Epidemiology of endocrine-related risk factors for breast cancer

Dual role of pregnancy in breast cancer risk

Reproductive history is one of the strongest risk factors for breast cancer in women. Pregnancy can promote short-term breast cancer risk, but also reduce a woman's lifetime risk of breast cancer. Changes in hormone levels before and after pregnancy are one of the key factors in breast cancer risk. This article summarizes the changes in hormone levels before and after pregnancy, and the roles of hormones in mammary gland development and breast cancer progression. Other factors, such as changes in breast morphology and mammary gland differentiation, changes in the proportion of mammary stem cells (MaSCs), changes in the immune and inflammatory environment, and changes in lactation before and after pregnancy, also play key roles in the occurrence and development of breast cancer. This review discusses the dual effects and the potential mechanisms of pregnancy on breast cancer risk from the above aspects, which is helpful to understand the complexity of female breast cancer occurrence.

Breast cancer prognosis through the use of multi-modal classifiers: current state of the art and the way forward

We present a survey of the current state-of-the-art in breast cancer detection and prognosis. We analyze the evolution of Artificial Intelligence-based approaches from using just uni-modal information to multi-modality for detection and how such paradigm shift facilitates the efficacy of detection, consistent with clinical observations. We conclude that interpretable AI-based predictions and ability to handle class imbalance should be considered priority.

Molecular authentication, metabolite profiling and in silico-in vitro cytotoxicity screening of endophytic Penicillium ramusculum from Withania somnifera for breast cancer therapeutics

In the present study, we isolated a potent endophytic fungus from the roots of Withania somnifera. The endophytic fungal strain was authenticated as Penicillium ramusculum SVWS3 based on morphological and molecular sequencing using four gene data and phylogenetic analyses. In vitro cytotoxicity studies unveiled the remarkable cytotoxic potential of the crude extract derived from P. ramusculum, exhibiting dose-dependent effects on MDA-MB-468 and MCF-7 cells. At a concentration of 100 µg/mL, the crude extract resulted in cell viability of 29.78% for MDA-MB-468 cells and 14.61% for MCF-7 cells. The IC50 values were calculated as 62.83 ± 0.93 µg/mL and 17.23 ± 1.43 µg/mL, respectively for MDA-MB-468 and MCF-7 cells. Caspase activation assay established the underlying mechanism of the crude extract depicting the activation of caspases 3 and 7, indicating the induction of apoptosis in MCF-7 cells. Chemotaxonomic profiling elucidated the ability of P. ramusculum to synthesize a diverse array of bioactive compounds, including Fasoracetam, Tryprostatin B, Odorinol, Thyronine, Brevianamide F, Proglumide, Perlolyrine, Tyrphostin B48, Baptifoline, etc. Molecular docking studies inferred that Baptifoline, Brevianamide F, Odorinol, Perlolyrine, Thyronine, Tryphostin B48, and Tryprostatin B were the lead compounds that could effectively interact with the five selected target receptors of breast cancer, further surpassing the positive controls analyzed. Pharmacokinetic profiling revealed that Baptifoline, Odorinol, and Thyronine depicted an excellent therapeutic profile of druggability. These findings collectively substantiate the anticancer activity of bioactive metabolites synthesized by P. ramusculum SVWS3. Hence, the endophytic P. ramusculum SVWS3 can be an authentic source for developing novel chemotherapeutic drug formulations.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03906-3.

Global epidemiology of breast cancer based on risk factors: a systematic review

Background

Numerous reviews of the epidemiology and risk factors for breast cancer have been published previously which heighted different directions of breast cancer.

Aim

The present review examined the likelihood that incidence, prevalence, and particular risk factors might vary by geographic region and possibly by food and cultural practices as well.

Methods

A systematic review (2017-2022) was conducted following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, reporting on epidemiological and risk factor reports from different world regions. Medical Subject Heading (MeSH) terms: "Breast neoplasm" "AND" country terms such as "Pakistan/epidemiology", "India/epidemiology", "North America/epidemiology", "South Africa/epidemiology" were used to retrieve 2068 articles from PubMed. After applying inclusion and exclusion terms, 49 papers were selected for systematic review.

