Estrogen Effects on the Mammary Gland in Early and Late Life and Breast Cancer Risk

Antipsychotic-induced Hyperprolactinemia in aging populations: Prevalence, implications, prevention and management

This paper reviews the prevalence, implications, prevention and management of antipsychotic-induced hyperprolactinemia in aging populations. Antipsychotics are indicated mainly for the treatment of psychotic illness but are also used in other conditions. Complications induced by antipsychotics increase with age, due to age-related changes in drug metabolism and excretion. Almost all antipsychotics lead to hyperprolactinemia by blocking dopamine D2 receptors in the anterior pituitary gland, which counteracts dopamine's inhibitory action on prolactin secretion. The main findings of this narrative review are that, though many of the known side effects of high prolactin levels lose their salience with age, the risk of exacerbating osteoporosis remains critical. Methods of preventing antipsychotic-induced hyperprolactinemia in older individuals include using antipsychotic medication (AP) as sparingly as possible and monitoring AP serum levels, regularly measuring prolactin levels, closely monitoring bone density, treating substance abuse, and teaching patients stress management techniques. When hyperprolactinemia symptoms cannot be otherwise managed, adjunctive drugs are available. Potential helpful adjuncts are: dopamine agonists, antipsychotics with partial agonist properties (e.g. aripiprazole), selective estrogen receptor modulators, and metformin. Because a gold standard for prevention/treatment has not been established, clinical decisions need to be made based on safety and individual circumstance.

Estradiol modulated colorectal cancer stem cells bioactivity and interaction with endothelial cells

This study aimed to evaluate the modulatory role of sex-related hormone estradiol on cancer stem cells with the origin of colorectal adenocarcinoma in vitro. Cancer stem cells were incubated with 100 nM estradiol for 48 h. The cell survival rate was analyzed using the MTT assay. Immunocytochemistry staining of Ki-67 and Inhibin and Apoptosis PCR array were done to measure proliferation/apoptosis. Cell migration was monitored via the Transwell Migration assay. The expression of exosome biogenesis genes was measured using a real-time PCR assay. The fatty acid profile was monitored using gas chromatography. The level of FAK, SQSTM1, ER, and SIRT1 was examined using Western blotting. Cancer stem-endothelial cell interaction was investigated using Surface Plasmon Resonance assay. Data showed no significant differences in cancer stem cell viability and proliferation between control and estradiol-treated groups (p>0.05). PCR array highlighted the up-regulation of both pro- and anti-apoptosis effectors in the treatment group compared to the control cells (p<0.05). Cell migration capacity was increased after treatment with estradiol (p<0.001). Both exocytosis and exosome biogenesis were decreased in cancer stem cells exposed to estradiol (p<0.05). Data showed the reduction of palmitic acid, and increase of Palmitoleic and Linolenic acids in estradiol-treated cells. Estrogen induced estrogen receptor, SQSTM1 proteins and decreased SIRT1 factor after 48 h. Surface Plasmon Resonance revealed the suppression of cancer stem-endothelial cell interaction and affinity. Estradiol could change the migration, juxtacrine and paracrine activities of cancer stem cells, showing the importance of sex-related hormones in the dynamic of cancer development.

Breast cancer in low-middle income countries: abnormality in splicing and lack of targeted treatment options

Breast cancer is a common malignancy among women worldwide. Regardless of the economic status of a country, breast cancer poses a burden in prevention, diagnosis and treatment. Developed countries such as the U.S. have high incidence and mortality rates of breast cancer. Although low incidence rates are observed in developing countries, the mortality rate is on the rise implying that low- to middle-income countries lack the resources for preventative screening for early detection and adequate treatment resources. The differences in incidence between countries can be attributed to changes in exposure to environmental risk factors, behaviour and lifestyle factors of the different population groups. Genomic modifications are an important factor that significantly alters the risk profile of breast tumourigenesis. The incidence of early-onset breast cancer is increasing and evidence shows that early onset of breast cancer is far more aggressive than late onset of the disease; possibly due to the difference in genetic alterations or tumour biology. Alternative splicing is a pivotal factor in the progressions of breast cancer. It plays a significant role in tumour prognosis, survival and drug resistance; hence, it offers a valuable option as a therapeutic target. In this review, the differences in breast cancer incidence and mortality rates in developed countries will be compared to low- to middle-income countries. The review will also discuss environmental and lifestyle risk factors, and the underlying molecular mechanisms, genetic variations or mutations and alternative splicing that may contribute to the development and novel drug targets for breast cancer.

