Hormonal effects on glioblastoma multiforme in the nude rat model

Estrogen signaling in healthy and tumor brain

Sex-specific differences in brain organization and function are widely explored in multidisciplinary studies, ranging from sociology and biology to digital modelling. In addition, there is growing evidence that natural or disturbed hormonal environments play a crucial role in the onset of brain disorders and pathogenesis. For example, steroid hormones, but also enzymes involved in steroidogenesis and receptors triggering hormone signaling are key players of gliomagenesis. In the present review we summarize the current knowledge about steroid hormone, particularly estrogens synthesis and signaling, in normal brain compared to the tumor brain. We will focus on two key molecular players, aromatase and the G Protein-Coupled Estrogen Receptor, GPER.

Sex-related incidence and survival differences in pediatric high-grade glioma subtypes: A population-based cohort study

Not much is known on sex differences in incidence, survival, and treatment characteristics for midline and hemispheric pHGGs. This population-based study confirms previously reported study results that found worse survival outcomes for malignant diffuse gliomas in girls in the age group 0-9 years. Additionally, in our study we pinpoint this difference to girls with midline pHGGs aged 0-4 years. We provide insight in the possible underlying mechanisms contributing to sex survival differences in pHGG patients. With first line treatment having no impact on the higher risk of dying for girls, but age and tumor characteristics having a neutralizing effect. The results of this population-based study serve as a basis for future pre-clinical and clinical studies to further unravel the underlying mechanisms responsible for the survival gap between sexes in midline pHGG.

Insights into the role of estrogens and androgens in glial tumorigenesis

Gliomas are more common in males than in females. Emerging evidence from several studies in vitro and in vivo have shown the role of estrogens and androgens in glial tumorigenesis. In recent times, studies have also shed light on the actions of estrogen receptors, alpha and beta, and androgen receptor. Here, we provide a comprehensive overview of the research hitherto on estrogens and androgens along with an emphasis on their receptors in glioma pathophysiology. Studies with conflicting results are discussed and future possibilities are put forward. A collective understanding of the studies on these steroid hormones in glioma may serve to create an amalgamated therapeutic approach; and thereby, augment the efforts in tackling this deadly disease.

Sex-Specific Differences in Glioblastoma

Sex differences have been well identified in many brain tumors. Even though glioblastoma (GBM) is the most common primary malignant brain tumor in adults and has the worst outcome, well-established differences between men and women are limited to incidence and outcome. Little is known about sex differences in GBM at the disease phenotype and genetical/molecular level. This review focuses on a deep understanding of the pathophysiology of GBM, including hormones, metabolic pathways, the immune system, and molecular changes, along with differences between men and women and how these dimorphisms affect disease outcome. The information analyzed in this review shows a greater incidence and worse outcome in male patients with GBM compared with female patients. We highlight the protective role of estrogen and the upregulation of androgen receptors and testosterone having detrimental effects on GBM. Moreover, hormones and the immune system work in synergy to directly affect the GBM microenvironment. Genetic and molecular differences have also recently been identified. Specific genes and molecular pathways, either upregulated or downregulated depending on sex, could potentially directly dictate GBM outcome differences. It appears that sexual dimorphism in GBM affects patient outcome and requires an individualized approach to management considering the sex of the patient, especially in relation to differences at the molecular level.

Androgen Receptor, Although Not a Specific Marker For, Is a Novel Target to Suppress Glioma Stem Cells as a Therapeutic Strategy for Glioblastoma

Targeting androgen receptor (AR) has been shown to be promising in treating glioblastoma (GBM) in cell culture and flank implant models but the mechanisms remain unclear. AR antagonists including enzalutamide are available for treating prostate cancer patients in clinic and can pass the blood-brain barrier, thus are potentially good candidates for GBM treatment but have not been tested in GBM orthotopically. Our current studies confirmed that in patients, a majority of GBM tumors overexpress AR in both genders. Enzalutamide inhibited the proliferation of GBM cells both in vitro and in vivo. Although confocal microscopy demonstrated that AR is expressed but not specifically in glioma cancer stem cells (CSCs) (CD133+), enzalutamide treatment significantly decreased CSC population in cultured monolayer cells and spheroids, suppressed tumor sphere-forming capacity of GBM cells, and downregulated CSC gene expression at mRNA and protein levels in a dose- and time-dependent manner. We have, for the first time, demonstrated that enzalutamide treatment decreased the density of CSCs in vivo and improved survival in an orthotopic GBM mouse model. We conclude that AR antagonists potently target glioma CSCs in addition to suppressing the overall proliferation of GBM cells as a mechanism supporting their repurposing for clinical applications treating GBM.

Impact of sex in the prevalence and progression of glioblastomas: the role of gonadal steroid hormones

BACKGROUND

As in other types of cancers, sex is an essential factor in the origin and progression of glioblastomas. Research in the field of endocrinology and cancer suggests that gonadal steroid hormones play an important role in the progression and prevalence of glioblastomas. In the present review, we aim to discuss the actions and mechanism triggered by gonadal steroid hormones in glioblastomas.

MAIN BODY

Glioblastoma is the most common malignant primary brain tumor. According to the epidemiological data, glioblastomas are more frequent in men than in women in a 1.6/1 proportion both in children and adults. This evidence, and the knowledge about sex influence over the prevalence of countless diseases, suggest that male gonadal steroid hormones, such as testosterone, promote glioblastomas growth. In contrast, a protective role of female gonadal steroid hormones (estradiol and progesterone) against glioblastomas has been questioned. Several pieces of evidence demonstrate a variety of effects induced by female and male gonadal steroid hormones in glioblastomas. Several studies indicate that pregnancy, a physiological state with the highest progesterone and estradiol levels, accelerates the progression of low-grade astrocytomas to glioblastomas and increases the symptoms associated with these tumors. In vitro studies have demonstrated that progesterone has a dual role in glioblastoma cells: physiological concentrations promote cell proliferation, migration, and invasion while very high doses (out physiological range) reduce cell proliferation and increases cell death.

