Estrogen receptor beta is expressed in human stomach adenocarcinoma

Pre-existing diabetes mellitus increases the risk of gastric cancer: A meta-analysis

AIM: To systematically assess the association between diabetes and incidence of gastric cancer.

METHODS: We searched MedLine (PubMed), EMBASE, and the Cochrane Library without any limitations with respect to publication date or language, we also searched the references of qualifying articles. Case-control studies and cohort studies comparing the risk of gastric cancer between diabetic patients and control subjects were included. We excluded studies reporting only standardized incidence ratios without control groups and those that investigated only mortality but not incidence. Seventeen studies met our criteria, and the qualities of these studies were assessed using the Newcastle-Ottawa Quality Assessment Scale. We performed a meta-analysis of pre-existing diabetes and gastric cancer incidence using the DerSimonian-Laird method for random-effects. For subgroup analyses, we separated the studies by study type, region, sex and method to determine confounding factors and reliability. We also conducted subgroup analyses to examine the effects of smoking, Helicobacter pylori (H. pylori) infection, and cancer site. Publication bias was evaluated using Begg’s test.

RESULTS: A random-effects model meta-analysis showed an increased gastric cancer risk in diabetic patients [relative risk (RR) = 1.19; 95%CI: 1.08-1.31]. Subgroup analyses indicated that this result persisted in cohort studies (RR = 1.20; 95%CI: 1.08-1.34), in studies on populations of both Western (RR = 1.18; 95%CI: 1.03-1.36) and Eastern countries (RR = 1.19; 95%CI: 1.02-1.38), in a female subgroup (RR=1.24; 95%CI: 1.01-1.52), and in highly qualified studies (RR = 1.17; 95%CI: 1.05-1.31). Moreover, these results persisted when the analysis was confined to studies adjusted for well-known gastric cancer risk factors such as smoking (RR = 1.17; 95%CI: 1.01-1.34) and H. pylori infection (RR = 2.35; 95%CI: 1.24-4.46).

CONCLUSION: Pre-existing diabetes mellitus may increase the risk of gastric cancer by approximately 19%. This effect seems to be unrelated to geographical region.

Expression profile and prognostic role of sex hormone receptors in gastric cancer

Background

Increasing interest has been devoted to the expression and possible role of sex hormone receptors in gastric cancer, but most of these findings are controversial. In the present study, the expression profile of sex hormone receptors in gastric cancer and their clinicopathological and prognostic value were determined in a large Chinese cohort.

Methods

The mRNA and protein expression of estrogen receptor alpha (ERα), estrogen receptor beta (ERβ), progesterone receptor (PR), and androgen receptor (AR) in primary gastric tumors and corresponding adjacent normal tissues from 60 and 866 Chinese gastric cancer patients was detected by real-time quantitative PCR and immunohistochemistry method, respectively. The expression profile of the four receptors was compared and their associations with clinicopathological characteristics were assessed by using Chi-square test. The prognostic value of the four receptors in gastric cancer was evaluated by using univariate and multivariate Cox regression analysis.

Results

The presence of ERα, ERβ, PR, and AR in both gastric tumors and normal tissues was confirmed but their expression levels were extremely low except for the predominance of ERβ. The four receptors were expressed independently and showed a decreased expression pattern in gastric tumors compared to adjacent normal tissues. The positive expression of the four receptors all correlated with high tumor grade and intestinal type, and ERα and AR were also associated with early TNM stage and thereby a favorable outcome. However, ERα and AR were not independent prognostic factors for gastric cancer when multivariate survival analysis was performed.

Conclusions

Our findings indicate that the sex hormone receptors may be partly involved in gastric carcinogenesis but their clinicopathological and prognostic significance in gastric cancer appears to be limited.

Different effects of ERβ and TROP2 expression in Chinese patients with early-stage colon cancer

Estrogen receptor beta (ERβ) and TROP2 expressed in colon carcinoma and might play an important role there. We explored the relationship of ERβ and TROP2 expression with the prognosis of early-stage colon cancer. ERβ and TROP2 levels were assessed by immunohistochemistry in normal mucosa and tumoral tissues from 220 Chinese patients with T(3)N(0)M(0) (stage IIa) and T(4)N(0)M(0) (stage IIb) colon cancer in the Cancer Center, Sun Yat-sen University, who underwent curative surgical resection between 1995 and 2003. The Cox proportional hazards regression model was applied to analyze the overall survival (OS) data, and the ROC curve, Kaplan-Meier estimate, log rank test, and Jackknife method were used to show the effect of ERβ and TROP2 expression at different stages of cancer. The 5-year survival rates were not significantly different between the patients with stage IIa and stage IIb colon cancer (83 vs. 80 %, respectively). The high expression of ERβ was related to decreasing OS in stage IIa and stage IIb colon cancer, while the high expression of TROP2 was related to decreasing OS in stage IIb colon cancer. The expression of ERβ and TROP2 has tumor-suppressive and tumor-promoting effect in stage IIa and stage IIb colon cancer, respectively.

Expression of estrogen receptors in gastric cancer and their clinical significance

BACKGROUNDS AND OBJECTIVES

The male predominance of gastric cancer suggests that female sex hormones may have a protective effect against gastric cancer. We evaluated the expression of estrogen receptors in gastric cancer tissue and cells and the clinical significance of ER-β expression in gastric cancer.

METHOD

ER-α, ER-β proteins extracted from normal stomach, gastric cancer tissues, and cultured gastric cancer cells (KATO-III, mkn28, mkn45, and mkn74) were assessed by Western blot analysis. The clinical significance of ER-β was explored using tissue microarray methods and immunohistochemical staining of specimens from 148 gastric cancers.

RESULTS

Both ER-α and β protein expression were noted in normal and gastric cancer tissues. However, in cultured gastric cells, only ER-β was noted in mkn28 and mkn74. Of 148 gastric cancers, 67 (45.3%) were ER-β positive. The ER-β positive group was associated with lower tumor stage, Lauren's intestinal type, negative perineural invasion, and free of recurrence. The ER-β positive group had a better 3-year survival compared with the negative group in survival analysis.