Sociodemographic factors and clinical presentation of women attending Cancer Detection Centre, Kolkata for breast examination

BACKGROUND

Breast cancer is the most common cancer in Indian women.

AIM

The aim of the study was to report the sociodemographic factors, habits, personal history, gynecological and obstetric history, the clinical presentation of Indian women, and analyze those factors with the diagnosis of breast cancer.

METHODS

This study is based on retrospective data collection from case files of women who attended the Cancer Detection Centre during January1995-September 2016.

RESULTS

Data analysis for 1196 women showed 31.5% aged between 26 and 35 years; 90.7% were Hindus; 61.3% school-educated; 77.0% housewives/unemployed; 80.6% married and 98.2% were non-vegetarian. Physical activity, medical history and gynecologic history of menarche, menstrual type, menopause, marital age, and breast feeding history had a strong correlation with clinical diagnosis (p<0.05). About 8.4% of the total population was diagnosed with breast cancer using smear cytology, FNAC, mammography, and USG.

CONCLUSIONS

Age, lack of proper education, marital status, food habit, physical activity, age of menarche, menstrual type, menopause, marital age, and breastfeeding history were highlighted as significant risk factors of breast cancer in Indian women. Smears from nipple discharges, FNAC, mammography, and USG are effective methods for breast cancer detection in low-cost setting where routine organized screening programs are not available.

RELEVANCE FOR PATIENTS

The study will identify important risk factors among women in the Eastern region of India. Thus, background information of patients can be used to emphasize the importance of organizing breast cancer screening while making public health policies and implementing breast cancer control programs.

Prospective breast cancer risk factors prediction in Saudi women

Women's health is affected by breast cancer worldwide and Saudi Arabia (SA) is no exception. Malignancy has enormous consequences for social, psychological and public health. The aim of this study was to examine the risk factors for Saudi women from breast cancer using logistic regression models. In 135 patient cases for different stages of breast cancer was used to study case management, 270 healthy women from King Abd Alla Medical City, Mecca, SA were taken to predict the probability of women developing breast cancer, logistic regression was analyzed taking factors such as age, marital status, family history, parity, age at first full-term pregnancy, menopausal status, body mass index (BMI) and breast feeding. The logistic regression model showed that there are important risk factors (age, marital status, family history, parity, age at first full-term pregnancy, menopausal status, body mass index, and breast feeding) in development of breast cancer. Fewer cases were observed in unmarried women, age ≤30, BMI ≤20. In contrast, more cases were found with women age 41-50 married, BMI > 30, a smaller number of children, not breast feeding, age of first pregnancy ≥30, menopausal status age at 46-50. Based on our data there is role of risk factors in developing breast cancer, less BMI, the increase number of children, breast feeding, which are playing as protective factor for breast cancer.

Inter-Individual Variation in Response to Estrogen in Human Breast Explants

Exposure to estrogen is strongly associated with increased breast cancer risk. While all women are exposed to estrogen, only 12% are expected to develop breast cancer during their lifetime. These women may be more sensitive to estrogen, as rodent models have demonstrated variability in estrogen sensitivity. Our objective was to determine individual variation in expression of estrogen receptor (ER) and estrogen-induced responses in the normal human breast. Human breast tissue from female donors undergoing reduction mammoplasty surgery were collected for microarray analysis of ER expression. To examine estrogen-induced responses, breast tissue from 23 female donors were cultured ex- vivo in basal or 10 nM 17β-estradiol (E2) media for 4 days. Expression of ER genes (ESR1 and ESR2) increased significantly with age. E2 induced consistent increases in global gene transcription, but expression of target genes AREG, PGR, and TGFβ2 increased significantly only in explants from nulliparous women. E2-treatment did not induce consistent changes in proliferation or radiation induced apoptosis. Responses to estrogen are highly variable among women and not associated with levels of ER expression, suggesting differences in intracellular signaling among individuals. The differences in sensitivity to E2-stimulated responses may contribute to variation in risk of breast cancer.