CONCLUSION

Gonadal steroid hormones can stimulate the progression of glioblastomas through the increase in proliferation, migration, and invasion. However, the effects mentioned above depend on the concentrations of these hormones and the receptor involved in hormone actions. Estradiol and progesterone can exert promoter or protective effects while the role of testosterone has been always associated to glioblastomas progression.

High expression of estrogen receptor alpha and aromatase in glial tumor cells is associated with gender-independent survival benefits in glioblastoma patients

Introduction

Glioblastoma multiforme (GBM) is a highly malignant glial tumor, affecting men more often than women. The reason for this gender-specific predominance remains unclear, raising the question whether these effects are subject to hormonal control. The purpose of this study was to examine the expression of estrogen receptor alpha (ERα) and aromatase in human GBM tissue samples in relation to patient survival and furthermore to investigate the effect of standard chemotherapy in combination with estradiol treatment on glioblastoma tumor cell lines in vitro.

Methods

60 tissue samples (31 male, 29 female) of GBM patients were analysed with immunohistochemistry for ERα and aromatase for survival analyses. The cell lines LN18 and LN229 were treated with 17β-estradiol (E2) in different dosing regimens and the cell viability was measured with MTT assay. After estradiol pre-treatment Temozolomide was added and tested again.

Results

High expression of ERα and aromatase in the GBM tissue samples was associated with significantly longer survival times of GBM patients, regardless of gender and body-mass-index. The treatment with high concentrations of estradiol resulted in lower tumor cell viability, compared to control. The cells significantly showed a stronger sensitivity against Temozolomid (TMZ) after estradiol pre-treatment.

Conclusion

ERα-expression of glial tumour cells seems to play an important prognostic role as a biomarker in GBM, as well as the expression of the enzyme Aromatase. The combined treatment of GBM with standard chemotherapy and estradiol may be beneficial to patient’s survival.

Long Term Survival in Patients Suffering from Glio-blastoma Multiforme: A Single-Center Observational Cohort Study

Background: Glioblastomas (GBM) are generally burdened, to date, by a dismal prognosis, although long term survivors have a relatively significant incidence. Our specific aim was to determine the exact impact of many surgery-, patient- and tumor-related variables on survival parameters. Methods: The surgical, radiological and clinical outcomes of patients have been retrospectively reviewed for the present study. All the patients have been operated on in our institution and classified according their overall survival in long term survivors (LTS) and short term survivors (STS). A thorough review of our surgical series was conducted to compare the oncologic results of the patients in regard to: (1) surgical-(2) molecular and (3) treatment-related features. Results: A total of 177 patients were included in the final cohort. Extensive statistical analysis by means of univariate, multivariate and survival analyses disclosed a survival advantage for patients presenting a younger age, a smaller lesion and a better functional status at presentation. From the histochemical point of view, Ki67 (%) was the strongest predictor of better oncologic outcomes. A stepwise analysis of variance outlines the existence of eight prognostic subgroups according to the molecular patterns of Ki67 overexpression and epidermal growth factor receptor (EGFR), p53 and isocitrate dehydrogenase (IDH) mutations. Conclusions: On the grounds of our statistical analyses we can affirm that the following factors were significant predictors of survival advantage: Karnofsky performance status (KPS), age, volume of the lesion, motor disorder at presentation and/or a Ki67 overexpression. In our experience, LTS is associated with a gross total resection (GTR) of tumor correlated with EGFR and p53 mutations with regardless of localization, and poorly correlated to dimension. We suppose that performing a standard molecular analysis (IDH, EGFR, p53 and Ki67) is not sufficient to predict the behavior of a GBM in regards to overall survival (OS), nor to provide a deeper understanding of the meaning of the different genetic alterations in the DNA of cancer cells. A fine molecular profiling is feasible to precisely stratify the prognosis of GBM patients.

Tibolone Effects on Human Glioblastoma Cell Lines

BACKGROUND

Ovarian steroid hormones are involved in modulating the growth of glioblastomas (the most common, aggressive, and lethal brain tumor) through the interaction with their intracellular receptors. Activation of sex hormone receptors is involved in glioblastomas progression. Tibolone (TIB) is a selective tissue estrogenic activity regulator widely prescribed to treat menopausal symptoms and to prevent bone lost. The effects of TIB on the growth of glioblastoma are unknown.

AIM OF THE STUDY

To evaluate the effects of TIB on cell number, migration, and invasion of two derived human glioblastoma cell lines (U251 MG and U87), as well as the role of this steroid in estrogen and progesterone receptors activity and content.

METHODS

U251-MG and U87 human glioblastoma cell lines were grown with different doses of TIB. The number of cells was determined and migration and invasion tests were carried out. Protein expression was performed by Western blot.

RESULTS

We observed that TIB (10 nM) increased the number of cells by inducing proliferation with no effects on cell migration or invasion. The increase in cell proliferation induced by TIB was blocked by estrogen (ERs) or progesterone receptor (PRs) antagonists, ICI 182, 780 and RU 486, suggesting that these receptors mediate proliferating actions of TIB; TIB also modified the content of ERs and PRs by increasing ER-α, ER-β, and PR-B, while decreased PR-A.

CONCLUSION

Our results suggest that TIB increases cell number and proliferation of human glioblastoma cells through the regulation of ERs and PRs actions and content.

Glioblastoma Multiforme and Breast Cancer: Report on 11 Cases and Clinico-Pathological Remarks

The association between breast cancer and glioblastoma multiforme has not been amply analyzed in the literature. We describe 11 female patients with a diagnosis of glioblastoma multiforme who were treated when younger for breast cancer. We believe that this association is not due to chance but rather to genetic changes in hormone status and in particular to sex hormones. Another important point of view is represented by the chemotherapy treatment of breast cancer, which could have a carcinogenic effect and explain the growth of glioblastoma. This consideration, in our opinion, is important, because more effort should be made to understand the pathogenesis of glioblastoma multiforme and to improve the therapeutic approaches.