CONCLUSION

Our results suggest that the presence of ER-β in gastric cancer could have a protective effect against invasiveness of gastric cancer. Further studies are needed to clarify the role of ER-β in gastric cancers.

[Relationship between expressions of estrogen and progesterone receptors and syndrome types of gastric carcinoma]

OBJECTIVE

To explore the relationship between expressions of estrogen (ER) and progesterone (PR) receptors and syndromes of traditional Chinese medicine (TCM) in gastric carcinoma and to establish prognostic indicators for gastric carcinoma.

METHODS

A total of 72 patients with gastric carcinoma were divided into six groups according to TCM syndrome differentiation. Specimens were collected after operation and ER and PR protein expressions were detected by EnVision immunohistochemical method.

RESULTS

The common syndromes in female patients with gastric carcinoma were disharmony between liver and stomach, yin impairment due to stomach heat, and insufficiency of both qi and blood; while in males, interior retention of stagnant toxin, interior retention of phlegm and dampness, and deficiency-cold in spleen and stomach were common. Different TCM syndromes were related with gender (P<0.01), pathology (P<0.01), cell differentiation (P<0.05), infiltration depth (P<0.01), lymphaden metastasis (P<0.05), distant metastasis (P<0.05), and TNM stage (P<0.01). Deficiency and excess syndromes were associated with gender (P<0.05), pathology (P<0.05), tumor location (P<0.01) and TNM stage (P<0.05). The deficiency syndromes were common in female patients. The total positive rates of ER and PR expressions were 8.33% and 37.5% respectively. There was a significant difference in PR expression among different TCM syndromes (P<0.01). PR expression was significantly higher in the syndrome of yin deficiency due to stomach heat than in the other syndromes. The PR expressions in deficiency syndromes were significantly higher than those in excess syndromes (P<0.01). No correlation was found between ER expression and different TCM syndromes.

CONCLUSION

There is a correlation between PR expression and different TCM syndromes in gastric carcinoma.

Cytoplasmic estrogen receptor β as a potential marker in human non-small cell lung carcinoma

OBJECTIVES

Estrogen has been reported to promote an increased susceptibility to lung cancer development. This study focusses on the role of cytoplasmic estrogen receptor β (c-ERβ) in NSCLC.

METHODS

NSCLC (n = 162) cases were analyzed using immunohistochemistry (IHC) for c-ERβ expression and its association with clinicopathological variables. Significance of c-ERβ expression was further examined using in vitro studies in NSCLC cell lines.

RESULTS

Among ERβ and aromatase positive NSCLC females, c-ERβ was significantly associated with greater tumor diameter and tended to be associated with worse overall survival. A549 and LCAM1 cells expressed aromatase, as well as c-ERβ and nuclear ERβ (n-ERβ). U0126 (MAPK/extracellular-signal-regulated kinase (ERK) inhibitor) abrogated MAPK phosphorylation, caused by estradiol via c-ERβ, more effectively than ICI 182780 (ER blocker) in either cell line. However, ICI 182780 completely abrogated the estrogen responsive elements (ERE)-luciferase activity caused by estradiol. Combination therapy with ICI 182780 and U0126 turned out to be far more effective than either treatment alone in either A549 or LCAM1 cells.

CONCLUSION

The results indicated that ERβ may contribute to NSCLC via non-genomic action of estrogen through its cytoplasmic form, in addition to the genomic actions via n-ERβ. These actions of estrogen in NSCLCs may be abrogated by combination therapy with ICI 182780 and U0126.

Sex hormones, hormonal interventions, and gastric cancer risk: a meta-analysis

Estrogens may influence gastric cancer risk, but published studies are inconclusive. We therefore carried out a meta-analysis addressing the associations of gastric cancer in women with menstrual and reproductive factors and with use of estrogen- and antiestrogen-related therapies. Searches of PubMed up to June, 2011 and review of citations yielded a total of 28 independent studies, including at least one exposure of interest. Random effects pooled estimates of relative risk (RR) and corresponding 95% CIs were calculated for eight exposures reported in at least five studies, including: age at menarche, age at menopause, years of fertility, parity, age at first birth, oral contraceptive use, hormone replacement therapy (HRT), and tamoxifen treatment. Longer years of fertility (RR = 0.74, 95% CI: 0.63-0.86) and HRT (RR = 0.77; 95% CI: 0.64-0.92) were each associated with decreased gastric cancer risk. Conversely, tamoxifen treatment was associated with increased risk (RR = 1.82; 95% CI: 1.39-2.38). The other five exposures were not significantly associated. Our analysis supports the hypothesis that longer exposure to estrogen effects of either ovarian or exogenous origin may decrease risk of gastric cancer. Additional studies are warranted to extend this finding and to identify the underlying mechanisms.

Sex steroid receptors in human lung diseases

Several epidemiological studies have reported that gender differences exist in clinical and biological manifestations of human lung diseases. In particular, women are far more likely to develop both neoplastic and non-neoplastic lung diseases than men. This gender difference above suggests that sex steroid may be involved in the pathogenesis of various lung diseases. These sex steroids mediate their effects through sex steroid receptors including estrogen receptors (ER) i.e. ERα and ERβ progesterone receptors (PR) i.e. PR-A and PR-B and androgen receptors (ARs), all of which have been reported to be expressed in lung tissue. Therefore it becomes important to clarify the potential roles of sex steroid receptor in both neoplastic and non-neoplastic lung diseases toward improved treatment options for the patients. In this review, we summarized a number of studies in humans and experimental animals that have identified possible roles of sex steroids in respiratory physiology and pathology.