Return to Work of Breast Cancer Survivors: Perspectives and Challenges for Occupational Physicians

Breast cancer is one of the most common diseases worldwide, mainly affecting the female gender. Considering the increase of breast cancer incidence and the decrease of mortality due to news diagnostic and therapeutic tools, the return to work issue after treatment is going to be very common in the next years. Occupational physicians therefore need to face the return to work and the fitness for work of workers previously diagnosed with breast cancer with a sufficient cultural and technical background. In addition to individual characteristics preceding the diagnosis, clinical outcome, lifestyles and occupational variables are the most impactful factors on return to work that need to be taken into account. The aim of this work is to analyze these factors and discuss the central role of occupational physicians in the decision-making process of returning to work in breast cancer survivors.

Assessment of interactions between 205 breast cancer susceptibility loci and 13 established risk factors in relation to breast cancer risk, in the Breast Cancer Association Consortium

BACKGROUND

Previous gene-environment interaction studies of breast cancer risk have provided sparse evidence of interactions. Using the largest available dataset to date, we performed a comprehensive assessment of potential effect modification of 205 common susceptibility variants by 13 established breast cancer risk factors, including replication of previously reported interactions.

METHODS

Analyses were performed using 28 176 cases and 32 209 controls genotyped with iCOGS array and 44 109 cases and 48 145 controls genotyped using OncoArray from the Breast Cancer Association Consortium (BCAC). Gene-environment interactions were assessed using unconditional logistic regression and likelihood ratio tests for breast cancer risk overall and by estrogen-receptor (ER) status. Bayesian false discovery probability was used to assess the noteworthiness of the meta-analysed array-specific interactions.

RESULTS

Noteworthy evidence of interaction at ≤1% prior probability was observed for three single nucleotide polymorphism (SNP)-risk factor pairs. SNP rs4442975 was associated with a greater reduction of risk of ER-positive breast cancer [odds ratio (OR)int = 0.85 (0.78-0.93), Pint = 2.8 x 10-4] and overall breast cancer [ORint = 0.85 (0.78-0.92), Pint = 7.4 x 10-5) in current users of estrogen-progesterone therapy compared with non-users. This finding was supported by replication using OncoArray data of the previously reported interaction between rs13387042 (r2 = 0.93 with rs4442975) and current estrogen-progesterone therapy for overall disease (Pint = 0.004). The two other interactions suggested stronger associations between SNP rs6596100 and ER-negative breast cancer with increasing parity and younger age at first birth.

CONCLUSIONS

Overall, our study does not suggest strong effect modification of common breast cancer susceptibility variants by established risk factors.

Estrogen Induces Mammary Ductal Dysplasia via the Upregulation of Myc Expression in a DNA-Repair-Deficient Condition

Mammary ductal dysplasia is a phenotype observed in precancerous lesions and early-stage breast cancer. However, the mechanism of dysplasia formation remains elusive. Here we show, by establishing a novel dysplasia model system, that estrogen, a female hormone, has the potential to cause mammary ductal dysplasia. We injected estradiol (E2), the most active form of estrogen, daily into scid mice with a defect in non-homologous end joining repair and observed dysplasia formation with cell proliferation at day 30. The protooncogene Myc is a downstream target of estrogen signaling, and we found that its expression is augmented in mammary epithelial cells in this dysplasia model. Treatment with a Myc inhibitor reduced E2-induced dysplasia formation. Moreover, we found that isoflavones inhibited E2-induced dysplasia formation. Our dysplasia model system provides insights into the mechanistic understanding of breast tumorigenesis and the development of breast cancer prevention.

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Excess amount of estrogen administration in scid mice induces mammary ductal dysplasia

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E2-induced Myc expression is one of the causes of dysplasia formation

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Progesterone and isoflavones have a potential to prevent E2-induced dysplasia

Activation of G-Protein-Coupled Receptor 30 Protects Neurons against Excitotoxicity through Inhibiting Excessive Autophagy Induced by Glutamate