Results

Results of selected articles were summarized based on risk factors, world regions and study type. Risk factors were classified into five categories: demographic, genetic and lifestyle risk factors varied among countries. This review article covers a variety of topics, including regions, main findings, and associated risk factors such as genetic factors, and lifestyle. Several studies revealed that lifestyle choices including diet and exercise could affect a person's chance of developing breast cancer. Breast cancer risk has also been linked to genetic variables, including DNA repair gene polymorphisms and mutations in the breast cancer gene (BRCA). It has been found that most of the genetic variability links to the population of Asia while the cause of breast cancer due to lifestyle modifications has been found in American and British people, indicating that demographic, genetic, and, lifestyle risk factors varied among countries.

Conclusion

There are many risk factors for breast cancer, which vary in their importance depending on the world region. However, further investigation is required to better comprehend the particular causes of breast cancer in these areas as well as to create efficient prevention and treatment plans that cater to the local population.

Exposure to Perfluoroalkyl Substances and Associations with Pubertal Onset and Serum Reproductive Hormones in a Longitudinal Study of Young Girls in Greater Cincinnati and the San Francisco Bay Area

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS), endocrine disrupting chemicals with worldwide exposure, cause changes in mammary gland development in rodents. A few human studies report delay in pubertal events with increasing perfluorooctanoic acid (PFOA) exposure, but to our knowledge none have examined reproductive hormone levels at thelarche.

METHODS

In a cohort of Greater Cincinnati (GC) and San Francisco Bay Area (SFBA) girls recruited at 6-8 years of age, clinical examinations were conducted annually or semiannually with sequential Tanner staging. PFAS concentrations were measured in the first serum sample of 704 girls. In 304 GC girls, estradiol (E 2 ), estrone (E 1 ), testosterone (T), and dihydroepiandrosterone sulfate (DHEAS) were measured in serum at four time points around puberty. Relationships between PFAS and age at thelarche, pubarche, and menarche were analyzed using survival and structural equation models. The association between PFAS and reproductive hormones was assessed using linear regression models.

RESULTS

Median PFOA serum concentrations in GC (N = 353 , 7.3  ng / mL ) and the SFBA (N = 351 , 5.8  ng / mL ) were higher than in the U.S.

POPULATION

In multivariable Cox proportional hazard models [adjusted for race, body mass index (BMI)], increasing serum log-transformed PFOA was associated with a delay in pubarche [hazard ratio  ( HR ) = 0.83 ; 95% CI: 0.70, 0.99] and menarche (HR = 0.04 ; 95% CI: 0.01, 0.25). Structural equation models indicated a triangular relationship between PFOA, BMI percentile, and the age at the pubertal milestone. Increased PFOA had a statistically significant direct effect of delay on all three milestones, as did BMI. Perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDeA), and 2-(N -methyl-perfluorooctane sulfonamido) acetic acid (Me-PFOSA-AcOH) also were associated with later thelarche, and Me-PFOSA-AcOH also with later pubarche. PFOA was inversely associated with DHEAS (p < 0.01 ), E 1 (p = 0.04 ), and T (p = 0.03 ) concentrations at 6 months prior to puberty.

CONCLUSIONS

PFAS may delay pubertal onset through the intervening effects on BMI and reproductive hormones. The decreases in DHEAS and E 1 associated with PFOA represent biological biomarkers of effect consistent with the delay in onset of puberty. https://doi.org/10.1289/EHP11811.