Aromatase in human lung carcinoma

Lung cancer is the leading cause of cancer mortality in both women and men worldwide but gender differences exist in their clinical and biological manifestations. In particular, among life time non-smoker, female are far more likely to develop lung carcinoma than male. Recent studies demonstrated that estrogens are synthesized in situ in both male and female lung cancers through aromatase, suggesting that sex steroid may contribute to the pathogenesis and development of lung carcinoma. In addition, human lung carcinomas have been recently demonstrated to be frequently associated with expression of estrogen receptors in both male and female patients and a lower expression of aromatase was reported to be associated with better prognosis. Preclinical studies further demonstrated that aromatase inhibitor (AI) suppressed the lung tumor growth both in vitro and in vivo. These findings all suggest a potential role of intratumoral aromatase in biological behavior of non-small cell lung cancer (NSCLC), the most common form of human lung malignancy. Therefore, AIs may become viable therapeutic options for disease management in NSCLC patients but further studies are definitely required to obtain a better understanding of the potential roles of intratumoral aromatase expression as a predictive biomarker for clinical outcome in these NSCLC patients.

Estrogen receptor β

CONTEXT

A new class of estrogen receptors was discovered in 1996 and named estrogen receptor β (ER-B); the traditional estrogen receptor, which until a little more than 10 years ago was thought of as the only estrogen receptor in existence, is now called estrogen receptor α. Estrogen receptor β has at least 5 isoforms, which may have different functions and have different tissue distribution. The significance of ER-B expression in tumors was first demonstrated in breast cancer, with several studies demonstrating that women with ER-B-positive breast cancers treated with adjuvant tamoxifen have better survival, independent of estrogen receptor α expression. Pathologists need to be more aware of this increasingly important protein, as it will soon find its way into routine clinical practice.

OBJECTIVE

To provide pathologists with a concise review of ER-B, with special emphasis on current and potential clinical relevance.

DATA SOURCES

A search of the English literature in PubMed (National Library of Medicine, Bethesda, Maryland) for articles with titles including "estrogen receptor beta," with emphasis on "immunohistochemistry." Abstracts were reviewed, and selected articles were used as the basis for writing this review, mostly based on their relevance to pathology.

CONCLUSIONS

Estrogen receptor β and its isoforms have wider tissue distribution, including the gastrointestinal tract, lung, and brain, than the traditional estrogen receptor, now called estrogen receptor α. Estrogen receptor β expression in breast cancer is associated with favorable outcome in women treated with adjuvant tamoxifen, even in tumors negative for estrogen receptor α. The clinical significance of ER-B expression in tumors other than breast is currently under investigation.

Prognostic role of estrogen receptor alpha and estrogen receptor beta in gastric cancer

BACKGROUND

The presence of estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta) have been reported in cell and tissue level in gastric cancer, but its impact on patients' survival remains unclear. This study was designed to investigate the expression level of ERalpha and ERbeta and to assess clinical significance of ERalpha and ERbeta expression in gastric cancer.

METHODS

The expression level of ERalpha and ERbeta were assessed by reverse-transcriptase polymerase chain reaction (RT-PCR) in 35 surgically resected gastric cancer and corresponding normal tissues and by immunohistochemical staining in 211 surgically resected gastric cancer and match normal tissues.

RESULTS

The expression level between ERalpha mRNA expression in gastric cancer tissues and match normal tissues had no statistically significant difference. The ERbeta mRNA level in normal tissues was significantly higher than that observed in gastric cancer tissues (P = 0.001). Neither ERalpha nor ERbeta mRNA expression levels had significant correlation with clinicopathologic parameters. Forty-eight of 211 (22.7%) gastric cancer tissues showed positive expression of ERalpha and ERbeta detected in gastric cancer. ERalpha-positive expression correlated with poorer overall survival (P = 0.014), as did the absence of ERbeta expression in patients with gastric cancer (P = 0.001). In multivariate analysis, the positive expression of ERalpha and the absence of ERbeta were significant independent prognostic factors for overall survival (hazard ratio 2.159, P = 0.013, and hazard ratio 2.016, P = 0.025 respectively).

CONCLUSIONS

Our results indicated that ERalpha and ERbeta were expressed in both gastric cancer and corresponding normal tissues. ERalpha expression and the absence of ERbeta expression are associated with poor survival.

Steroids mediate resistance to the bactericidal effect of phosphatidylcholines against Helicobacter pylori

Helicobacter pylori assimilates various steroids as membrane lipid components, but it can also survive in the absence of steroids. It thus remains to be clarified as to why the organism relies on steroid physiologically. In this study, we have found that phosphatidylcholine carrying a linoleic acid molecule or arachidonic acid molecule has the potential to kill steroid-free H. pylori. The bactericidal action of phosphatidylcholines against H. pylori was due to the lytic activity of the phosphatidylcholines themselves and not due to the lytic activity of the unsaturated fatty acids or lyso-phosphatidylcholine resulting from the hydrolysis of the phosphatidylcholines. In contrast to the steroid-free H. pylori, the organism that absorbed and glucosylated free cholesterol was unaffected by the bactericidal action of the phosphatidylcholines. Similarly, H. pylori that absorbed estrone without glucosylating it also resisted the bactericidal action of the phosphatidylcholines. The steroids absorbed by H. pylori existed in both the outer and inner membranes, while the glucosyl-steroids produced via the steroid absorption were localized in the outer membrane rather than in the inner membrane. These results indicate that H. pylori absorbs the steroids to reinforce the membrane lipid barrier and thereby expresses resistance to the bacteriolytic action of hydrophobic compounds such as phosphatidylcholine.

Estrogen and gastrointestinal malignancy

The concept that E2 exerts an effect on the gastrointestinal tract is not new and its actions on intestinal mucosa have been investigated for at least three decades. An attempt to consolidate results of these investigations generates more questions than answers, thus suggesting that many unexplored avenues remain and that the full capabilities of this steroid hormone are far from understood. Evidence of its role in esophageal, gastric and gallbladder cancers is confusing and often equivocal. The most compelling evidence regards the protective role conferred by estrogen (or perhaps ERbeta) against the development and proliferation of colon cancer. Not only has the effect been described but also many mechanisms of action have been explored. It is likely that, along with surgery, chemotherapy and radiotherapy, hormonal manipulation will play an integral role in colon cancer management in the very near future.