Cross-species transcriptional analysis reveals conserved and host-specific neoplastic processes in mammalian glioma

Glioma is a unique neoplastic disease that develops exclusively in the central nervous system (CNS) and rarely metastasizes to other tissues. This feature strongly implicates the tumor-host CNS microenvironment in gliomagenesis and tumor progression. We investigated the differences and similarities in glioma biology as conveyed by transcriptomic patterns across four mammalian hosts: rats, mice, dogs, and humans. Given the inherent intra-tumoral molecular heterogeneity of human glioma, we focused this study on tumors with upregulation of the platelet-derived growth factor signaling axis, a common and early alteration in human gliomagenesis. The results reveal core neoplastic alterations in mammalian glioma, as well as unique contributions of the tumor host to neoplastic processes. Notable differences were observed in gene expression patterns as well as related biological pathways and cell populations known to mediate key elements of glioma biology, including angiogenesis, immune evasion, and brain invasion. These data provide new insights regarding mammalian models of human glioma, and how these insights and models relate to our current understanding of the human disease.

Regulation of p53wt glioma cell proliferation by androgen receptor-mediated inhibition of small VCP/p97-interacting protein expression

The incidence of glioma in men is higher than that in women; however, little is known about the expression and basic function of the androgen receptor (AR) in gliomas. AR inhibited the small VCP/p97-interacting protein (SVIP) on the transcriptional level was previously reported. The present study shows that the protein level of AR is highly expressed in cell lines of the nervous system. Moreover, the AR expression is increased while SVIP expression is decreased in tumor tissue of glioma patients, which is in agreement with the progressing WHO grades. A statistically significant increase in serum testosterone level of glioma patients compared with that of non-cancer patients was also detected. Furthermore, it has been proved that SVIP is down-regulated as well as AR is up-regulated in glioma cell lines with R1881 treatment. Interestingly, the depletion of SVIP using siRNA facilitated cell proliferation and decreased p53 expression. In addition, overexpression of SVIP increased cell death only in p53^wt cell lines. Moreover, U87MG cells, p53^wt cell line was susceptible to AR antagonists in vitro and in vivo. The current study provides insight into the biological role of AR in suppressing SVIP and p53 and promoting the progression of glioma as well as the clinical treatment of glioma patients.

Female sex, good performance status, and bevacizumab-induced hypertension associated with survival benefit in Asian patients with recurrent glioblastoma treated with bevacizumab

AIM

The goals of this study were to assess the activity and safety profile of bevacizumab in Taiwan Chinese patients with recurrent glioblastoma, to determine whether their response differed from that reported in other clinical trials, and to examine potential prognostic factors for survival.

METHODS

We retrospectively assessed patients who received bevacizumab for recurrent glioblastoma between 2012 and 2015. Twelve predefined variables and the outcomes of our cohort were analyzed.

RESULTS

In total, 76 patients with recurrent glioblastoma were analyzed. The overall response rate was 59.2%, including 19 patients (25.0%) with complete response and 26 patients (34.2%) with partial response. The median progression-free survival and overall survival were 5.2 months (95% confidence interval [CI], 4.6-5.8 months) and 7.8 months (95% CI, 5.8-9.8 months), respectively. Multivariate analysis identified sex and grade 3 posttreatment hypertension (systolic ≥ 160 mmHg or diastolic ≥ 100 mmHg) as the only independent predictive factors for progression-free survival and overall survival. Eastern Cooperative Oncology Group performance status was also found to be independently predictive of improved overall survival.

CONCLUSION

We showed good responses using bevacizumab and the progression-free survival and overall survival were comparable with those previously reported. The adverse events of bevacizumab in our study were generally acceptable and manageable. Female sex, good performance status, and grade 3 posttreatment hypertension were suggested to be associated with survival benefits.

Bilateral Triple-Negative Invasive Breast Cancer with a BRCA2 Mutation, and Glioblastoma: A Case Report and Literature Review

Breast cancer is the second leading cause of death among women in North America. Glioblastoma is the most common primary malignant central nervous system tumor in adults. The majority of hereditary breast cancers are associated with deleterious mutations in the BRCA1 and BRCA2 genes. Although few case reports have described the incidence of glioblastoma in patients previously diagnosed with breast cancer, any association between BRCA2 mutations and glioblastoma has not been demonstrated to date. Herein, we report a woman who is a carrier of a familial BRCA2 mutation, and was previously diagnosed with triple-negative breast cancer (TNBC) and subsequently with a second primary TNBC and glioblastoma. Further investigation is required to define the possible relationship between these two aggressive malignances and the BRCA2 mutation, which might be critical for the proper management and treatment of this disease.

An integrative view on sex differences in brain tumors

Sex differences in human health and disease can range from undetectable to profound. Differences in brain tumor rates and outcome are evident in males and females throughout the world and regardless of age. These observations indicate that fundamental aspects of sex determination can impact the biology of brain tumors. It is likely that optimal personalized approaches to the treatment of male and female brain tumor patients will require recognizing and understanding the ways in which the biology of their tumors can differ. It is our view that sex-specific approaches to brain tumor screening and care will be enhanced by rigorously documenting differences in brain tumor rates and outcomes in males and females, and understanding the developmental and evolutionary origins of sex differences. Here we offer such an integrative perspective on brain tumors. It is our intent to encourage the consideration of sex differences in clinical and basic scientific investigations.

Multiparametric magnetic resonance in the assessment of the gender differences in a high-grade glioma rat model

Background

Glioblastoma, the most frequent and aggressive of all astrocytomas, presents a clear predominance in male humans, but the assessment of sexual differences in its tumourigenesis and growth has received little attention so far. In this study, we aim to identify gender-dependent surrogate markers in an animal model of this cancer by means of magnetic resonance (MR) imaging and biochemical and behavioural studies.

Methods

A high-grade glioma model developed in male and female rats was used. Multiparametric magnetic resonance images and localized spectra were acquired. The MR parameters linked to tumoural features were quantified. Motor and metabolic activity was also assessed. Postmortem analyses were carried out to measure indicators of malignancy, tumoural metabolism and viability of the blood-brain barrier (BBB).