PFAS and Phthalate/DINCH Exposure in Association with Age at Menarche in Teenagers of the HBM4EU Aligned Studies

Early puberty has been found to be associated with adverse health outcomes such as metabolic and cardiovascular diseases and hormone-dependent cancers. The decrease in age at menarche observed during the past decades has been linked to an increased exposure to endocrine-disrupting compounds (EDCs). Evidence for the association between PFAS and phthalate exposure and menarche onset, however, is inconsistent. We studied the association between PFAS and phthalate/DINCH exposure and age at menarche using data of 514 teenagers (12 to 18 years) from four aligned studies of the Human Biomonitoring for Europe initiative (HBM4EU): Riksmaten Adolescents 2016-2017 (Sweden), PCB cohort (follow-up; Slovakia), GerES V-sub (Germany), and FLEHS IV (Belgium). PFAS concentrations were measured in blood, and phthalate/DINCH concentrations in urine. We assessed the role of each individual pollutant within the context of the others, by using different multi-pollutant approaches, adjusting for age, age- and sex-standardized body mass index z-score and household educational level. Exposure to di(2-ethylhexyl) phthalate (DEHP), especially mono(2-ethyl-5-hydroxyhexyl) phthalate (5OH-MEHP), was associated with an earlier age at menarche, with estimates per interquartile fold change in 5OH-MEHP ranging from -0.34 to -0.12 years in the different models. Findings from this study indicated associations between age at menarche and some specific EDCs at concentrations detected in the general European population, but due to the study design (menarche onset preceded the chemical measurements), caution is needed in the interpretation of causality.

Verbal ability in postmenopausal women in relation to age, cognitive and reproductive factors

Word-finding difficulties have been associated with age and, in women, lowered sex hormone levels following menopause. However, there is limited understanding of the ways that specific aspects of word-finding are shaped by women's age, reproductive histories, and background factors such as education. The current study investigated the effects of age, cognitive and reproductive factors on word-finding abilities in 53 healthy postmenopausal women aged 48-79. A questionnaire was used to gather demographic information and reproductive history. A battery of verbal fluency, continuous series, and naming tasks was designed to assess word-finding across different sensory modalities and cognitive demands. Category and letter fluency were quantified as total number of correct words produced on each task. For continuous series, switch rates and switch costs were computed. For the naming tasks, accuracy and latency measures were used. There were three key findings. Firstly, there was a consistent positive association between education and all word-finding measures, i.e., verbal fluency, continuous series, and naming. Secondly, age-related declines were seen on tasks heavily dependent on working memory such as the continuous series task. Thirdly, reproductive factors across the lifespan such as age at menarche and reproductive years showed subtle effects on naming abilities, but not on verbal fluency or continuous series. The results highlight that word-finding abilities in healthy postmenopausal women are shaped by factors associated with their early years (education, age at menarche) and later adult life (age, reproductive years). The study also distinguished between the more global effects of education, and the more task-specific associations with age and reproductive variables, on verbal task performance after menopause.

Perfluorohexane sulfonate (PFHxS) disturbs the estrous cycle, ovulation rate, oocyte cell communication and calcium homeostasis in mice

Perfluoroalkyl substances are man-made chemicals with ample consumer and industrial applications. They are widely used and are resistant to environmental and metabolic degradation. Several studies have evaluated the effects of Perfluorohexane sulfonate on reproduction. However, there are few reports exploring the cell and molecular mechanisms of its toxicity in the ovary. The aim of this study was to investigate the effects of PFHxS exposure on the estrous cycle, ovulation rate, and the underlying mechanisms of action in female mice in vivo. The animals received a single sub-lethal dose of PFHxS (25.1 mg/kg, 62.5 mg/kg) or vehicle and were stimulated to obtain immature cumulus cell-oocyte complexes (COCs) from the ovaries, or superovulated to develop mature COCs. To evaluate oocyte physiology, Gap-junction intercellular communication (GJIC) was analyzed in immature COCs and calcium homeostasis was evaluated in mature oocytes. PFHxS exposure prolonged the estrous cycle and decreased ovulation rate in female mice. Connexins, Cx43 and Cx37, were downregulated and GJIC was impaired in immature COCs, providing a possible mechanism for the alterations in the estrous cycle and ovulation. No morphological abnormalities were observed in the mature PFHxS-exposed oocytes, but calcium homeostasis was affected. This effect is probably due, at least partially, to deregulation of the endoplasmic reticulum calcium modulator, Stim1. These mechanisms of ovarian injury could explain the reported correlation among PFHxS levels and subfertility in women undergoing fertility treatments.