Anabolic utilization of steroid hormones in Helicobacter pylori

In this study, we have demonstrated that Helicobacter pylori absorbs a steroid prehormone (pregnenolone) and two androgens (dehydroepiandrosterone and epiandrosterone), glucosylates these steroids, and utilizes glucosyl-steroid hormone compounds as the membrane lipid components. The only common structure among the steroid prehormone and the two androgens is a 3beta-OH in the steroid framework. Our results indicate that the 3beta-OH in the steroid hormones is a crucial conformation required for steroid glucosylation by H. pylori. In addition, we found that H. pylori absorbs and holds estrogens possessing 3-OH (estrone and estradiol) into the membrane. The effective absorption of estrogen into the membrane appeared to be controlled by the number of hydroxyl groups modifying the steroid framework. In contrast, H. pylori induced neither membrane absorption nor glucosylation of the other steroid hormones possessing 3=O (progesterone, androstenedione and testosterone) or 3alpha-OH (androsterone). These results indicate that H. pylori selectively absorbs 3beta-OH and 3-OH steroid hormones, and utilizes only 3beta-OH steroid hormones as the materials for glucosylation.

Estrogen receptor beta functions through nongenomic mechanisms in lung cancer cells

Recent studies have shown that estrogens promote the growth of lung cancer cells and may potentially be responsible for increased susceptibility to lung cancer in women. These observations raise the possibility of using antiestrogens in treating and preventing lung cancer. However, it is not clear how estrogen receptors (ERs) modulate the growth of non-small cell lung cancer (NSCLC) cells. Our Western blotting and real-time PCR analysis showed that NSCLC cells expressed ERbeta, but not ERalpha. In addition, ERbeta-specific ligands, but not ERalpha-specific ligands, promoted the growth of lung cancer cells. Furthermore, knockdown of ERbeta by short hairpin RNA constructs resulted in loss of estrogen-dependent growth of lung cancer cells. Interestingly, endogenous ERbeta failed to transcriptionally activate estrogen response element (ERE)-luciferase constructs in NSCLC cells, suggesting a lack of genomic function. Upon further investigation, ERbeta was found to be in the cytoplasm in all lung cancer cells and failed to translocate to the nucleus in the presence of estrogen, as observed by biochemical, ArrayScan, and confocal microscopy experiments. Nonetheless, estrogen caused rapid activation of cAMP, Akt, and MAPK signaling pathways in lung cancer cells. Immunohistochemical analysis of lung tumor biopsies showed strong ERbeta staining in the cytoplasm, whereas no staining was observed for ERalpha. In conclusion, our results suggest that that proliferative effects of estrogen in lung cancer cells is mediated primarily, if not exclusively, by the nongenomic action of ERbeta.

Cytochrome P450 aromatase gene (CYP19) expression in gastric cancer

BACKGROUND

The secretion of biologically active estrogen through the conversion of circulating precursor androgens has been suggested to play important roles in the pathophysiology of estrogen-dependent carcinomas. In the present study, we examined aromatase expression in gastric carcinoma.

METHODS

Nineteen specimens of gastric carcinoma were obtained from Japanese patients at the Department of Surgery, Tottori University Hospital, Japan. Nontumoral tissues adjacent to the carcinoma were also available for analysis. The histological features of the gastric carcinomas were as follows: 8 intestinal-type and 11 diffuse-type adenocarcinomas. Tissue specimens removed at surgery were used for the preparation of RNA or for immunohistochemical analysis. Six cell lines derived from human gastric cancers were also used as a model system. Using conventional and real-time reverse transcription-polymerase chain reactions, aromatase mRNA expression and promoter usage were assayed. Immunohistochemical analysis was performed using an anti-aromatase antibody.

RESULTS

We demonstrated the molecular basis of aromatase mRNA expression, which depended on three proximal promoters in tumoral and nontumoral tissues, for the first time. The tumoral tissues exhibited positive staining for anti-aromatase antibody. At the same time, positive staining was also observed in nontumoral mucosa, predominantly in the parietal cells.

CONCLUSION

We provide evidence suggesting a mechanism for the secretion of estrogen through the conversion of a precursor androgen in tumoral and nontumoral tissues in the stomach.

Estrogen and progesterone receptor isoforms expression in the stomach of Mongolian gerbils

AIM: We studied the estrogen receptor (ER) and progesterone receptor (PR) isoforms expression in gastric antrum and corpus of female gerbils and their regulation by estradiol (E2) and progesterone (P4).

METHODS: Ovariectomized adult female gerbils were subcutaneously treated with E2, and E2 + P4. Uteri and stomachs were removed, the latter were cut along the greater curvature, and antrum and corpus were excised. Proteins were immunoblotted using antibodies that recognize ER-alpha, ER-beta, and PR-A and PR-B receptor isoforms. Tissues from rats treated in the same way were used as controls.

RESULTS: Specific bands were detected for ER-alpha (68 KDa), and PR isoforms (85 and 120 KDa for PR-A and PR-B isoforms, respectively) in uteri, gastric antrum and corpus. We could not detect ER-beta isoform. PR isoforms were not regulated by E2 or P4 in uterus and gastric tissues of gerbils. ER-alpha isoform content was significantly down-regulated by E2 in the corpus, but not affected by hormones in uterus and gastric antrum.

CONCLUSION: The presence of ER-alpha and PR isoforms in gerbils stomach suggests that E2 and P4 actions in this organ are in part mediated by their nuclear receptors.

Endogenous estrogen exposure in relation to distribution of histological type and estrogen receptors in gastric adenocarcinoma

BACKGROUND

Estrogen might protect women against gastric adenocarcinoma of the intestinal histological type. We addressed this hypothesis and proposed that gastric estrogen receptors (ERs) are involved.

METHODS

A population-based cohort of patients with gastric adenocarcinoma diagnosed in 1958-2004 in the county of Stockholm was identified through the Swedish Cancer Register. The patients were categorized regarding their endogenous estrogen exposure at diagnosis into: women aged less than 50 years, labelled "exposed women" (n=364), men aged less than 50 years, labelled "unexposed men" (n=396), and women aged more than 70 years, labelled "unexposed women" (n=3008). Tumor specimens were reviewed, and 289 cases were classified into intestinal (n=101) or diffuse type (n=188). Cases of intestinal adenocarcinomas (n=45) were tested for presence of ERalpha, ERbeta, and ERbeta cx by immunohistochemistry.

