010. Cox proportional hazard regression was used to calculate the hazard ratio (HR) of coexisting asthma, COPD, and/or TB to estimate all-cause mortality risk. During the study period, 13,399 cases of lung adenocarcinoma were identified. The HRs of adenocarcinoma in men and women were 1.20 (95% confidence interval [CI], 1.10-1.30) and 1.05 (95% CI, 0.95-1.16), respectively, for individuals with asthma, 1.32 (95% CI, 1.16-1.51) and 0.97 (95% CI, 0.89-1.05), respectively, for COPD, and 0.99 (95% CI, 0.93-1.06) and 1.06 (95% CI, 0.86-1.32), respectively, for individuals with TB. Specifically, among men with coexisting pulmonary diseases, the HRs were 1.63 (95% CI, 1.25-2.13), 1.31 (95% CI, 1.08-1.59), and 1.23 (95% CI, 1.11-1.36) for individuals with asthma + COPD + TB, asthma + COPD, and COPD + TB, respectively. However, there was no increase risk of mortality among women with coexisting pulmonary diseases. Coexisting pulmonary diseases are at an elevated risk of mortality among male patients with lung adenocarcinoma. Such patients deserve greater attention while undergoing cancer treatment.

Estrogen receptors as the novel therapeutic biomarker in non-small cell lung cancer

Although a wide range of studies have addressed the relationship between estrogen receptor (ER) expression and prognosis in non-small cell lung cancer (NSCLC), that relationship remains controversial. This is in large part because there is no consensus on the rate of ER expression in NSCLC or on the intracellular distribution of ER expression. This suggests that establishing the relationship between ER expression and prognosis will require standardization of the antibodies used as well as the definition of a positive response. For example, it is supposed from previous studies that ERs in the cytoplasm and nucleus have different relationships to prognosis than ERs in the cytoplasm. Moreover, ER signaling in NSCLC is known to be affected by aromatase, progesterone receptor and epidermal growth factor receptor mutation. However, there has been little functional analysis these mutants and subtypes. This review will focus on what is known about the role of ERs in NSCLC and whether ER can be a useful prognostic marker or therapeutic target in NSCLC.

Association of oral contraceptives use and lung cancer risk among women: an updated meta-analysis based on cohort and case-control studies

BACKGROUND

Previous studies on the association of oral contraceptives (OC) use and lung cancer generated inconsistent findings. The aim of this study was to confirm any definite correlation between OC use and lung cancer risk.

METHODS

Publications were reviewed and obtained through PubMed and EMBASE databases literature search up to November, 2013. Reference lists from retrieved articles were also reviewed. The language of publication was restricted to English. A meta-analysis was performed to evaluate the association by calculating pooled odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

A total of 14 studies consisting of 9 case- control studies and 5 cohort studies were finally included in this meta-analysis. There was no significant association observed between OC use and lung cancer risk in the overall analysis (OR=0.91; 95% CI=0.81-1.03). There was a significant protective effect in Europe (OR=0.74; 95% CI=0.60-0.91) and a borderline significant protective effect with an adenocarcinoma histology (OR=0.90; 95% CI=0.80-1.01) in subgroup analyses. No association was observed for methodological quality of study, study design, smoking status and case number of study.

CONCLUSION

This meta-analysis suggests that OC use is not likely to be associated with the risk of lung cancer at all. While a significant protective effect of OC use on lung cancer was observed in Europe, interpretation should be cautious because of the potential biases of low-quality studies. At the same time, more attention should be paid to the possible association of OC use with adenocarcinoma of lung. Our findings require further research, with well-conducted and large-scale epidemiological studies to confirm effects of OC use on lung cancer.

Estrogen receptor 1 gene expression and its combination with estrogen receptor 2 or aromatase expression predicts survival in non-small cell lung cancer

The biological roles of estrogen receptor 1 (ERS1), estrogen receptor 2 (ERS2), and aromatase (CYP19A1) genes in the development of non-small cell lung cancer (NSCLC) is unclear, as is the use of their expression as a prognostic factor. The aim of this study was to investigate the prognostic value of estrogen receptors and aromatase mRNA expression, along with aromatase protein concentration, in resected NSCLC patients. Tumor and non-tumor lung tissue samples were analyzed for the mRNA expression of ERS1, ERS2 and CYP19A1 by RT-PCR. Aromatase concentration was measured with an ELISA. A total of 96 patients were included. ERS1 expression was significantly higher in non-tumor tissue than in tumor samples. Two gene expression categories were created for each gene (and protein): high and low. ERS1 high category showed increased overall survival (OS) when compared to the low expression category. Aromatase protein concentration was significantly higher in tumor samples. Higher ERS1 expression in tumor tissues was related to longer overall survival. The analysis of gene expression combinations provides evidence for longer OS when both ERS1 and ERS2 are highly expressed. ESR1, alone or in combination with ERS2 or CYP19A1, is the most determining prognostic factor within the analyzed 3 genes. It seems that ERS1 can play a role in NSCLC prognosis, alone or in combination with other genes such as ERS2 or Cyp19a1. ERS2 in combination with aromatase concentration could have a similar function.

Targeting the estrogen pathway for the treatment and prevention of lung cancer

The estrogen signaling pathway is involved in the biology of non-small-cell lung cancer and represents a novel therapeutic target for lung cancer. This is supported by epidemiological evidence, preclinical studies and recent data from clinical trials. Antiestrogens and inhibitors of estrogen synthesis have been shown to inhibit lung tumor growth as well as prevent lung tumorigenesis in preclinical models both in vitro and in vivo. Two clinical trials testing the effectiveness of hormonal strategies in advanced non-small-cell lung cancer have recently been completed with promising results. Future work in this field should focus on identification of patients that would benefit from hormone modulators so that they can be used earlier in the course of disease or for chemoprevention.