History of infertility and risk of breast cancer: a prospective cohort study

PURPOSE

Research on infertility and risk of breast cancer has been conflicting, potentially because many well-established breast cancer risk factors, such as pregnancy history, are strongly correlated with infertility.

METHODS

We followed participants in the Nurses' Health Study II from 1989 to 2015 (n = 103,080) for the development of invasive breast cancer and calculated Hazard Ratios (HR) and 95% confidence intervals (CI) using Cox regression. Participants with a self-reported history of infertility (12 months of trying without conception) were compared to gravid women with no history of infertility. We classified breast cancer by menopausal status and investigated mediation by reproductive factors.

RESULTS

Over 26 years of follow-up, 26,208 (25.4%) women reported a history of infertility, and 3,201 women were newly diagnosed with invasive breast cancer. We observed no association between infertility history and risk of overall breast cancer (HR: 1.05, 95% CI: 0.97-1.14) or premenopausal breast cancer (RR: 0.93, 95% CI: 0.83-1.03). However, we observed a modest association between history of infertility and risk of postmenopausal breast cancer (HR: 1.13, 95% CI: 1.00-1.28), approximately 50% of which could be attributed to lower total parity and later age at first birth (95% CI: 8.2%-91.0%).

CONCLUSIONS

Women with a history of infertility were at increased risk of postmenopausal breast cancer. Older age at first birth and lower total parity explained approximately half of the association between infertility and risk of postmenopausal breast cancer.

RANKL and RANK in Cancer Therapy

Receptor activator of nuclear factor-κB (RANK) and its ligand (RANKL) are key regulators of mammalian physiology such as bone metabolism, immune tolerance and antitumor immunity, and mammary gland biology. Here, we explore the multiple functions of RANKL/RANK in physiology and pathophysiology and discuss underlying principles and strategies to modulate the RANKL/RANK pathway as a therapeutic target in immune-mediated cancer treatment.

The Role of Lead and Cadmium in Gynecological Malignancies

Lead and cadmium are non-essential and toxic heavy metals. Their presence and elevated levels can lead to many pathologies. They disrupt the antioxidant properties of many enzymes, consume the resources of antioxidant cells, and thus participate in the generation of oxidative stress, which may result in DNA damage. In addition, they have been found to be carcinogenic through their genotoxic properties. They have been shown to be present in various types of cancer, including cancer of the female reproductive system. Both metals have been recognized as metalloestrogens, which are important in hormone-related cancers. Participation in the oncogenesis of ovarian, endometrial and cervical cancer was analysed in detail, using the available research in this field. We emphasize their role as potential biomarkers in cancer risk and diagnosis as well as advancement of gynaecological malignancies.

Breast Cancer Incidence Patterns in the Saudi Female Population: A 17-Year Retrospective Analysis

Background and Objectives: Breast cancer is considered the most commonly diagnosed type of cancer among women globally and in Saudi Arabia. This study aimed to assess breast cancer incidence patterns and trends among the Saudi female population. Materials and Methods: Breast cancer incidence parameters were obtained from the Saudi Cancer Registry (SCR). The data were retrospectively analyzed for the period from 2001 to 2017 to investigate changes in incidence rates. Temporal trends were also analyzed through joinpoint regression analysis and were dissected by age groups and administrative regions. Results: During the specified period, breast cancer jumped by 55% to constitute 30.9% of all cancer cases among Saudi females. The median age at diagnosis increased to reach 51 years at the end of that period, with an overall increase of 6.3%. The overall Age-Standardized Incidence Rate (ASR) escalated by 151.7% from 11.8/100,000 to 29.7/100,000 population for that period. The Eastern region noticeably had the highest ASR and peaked at 52.2/100,000 population. The joinpoint analysis of the ASR showed increased trends, with an annual percent change (APC) of 5.13% (p < 0.05, [95% CI 4−6.3]). An age-specific analysis was also performed and showed that the age group 70−74 years had the highest trend (APC 10.2%, [95% CI 7.2−13.4], p < 0.05). Region-specific analysis revealed that the Jouf region had the highest trend among the regions (APC 8.8%, [95% CI 3.7−14.2], p < 0.05). Conclusions: Our analysis indicates increased breast cancer incidence in Saudi Arabia with an alarming pace. With the existing trend, it is expected that Saudi Arabia will continue to display an increase in breast cancer incidence. Long-term preventive measures and more effective screening strategies are warranted to alleviate the burden of the disease.