RESULTS

Compared to "exposed women", the intestinal type of gastric adenocarcinoma was more than four times more common among "unexposed men" (odds ratio [OR], 4.7; 95% confidence interval [CI], 2.2-10.3) and nine times more common among "unexposed women" (OR, 9.1; 95% CI, 4.3-19.6). No differences in ER expression were found. A comparison of ERs in tissues taken from the tumors and adjacent gastric mucosa revealed a loss of ERbeta and a gain of ERalpha in the tumor cells. The presence of ERbeta cx was identified for the first time in gastric tumors.

CONCLUSION

Gastric adenocarcinoma of the intestinal type is less common in women with high endogenous estrogen exposure, indicating a preventive effect of estrogen. No differences in the distribution of ERs was found between the three estrogen exposure groups. The presence of ERbeta cx in gastric cancer warrants further investigation.

Oestrogen and the enigmatic male predominance of gastric cancer

Gastric cancer is the second most common cause of cancer death worldwide, and annually it causes over 150,000 deaths in Europe and 700,000 deaths globally. The incidence of gastric cancer shows an enigmatic male dominance with a male-to-female ratio of about 2:1. This sex ratio cannot be entirely attributed to the differences in the prevalence of known risk factors between the sexes. This review focuses on the potential role of oestrogen in explaining the male predominance in gastric cancer. Some data argue in favour of sex hormonal influence. Women with a longer fertility life and those on hormone replacement therapy seem to have a decreased risk of gastric cancer, and men who have been treated with oestrogen for prostate cancer have a decreased risk. Use of tamoxifen in women seems to increase their risk of gastric cancer. Animal studies indicate that oestrogen may offer protection against the development of this cancer as for example ovariectomised mice are at an increased risk, whilst administration of female sex hormones decreases the incidence of gastric cancer. Oestrogen may exert its effect by acting on oestrogen receptors (ERs). Both ERalpha, ERbeta and the latest discovered ERbetacx have been identified in gastric tissue. The biological means behind this is not yet clear but various mechanisms have been suggested. There are indications that oestrogen may lead to an increased expression of trefoil factor proteins, which protect mucous epithelia or inhibit the expression of c-erb-2 oncogene.

Gastric metastases originating from occult breast lobular carcinoma: diagnostic and therapeutic problems

Background

Breast cancer is the most frequent malignant tumour to metastasize into the gastrointestinal tract in female and is second only to malignant melanoma. Nevertheless gastrointestinal metastases arising from breast cancer are quite rare. The upper gastrointestinal tract is more frequently involved and lobular infiltrating carcinoma has a greater predilection compared to the ductal type.

Case presentation

The authors describe the case of a 70 years old woman with a preoperative diagnosis of gastric undifferentiated medullary – type carcinoma, which was the first manifestation of an occult breast carcinoma. The primary site of carcinoma was identified with the use of a panel of selected immunohistochemical markers.

Conclusion

Our goal in this case report is to increase the awareness of surgeons and clinicians to rule out the possibility of mammary origin in circumstance of gastric cancer occurring in female, even in patients without a previous or concurrent history of breast carcinoma. Although not a particularly common event, it is, nevertheless, reported in the literature. The differentiation between primary gastric carcinoma and metastatic breast carcinoma is essential for planning the correct therapeutic approach, in order to avoid the patient unnecessary surgery.

Tamoxifen exposure in relation to gastric adenocarcinoma development

Epidemiological research has indicated that the anti-oestrogen tamoxifen, used in breast cancer therapy, may increase the risk of gastric adenocarcinoma of the intestinal but not of the diffuse type. To test this hypothesis, and evaluate possible involvement of oestrogen receptors (ERs), we conducted a study amongst tamoxifen users and non-users. The study participants comprised women in the county of Stockholm who in the Swedish Cancer Register were first recorded with breast cancer and subsequently gastric cancer during the period January 1958-August 2005. Medical records were scrutinised to verify the diagnoses and classify into use or non-use of tamoxifen. Tumour material was reviewed histologically to verify gastric adenocarcinoma diagnosis and classify these cancers into intestinal or diffuse type. Intestinal adenocarcinomas were analysed immunohistochemically for the presence of ER alpha, beta and beta cx. Amongst 68 women with verified gastric adenocarcinoma, 30 had been treated with tamoxifen and 38 not. The intestinal type of gastric adenocarcinoma was not more frequent amongst tamoxifen users (27%) than amongst non-users (34%) (p=0.601). There were no material differences between the tamoxifen groups regarding distribution of any of the three ERs of the intestinal adenocarcinoma specimens. Tamoxifen users had a shorter latency between breast cancer and gastric adenocarcinoma (4 versus 13 years) which was similar in the intestinal and diffuse types. This study does not support the hypothesis that tamoxifen increases the isolated risk of the intestinal type, but it indicates that tamoxifen use might accelerate the tumour progression or increase the overall risk of gastric adenocarcinoma.

Parity and risk of stomach cancer by sub-site: a national Swedish study

We investigated stomach cancer risk by anatomic sub-site in relation to parity, as a marker for higher exposure to sex hormones, in a case-control study, nested within a cohort of 2,406,439 Swedish women born in 1925 or later and followed from 1970 or age 30 until emigration, death, any cancer diagnosis, or through 2004, whichever occurred first. We identified 286 cardia and 2498 non-cardia stomach cancer cases with five matched controls for each case. Cross-linkage with the Multi-Generation Register provided information about reproductive history. Using conditional logistic regression models for estimating odds ratios (ORs) and corresponding 95% confidence intervals (CIs), adjusted for education level and occupation, we found no association between any aspect of parity and non-cardia stomach cancer (OR=1.01, 95% CI 0.89-1.15, comparing parous with nulliparous women). However, a 30% risk reduction for postmenopausal cardia cancer (OR=0.7, 95% CI 0.4-1.0) was noted among parous relative to nulliparous women and the risk for premenopausal cardia cancer fell with increasing number of children (P for trend=0.04). Our results indicate that exposure to female sex hormones does not protect against non-cardia stomach cancer and does not explain male predominance. The observed moderate inverse relationship between parity and cardia cancer may be mediated by non-hormonal factors and warrants further study.

