Expression of estrogen receptor α and β in esophageal squamous cell carcinoma

Estrogen receptor beta (ERβ) in esophageal cancer - a systematic review and meta-analysis

BACKGROUND

Esophageal cancer is the eighth most common cause of cancer-related deaths worldwide. There are two main histological subtypes of esophageal cancer: adenocarcinoma and squamous cell carcinoma. Among the factors associated with the development of esophageal cancer, estrogen receptor beta (ERβ) has been found to have a clinical significance.

AIM

To investigate the relationship between ERβ expression and esophageal cancer.

METHODS

English Medical literature searches were conducted for ERβ expression in patients with esophageal cancer versus healthy controls. Searches were performed up to August 31, 2023, using MEDLINE, PubMed, Embase and Google Scholar. Meta-analysis was performed by using Comprehensive meta-analysis software (Version 4, Biostat Inc., Englewood, NJ, USA). Pooled odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated. Heterogeneity was evaluated using Cochrane Q-test, and it was considered present if the Q-test P value was less than 0.10. I2 statistic was used to measure the proportion of inconsistency in individual studies, with I2 > 50% representing heterogeneity. We also calculated a potential publication bias.

RESULTS

Ten studies representing 11 substudies were selected according to the inclusion criteria. The odds ratio of ERβ expression in fixed effect analysis was 0.448, 95% CI: 0.237 to 0.846, 55.2% lower in esophageal cancer than in normal mucosa. Heterogeneity and inconsistency were low, and no publication bias was demonstrated.

CONCLUSION

This meta-analysis showed that ERβ expression is lower in esophageal cancer biopsy specimens than in healthy controls, this finding may have a significant effect on survival and can lead to new therapeutic avenues.

Different Expression Pattern of G Protein-Coupled Estrogen Receptor GPER1 in Esophageal Squamous Cell Carcinoma and Adenocarcinoma

Esophageal carcinoma is a male-dominant malignancy worldwide, and esophageal adenocarcinoma (EAC) shows more significant sex bias than esophageal squamous cell carcinoma (ESCC) in morbidity and mortality. The G protein-coupled estrogen receptor 1 (GPER1) is involved in several sex-related cancers; however, its expression level in esophageal carcinoma has been poorly investigated and its role is not precisely defined, depending on histological types. In the present study, the mRNA levels of GPER1 in esophageal carcinoma were collected from GEPIA and Oncomine databases for meta-analyses. The protein expression levels of GPER1 were detected by immunohistochemistry in the tissue microarray of EAC and ESCC. The GPER1 selective agonist G1, antagonist G15, and siRNA were applied in vitro to investigate their impacts on esophageal cell lines. Analysis of the RNA levels from the databases showed a decreased expression of GPER1 in overall esophageal carcinoma, and low expression levels of GPER1 were found to be associated with low survival of tumor patients. However, in the subgroup of EAC and its precancerous lesion, Barrett's esophagus, overexpression of GPER1 RNA was increased when compared with the normal tissues. The average staining scores of GPER1 protein in the tissue microarray of EAC were significantly higher than normal esophageal samples, and the rate of positive staining increased with the grade of poor tumor differentiation. The scores of GPER1 protein in ESCC tissues were lower than those in the normal tissues. The results from cell line experiments in vitro showed that the GPER1 agonist G1 inhibited proliferation and promoted apoptosis of ESCC cells EC109 with positive expression of GPER1. G1 had no obvious effect on normal esophageal NE2 cells with weak expression of GPER1. In addition, GPER1 RNA knockdown and application of antagonist G15 reversed the effects of G1 on EC109. The results of this study indicate that the expression levels of GPER1 are higher in EAC than in ESCC, which might be correlated with the dimorphic estrogen signaling pathway in different types of esophageal carcinoma.