Results

Statistically significant differences dependent on the animal sex were found in the study of pathological indicators like oedema, inflammation, cellularity and microvasculature. Results suggest higher cell proliferative rate, inflammation and vasogenic oedema and or necrosis in glioma-bearing male rats. Haemodynamic parameters measured indicated a major disruption of the BBB, postmortem confirmed, in this sex. Metabolomic and energetic metabolism activity data are in agreement with a major malignancy and aggressiveness of this cancer model on males.

Conclusions

Gender differences should be taken into account in preclinical studies of glioblastoma models, in the characterization of the tumoural behaviour and consequently in the development and validation of new therapeutic approaches. MR imaging and spectroscopy allow to non-invasively monitor this sexual dimorphism in the diagnosis and prognosis of brain cancer.

Assessment of glioma risk associated with an inherited variant at chromosome 11q23

It is still unclear whether or not rs498872 at 11q23.3 increases the risk of developing glioma, because the previous literature has reported mixed findings. We carried out a meta-analysis with an aim to test the hypothesis that rs498872 contributes to the development of glioma. Eligible studies were identified through databases including the Chinese biomedical literature database, China national knowledge infrastructure, Science Direct, Embase and PubMed. The risk of glioma (OR and 95% CI) was evaluated with the fixed-effects model or the random-effects model. Sensitivity analysis and publication bias tests were performed to check the reliability of our findings. Ten independent populations representing three ethnicities were analyzed in this study. We found 1.17-1.34-fold increased risk of glioma associated with rs498872 genotypes (OR 1.34, 95% CI 1.22-1.46; OR 1.24, 95% CI 1.14-1.35; OR 1.20, 95% CI 1.10-1.31; OR 1.17, 95% CI 1.08-1.27). In the stratified analysis by ethnicity, we also observed a significant increase in the risk of glioma in both Americans and Europeans. The results of our study support that the rs498872 polymorphism at 11q23.3 locus may be an important risk factor for glioma risk.

Gender effect in experimental models of human medulloblastoma: does the estrogen receptor β signaling play a role?

Background

The male-to-female sex ratio for medulloblastoma (MB) is approximately 1.5∶1, female gender being also a favorable prognostic factor. This study aimed at evaluating the impact of gender on MB tumorigenesis.

Methods

In vitro activity of 17β-estradiol (E₂), DPN [2,3-bis(4-hydroxyphenyl)-propionitrile, a selective estrogen receptor β (ERβ)-agonist], PPT [4,4′,4″-(4-Propyl-[1H]-pyrazole-1,3,5-triyl) trisphenol, a selective ERα-agonist] or DHT (5 alpha-dihydrotestosterone) was evaluated in three human MB cell lines. D283 Med cells were transplanted into athymic mice.

Results

A significant expression of ERβ, with little or no ERα, and low AR (androgen receptor) was found in MB cell lines. The compounds tested did not affect cell proliferation. In vivo, we observed a significantly lower growth of D283 Med in nude female mice compared to males. At microscopic examination, tumors from females showed a shift towards differentiation, as evaluated by lower nestin, and higher NSE (neuron-specific enolase) and GFAP (glial fibrillary acidic protein) expression compared to males. Tumors from females also showed lower Ki67 and p53 expression. The wild-type ERβ protein (ERβ1) was lost in male tumors, while it was a permanent feature in females, and a strong negative correlation was found between Ki67 and ERβ1 expression. Conversely, tumor levels of ERβ2 and ERβ5 did not significantly differ between genders. Increased levels of cyclin-dependent kinase inhibitor p21 were observed in females, suggesting that estrogen may decrease tumor growth through blocking cell cycle progression. An inhibition of the insulin-like growth factor I (IGF-I) signaling was also evident in females.

Conclusion

We provides mechanistic evidence supporting the idea that ERβ1 signaling may have pro-differentiation and tumor suppressive function in medulloblastomas.

Antioxidants delay clinical signs and systemic effects of ENU induced brain tumors in rats

According to our previous study suggesting that antioxidant properties of phytochemicals in the diet decrease glioma aggressiveness, we used a SUVIMAX-like diet ("Supplementation en VItamines et Minéraux AntioXydants") (enriched with alpha-tocopherol, beta carotene, vitamin C, zinc, and sodium selenite), adapted to rats. The present results showed that each of the antioxidants inhibited growth of glioma cells in vitro. When used in combination for in vivo studies, we showed a highly significant delay in the clinical signs of the disease, but not a statistical significant difference in the incidence of glioma in an Ethyl-nitrosourea (ENU)-model. The SUVIMAX-like diet decreased candidate markers of tumoral aggressiveness and gliomagenesis progression. The mRNA expressions of 2 common markers in human glioma: Mn-SOD (Manganese Superoxide Dismutase) and IGFBP5 (insulin growth factor binding protein) were reduced in the tumors of rats fed the antioxidant diet. In addition, the transcripts of two markers linked to brain tumor proliferation, PDGFRb (platelet-derived growth factor receptor beta) and Ki-67, were also significantly decreased. On the whole, our results suggest a protective role for antioxidants to limit aggressiveness and to some extent, progression of gliomas, in a rat model.

Exogenous and endogenous hormones in relation to glioma in women: a meta-analysis of 11 case-control studies

BACKGROUND AND OBJECTIVE

Previous investigations of glioma risk in women have focused on oral contraceptive (OC), hormone replacement therapy (HRT), and reproductive factors. However, the results of published studies were inconclusive and inconsistent. Thus, a meta-analysis based on published case-control studies was performed to assess the role of exogenous and endogenous hormones factors in glioma risk.

METHODS

The PubMed and EMBASE databases were searched without any restrictions on language or publication year. Reference lists from retrieved articles were also reviewed. We included case-control studies reporting relative risks (RRs) with corresponding 95% confidence intervals (CIs) (or data to calculate them) between oral contraceptive (OC) and hormone replacement therapy (HRT) use, reproductive factors and glioma. Random-effects models were used to calculate the summary risk estimates.