Light and electron microscopic studies on the effect of a contraceptive drug on the stomach of mouse

The present study was an investigation of the effect of the contraceptive drug, Nordette, on the stomach of the mouse when administered daily at a recommended therapeutic dose rate of 0.0026 mg kg(-1) for 30 days. Extensive light and electron microscopic changes were noticed. The drug caused enlargement in the all types of cells. The oxyntic cells appeared hypertrophied with irregular cell boundaries, enlarged nuclei and faintly stained cytoplasm. Their cytoplasm contained irregularly distributed mitochondria with dense matrix, decreased rER, obviously increased sER, disorganized intracellular canaliculi and some lysosomes. The peptic cells appeared enlarged and contained hypertrophied rough endoplasmic reticulum and an increase amount of ribosomes and secretory granules. There was an increase in the amount of the secretory granules in the lumen of the gastric gland. The mucus cells at the upper region of the gastric gland were greatly decreased. Smooth muscle fibers showed enlargement and degeneration. The submucosa and lamina propria showed vacuolation. The most pathological effects were restricted to the obvious decrease of the lymphoid cells in the submucosa and lamina propria. Dilatation and congestion of the blood vessels and blood capillaries were noticed. Blood capillaries lined by enlarged endothelial cells containing enlarged heterochromatic nuclei.

ERbeta scientific visions translate to clinical uses

Estrogen receptor beta (ERbeta) was discovered in 1995 and reported on in 1996. During the 10 years following this event, our understanding of estrogen signaling has changed remarkably. We now know that estradiol, the major endogenous activator of ER, is non-selective for the two receptors, and that ERalpha and ERbeta are, in many contexts, antagonistic against one another, an example of a yin/yang relationship, perhaps nature's way to accomplish subtle regulatory changes of estrogen signaling as a response to ever-shifting physiological requirements. Needless to say, this knowledge is of paramount significance pharmaceutically, and several ERbeta-selective agonists, intended for use against a multitude of diseases, have already been synthesized and patented by drug companies. Clearly, the next 5-10 years will be extremely exciting in view of results from clinical trials testing the clinical utility of ERbeta targeted drugs.

Menstrual and Reproductive Risk Factors and Risk for Gastric Adenocarcinoma in Women: Findings From the Canadian National Enhanced Cancer Surveillance System

PURPOSE

The role of menstrual and reproductive risk factors for gastric cancer has not been well studied.

METHODS

This population-based case-control study included 326 women aged 20 to 74 years with gastric adenocarcinoma. Controls were 326 women frequency matched on age. Data for reproductive and/or hormonal exposure and gastric cancer risk factors were captured through self-administered questionnaire.

RESULTS

Later age at menarche was associated with increased risk for adenocarcinoma compared with menarche onset at younger than 13 years of age (13 to 14 years: odds ratio [OR], 1.45; 95% confidence interval [CI], 1.00-2.10; > or =15 years: OR, 1.93; 95% CI, 1.19-3.13). Compared with premenopause, natural menopause was associated with increased risk for adenocarcinoma (OR, 1.99; 95% CI, 0.98-4.05). Compared with nulliparity, 4 or more births were associated with decreased risk for gastric cancer, as was being pregnant for 5 months or longer if the first pregnancy occurred at younger than 24 years (OR, 0.55; 95% CI, 0.31-0.96) or 25 years or older (OR, 0.67; 95% CI, 0.38-1.18). Oral contraceptives and hormone replacement therapy were associated with a non-statistically significant decreased risk.

CONCLUSION

These findings suggest that hormonal factors associated with greater exposure to estrogen and/or progesterone may be associated with decreased risk for gastric cancer.

Hormone replacement therapy and risks of oesophageal and gastric adenocarcinomas

Oesophageal and gastric adenocarcinoma share an unexplained male predominance, which would be explained by the hypothesis that oestrogens are protective in this respect. We carried out a nested case–control study of hormone replacement therapy (HRT) among 299 women with oesophageal cancer, 313 with gastric cancer, and 3191 randomly selected control women, frequency matched by age and calendar year in the General Practitioners Research Database in the United Kingdom. Data were adjusted for age, calendar year, tobacco smoking, alcohol consumption, body mass index, hysterectomy, and upper gastrointestinal disorders. Among 1 619 563 person-years of follow-up, more than 50% reduced risk of gastric adenocarcinoma was found among users of HRT compared to nonusers (odds ratio (OR), 0.48, 95% confidence interval (CI) 0.29–0.79). This inverse association appeared to be stronger for gastric noncardia (OR 0.34, 95% CI 0.14–0.78) and weaker for gastric cardia tumours (OR 0.68, 95% CI 0.23–2.01). There was no association between HRT and oesophageal adenocarcinoma (OR 1.17, 95% CI 0.41–3.32).

Regulation of mitochondrial respiratory chain structure and function by estrogens/estrogen receptors and potential physiological/pathophysiological implications

It is well known that the biological and carcinogenic effects of 17beta-estradiol (E2) are mediated via nuclear estrogen receptors (ERs) by regulating nuclear gene expression. Several rapid, non-nuclear genomic effects of E2 are mediated via plasma membrane-bound ERs. In addition, there is accumulating evidence suggesting that mitochondria are also important targets for the action of estrogens and ERs. This review summarized the studies on the effects of estrogens via ERs on mitochondrial structure and function. The potential physiological and pathophysiological implications of deficiency and/or overabundance of these E2/ER-mediated mitochondrial effects in stimulation of cell proliferation, inhibition of apoptosis, E2-mediated cardiovascular and neuroprotective effects in target cells are also discussed.