A bibliometric analysis of the top 100 most cited papers and research trends in breast cancer related BRCA1 and BRCA2 genes

This study aimed to identify, characterize, and map the important attributes of the top 100 most cited papers on BRCA1 and BRCA2 genes. The scientific literature on BRCA1 and BRCA2 was searched in the Web of Science Core Collection database using the keywords "BRCA1" OR "BRCA2" (Title). The top 100 most cited papers were selected based on citations. The obtained data were exported into HistCiteTM, RStudio, and VOSviewer software for prerequisite analysis. The top 100 most cited papers on BRCA1 and BRCA2 were authored by 932 authors from 24 countries and published in 27 journals. These papers were cited 79,713 times, ranging from 441 to 4671 citations. The highly cited paper was cited 4671 times and published in Science (1994). The leading author, journal, publication year, institution, and country were Easton DF (n = 16), Nature Genetics (n = 11), 2002 (n = 11), University of Pennsylvania (n = 17), and the USA (n = 76), respectively. The results show that all the top 100 papers were produced in developed countries. The collaboration index among the authors was 9.49. The most frequently appeared keywords were ovarian-cancer, breast-cancer, mutations, gene, and familial breast. In recent times, the trend topics were patients, mutations, carriers, ovarian, and risk.

From Immunohistochemistry to New Digital Ecosystems: A State-of-the-Art Biomarker Review for Precision Breast Cancer Medicine

Simple Summary

In this state-of-the-art breast biomarker review, we have tried to imagine and illustrate future, emerging digital breast cancer ecosystems which allow for greater incorporation of traditional immunohistochemical and molecular biomarkers, WSI, and radiomic features.

Abstract

Breast cancers represent complex ecosystem-like networks of malignant cells and their associated microenvironment. Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) are biomarkers ubiquitous to clinical practice in evaluating prognosis and predicting response to therapy. Recent feats in breast cancer have led to a new digital era, and advanced clinical trials have resulted in a growing number of personalized therapies with corresponding biomarkers. In this state-of-the-art review, we included the latest 10-year updated recommendations for ER, PR, and HER2, along with the most salient information on tumor-infiltrating lymphocytes (TILs), Ki-67, PD-L1, and several prognostic/predictive biomarkers at genomic, transcriptomic, and proteomic levels recently developed for selection and optimization of breast cancer treatment. Looking forward, the multi-omic landscape of the tumor ecosystem could be integrated with computational findings from whole slide images and radiomics in predictive machine learning (ML) models. These are new digital ecosystems on the road to precision breast cancer medicine.

Induced mammary cancer in rat models: pathogenesis, genetics, and relevance to female breast cancer

Mammary cancer, or breast cancer in women, is a polygenic disease with a complex etiopathogenesis. While much remains elusive regarding its origin, it is well established that chemical carcinogens and endogenous estrogens contribute significantly to the initiation and progression of this disease. Rats have been useful models to study induced mammary cancer. They develop mammary tumors with comparable histopathology to humans and exhibit differences in resistance or susceptibility to mammary cancer depending on strain. While some rat strains (e.g., Sprague-Dawley) readily form mammary tumors following treatment with the chemical carcinogen, 7,12-dimethylbenz[a]-anthracene (DMBA), other strains (e.g., Copenhagen) are resistant to DMBA-induced mammary carcinogenesis. Genetic linkage in inbred strains has identified strain-specific quantitative trait loci (QTLs) affecting mammary tumors, via mechanisms that act together to promote or attenuate, and include 24 QTLs controlling the outcome of chemical induction, 10 QTLs controlling the outcome of estrogen induction, and 4 QTLs controlling the outcome of irradiation induction. Moreover, and based on shared factors affecting mammary cancer etiopathogenesis between rats and humans, including orthologous risk regions between both species, rats have served as useful models for identifying methods for breast cancer prediction and treatment. These studies in rats, combined with alternative animal models that more closely mimic advanced stages of breast cancer and/or human lifestyles, will further improve our understanding of this complex disease.