Demystifying the Functional Role of Nuclear Receptors in Esophageal Cancer

Esophageal cancer (EC), an aggressive and poorly understood disease, is one of the top causes of cancer-related fatalities. GLOBOCAN 2020 reports that there are 544,076 deaths and 604,100 new cases expected worldwide. Even though there are various advancements in treatment procedures, this cancer has been reported as one of the most difficult cancers to cure, and to increase patient survival; treatment targets still need to be established. Nuclear receptors (NRs) are a type of transcription factor, which has a key role in several biological processes such as reproduction, development, cellular differentiation, stress response, immunity, metabolism, lipids, and drugs, and are essential regulators of several diseases, including cancer. Numerous studies have demonstrated the importance of NRs in tumor immunology and proved the well-known roles of multiple NRs in modulating proliferation, differentiation, and apoptosis. There are surplus of studies conducted on NRs and their implications in EC, but only a few studies have demonstrated the diagnostic and prognostic potential of NRs. Therefore, there is still a paucity of the role of NRs and different ways to target them in EC cells to stop them from spreading malignancy. This review emphasizes the significance of NRs in EC by discussing their diverse agonists as well as antagonists and their response to tumor progression. Additionally, we emphasize NRs’ potential to serve as a novel therapeutic target and their capacity to treat and prevent EC.

Increased prognostic value of clinical–reproductive model in Chinese female patients with esophageal squamous cell carcinoma

BACKGROUND

In China, it has been well recognized that some female patients with esophageal squamous cell carcinoma (ESCC) have different overall survival (OS) time, even with the same tumor-node-metastasis (TNM) stage, challenging the prognostic value of the TNM system alone. An effective predictive model is needed to accurately evaluate the prognosis of female ESCC patients.

AIM

To construct a novel prognostic model with clinical and reproductive data for Chinese female patients with ESCC, and to assess the incremental prognostic value of the full model compared with the clinical model and TNM stage.

METHODS

A new prognostic nomogram incorporating clinical and reproductive features was constructed based on univariatie and Cox proportional hazards survival analysis from a training cohort (n = 175). The results were recognized using the internal (n = 111) and independent external (n = 85) validation cohorts. The capability of the clinical–reproductive model was evaluated by Harrell’s concordance index (C-index), Kaplan–Meier curve, time-dependent receiver operating characteristic (ROC), calibration curve and decision curve analysis. The correlations between estrogen response and immune-related pathways and some gene markers of immune cells were analyzed using the TIMER 2.0 database.

RESULTS

A clinical–reproductive model including incidence area, age, tumor differentiation, lymph node metastasis (N) stage, estrogen receptor alpha (ESR1) and beta (ESR2) expression, menopausal age, and pregnancy number was constructed to predict OS in female ESCC patients. Compared to the clinical model and TNM stage, the time-dependent ROC and C-index of the clinical–reproductive model showed a good discriminative ability for predicting 1-, 3-, and 5-years OS in the primary training, internal and external validation sets. Based on the optimal cut-off value of total prognostic scores, patients were classified into high- and low-risk groups with significantly different OS. The estrogen response was significantly associated with p53 and apoptosis pathways in esophageal cancer.

CONCLUSION

The clinical–reproductive prognostic nomogram has an incremental prognostic value compared with the clinical model and TNM stage in predicting OS in Chinese female ESCC patients.

Role of estrogen receptors in health and disease

Estrogen receptors (ERs) regulate multiple complex physiological processes in humans. Abnormal ER signaling may result in various disorders, including reproductive system-related disorders (endometriosis, and breast, ovarian, and prostate cancer), bone-related abnormalities, lung cancer, cardiovascular disease, gastrointestinal disease, urogenital tract disease, neurodegenerative disorders, and cutaneous melanoma. ER alpha (ERα), ER beta (ERβ), and novel G-protein-coupled estrogen receptor 1 (GPER1) have been identified as the most prominent ERs. This review provides an overview of ERα, ERβ, and GPER1, as well as their functions in health and disease. Furthermore, the potential clinical applications and challenges are discussed.

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.

The prognostic values of estrogen receptor alpha and beta in patients with gastroesophageal cancer: A meta-analysis

BACKGROUND

Published studies have investigated the prognostic roles of estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ) in gastroesophageal cancer patients with the controversial results. The aim of the study was to systematically evaluate the impacts of ERα and ERβ on the overall survival (OS) in patients.

METHOD

Relevant eligible studies were extracted from PubMed, Embase, Web of Science, CNKI and Wanfang databases (from the start date to November 2018) following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. HR (hazard ratio) with 95% confidence intervals (CIs) were used to assess the prognostic values of ERα and ERβ for OS in patients.