Expression of oestrogen receptor and loss of E-cadherin are diagnostic for gastric metastasis of breast carcinoma

AIMS

To investigate whether immunohistochemical staining for oestrogen receptor (ER)alpha, progesterone receptor (PgR) and E-cadherin might be useful to differentiate between metastatic breast carcinoma and primary gastric carcinoma.

METHODS

Gastric biopsies of 75 patients containing adenocarcinoma were stained for ERalpha, PgR and E-cadherin. Included were: Group A, 28 patients with primary gastric cancer; Group B, 28 patients with an adenocarcinoma containing gastric biopsy and a clinical diagnosis of metastatic breast carcinoma; Group C, all consecutive patients with a positive gastric biopsy in 2001 (n = 19) without clinical history of breast carcinoma and not followed by gastric resection (control group).

RESULTS

All ERalpha+ or PgR+ carcinomas (n = 20) were of patients with a previous or concurrent history of breast carcinoma: 19 in group B, one in group C. In addition, absence of E-cadherin staining was seen significantly more often in patients with metastatic breast carcinoma than in patients with primary gastric cancer (P < 0.001).

CONCLUSION

Positive immunohistochemical staining for ERalpha or PgR of an adenocarcinoma in a gastric biopsy is diagnostic for metastatic breast carcinoma. Moreover, when carcinoma in a gastric biopsy is negative for E-cadherin staining, metastatic breast carcinoma should be considered.

Hormone replacement therapy in cancer survivors

OBJECTIVE

Thousands of women are treated each year for cancer; many of these are already in menopause, while other younger patients will go into early menopause due to surgery, or chemotherapy, or the need for radiotherapy to the pelvic region. In most cases the oncologist and the gynaecologist would advise these women against the use of HRT. The purpose of this paper is to review biological and clinical evidences in favour and against HRT use in the different tumours and to propose an algorithm that can help choosing the treatment for the single woman.

METHODS

We performed a systematic literature review through April 2002 concerning: (1) biological basis of hormonal modulation of tumour growth; (2) epidemiological data on the impact of HRT on different cancers risk in healthy women; (3) safety of HRT use in cancer survivors; (4) alternatives to HRT.

RESULTS

With the exception of meningioma, breast and endometrial cancer, there is no biological evidence that HRT may increase recurrence risk. In women with previous breast and endometrial cancer HRT is potentially hazardous on a biological basis, even if published data do not show any worsening of prognosis.

CONCLUSIONS

Even if a cautious approach to hormonal-dependent neoplasias is fully comprehensible and the available alternative treatment should be taken into greater consideration, the reticence to prescribe HRT in women previously treated for other non hormone-related tumours has neither a biological nor a clinical basis. An algorithm based on present knowledge is proposed.

Estrogen receptor beta and breast cancer

A second estrogen receptor, estrogen receptor-beta, was identified in 1996 and has led to an intensive re-evaluation of the role of estrogens in normal physiological and disease processes. While much has been learnt about this new receptor, there remain many outstanding questions, particularly regarding its prognostic significance and therapeutic implications.

Estrogen receptor beta expression in vascular neoplasia: an analysis of 53 benign and malignant cases

The importance of estrogen in vascular neoplasia is suggested by a predilection for women and a tendency for rapid growth during pregnancy. Although early experiments using radioligand assays demonstrated estrogen receptor (ER) expression, these findings were not confirmed by subsequent immunohistochemical studies which were performed with antibodies raised against ER alpha. A newly discovered estrogen receptor subtype, ER beta, has not been previously characterized in vascular lesions. In order to verify the expression of estrogen receptors in vascular neoplasms as well as to clarify the inconsistency between radioligand and early immunohistochemical studies, we examined a series of 53 benign and malignant vascular neoplasms for ER beta expression. All of the subtypes of vascular neoplasia examined had nuclear expression of ER beta. The majority of cases (94%) displayed 2+ to 3+ staining. The discrepancy between radioligand studies and previous immunohistochemical studies is attributable to the use of antibodies raised against ER alpha, which is not expressed in vascular lesions, and not ER beta, which is broadly expressed in both benign and malignant vascular neoplasms. Although ER beta may be of limited diagnostic use in vascular neoplasia due to its broad expression, the potential exists for a therapeutic approach using ER agonists.

Tools for making correct decisions regarding hormone therapy. Part II. organ response and clinical applications

OBJECTIVE

To review existing scientific knowledge of the complicated and variable behavior and response to hormone therapy (HT) of different organs during aging, and to summarize long-term consequences on human health.

DESIGN

A MEDLINE computer search was performed to identify relevant articles.

RESULT(S)

Five body organs were evaluated. [1]. Physiologic aging of the bone has deleterious consequences on women's health and quality of life. Bone fractures could be attributed to the combination of estrogen depletion and osteoporosis, mechanisms of applied forces, and disturbed brain function, partially reversible by timely estrogen administration. [2]. Estrogen seems to have a profound neuroprotective effect. As physiologic aging of the brain is an unhealthy phenomenon, possible intervention is justified. The therapeutic time window seems crucial. [3]. The differentiation between response of a healthy or already damaged organ to sex hormones is the key factor to understanding the possible cardioprotective effects. [4]. Based on doubling time of tumor cells, intracrinology, epidemiological data on breast cancer, and behavior of breast cancer survivors in response to estrogen treatment, estrogen seems to be mainly a promoter and even a protector of breast cancer survivors. [5]. Colon cancer appears to be an estrogen-dependent tumor with a wide therapeutic window, as every report regardless of age and dose demonstrates protective effects.

CONCLUSION(S)

Knowledge of each organ's response to aging and sex hormone substitutions demonstrates that the organs could benefit from properly designed intervention. In the wake of the publication of the Women's Health Initiative study, which shocked the medical community, we suggest that the results be reevaluated according to the aforementioned principles, and that menopausal medicine could play an important role.