Long-term weight change and risk of breast cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) study

BACKGROUND

The role of obesity and weight change in breast-cancer development is complex and incompletely understood. We investigated long-term weight change and breast-cancer risk by body mass index (BMI) at age 20 years, menopausal status, hormone replacement therapy (HRT) and hormone-receptor status.

METHODS

Using data on weight collected at three different time points from women who participated in the European Prospective Investigation into Cancer and Nutrition (EPIC) study, we investigated the association between weight change from age 20 years until middle adulthood and risk of breast cancer.

RESULTS

In total, 150 257 women with a median age of 51 years at cohort entry were followed for an average of 14 years (standard deviation = 3.9) during which 6532 breast-cancer cases occurred. Compared with women with stable weight (±2.5 kg), long-term weight gain >10 kg was positively associated with postmenopausal breast-cancer risk in women who were lean at age 20 [hazard ratio (HR) = 1.42; 95% confidence interval 1.22-1.65] in ever HRT users (HR = 1.23; 1.04-1.44), in never HRT users (HR = 1.40; 1.16-1.68) and in oestrogen-and-progesterone-receptor-positive (ER+PR+) breast cancer (HR = 1.46; 1.15-1.85).

CONCLUSION

Long-term weight gain was positively associated with postmenopausal breast cancer in women who were lean at age 20, both in HRT ever users and non-users, and hormone-receptor-positive breast cancer.

Anti-cancer potentials of Gynura procumbens leaves extract against two canine mammary cancer cell lines

BACKGROUND

The anti-cancer effects of Gynura procumbens leaves extract (GPE) have been reported in various human cancers. However, the anti-cancer effects and molecular mechanisms of this extract on canine mammary cancer (CMC) have not yet been elucidated.

OBJECTIVES

The main goal of this study was to investigate the anti-cancer properties of GPE against two CMC cell lines (CHMp-13a and CHMp-5b).

METHODS

The GP leaves were extracted with 80% ethanol. Anti-cancer potentials of GPE on CHMp-13a and CHMp-5b cancer cell lines using dimethyl-2-thiazolyl-2,5-diphenyl-2H-tetrazolium bromide (MTT), wound healing, transwell migration, and caspase 3/7 activity assays were evaluated. The mRNA expression levels of two oncogenes: epidermal growth factor receptor (EGFR) and twist family bHLH transcription factor 1 (TWIST) and one tumour suppressor gene: phosphatase and tensin homolog (PTEN) in these cell lines were determined by quantitative real-time PCR (qRT-PCR). In addition, The EGFR and PTEN protein levels as well as protein kinase B (AKT) and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation levels expression were also evaluated by western blot analysis.

RESULTS

The results showed that GPE caused a significant concentration- and time-dependent reduction in cell proliferation of both CHMp-13a and CHMp-5b cells, detected by MTT assays. This extract also significantly suppressed cancer cell migration in both cell lines, tested by wound healing and transwell migration assays. Additionally, the increase in caspase 3/7 activity observed in both CMC cell treated with GPE suggests that GPE induced caspase 3/7 dependent apoptosis. Moreover, GPE significantly decreased EGFR mRNA and protein expression levels compared to control in both cell lines in a dose-dependent manner.

CONCLUSION

These findings emphasized that GPE has an in vitro anti-cancer activity against CMC by inhibiting EGFR signalling pathway. Thus, GPE may serve as an alternative therapy in CMC with high EGFR expression.