RESULTS

High ERα expression was associated with poor OS (HR = 1.58, 95% CI = 1.29-1.94, P < .001) and ERβ with better OS (HR = 0.56, 95% CI = 0.37-0.83, P = .004) in gastroesophageal cancer. Furthermore, unfavorable OS was found in Chinese gastroesophageal patients with higher ERα expression (HR = 1.57, 95% CI = 1.25-1.96, P < .001) and better OS with higher ERβ expression (HR = 0.51, 95% CI = 0.31-0.83, P < .01) in our subgroup analysis. Meanwhile, worse OS was found in esophageal squamous cell carcinoma (ESCC) patients with high ERα expression (HR = 1.74, 95% CI = 1.33-2.26, P < .001), and favorable OS in ESCC with ERβ overexpression (HR = 0.40, 95% CI = 0.31-0.52, P < .001). Besides, high ERα expression was associated with lower tumor differentiation in ESCC (OR = 1.64; 95% CI = 1.02-2.64, P = .04) and ERβ was linked with better tumor differentiation in gastric adenocarcinoma (GCA) (OR = 0.49; 95% CI = 0.26-0.94, P = .03).

CONCLUSIONS

ERα and ERβ might serve as potential prognostic biomarkers for gastroesophageal cancer patients. ERα overexpression predicted poor OS and lower tumor differentiation, and ERβ suggested favorable OS and better tumor differentiation. Further related studies should be performed to test these results.

Prognostic value of estrogen receptor-α and progesterone receptor in curatively resected colorectal cancer: a retrospective analysis with independent validations

Background

Prognostic assessment is crucial for optimal treatment. The aim of our study was to investigate the potential impact of estrogen receptor-α (ER-α) and progesterone receptor (PR) on the prognosis of colorectal cancer (CRC) patients who received curative resection.

Methods

Retrospective evaluation of two independent cohorts of CRC patients maintained prospectively in 2009–2010 (training set) (n = 148) and 2007–2009 (internal validation set) (n = 485). Furthermore, we used an external independent CRC cohort from The Cancer Genome Atlas (TCGA) (n = 511) for further validation. ER-α and PR expression as well as other potential prognostic factors were retrospectively evaluated in training set with respect to overall survival (OS), local relapse free survival (LRFS) and distant metastasis free survival (DMFS). The prognostic factors found in training set will be validated in two validation cohorts.

Results

On univariate analysis for the training set, OS, LRFS and DMFS were not associated with PR expression. While patients with ER-αexpression were found to have poor prognosis. In addition, multivariate analysis showed that ER-αexpression maintained significance with respect to OS (HR, 5.06; p = 0.002), LRFS (HR, 8.81; p = 0.002) and DMFS (HR, 8.07; p = 0.004). Similarly, ER-α expression showed prognostic significance with respect to OS with hazard ratios (HRs) of 1.572 (95% CI: 1.001–2.467, p = 0.049) and 1.624 (95% CI: 1.047–2.520, p = 0.031) for the internal and external validation cohort, respectively.

Conclusion

ER-α expression was a biomarker of poor prognosis and it might inform treatment decision for high risk CRC patients. However, PR expression was not associated with survival outcomes.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5918-4) contains supplementary material, which is available to authorized users.

17β-Estradiol protects the esophageal epithelium from IL-13-induced barrier dysfunction and remodeling

BACKGROUND

The incidence of eosinophilic esophagitis (EoE) is greater in male than female subjects, and the underlying molecular basis for this sex bias remains unclear.

OBJECTIVE

We sought to delineate the contribution of the sex hormone estrogen to the EoE phenotype and esophageal epithelial barrier function and remodeling.

METHODS

We performed demographic and incidence analyses of EoE in male and female subjects from a single-center pediatric cohort. Estrogen-responsive gene expression analyses and estrogen receptor (ESR) immunofluorescence staining of esophageal biopsy specimens from patients with EoE and control subjects were performed. The effect of 17β-estradiol (E2) on IL-13-induced signaling pathways, gene expression, and esophageal epithelial architecture and barrier function in a primary human esophageal keratinocyte cell (EPC2) culture system (EPC2-air-liquid interface) was examined.