Autophagy is a protecting intracellular pathway to transmit unnecessary or dysfunctional components to the lysosome for degeneration. Autophagic imbalance is connected with neurodegeneration. Neurodegenerative diseases including Parkinson's disease, Alzheimer's disease, and Huntington's disease are closely related to excitotoxicity and neuronal loss. Activation of G-protein-coupled receptor 30 (GPR30), an estrogen membrane receptor, protects neurons from excitotoxicity-induced cell death. However, whether autophagy is involved in the neuroprotective effect of GPR30 activation is not well-known. In this study, methyl thiazolyl tetrazolium (MTT), Western blot, monodansylcadaverine (MDC) staining, and immunofluorescent staining were employed to detect the role of autophagy in cultured primary cortical neurons after glutamate exposure and G1 treatment. Pretreatment of G1 (GPR30 specific agonist) reduced neuronal loss through inhibiting excessive autophagy induced by glutamate exposure, which was blocked by GPR30 antagonist G15, phosphatidylinositol-3-kinase (PI3K), and the mammalian target of rapamycin (mTOR) inhibitors. These data suggest that GPR30 protects neurons from cell loss primarily by modulating PI3K-AKT-mTOR signaling pathway. In addition, G1 alone did not affect the basal autophagy and cell viability. We conclude that GPR30 activation reduces glutamate-induced excessive autophagy in neurons and protects neurons against excitotoxicity.

Early Steps of Mammary Stem Cell Transformation by Exogenous Signals; Effects of Bisphenol Endocrine Disrupting Chemicals and Bone Morphogenetic Proteins

Estrogens are major regulators of the mammary gland development, notably during puberty, via estrogen receptor (ER) activation, leading to the proliferation and differentiation of mammary cells. In addition to estrogens, the bone morphogenetic proteins (BMPs) family is involved in breast stem cell/progenitor commitment. However, these two pathways that synergistically contribute to the biology of the normal mammary gland have also been described to initiate and/or promote breast cancer development. In addition to intrinsic events, lifestyle habits and exposure to environmental cues are key risk factors for cancer in general, and especially for breast cancer. In the latter case, bisphenol A (BPA), an estrogen-mimetic compound, is a critical pollutant both in terms of the quantities released in our environment and of its known and speculated effects on mammary gland biology. In this review, we summarize the current knowledge on the actions of BMPs and estrogens in both normal mammary gland development and breast cancer initiation, dissemination, and resistance to treatment, focusing on the dysregulations of these processes by BPA but also by other bisphenols, including BPS and BPF, initially considered as safer alternatives to BPA.

Estrogen receptors genotypes and canine mammary neoplasia

BACKGROUND

Estrogens are essential for the development and proper function of several hormone-dependent organs. There are, however, several lines of evidence associating estrogens with mammary carcinogenesis. A marked individual genetic variability concerning estrogens biosynthesis, metabolism and mechanism of action was recognized and associated with human breast cancer susceptibility, clinical features and progression. Although some genetic variations in canine ESR1 gene were reported, their influence in clinicopathological features and progression of canine mammary tumors has not been fully evaluated. This study aims to assess the influence of SNPs in ESR1 gene (rs397512133, rs397510462, rs851327560, rs397510612, rs852887655, rs852684753 and rs852398698) in canine mammary tumors characteristics and progression. A group of 155 non-neutered bitches with mammary tumors was included in the study. Follow-up information was assessed 24 months after surgery.

RESULTS

Genetic profiles associated with a later onset of mammary tumors and less aggressive clinicopathological features, namely smaller tumor size (≤ 3 cm) with extensive tubular differentiation and low canine-adapted prognostic index (vet-NPI), were identified in this study.

CONCLUSIONS

Our data suggest that the ESR1 genetic profile may help on the decision regarding the selection of individual tailored preventive measures against canine mammary tumors development, such as early neutering.

RLIP: An existential requirement for breast carcinogenesis

Breast cancer (BC) is the most common cancer among women worldwide. Due to its complexity in nature, effective BC treatment can encounter many challenges. The human RALBP1 gene encodes a 76-kDa splice variant protein, RLIP (ral-binding protein1, RalBP1), a stress-protective mercapturic acid pathway (MAP) transporter protein, that also plays a key role in regulating clathrin-dependent endocytosis (CDE) as a Ral effector. Growing evidence shows that targeting RLIP may be an effective strategy in cancer therapy, as RLIP is over-expressed in multiple cancers and is known to induce resistance to apoptosis and chemotherapeutic drugs. Recent studies demonstrated that RLIP is expressed in human BC tissues, as well as BC cell lines. Knockdown of RLIP resulted in apoptotic death of BC cells in vitro, and targeted inhibition and depletion of RLIP resulted in regression of BC in xenograft studies of nude mice. Signaling studies showed that RLIP depletion inhibited endocytosis and differentially regulated signaling to Akt, Myc, and ERK1/2. However, the proliferation and multi-specific transport mechanisms that promote RLIP-mediated cell death in BC are not well understood. In this review, we will discuss a missing but an essentially determining and connecting piece of the puzzle on the understanding of proliferation and transport mechanisms by focused analyses of the apoptotic, drug- and radiation-sensitivity regulated by RLIP, a stress-responsive non-ATP-binding cassette (ABC), high capacity MAP transporter, in breast cancer.