Enhanced IFNα Signaling Promotes Ligand-Independent Activation of ERα to Promote Aromatase Inhibitor Resistance in Breast Cancer

Aromatase inhibitors (AIs) reduce estrogen levels up to 98% as the standard practice to treat postmenopausal women with estrogen receptor-positive (ER+) breast cancer. However, approximately 30% of ER+ breast cancers develop resistance to treatment. Enhanced interferon-alpha (IFNα) signaling is upregulated in breast cancers resistant to AIs, which drives expression of a key regulator of survival, interferon-induced transmembrane protein 1 (IFITM1). However, how upregulated IFNα signaling mediates AI resistance is unknown. In this study, we utilized MCF-7:5C cells, a breast cancer cell model of AI resistance, and demonstrate that these cells exhibit enhanced IFNα signaling and ligand-independent activation of the estrogen receptor (ERα). Experiments demonstrated that STAT1, the mediator of intracellular signaling for IFNα, can interact directly with ERα. Notably, inhibition of IFNα signaling significantly reduced ERα protein expression and ER-regulated genes. In addition, loss of ERα suppressed IFITM1 expression, which was associated with cell death. Notably, chromatin immunoprecipitation experiments validated that both ERα and STAT1 associate with ERE sequences in the IFITM1 promoter. Overall, hyperactivation of IFNα signaling enhances ligand-independent activation of ERα, which promotes ER-regulated, and interferon stimulated gene expression to promote survival in AI-resistant breast cancer cells.

Outcomes of screening mammography performed prior to fertility treatment in women ages 40-49

OBJECTIVE

There are currently various conflicting recommendations for breast cancer screening with mammography in women between ages 40-49. There are no specific guidelines for breast cancer screening in women of this age group prior to assisted reproductive technology (ART) for the treatment of infertility. The purpose of our study was to evaluate outcomes of screening mammography, specifically ordered for the purpose of pre-fertility treatment clearance in women aged 40-49 years old.

MATERIALS AND METHODS

This was an IRB approved retrospective study of women aged 40-49 presenting for screening mammography prior to ART between January 2010 and October 2018. Clinical history, imaging, and pathology results were gathered from the electronic medical record. Descriptive statistics were performed.

RESULTS

Our study cohort consisted of 118 women with a mean age of 42 years (range 40-49). Sixteen of 118 (14%) women were recalled from screening for additional diagnostic work-up. Five of the 16 (31%) were recommended for biopsy (BI-RADS 4 or 5). One of 5 biopsies yielded a malignant result (PPV 20%). Overall cancer detection rate was 0.85% or 8.5 women per 1000 women screened. The single cancer in this cohort was an ER+ PR+ HER2- invasive ductal carcinoma.

CONCLUSION

Screening mammography in women 40-49 performed prior to initiation of ART may identify asymptomatic breast malignancy. In accordance with ACR and SBI guidelines to screen women of this age group, women of this age group should undergo screening mammography prior to ART.

A history of previous childbirths is linked to women's white matter brain age in midlife and older age

Maternal brain adaptations occur in response to pregnancy, but little is known about how parity impacts white matter and white matter ageing trajectories later in life. Utilising global and regional brain age prediction based on multi-shell diffusion-weighted imaging data, we investigated the association between previous childbirths and white matter brain age in 8,895 women in the UK Biobank cohort (age range = 54-81 years). The results showed that number of previous childbirths was negatively associated with white matter brain age, potentially indicating a protective effect of parity on white matter later in life. Both global white matter and grey matter brain age estimates showed unique contributions to the association with previous childbirths, suggesting partly independent processes. Corpus callosum contributed uniquely to the global white matter association with previous childbirths, and showed a stronger relationship relative to several other tracts. While our findings demonstrate a link between reproductive history and brain white matter characteristics later in life, longitudinal studies are required to establish causality and determine how parity may influence women's white matter trajectories across the lifespan.

Breast Cancer-Epidemiology, Risk Factors, Classification, Prognostic Markers, and Current Treatment Strategies-An Updated Review

Simple Summary

Breast cancer is the most common cancer among women. It is estimated that 2.3 million new cases of BC are diagnosed globally each year. Based on mRNA gene expression levels, BC can be divided into molecular subtypes that provide insights into new treatment strategies and patient stratifications that impact the management of BC patients. This review addresses the overview on the BC epidemiology, risk factors, classification with an emphasis on molecular types, prognostic biomarkers, as well as possible treatment modalities.