Smoking out reproductive hormone actions in lung cancer

Experimental and population-based evidence has been steadily accumulating that steroid hormones are fundamentally involved in the biology of the lung. Both estrogen and progesterone receptors are present in normal and malignant lung tissue, and the reproductive hormones that bind these receptors have a role in lung development, lung inflammation, and lung cancer. The estrogen receptor-β (ER-β) was discovered in the 1990s as a novel form of ER that is transcribed from a gene distinct from ER-α, the receptor previously isolated from breast tissue. Interestingly, ER-β is the predominate ER expressed in normal and malignant lung tissue, whereas inflammatory cells that infiltrate the lung are known to express both ER-α and ER-β. Although there is evidence from animal models for the preferential effects of ER-β in the lungs of females, human lung tumors from males often contain comparable numbers of ER-β-positive cells and male-derived lung cancer cell lines respond to estrogens. Lung tumors from both males and females also express CYP19 (aromatase), the rate-limiting enzyme in estrogen synthesis that converts testosterone to estrone and β-estradiol. Thus, testosterone acts as a precursor for local estrogen production within lung tumors, independent of reproductive organs. This review discusses the recent literature findings about the biology of the ERs, aromatase, and the progesterone receptor in lung cancer and highlights the ongoing clinical trials and future therapeutic implications of these findings.

Estrongenic steroid hormones in lung cancer

It is becoming increasingly clear that steroid hormones are involved in the biology of many organs outside the reproductive system. Evidence has been accumulating since the mid 1990s that the lung contains receptors for both estrogen and progesterone and that these hormones have some role in lung development, pulmonary inflammation, and lung cancer. The estrogen receptor β (ERβ) is the major ER expressed in lung tissues, while inflammatory cells capable of infiltrating the lung are reported to express both ERα and ERβ. Although there is evidence in animals of preferential effects of ERβ in the lungs of females, human lung tumors from males also contain ERβ-positive cells and express aromatase, the enzyme that converts testosterone to estrogens. This review will discuss current literature findings on the role of the ERs and the progesterone receptor (PR), as well CYP19 (aromatase), the rate-limiting enzyme in the synthesis of estrogen, in lung cancer.

The validation of estrogen receptor 1 mRNA expression as a predictor of outcome in patients with metastatic non-small cell lung cancer

The prognostic role of estrogen receptors in lung cancer is not validated. Results from patients with early stage non-small lung cancer patients indicate a prognostic role of estrogen receptor 1 (ESR1) mRNA expression in these patients. Automated RNA extraction from paraffin and RT-quantitative PCR was used for evaluation of tumoral ESR1 and progesterone receptor (PGR) mRNA expression. The test cohort consisted of 31 patients with advanced or metastatic non-small cell lung cancer (NSCLC) patients, treated in a first-line registry trial. For validation, 53 patients from a randomized multicentre first-line study with eligible tumor samples were evaluated. There was no significant correlation of ESR1 expression with clinical characteristics. ESR1 high expression was of significant positive prognostic value in the training set with a median overall survival (OS) of 15.9 versus 6.2 months for high versus low ESR1 expression patients (p = 0.0498, HR 0.39). This could be confirmed in the validation cohort with a median OS of 10.9 versus 5.0 months in ESR1 high versus low patients, respectively (p = 0.0321, HR 0.51). In the multivariate analysis adjusted for histological subtype, gender, age and performance status, ESR1 expression remained an independent prognostic parameter for survival in both cohorts. In contrast to ESR1, PGR expression was not able to separate prognostic groups or to predict outcome significantly (for OS; p = 0.94). Our study shows that ESR1 mRNA as assessed by qPCR represents a reliable method for detecting ESR1 expression in NSCLC and that ESR1 expression is an independent prognostic factor in metastatic NSCLC.

The expression of estrogen receptors β2, 5 identifies and is associated with prognosis in non-small cell lung cancer

Estrogens play a pivotal role in the development and progression of non-small lung cancer (NSCLC). With the discovery of estrogen receptor β (ERβ) isoforms, some controversial roles of ERβ were explained adequately in NSCLC. In this study, our aim is to elucidate expression, distribution, and prognostic significance of ERβ 1, 2, 5 in NSCLC. Estrogen receptors β1, 2, 5 protein expression were confirmed by Western-blot analysis in all frozen tissues, and immunohistochemistry (IHC). Nuclear and cytoplasmic staining was evaluated and correlated with histopathologic characteristics, overall survival (OS) and disease-free survival (DFS) via Pearson χ (2) square, Kaplan-Meier plots and Cox proportional hazard models. ERβ1 was commonly found in the cytoplasm and was the most abundant isofroms followed by ERβ2 and ERβ5 which were localized in the cytoplasm and nucleus. In contrast to BPL, both in nucleus and cytoplasm, ERβ1, ERβ2, and ERβ5 were over expressed all in NSCLC (P < 0.05). IHC results were correlated with pathological and clinical follow-up data to delineate the distinct roles of ERβ1, ERβ2, and ERβ5 in NSCLC. nERβ1 "nuclear", cERβ2 and cERβ5 "cytoplasm" were in a negative correlation with the pathological stage and lymph node metastasis. In a Kaplan-Meier analysis, the expression cERβ2 and cERβ5 identified a group of patients with the longest DFS and OS. Cox proportional hazard models revealed that cERβ2 and cERβ5 predicted long time to DFS and OS. This is the first study to uncover the expression of ERβ1, ERβ2, and ERβ5, and show that they were over expressed in NSCLC. Meantime, we find that positive expression of cERβ2 and cERβ5 were in a positive correlation with DFS, and have prognostic values for the progression of NSCLC.