[Targeted binding of estradiol with ESR1 promotes proliferation of human chondrocytes in vitro by inhibiting activation of ERK signaling pathway]

OBJECTIVE

To investigate the effect of estradiol (E2)/estrogen receptor 1 (ESR1) on the proliferation of human chondrocytes in vitro and explore the molecular mechanism.

METHODS

The Ad-Easy adenovirus packaging system was used to construct and package the ESR1-overexpressing adenovirus Ad-ESR1. Western blotting and qPCR were used to detect the expression of ESR1 protein and mRNA in human chondrocyte C28I2 cells. In the cells treated with different adenoviruses, the effects of E2 were tested on the expressions of proteins related with cell autophagy and apoptosis and the phosphorylation of ERK signaling pathway using Western blotting. Immunofluorescence assay was used to observe the intracellular autophagic flow, flow cytometry was performed to analyze the cell apoptosis rate and the cell cycle changes, and qPCR was used to detect the expressions of PCNA, cyclin B1 and cyclin D1 mRNAs. The inhibitory effect of the specific inhibitor of ERK on the expressions of autophagy- and apoptosis-related genes at both the protein and mRNA levels were detected using Western blotting and qPCR.

RESULTS

Transfection with the recombinant adenovirus overexpressing ESR1 and E2 treatment of C28I2 cells significantly enhanced the expressions of autophagy-related proteins LC3, ATG7, promoted the colocalization of LC3 and LAMP1 in the cytoplasm, increased the expressions of the proliferation-related marker genes PCNA, cyclin B1 and cyclin D1, and supressed the expressions of cleaved caspase-3, caspase-12 and pERK. RNA interference of ESR1 obviously lowered the expression levels of autophagy-related proteins in C28I2 cells, causing also suppression of the autophagic flow, increments of the expressions of apoptosis-related proteins and pERK, and down-regulated the expressions of the proliferation marker genes. Blocking ERK activation with the ERK inhibitor obviously inhibited the effects of E2/ESR1 on autophagy, proliferationrelated gene expressions and cell apoptosis.

CONCLUSIONS

The targeted binding of E2 with ESR1 promotes the proliferation of human chondrocytes in vitro possibly by inhibiting the activation of ERK signaling pathway to promote cell autophagy and induce cell apoptosis.

Bone Mineral Density and Breast Cancer Incidence and Mortality in Postmenopausal Women: A Long-Term Follow-Up Study

Purpose: To examine whether bone mineral density (BMD) is predictive of breast cancer risk and mortality in a population of early postmenopausal women participating in a medical prevention program in western Austria. Patients and Methods: Between May 1991 and February 1999, lumbar spine BMD was measured by dual-energy X-ray absorptiometry (N = 1163, mean age 56.9 ± 5.7 years) or quantitative computed tomography (N = 2283, mean age 56.8 ± 5.4 years) in 3446 women aged ≥50 years. Data on medication and lifestyle factors were collected by questionnaire. Participants were prospectively followed up for breast cancer incidence, and breast cancer patients were followed up for mortality. To calculate risk of breast cancer and mortality, Cox proportional hazards models were applied. Results: During median follow-up of 20.7 years, 185 invasive breast cancer cases and 22 deaths due to breast cancer occurred. Risk of breast cancer in the highest versus the lowest BMD quartile was nonsignificantly reduced, in particular when follow-up was restricted to 10 years (hazard ratio 0.53, 95% confidence interval 0.25-1.12). There was no risk reduction when follow-up began 10 years after BMD measurement. There was no association between BMD and all-cause or breast cancer-specific mortality among breast cancer patients, but a trend toward reduced mortality risk in the highest BMD quartile. Conclusions: We hypothesize that BMD is not reflective of estrogen exposure and not predictive of breast cancer risk, at least in young postmenopausal women. Confounders such as vitamin D might underlie low breast cancer risk at high BMD, thus mirroring better health status.