RESULTS

We observed a male predominance in patients with EoE. Analyses of RNA sequencing data sets revealed a significant dysregulation of the estrogen-responsive gene network and expression of ESR1 and ESR2 in esophageal biopsy specimens from patients with EoE compared with control subjects. IL-13 stimulation of EPC2-air-liquid interface cells led to altered cellular architecture with induced dilation of intercellular spaces and barrier dysfunction. Pretreatment of EPC2s with E2 prior to IL-13 exposure abrogated IL-13-induced architectural changes and esophageal barrier dysfunction. Mechanistically, E2-protective effects were dependent on ESR2 and associated with diminishing of IL-13-induced tyrosine kinase 2 and signal transducer and activator of transcription 6 phosphorylation and EoE-dysregulated gene expression.

CONCLUSIONS

Estrogen-responsive genes are modified in patients with EoE compared with control subjects. E2 attenuated IL-13-induced architectural changes and esophageal epithelial barrier dysfunction through inhibition of the IL-13/tyrosine kinase 2/signal transducer and activator of transcription 6 pathway via ESR2-dependent process. Estrogen hormone signaling may protect against development of EoE in female subjects.

The prognostic value of sex hormone receptors expression in laryngeal carcinoma

Laryngeal cancer was identified as the second most common respiratory system malignancy with squamous cell carcinoma being the most common malignant tumor of the larynx. Larynx being a secondary sex organ showing physiological changes during puberty, raises inquiry about the relationship between sex hormones receptors as estrogen receptors (ER), progesterone receptors (PR), androgen receptors (AR) and the development of laryngeal carcinoma. This study was carried out in cancer tissue samples from 50 patients with laryngeal squamous cell carcinoma. Immunohistochemical staining using ER-β, PR, and AR was carried out. The immunohistochemical expression of ER-β, PR and AR was positive in 56%, 50% and 64% of cases respectively. ER-β, and PR expression were significantly higher in poorly differentiated cases and cases with lymphatic invasion while AR expression was significantly lower in poorly differentiated cases and with lymphatic invasion. In conclusion, ER-β and PR may be considered as markers for poor biological behavior of laryngeal carcinoma.

Expression of phosphorylated estrogen receptor beta is an independent negative prognostic factor for pancreatic ductal adenocarcinoma

PURPOSE

The role of estrogen receptor beta (ER-β) expression in pancreatic ductal adenocarcinoma (PDAC) is largely unknown. Ligand-independent phosphorylation and activation of ER-β may play a relevant role in the IL-6/STAT3 signaling pathway and, as a result, in tumor progression. Here, we examined the effect of ER-β, phosphorylated ER-β (pER-β), STAT3, phosphorylated STAT3 (pSTAT3) and IL-6 expression on the overall and recurrence-free survival in a cohort of patients with resected PDAC.

METHODS

We identified 175 patients who underwent pancreatic resection for PDAC. Tissue microarrays were constructed from the archival tumor specimens. These were stained with specific antibodies for the above molecules. The expression of the markers was then correlated with clinicopathological parameters and survival analysis was performed.

RESULTS

High nuclear expression of ER-β was found in 61.7% and pER-β in 80.6% of the tumors. STAT3 was expressed in 54.3% of the tumor samples, pSTAT3 in 68% and IL-6 in 76.6%. The median overall survival for patients with low pER-β expression was 29 months, whereas for patients with high pER-β expression was 15.1 months (p = 0.016). Multivariate analysis revealed that pER-β expression was an independent factor correlating with shorter overall survival (hazard ratio 1.9; p = 0.013) and disease-free survival (hazard ratio 1.9; p = 0.029).

CONCLUSIONS

Expression of pER-β constitutes an independent prognostic marker for PDAC and is correlated with poor prognosis. These data may help in identifying novel drug targets in PDAC and patients who could benefit from additional therapeutic regimens, including selective estrogen receptor modulators.