RESULTS

Finally, 11 eligible studies with 4860 cases and 14,740 controls were identified. A lower risk of glioma was observed among women who were ever users of exogenous hormones (OC RR = 0.707, 95% CI = 0.604-0.828; HRT: RR = 0.683, 95% CI = 0.577-0.808) compared with never users. An increased glioma risk was associated with older age at menarche (RR = 1.401, 95% CI = 1.052-1.865). No association was observed for menopause status, parous status, age at menopause, or age at first birth and glioma risk.

CONCLUSION

The results of our study support the hypothesis female sex hormones play a role in the development of glioma in women. Additional studies are warranted to validate the conclusion from this meta-analysis and clarity the underlying mechanisms.

Parity, age at first birth, and risk of death from brain cancer: a population-based cohort study in Taiwan

Background

This study was undertaken to examine whether there is an association between parity and age at first birth and risk of death from brain cancer.

Methods

The study cohort consisted of 1,292,462 women who had a first and singleton childbirth between Jan. 1, 1978 and Dec. 31, 1987. We tracked each woman from the time of their first childbirth to December 31, 2009, and their vital status was ascertained by linking records with the computerized mortality database. Cox proportional hazard regression models were used to estimate the hazard ratios (HR) of death from brain cancer associated with parity and age at first birth.

Results

There were 316 brain cancer deaths during 34,980,246 person-years of follow-up. The mortality rate of brain cancer was 0.90 cases per 100,000 person-years. The adjusted HR was 1.35 (95% CI= 0.91-2.01) for women who gave birth between 21 and 25, 1.61 (95% CI=1.05-2.45) for women who gave birth after 25 years of age, respectively, when compared with women who gave birth less than 20 years. A trend of increasing risk of brain cancer was seen with increasing age at first birth. The adjusted HR were 0.73 (95% CI= 0.53-0.99) for women who had 2 children, and 0.60 (95% CI =0.43-0.83) for women with 3 or more births, respectively, when compared with women who had given birth to only 1 child. There was a significant decreasing trend in the HRs of brain cancer with increasing parity.

Conclusions

This study provides evidence that reproductive factors (parity and early age at first birth) may confer a protective effect on the risk of death from brain cancer.

Comparison between symptomatic treatment and lomustine supplementation in 71 dogs with intracranial, space-occupying lesions

Brain neoplasia is diagnosed in an increasing number of dogs. Consequently, there is a higher need for an effective treatment. Chemotherapy is considered in cases where surgery or radiation is not optional. The objective of this retrospective study was to evaluate the difference in median survival time (MST) of dogs with intracranial masses, treated symptomatically with corticosteroids and anti-epileptic drugs, compared with the same symptomatic treatment supplemented with lomustine. The records of 71 dogs with intracranial masses were retrospectively evaluated. Fifteen dogs were treated symptomatically with corticosteroids and anti-epileptics, and 56 dogs received additional therapy with lomustine. There was no statistically significant difference in MST between both groups, being 60 and 93 days, respectively. Age, duration of symptoms, intracranial localization of the mass and intra- or extra-axial localization had no influence on survival time. However, female dogs survived significantly longer than male dogs.

Joint associations between genetic variants and reproductive factors in glioma risk among women

In a pooled analysis of 4 US epidemiologic studies (1993-2001), the authors evaluated the role of 5 female reproductive factors in 357 women with glioma and 822 controls. The authors further evaluated the independent association between 5 implicated gene variants and glioma risk among the study population, as well as the joint associations of female reproductive factors (ages at menarche and menopause, menopausal status, use of oral contraceptives, and menopausal hormone therapy) and these gene variants on glioma risk. Risk estimates were calculated as odds ratios and 95% confidence intervals that were adjusted for age, race, and study. Three of the gene variants (rs4295627, a variant of CCDC26; rs4977756, a variant of CDKN2A and CDKN2B; and rs6010620, a variant of RTEL1) were statistically significantly associated with glioma risk in the present population. Compared with women who had an early age at menarche (<12 years of age), those who reported menarche at 12-13 years of age or at 14 years of age or older had a 1.7-fold higher risk and a 1.9-fold higher risk of glioma, respectively (P for trend = 0.009). Postmenopausal women and women who reported ever having used oral contraceptives had a decreased risk of glioma. The authors did not observe joint associations between these reproductive characteristics and the implicated glioma gene variants. These results require replication, but if confirmed, they would suggest that the gene variants that have previously been implicated in the development of glioma are unlikely to act through the same hormonal mechanisms in women.

Protective role of 17 β-estradiol on medulloblastoma development in Patched 1 heterozygous mice

Medulloblastoma (MB) is the most common pediatric tumor of the CNS, representing ∼20% of all childhood CNS tumors. Although in recent years many molecular mechanisms that control MB development have been clarified, the effects of biological factors such as sex on this tumor remain to be explained. Epidemiological data, in fact, indicate a significant difference in the incidence of MB between the 2 sexes, with considerably higher susceptibility of males than females. Besides this different susceptibility, female sex is also a significant favorable prognostic factor in MB, with girls having a much better outcome. Despite these literature data, there has been little investigation into estrogen influence on MB development. In our study, we evaluated how hormone deficiency resulting from ovariectomy and hormone replacement influences the development of early and advanced MB stages in Patched1 heterozygous mice, a well-characterized mouse model of radiation-induced MB. Susceptibility to MB development was significantly increased in ovariectomized Ptch1(+/-) females and restored to levels observed in control mice after estrogen replacement. We next investigated the molecular mechanisms by which estrogen might influence tumor progression and show that ERβ, but not ERα, is involved in modulation of MB development by estrogens. Finally, our study shows that a functional interaction between estrogen- and IGF-I-mediated pathways may be responsible for the effects observed.

Brain tumors and hormonal factors: review of the epidemiological literature

BACKGROUND

To date, the etiology of primary tumors of the central nervous system (mainly gliomas and meningiomas) is poorly understood. The role of sex hormones has been suggested, based on clinical, experimental, biological, and epidemiological data.

OBJECTIVE

To review the epidemiological studies on the relation between hormonal factors and the occurrence of glioma and meningioma, in order to identify new research developments.