microRNA Let-7b: A Novel treatment for endometriosis

Endometriosis is an oestrogen-dependent, chronic inflammatory disease that affects 10% of reproductive-aged women. Current treatment options depend on female sex steroid hormone modulation; however, all have side effects and are not useful in women who want to conceive. microRNAs treatments have provided promising results for some chronic diseases and cancers. We have previously shown the microRNA Let-7b is repressed in endometriosis and that loss of Let-7 contributes to the pathophysiology of the disease. Here, we propose using microRNA Let-7b for the treatment of endometriosis in a murine model. Endometriosis was treated using microRNA Let-7b or a scrambled control microRNA. Let-7b treatment resulted in reduced endometriosis lesion size. Decreased gene expression was noted in several genes known to promote endometriosis growth including ER-α, ER-ß, Cyp19a, KRAS 4A, KRAS 4B and IL-6. These results indicate that microRNA Let-7b has a pleiotropic role in endometriosis pathophysiology affecting oestrogen signalling, inflammation and growth factor receptors. Local treatment of endometriosis with Let-7b is a promising therapy for endometriosis that simultaneously affects multiple pathways driving endometriosis without systemic hormonal side effects.

TLR4/MyD88 signaling determines the metastatic potential of breast cancer cells

The influence of Toll-like receptor (TLR)4/myeloid differentiation factor (MyD)88 signaling on the invasion and metastasis of cancer cells has been previously reported. The purpose of the present study was to determine the role of TLR4/MyD88 in breast cancer cell migration and invasion, and to discover novel therapeutic targets for breast cancer treatment. TLR4, MyD88 and high mobility group box 1 (HMGB1) mRNA expression levels were assessed in highly invasive human MDA-MB-231 breast cancer cells, breast cancer cells with a low rate of invasion (MCF-7) and normal human MDA-Kb2 mammary gland cells by reverse transcription-quantitative polymerase chain reaction. The protein expression levels of these markers were detected by western blotting and immunofluorescence. Randomly selected breast cancer and paracarcinoma tissues were used to measure TLR4 and MyD88 protein expression levels by immunohistochemistry. The mRNA and protein expression levels of TLR4 and MyD88 were significantly higher in MDA-MB-231 cells compared with either MCF-7 cells or MDA-Kb2 cells. The mRNA and protein expression levels of HMGB1 were comparable in the two breast cancer cell lines, with no statistical difference (P>0.05). TLR4 and MyD88 protein expression levels were also significantly higher in breast cancer tissues compared with paracarcinoma tissues (P<0.05). TLR4 and MyD88 protein expression levels were positively correlated with axillary lymph node metastasis and histological grade (P<0.05). TLR4/MyD88 expression levels were positively correlated with the metastasis of breast cancer cells. TLR4/MyD88 may be useful as a novel biomarker to evaluate the prognosis and treatment of patients with breast cancer.

Estrogen promotes estrogen receptor negative BRCA1-deficient tumor initiation and progression

BACKGROUND

Estrogen promotes breast cancer development and progression mainly through estrogen receptor (ER). However, blockage of estrogen production or action prevents development of and suppresses progression of ER-negative breast cancers. How estrogen promotes ER-negative breast cancer development and progression is poorly understood. We previously discovered that deletion of cell cycle inhibitors p16Ink4a (p16) or p18Ink4c (p18) is required for development of Brca1-deficient basal-like mammary tumors, and that mice lacking p18 develop luminal-type mammary tumors.

METHODS

A genetic model system with three mouse strains, one that develops ER-positive mammary tumors (p18 single deletion) and the others that develop ER-negative tumors (p16;Brca1 and p18;Brca1 compound deletion), human BRCA1 mutant breast cancer patient-derived xenografts, and human BRCA1-deficient and BRCA1-proficient breast cancer cells were used to determine the role of estrogen in activating epithelial-mesenchymal transition (EMT), stimulating cell proliferation, and promoting ER-negative mammary tumor initiation and metastasis.