Characterization of serum estradiol level and tissue estrogen receptor immunostaining with clinical response and reproductive factor changes in Chinese female patients with esophageal squamous cell carcinoma

Pre-menopausal female patients have a prolonged survival than post-menopausal patients, indicating that estrogen and/or estrogen receptor (ER) may have some biological effects on prognosis. ER expression in cancer tissue has been reported to be a significant prognostic marker in multiple human cancers. However, the prognostic value of estrogen and/or ER on female patients with esophageal squamous cell carcinoma (ESCC) is rarely reported. The present study was undertaken to elucidate the associations of serum estradiol level, tissue estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ) expression with clinical response and reproductive factor changes in 387 female ESCC patients. Radioimmunoassay revealed that serum estradiol level was higher in pre-menopausal than those in peri-menopausal and post-menopausal patients. Furthermore, patients with higher serum estradiol level appeared to have a better survival. Immunostaining results suggested that ERα positive (+) expression was mainly located in cytoplasm of tumor cells with a positive rate of 69.9% and ERβ (+) was mainly located in nucleus of tumor cells with a positive rate of 64.9%. We did not find the relations of ER expression with tumor invasion (P>0.05), lymph node metastasis (P>0.05), TNM staging (P>0.05) and treatment method (P>0.05). Surprisingly, ERα (+) expression was higher in post-menopausal patients than those in pre-menopausal patients (P<0.05). Patients with number of pregnancy≥4 have a higher ERβ (+) expression than those patients with≤3 (P<0.05). Univariate and multivariate survival analysis showed that ERβ (+) expression in addition to ERα (-) expression are favorable prognostic markers in female ESCC patients (P<0.05). Further related study is needed to in-depth explore the potential mechanisms of ERα and ERβ in survival of female patients with ESCC.

Expression of G protein-coupled oestrogen receptor in melanoma and in pregnancy-associated melanoma

BACKGROUND

The hormone sensitivity of melanoma and the role of 'classical' oestrogen receptor (ER) α and β in tumour progression have been intensively studied with rather contradictory results. The presence of 'non-classical' G protein-coupled oestrogen receptor (GPER) has not been investigated on human melanoma tissues.

OBJECTIVE

To analyse the expression of GPER, ERα and ERβ in pregnancy-associated (PAM) and in non-pregnancy-associated (NPAM) melanomas in correlation with traditional prognostic markers and disease-free survival (DFS).

METHODS

Receptor protein levels were tested using immunohistochemistry in 81 formalin-fixed paraffin-embedded melanoma tissues. PAMs (n = 38) were compared with age- and Breslow thickness-matched cases (n = 43) including non-pregnant women (NPAM-W) (n = 22) and men (NPAM-M) (n = 21). The association between receptor expression and DFS was analysed by uni- and multivariate Cox proportional hazards regression.

RESULTS

G protein-coupled oestrogen receptor was detected both in PAMs and NPAMs. In 39 of the 41 (95.1%) GPER-positive melanomas, GPER and ERβ were co-expressed. GPER/ERβ-positive melanomas were significantly more common in PAM compared to NPAM (P = 0.0001) with no significant difference between genders (P = 0.4383). In PAMs, the distribution of GPER and ERβ was similar (78.4% vs. 81.6%; P = 0.8504), while in NPAM, ERβ was the representative ER (60.5% vs. 27.9%; P = 0.0010) without gender difference (59.1% vs. 61.9%). GPER-/ERβ-positive melanomas were associated with lower Breslow thickness, lower mitotic rate and higher presence of peritumoral lymphocyte infiltration (PLI) compared to GPER-/ERβ-negative cases (P = 0.0156, P = 0.0036 and P = 0.0001) predicting a better DFS (HR = 0.785, 95% CI 0.582-1.058). Despite the significantly higher frequency of GPER and ERβ expression in PAM, no significant difference was found in DFS between PAM and NPAM. All but one case failed to show ERα expression.

CONCLUSIONS

The presence of GPER and its simultaneous expression with ERβ can serve as a new prognostic indicator in a significant subpopulation of melanoma patients.

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.

Tamoxifen enhances the cytotoxicity of conventional chemotherapy in esophageal adenocarcinoma cells

INTRODUCTION

Esophageal adenocarcinoma is a lethal malignancy which is increasing in incidence, and many patients receive chemotherapy as part of their treatment. We have previously demonstrated that esophageal adenocarcinoma-derived cell lines respond to treatment with estrogen receptor modulators, such as tamoxifen. Reports from breast cancer suggest that tamoxifen may attenuate the efficacy of other chemotherapeutic agents. We have therefore assessed the response of esophageal adenocarcinoma cell lines to tamoxifen therapy when given in combination with conventional agents.