METHODS

Articles published until September 2010 were selected by considering exogenous and endogenous exposures and specific brain tumors. Standardized information was collected from 20 articles: 15 concerning gliomas and 13 meningiomas.

RESULTS

An increased glioma risk was observed with later menarche and menopause, while a reduced glioma risk was observed with hormone replacement therapy (HRT) and oral contraceptive use, despite duration of use had no effect on risk. Meningioma risk increased after menopause and with HRT use. No clear association was found with pregnancy and breastfeeding.

CONCLUSION

Results are globally concordant with the biologic hypothesis assuming that female sex hormones are protective against glioma and may increase the risk of meningioma. However, new epidemiological studies should be conducted in order to confirm these associations and to refine the role of hormonal factors in brain etiology.

Reproductive factors and exogenous hormone use and risk of adult glioma in women in the NIH-AARP Diet and Health Study

Experimental evidence suggests that estrogen and other steroid hormones may protect against glioma. Although epidemiologic studies provide only weak support for a role of exogenous or endogenous hormones in gliogenesis, few cohort studies have addressed this question. The authors, therefore, examined the association between menstrual and reproductive factors, exogenous hormone use, and glioma risk among 225,355 women aged 50-71 years who completed the baseline questionnaire in the NIH-AARP Diet and Health Study. During 7.5 years of follow-up, 174 cases of incident, primary glioma were ascertained. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI) for exposures, taking potential confounders into account. Older age at menarche was positively associated with risk: HR 1.67 (95% CI: 1.03, 2.69). Other reproductive factors, including age at first live birth, parity, age at menopause, type of menopause (natural vs. medical) and exogenous hormone use showed no association with glioma risk. The results were similar when the analysis was restricted to cases with glioblastoma (N = 130). The present study provides only limited support for the hypothesis that menstrual/reproductive factors or exogenous hormone use play a role in gliogenesis.

Reproductive factors and hormone use and risk of adult gliomas

Previous research suggests there may be a hormonal influence on glioma risk as evidenced by lower rates in females, change in incidence rates around ages at menarche and menopause, and presence of hormone receptors in glial tumors. Using the large San Francisco Bay Area Adult Glioma Study, we investigated whether reported reproductive factors and hormone use were associated with gliomas overall or with histologic subtypes among female cases (n = 619) and controls (n = 650). We found that reproductive factors were generally not associated with gliomas. Weak to moderately elevated odds ratios were observed for self-reported later age at menarche (14+ vs. 12-13 years old: adjusted odds ratio (AOR) = 1.39, 95% confidence interval (CI): 1.02-1.89), particularly for non-glioblastoma histologies (AOR = 1.64, 95% CI: 1.11-2.43). Inverse associations were observed for ever self-reported use of exogenous hormones (oral contraceptive use: AOR = 0.72, 95% CI: 0.53-0.99; postmenopausal hormone use: AOR = 0.56, CI: 0.37-0.84). However, cumulative hormone exposure defined multiple ways demonstrated no clear pattern of association. The results of this study suggest that any protective effect of hormones on gliomas may be limited to exogenous hormones, but a more detailed history of exogenous hormone use is needed to confirm findings.

Prognostic value of perfusion MR imaging of high-grade astrocytomas: long-term follow-up study

BACKGROUND AND PURPOSE

Although the prognostic value of perfusion MR imaging in various gliomas has been investigated, that in high-grade astrocytomas alone has not been fully evaluated. The purpose of this study was to evaluate retrospectively whether the tumor maximum relative cerebral blood volume (rCBV) on pretreatment perfusion MR imaging is of prognostic value in patients with high-grade astrocytoma.

MATERIALS AND METHODS

Between January 1999 and December 2002, 49 patients (30 men, 19 women; age range, 23-76 years) with supratentorial high-grade astrocytoma underwent MR imaging before the inception of treatment. The patient age, sex, symptom duration, neurologic function, mental status, Karnofsky Performance Scale, extent of surgery, histopathologic diagnosis, tumor component enhancement, and maximum rCBV were assessed to identify factors affecting survival. Kaplan-Meier survival curves, the logrank test, and the multivariate Cox proportional hazards model were used to evaluate prognostic factors.

RESULTS

The maximum rCBV was significantly higher in the 31 patients with glioblastoma multiforme than in the 18 with anaplastic astrocytoma (P < .03). The 2-year overall survival rate was 67% for 27 patients with a low (< or =2.3) and 9% for 22 patients with a high (>2.3) maximum rCBV value (P < .001). Independent important prognostic factors were the histologic diagnosis (hazard ratio = 9.707; 95% confidence interval (CI), 3.163-29.788), maximum rCBV (4.739; 95% CI, 1.950-11.518), extent of surgery (2.692; 95% CI, 1.196-6.061), and sex (2.632; 95% CI, 1.153-6.010).

CONCLUSION

The maximum rCBV at pretreatment perfusion MR imaging is a useful clinical prognostic biomarker for survival in patients with high-grade astrocytoma.

Influence of persistent contaminants and steroid hormones on glioblastoma cell growth

Glioblastoma multiforme (GBM), a malignancy characterized by its rapid progression, presents a lower risk of occurrence in women during their reproductive years. Necrosis of brain tissue during tumor invasion releases free lipids, and therefore might release contaminants stored in phospholipid-rich neuronal tissue. This study assesses the growth response of two human glioblastoma cell lines, T98G and U138-MG, treated with environmental chemicals known or likely to persist within the brain. Persistent chlorinated pesticides, industrial contaminants, persistent perfluorinated chemicals, and steroid hormones were assayed over a range of concentrations. Although cytotoxic effects were seen in both T98G and U138-MG cells, proliferative responses occurred only in the T98G cell line. Dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), and polychlorinated biphenyl (PCB) 153 were cytotoxic in both lines at 5000 nM. Perfluorodecanoic acid (PFDA), perfluorooctane sulfonate (PFOS), and testosterone stimulated proliferation in the T98G cells at 500, 1000, and 1000 nM, respectively. However, a perfluorinated salt (ammonium perfluorooctanoate; C8) and a weak androgen (dihydroepiandrosterone; DHEA) did not affect relative cell number in this GBM line, suggesting the proliferative effect is not through the activation of an androgen receptor. Exposure to environmental chemicals that result in a mitogenic response may increase the rate of glioblastoma tumor growth and result in the development of more aggressive forms of GBM tumors.