RESULTS

Estrogen stimulated the proliferation and tumor-initiating potential of both ER-positive Brca1-proficient and ER-negative Brca1-deficient tumor cells. Estrogen activated EMT in a subset of Brca1-deficient mammary tumor cells that maintained epithelial features, and enhanced the number of cancer stem cells, promoting tumor progression and metastasis. Estrogen activated EMT independent of ER in Brca1-deficient, but not Brca1-proficient, tumor cells. Estrogen activated the AKT pathway in BRCA1-deficient tumor cells independent of ER, and pharmaceutical inhibition of AKT activity suppressed EMT and cell proliferation preventing BRCA1 deficient tumor progression.

CONCLUSIONS

This study reveals for the first time that estrogen promotes BRCA1-deficient tumor initiation and progression by stimulation of cell proliferation and activation of EMT, which are dependent on AKT activation and independent of ER.

Chemoprevention of LA7-Induced Mammary Tumor Growth by SM6Met, a Well-Characterized Cyclopia Extract

Breast cancer (BC) is the leading cause of cancer-related deaths in women. Chemoprevention of BC by using plant extracts is gaining attention. SM6Met, a well-characterized extract of Cyclopia subternata with reported selective estrogen receptor subtype activity, has shown tumor suppressive effects in a chemically induced BC model in rats, which is known to be estrogen responsive. However, there is no information on the estrogen sensitivity of the relatively new orthotopic model of LA7 cell-induced mammary tumors. In the present study, the potential chemopreventative and side-effect profile of SM6Met on LA7 cell-induced tumor growth was evaluated, as was the effects of 17β-estradiol and standard-of-care (SOC) endocrine therapies, such as tamoxifen (TAM), letrozole (LET), and fulvestrant (FUL). Tumor growth was observed in the tumor-vehicle control group until day 10 post tumor induction, which declined afterward on days 12-14. SM6Met suppressed tumor growth to the same extent as TAM, while LET, but not FUL, also showed substantial anti-tumor effects. Short-term 17β-estradiol treatment reduced tumor volume on days prior to day 10, whereas tumor promoting effects were observed during long-term treatment, which was especially evident at later time points. Marked elevation in serum markers of liver injury, which was further supported by histological evaluation, was observed in the vehicle-treated tumor control, TAM, LET, and long-term 17β-estradiol treatment groups. Alterations in the lipid profiles were also observed in the 17β-estradiol treatment groups. In contrast, SM6Met did not augment the increase in serum levels of liver injury biomarkers caused by tumor induction and no effect was observed on lipid profiles. In summary, the results from the current study demonstrate the chemopreventative effect of SM6Met on mammary tumor growth, which was comparable to that of TAM, without eliciting the negative side-effects observed with this SOC endocrine therapy. Furthermore, the results of this study also showed some responsiveness of LA7-induced tumors to estrogen and SOC endocrine therapies. Thus, this model may be useful in evaluating potential endocrine therapies for hormone responsive BC.

Oxybenzone Alters Mammary Gland Morphology in Mice Exposed During Pregnancy and Lactation

Hormones and endocrine-disrupting chemicals are generally thought to have permanent “organizational” effects when exposures occur during development but not adulthood. Yet, an increasing number of studies have shown that pregnant females are disrupted by endocrine-disrupting chemical exposures, with some effects that are permanent. Here, we examined the long-term effects of exposure to oxybenzone, an estrogenic chemical found in sunscreen and personal care products, on the morphology of the mammary gland in mice exposed during pregnancy and lactation. Female mice were exposed to vehicle or 30, 212, or 3000 µg oxybenzone/kg/d, from pregnancy day 0 until weaning. A nulliparous group, receiving vehicle treatment, was also evaluated. Mammary glands were collected 5 weeks after involution for whole-mount, histological, immunohistochemical, and molecular analyses. Exposure to 3000 µg oxybenzone/kg/d induced permanent changes to ductal density that was significantly different from both the nulliparous and vehicle groups. The two highest doses of oxybenzone similarly induced an intermediate phenotype for expression of progesterone receptor. A monotonic, dose-dependent increase in cell proliferation was also observed in the oxybenzone-treated females, becoming statistically significant at the highest dose. Finally, oxybenzone exposure induced an intermediate phenotype for Esr1 expression in all oxybenzone-treated groups. These data suggest that oxybenzone, at doses relevant to human exposures, produces long-lasting alterations to mammary gland morphology and function. Further studies are needed to determine if exposure to this chemical during pregnancy and lactation will interfere with the known protection that pregnancy provides against breast cancer.