Mitochondrial localization of ERalpha and ERbeta in human MCF7 cells

We observed previously that estrogen treatment increased the transcript levels of several mitochondrial DNA (mtDNA)-encoded genes for mitochondrial respiratory chain (MRC) proteins and MRC activity in rat hepatocytes and human Hep G2 cells. Others have reported detection of estrogen receptors (ER), ERalpha and ERbeta, in mitochondria of rabbit ovarian and uterine tissue. In this study, we have extended these observations. Using cellular fractionation and Western blot with ERalpha- and ERbeta-specific antibodies, we observed that ERalpha and ERbeta are present in mitochondria of human MCF7 cells and that the mitochondrial ERalpha and ERbeta account for 10 and 18%, respectively, of total cellular ERalpha and ERbeta in 17beta-estradiol (E(2))-treated MCF7 cells. We also found that E(2) significantly enhanced the amounts of mitochondrial ERalpha and ERbeta in a time- and concentration-dependent manner and that these effects are accompanied by a significant increase in the transcript levels of mtDNA-encoded genes, i.e., cytochrome c oxidase subunits I and II. Moreover, we demonstrated that these E(2)-mediated effects were inhibited by the pure ER antagonist, ICI-182780, indicating the involvement of ERs. Using immunohistochemistry with confocal microscopy and immunogold electron microscopy, we demonstrated that ERalpha and ERbeta are located within the MCF7 cell mitochondrial matrix. Computer analysis identified a putative internal mitochondrial targeting peptide signal within human ERbeta, suggesting an inherent potential for ERbeta to enter mitochondria. These findings confirm the observations of others and provide additional support for this novel localization of the ERs and for a potentially important role of the ER in the regulation of mtDNA transcription.

Systemic distribution of estrogen-responsive finger protein (Efp) in human tissues

Estrogen-responsive finger protein (Efp), a target gene product of estrogen receptor (ER), is considered essential for estrogen-dependent cell proliferation. The biological significance of Efp remains unclear in human tissues, and therefore, we examined systemic distribution of Efp in human adult and fetal tissues using RT-PCR and immunohistochemistry. Efp mRNA expression was marked in the placenta and uterus, high in the thyroid gland, aorta, and spleen in adult, and relatively low in other human adult and fetal tissues examined in this study. Efp immunoreactivity was detected in epithelium of various adult tissues, and was also detected in cytotrophoblasts of the placenta and splenic macrophages. Efp immunolocalization in human fetus was generally similar as that in adult. These Efp-positive cells were previously reported to be associated with ERalpha and/or ERbeta expression. Therefore, these results indicate that Efp is widely expressed and may play important roles in various human tissues possibly through ERs.

Androgen receptor (AR) expression is an independent unfavorable prognostic factor in gastric cancer

PURPOSE

To investigate the expression of sex steroid receptors in gastric cancer and to correlate their tumor expression profile with the clinicopathological parameters and overall survival of the patients.

METHODS

Immunohistochemical methodology was employed in formalin-fixed paraffin-embedded sections from 86 patients with gastric carcinoma. Monoclonal antibodies against androgen (AR), estrogen (ER), and progesterone (PR) receptors were used. Survival rates were estimated by the Kaplan-Meier method and compared using the log-rank test. Multivariate analysis was performed by the Cox proportional hazards model.

RESULTS

Fifteen (17.4%) cases of gastric adenocarcinomas were positive for AR, two (2.3%) were positive for PR and three (3.5%) were positive for ER. Significantly higher AR expression was found in tumors with metastases to lymph nodes (P = 0.03). Patients with AR-positive tumors (AR+) had worse prognosis than (AR-) patients (median survival 9 months vs 24 months, P = 0.03). Patients with AR- and heat shock protein 27 (HSP27)-positive tumors (AR+/HSP27+) had a median survival of 6 months, whereas (AR-/HSP27-) patients had a median survival of 42 months (P = 0.017). Multivariate analysis revealed that AR expression and UICC stage were independent factors of unfavorable prognosis (P = 0.037 and P = 0.0055, respectively).

CONCLUSIONS

Identification of AR-positive gastric carcinomas in gastric biopsies may warrant a more aggressive therapeutic approach and anti-androgen or AR-targeted agents may represent a novel strategy in tackling this devastating malignancy.

Expression of estrogen receptor and estrogen receptor messenger RNA in gastric carcinoma tissues

AIM: To study estrogen receptor (ER) and estrogen receptor messenger RNA (ERmRNA) expression in gastric carcinoma tissues and to investigate their association with the pathologic types of gastric carcinoma.

METHODS: The expression of ER and ERmRNA in gastric carcinoma tissues (15 males and 15 females, 42-70 years old) was detected by immunohistochemistry and in situ hybridization, respectively.

RESULTS: The positive rate of ER (immunohistochemistry) was 33.3% in males and 46.7% in females. In Borrmann IV gastric carcinoma ER positive rate was greater than that in other pathologic types, and in poorly differentiated adenocarcinoma and signet ring cell carcinoma the positive rates were greater than those in other histological types of both males and females (P < 0.05). The ER was more highly expressed in diffused gastric carcinoma than in non-diffused gastric carcinoma (P < 0.05). The ER positive rate was also related to regional lymph nodes metastases (P < 0.05), and was significantly higher in females above 55 years old, and higher in males under 55 years old (P < 0.05). The ERmRNA (in situ hybridization) positive rate was 73.3% in males and 86.7% in females. The ERmRNA positive rates were almost the same in Borrmann I, II, III and IV gastric carcinoma (P > 0.05). ERmRNA was expressed in all tubular adenocarcinoma, poorly differentiated adenocarcinoma and signet ring cell carcinoma (P < 0.05). The ERmRNA positive rate was related to both regional lymph nodes metastases and gastric carcinoma growth patterns, and was higher in both sexes above 55 years old but without statistical significance (P > 0.05). The positive rate of ERmRNA expression by in situ hybridization was higher than that of ER expression by immunohistochemistry (P < 0.05).

CONCLUSION: ERmRNA expression is related to the pathological behaviors of gastric carcinoma, which might help to predict the prognosis and predict the effectiveness of endocrine therapy for gastric carcinoma.