Multicentric Glioblastoma Multiforme in a Patient with BRCA-1 Invasive Breast Cancer

Breast cancer is the most common cancer in women. Germline mutations in BRCA-1 and BRCA-2 significantly increase the risk of developing breast and ovarian cancers, and are also associated with an increased incidence of primary cancers at other sites. We report the case of a 46-year-old woman previously treated for ductal adenocarcinoma of the breast with BRCA-1 who subsequently was diagnosed with multicentric glioblastoma multiforme (GBM) in the right temporal and right occipital lobes. We briefly discuss the incidence of BRCA-1 mutations in breast cancer as well as other primary neoplasms and consider potential mechanisms shared in the pathogenesis of breast and glial tumors.

Reproductive and hormonal factors and risk of brain tumors in adult females

Causes of brain tumors are largely unknown, and there is an urgent need to identify possible risk factors. Several observations point to a possible role of reproductive hormones, but few epidemiologic studies have examined whether reproductive factors, such as age at menarche and parity, are associated with brain tumor risk. We conducted a multi-center case-control study of newly diagnosed glioma (n = 212) and meningioma (n = 151) and frequency-matched controls (n = 436) in women from hospitals in Phoenix, Arizona; Boston, Massachusetts; and Pittsburgh, Pennsylvania between 1994 and 1998. Research nurses interviewed patients regarding potential risk factors for brain tumors, including reproductive factors and hormone use. Unconditional logistic regression analyses were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Risk of glioma increased with older age at menarche [OR = 1.90 (95% CI = 1.09-3.32) for age at menarche > or =14 vs. <12 years]. Early age at first birth was associated with reduced risk of glioma [OR = 0.43 (95% CI = 0.23-0.83) for a first birth before age 20 vs. nulliparity], but there was little effect of number of births. Exogenous hormone use was also associated with a lower risk of glioma, but risks did not vary systematically according to duration of use or age at first use. Possibly owing to low statistical power, there were few noteworthy associations between meningioma and reproductive factors, other than a nonsignificant (p = 0.09) trend of increasing risk with increasing age at menopause. The findings suggest that hormonal exposures early in life may be associated with risk of glioma, but the evidence is inconsistent and does not point clearly to a specific causal or protective hypothesis.

The influence of sex and the presence of giant cells on postoperative long-term survival in adult patients with supratentorial glioblastoma multiforme

OBJECT

Glioblastoma multiforme (GBM) remains incurable by conventional treatments, although some patients experience long-term survival. A younger age, a higher Karnofsky Performance Scale (KPS) score, more aggressive treatment, and long progression-free intervals have been reported to be positively associated with long-term postoperative patient survival. The aim of this retrospective study was the identification of additional favorable prognostic factors affecting long-term survival in surgically treated adult patients with supratentorial GBM.

METHODS

Of 113 adult patients newly diagnosed with histologically verified supratentorial GBM who were enrolled in Phase III trials during the period between 1987 and 1998, six (5.3%) who survived for longer than 5 years were defined as long-term survivors, whereas the remaining 107 patients served as controls. All six were women and were compared with the controls; they were younger (mean age 44.2 years, range 31-60 years), and their preoperative KPS scores were higher (mean 85, range 60-100). Four of the six patients underwent gross-total resection. In five patients (83.3%) the progression-free interval was longer than 5 years and in three a histopathological diagnosis of giant cell GBM was made. This diagnosis was not made in the other 107 patients.

CONCLUSIONS

Among adult patients with supratentorial GBM, female sex and histopathological characteristics consistent with giant cell GBM may be predictive of a better survival rate, as may traditional factors (that is, younger age, good KPS score, more aggressive resection, and a long progression-free interval).

Expression of pituitary tumor transforming gene (PTTG) and its binding protein in human astrocytes and astrocytoma cells: function and regulation of PTTG in U87 astrocytoma cells

Human securin, pituitary tumor transforming gene (PTTG), is a protooncogene. Here we report expressions of PTTG and its interacting protein, PTTG-binding factor in human astrocytic cells. PTTG expression was higher in malignant cells than in primary astrocytes, whereas PTTG-binding factor was not. Using a xenotransplantable, glioma cell line (U87), we observed that knocking down PTTG mRNA by RNA silencing inhibited serum-induced proliferation by approximately 50%. Furthermore, in U87 cells PTTG expression was up-regulated by promalignant ligands epithelial growth factor (EGF) and TGFalpha, both at the protein and mRNA levels. PTTG induction by EGF receptor (EGFR) ligands could be blocked by the specific EGFR inhibitor, AG1478. Hepatocyte growth factor (HGF) also induced PTTG but to a lesser extent than EGF. Although EGF stimulates HGF secretion in U87 cells, the effect of EGF on PTTG mRNA expression is independent of HGF as neutralizing antibody against HGF failed to abolish EGF-induced up-regulation of PTTG mRNA. PTTG mRNA was unchanged by incubating U87 cells with the promalignant growth factor TGFbeta, apoptosis inducing TNFalpha and ligands for nuclear receptors, such as retinoic acid and retinoid X receptors and peroxisome proliferator-activated receptor-gamma, known for their growth-inhibitory and apoptosis-inducing effects on gliomas. In addition, 17beta-estradiol and Ca2+, known to activate PTTG expression, did not change PTTG mRNA levels in U87 cells. In summary, we show higher PTTG expression in astrocytoma than normal astrocytes and secondly, PTTG is involved in glioma cell growth. Finally, regulation of its expression has glioma-specific features and is selectively regulated by promalignant cytokines including EGFR ligands and HGF.