Cancer incidence in Yemen from 1997 to 2011: a report from the Aden cancer registry

Background

This study aims to report on the trend and incidence of cancers in Yemen (Aden) using data from Aden Cancer Registry (ACR), as a population-based cancer registry in Yemen over a period of 15 years (1997–2011). Such comprehensive, valid and detailed information on cancer trend is badly needed for planning a cancer control program in the country.

Methods

All cancer cases were abstracted from patients’ medical records – based on clinical, histopathology, and radiological diagnosis. Data were coded using the International Classification of Diseases for Oncology (ICD-O) and the International Classification of Childhood Cancer (ICCC-3) to code childhood tumors. The CanReg4 program was used to analyze the data for 15 years study period.

Results

A total of 6974 cases were included in this study, 47% were males and 53% females. The overall annual incidence rate was 21.6/100,000 populations; however, the incidence in males was little lower than in females (20.0 and 22.9 per 100,000 populations, respectively). The top five cancers among males were leukaemia (10.5%), nonhodgkin lymphoma [(NHL), 10.1%], colon (7.5%), Hodgkin diseases [(HD), 6.1%] and stomach cancer (5.1%). For females, breast cancer was the top (30.0%), followed by leukaemia (7.6%), NHL (6.6%), colonic (4.9%) and ovarian cancer (4.5%).

Conclusion

Our findings reveal that, there is urgent need to commence the early screening of breast cancer due to its high frequency among Yemeni women. The government should give more support for cancer registries in the country to sustain its vital contribution to cancer care.

HSD17B1 expression induces inflammation-aided rupture of mammary gland myoepithelium

Hydroxysteroid (17-beta) dehydrogenase type 1 (HSD17B1) converts low-active estrogen estrone to highly active estradiol. Estradiol is necessary for normal postpubertal mammary gland development; however, elevated estradiol levels increase mammary tumorigenesis. To investigate the significance of the human HSD17B1 enzyme in the mammary gland, transgenic mice universally overexpressing human HSD17B1 were used (HSD17B1TG mice). Mammary glands obtained from HSD17B1TG females at different ages were investigated for morphology and histology, and HSD17B1 activity and estrogen receptor activation in mammary gland tissue were assessed. To study the significance of HSD17B1 enzyme expression locally in mammary gland tissue, HSD17B1-expressing mammary epithelium was transplanted into cleared mammary fat pads of wild-type females, and the effects on mammary gland estradiol production, epithelial cells and the myoepithelium were investigated. HSD17B1TG females showed increased estrone to estradiol conversion and estrogen-response element-driven estrogen receptor signaling in mammary gland tissue, and they showed extensive lobuloalveolar development that was further enhanced by age along with an increase in serum prolactin concentrations. At old age, HSD17B1TG females developed mammary cancers. Mammary-restricted HSD17B1 expression induced lesions at the sites of ducts and alveoli, accompanied by peri- and intraductal inflammation and disruption of the myoepithelial cell layer. The lesions were shown to be estrogen dependent, as treatment with an antiestrogen, ICI 182,780, starting when lesions were already established reversed the phenotype. These data elucidate the ability of human HSD17B1 to enhance estrogen action in the mammary gland in vivo and indicate that HSD17B1 is a factor inducing phenotypic alterations associated with mammary tumorigenesis.

Risk Factors and Preventions of Breast Cancer

Breast cancer is the second leading cause of cancer deaths among women. The development of breast cancer is a multi-step process involving multiple cell types, and its prevention remains challenging in the world. Early diagnosis of breast cancer is one of the best approaches to prevent this disease. In some developed countries, the 5-year relative survival rate of breast cancer patients is above 80% due to early prevention. In the recent decade, great progress has been made in the understanding of breast cancer as well as in the development of preventative methods. The pathogenesis and tumor drug-resistant mechanisms are revealed by discovering breast cancer stem cells, and many genes are found related to breast cancer. Currently, people have more drug options for the chemoprevention of breast cancer, while biological prevention has been recently developed to improve patients' quality of life. In this review, we will summarize key studies of pathogenesis, related genes, risk factors and preventative methods on breast cancer over the past years. These findings represent a small step in the long fight against breast cancer.