METHODS

Two estrogen receptor (ER)-positive esophageal adenocarcinoma cell lines (OE-19 and OE-33) were treated with combinations of tamoxifen, cisplatin and 5-fluorouracil (5-FU). Effects on cell viability were measured using an MTS assay, and cell death was detected with annexin V/propidium iodide flow cytometry. To assess whether the efficacy of tamoxifen in these cell lines might be relevant to the clinical setting, we analyzed ER status in 10 esophageal adenocarcinoma tissue specimens by immunohistochemistry.

RESULTS

IC50 values (μM) for OE-19 and OE-33 were 11.2 and 7.1 for tamoxifen, 19.6 and 4.7 for cisplatin, and 1.7 and 5.9 for 5-FU, respectively. Cell death was detected in 11.9% and 15.8% of cells treated with tamoxifen, 7.9% and 8.7% cells treated with cisplatin, and 3.6% and 8.6% cells treated with 5-FU at their IC50s. The addition of tamoxifen to cisplatin increased cell death by 11.4% in OE-19 (p < 0.0001) and 16.3% in OE-33 (p < 0.0001). Similarly, the addition of tamoxifen to 5-FU increased cell death by 11.6% in OE-19 (p < 0.0001) and 15.9% in OE-33 (p < 0.0001). Eight of 10 tissue specimens showed positive staining for ERα and 7 of 10 for ERβ.

CONCLUSIONS

In a cell culture model the addition of tamoxifen to conventional chemotherapy appears to be both feasible and beneficial. Expression of ERα and ERβ was also confirmed in esophageal adenocarcinoma tissues.

Population attributable fraction of Esophageal squamous cell carcinoma due to smoking and alcohol in Uganda

Background

Despite the high rates and regional variation of esophageal squamous cell carcinoma (ESCC) in East Africa, the contributions of smoking and alcohol to the ESCC burden in the general population are unknown.

Methods

We conducted a case-control study of patients presenting for upper gastrointestinal endoscopic examination at Mbarara Regional Referral Hospital, Uganda. Sociodemographic data including smoking and alcohol intake were collected prior to endoscopy. Cases were those with histological diagnosis of ESCC and controls were participants with normal endoscopic examination and gastritis/duodentitis or normal histology. We used odds ratios associated with ESCC risk to determine the population attributable fractions for smoking, alcohol use, and a combination of smoking and alcohol use among adults aged 30 years or greater who underwent upper gastrointestinal endoscopy.

Results

Our study consisted of 67 cases and 142 controls. Median age was 51 years (IQR 40–64); and participants were predominantly male (59 %). Dysphagia and/or odynophagia as indications for endoscopy were significantly more in cases compared to controls (72 % vs 6 %, p < 0.0001). Male gender and increasing age were statistically associated with ESCC. In the unadjusted models, the population attributable fraction of ESCC due to male gender was 55 %, female gender - 49 %, smoking 20 %, alcohol 9 % and a combination of alcohol & smoking 15 %. After adjusting for gender and age, the population attributable fraction of ESCC due to smoking, alcohol intake and a combination of alcohol & smoking were 16, 10, and 13 % respectively.

Conclusion

In this population, 13 % of esophageal squamous cell carcinoma cases would be avoided if smoking and alcohol use were discontinued. These results suggest that other important risk factors for ESCC in southwestern Uganda remain unknown.

Role of estrogen receptors in digestive system tumors

Estrogen receptors are steroid hormone receptors that modulate the expression of target genes when bound to ligand. Humans have two ligand-activated transcription factors that bind to estrogen, encoded by separate genes, estrogen receptor α (ERα) and estrogen receptor β (ERβ). In addition, the membrane localized G protein-coupled estrogen receptor 1 (GPER1) can be activated by estradiol and mediate non-genomic signaling. Many studies have described the role of estrogen receptors in human cancers. Digestive system tumors account for a large proportion of all the tumors, and the mortality is very high in many digestive system tumors, such as esophageal cancer, gastric cancer, hepatocellular carcinoma, colorectal cancer, cholangiocarcinoma and pancreatic carcinoma. This review summarizes the role of estrogen receptors in digestive system tumors, aiming at finding new routes for the rational design of targeted anticancer therapies for digestive system tumors.