2-Methoxyestradiol inhibits proliferation of normal and neoplastic glial cells, and induces cell death, in vitro

2-Methoxyestradiol (2ME), a metabolite of estradiol (E), inhibits proliferation of various tumor cells. In this study we determined the effect of 2ME on human glioblastoma cell lines, in vitro. We compared these cells with cultured astrocytes obtained from traumatized adult rat striatum. Exposure to 2ME had a strong antiproliferative effect on human glioblastoma and caused an increase in the population of apoptotic cells, detected by flow cytometry, in some of the investigated cell lines. A significant number of cells were blocked in the G2/M phase of the cell cycle. Concurrently, the population of cells in the G1 phase decreased in all glioblastoma cell lines. Staining with Hoechst 33258 revealed abnormal nuclear morphology in the proliferating cells treated with 2ME. Treatment with 2ME induced upregulation of wild type p53 in one of the human glioblastoma cell lines as well as in proliferating adult rat astrocytes. We conclude that 2ME inhibits the growth of human glioblastoma cell lines and induces apoptosis, in vitro. This compound deserves further investigation as a treatment for gliomas.

Correlation between Promoter Hypermethylation of the O6-Methylguanine-Deoxyribonucleic Acid Methyltransferase Gene and Prognosis in Patients with High-grade Astrocytic Tumors Treated with Surgery, Radiotherapy, and 1-(4-Amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea-based Chemotherapy

OBJECTIVE

O 6-Methylguanine-deoxyribonucleic acid methyltransferase (MGMT) is a deoxyribonucleic acid repair protein associated with the chemoresistance of chloroethylnitrosoureas. We investigated whether MGMT promoter hypermethylation is associated with prognosis in patients with high-grade astrocytic tumors treated uniformly with surgery, radiotherapy, and 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU)-based chemotherapy.

METHODS

Using the methylation-specific polymerase chain reaction, we assayed promoter hypermethylation of the MGMT gene in tumor deoxyribonucleic acid from 116 adult patients with supratentorial high-grade astrocytic tumors (42 anaplastic astrocytomas [AAs] and 74 glioblastomas multiforme [GBMs]). The Cox proportional hazards model was used in forward stepwise regression to assess the relative role of prognostic factors (i.e., age at surgery, sex, Karnofsky Performance Scale score, extent of surgical resection, methylation status of the MGMT promoter, and association between MGMT promoter methylation and survival).

RESULTS

MGMT promoter hypermethylation was confirmed in 19 (45.2%) of 42 AA patients and 33 (44.6%) of 74 GBM patients. It was significantly associated with both longer overall and progression-free survival time in AA but not GBM patients.

CONCLUSION

Our results demonstrate that MGMT promoter hypermethylation is associated with longer survival time in patients with AA who were treated with surgery, radiotherapy, and ACNU-based chemotherapy but not in patients with GBM.

Analysis of homozygous deletion of the p16 gene and correlation with survival in patients with glioblastoma multiforme

OBJECT

One of the most frequent genetic abnormalities found in patients with glioblastoma multiforme (GBM) is homozygous deletion of the p16 tumor suppressor gene. The authors investigated whether this deletion is associated with prognosis in patients with GBM.

METHODS

In 46 adult patients with supratentorial GBM, homozygous deletion of the p16 gene in tumor DNA was examined using the multiplex polymerase chain reaction assay. The deletion was confirmed in 14 (30.4%) of 46 patients, eight (30.8%) of 26 men and six (30.0%) of 20 women. Cox proportional hazard regression analysis, adjusted for age at surgery, the Karnofsky Performance Scale score, extent of resection, and the MIB-1 labeling index. revealed that homozygous deletion of the p16 gene was significantly associated with overall survival and progression-free survival in men, but not in women.

CONCLUSIONS

The results of this study suggest that p16 homozygous deletion is a significant unfavorable prognostic factor in male patients with GBM.

The impact of age and sex on the incidence of glial tumors in New York state from 1976 to 1995

OBJECT

In this study the authors describe secular trends in the incidence of three glial tumors--glioblastoma multiforme (GBM), astrocytoma not otherwise specified (ANOS), and anaplastic astrocytoma (AA)--in New York state from 1976 through 1995. They also describe the effect of age and sex on the relative risk (RR) for these tumors, specifically GBM.

METHODS

Crude, age-, and sex-specific incidence rates were calculated for each tumor type from 1976 to 1995 by using data from the New York State Cancer Registry. Age-adjusted incidence rates were calculated by the direct standardization procedure, in which the 1970 United States Census Population Standard Million is used. The RR of GBM for the female population was calculated and plotted. Statistical comparisons were made using Pearson's correlation coefficient and regression analysis with the coefficient of variation.

CONCLUSIONS

The age-adjusted incidence of these three glial tumors increased during the study period. Increases in age-specific incidence of GBM were primarily limited to patients 60 years of age or older. The reasons for these increases cannot be fully explained with the data. Those in the female population had a lower risk of developing these tumors than those in the male. For GBM, the protective effect of sex was first evident at the approximate age of menarche, was greatest at the approximate age of menopause, and decreased in postmenopausal age strata. The overall protective effect of female sex and the described trend in RR for GBM in the female population suggests that sex hormones and/or genetic differences between males and females may play a role in the pathogenesis of this tumor.

Determination of cDNA, gene structure and chromosomal localization of the novel human 17beta-hydroxysteroid dehydrogenase type 7(1)

We have identified human 17beta-hydroxysteroid dehydrogenase type 7 (17beta-HSD 7). The novel human cDNA encodes a 37 kDa protein that shows 78 and 74% amino acid identity with rat and mouse 17beta-HSD 7, respectively. These enzymes are responsible for estradiol production in the corpus luteum during pregnancy, but are also present in placenta and several steroid target tissues (breast, testis and prostate) as revealed by RT-PCR. The human 17beta-HSD 7 gene (HSD17B7) consists of nine exons and eight introns, spanning 21. 8 kb and maps to chromosome 10p11.2 close to susceptibility loci for tumor progression, obesity and diabetes. The HSD17B7 promoter (1.2 kb) reveals binding sites for brain-specific and lymphoid transcription factors corresponding to additional expression domains in hematopoietic tissues and the developing brain as identified by in silico Northern blot.