Abstract

Breast cancer (BC) is the most frequently diagnosed cancer in women worldwide with more than 2 million new cases in 2020. Its incidence and death rates have increased over the last three decades due to the change in risk factor profiles, better cancer registration, and cancer detection. The number of risk factors of BC is significant and includes both the modifiable factors and non-modifiable factors. Currently, about 80% of patients with BC are individuals aged >50. Survival depends on both stage and molecular subtype. Invasive BCs comprise wide spectrum tumors that show a variation concerning their clinical presentation, behavior, and morphology. Based on mRNA gene expression levels, BC can be divided into molecular subtypes (Luminal A, Luminal B, HER2-enriched, and basal-like). The molecular subtypes provide insights into new treatment strategies and patient stratifications that impact the management of BC patients. The eighth edition of TNM classification outlines a new staging system for BC that, in addition to anatomical features, acknowledges biological factors. Treatment of breast cancer is complex and involves a combination of different modalities including surgery, radiotherapy, chemotherapy, hormonal therapy, or biological therapies delivered in diverse sequences.

Metabolic syndrome and unfavorable outcomes on body composition and in visceral adiposities indexes among early breast cancer women post-chemotherapy

PURPOSE

The study objected to investigate potential changes in metabolic, dietary, and nutritional status in women with stages I-III breast cancer exposed to chemotherapy.

METHODS

Women who were starting chemotherapy with no previous treatment were recruited. Anthropometrics, bioelectrical impedance analysis, handgrip strength, blood pressure and blood sample were collected. Visceral adiposity index and lipid accumulation product were calculated. Dietary intake was evaluated, and the multiple source methods program was applied. Metabolic syndrome (MetS) was assessed following the NCEP-ATP III criteria (defined as 3 of 5 components of MetS). All data were collected at 2-time points: diagnosis (T0) and after 1 month of completion of therapy (T1). Mean, standard deviation, percentage, and ANOVA in SAS Studio® were used to explore the results.

RESULTS

61 women were included. We did not find any changes in anthropometrics and body composition. However, phase angle, extracellular water (EX) and ratio EX to total body water had expressive changes (p < 0.001). The results showed changes in lipid profile (p < 0.001), and greater unfavorable outcomes on adiposities index (p < 0.001). At the end of the study, 68,8% (N = 42) of the women developed MetS post-chemotherapy.

CONCLUSION

We have found supporting evidence for chemotherapy treatment resulting in worsening of nutritional markers, lipid profile and adiposity markers. After chemotherapy part of the sample developed MetS, even without changes in body weight, fat mass, and food intake. Breast cancer patients may benefit from targeted interventions before starting chemotherapy to prevent MetS post-treatment, and therefore reduce the risk of cardiovascular disease. Further investigation into this theme is needed.

No association between adult sex steroids and hand preference in humans

BACKGROUND

There is ongoing debate about the effects of hormones on the lateralization of the developing brain. In humans, there are conflicting theories of how testosterone during development should affect lateralization. Empirical studies linking prenatal and postnatal testosterone levels to hand preference (a proxy for lateralization) are similarly mixed. Links between hand preference and health may also suggest a mediating role of steroid hormones such as testosterone and estradiol. Studies to date of adult steroid hormones and handedness have been hindered by samples that contain small numbers of non-right-handers.

RESULTS

In the largest study of the phenomenon to date, I find that the testosterone (n = 7290) and estradiol (n = 3700) levels of left- and mixed-handed adults are no different to those of right-handers. All Bayesian 95% highest density intervals contained 0.

DISCUSSION AND CONCLUSIONS

The results have implications for studies that show elevated risk of hormonal-related mental and physical disorders in left-handed individuals.

A comprehensive review on the carcinogenic potential of bisphenol A: clues and evidence

Bisphenol A [BPA; (CH₃)₂C(C₆H₄OH)₂] is a synthetic chemical used as a precursor material for the manufacturing of plastics and resins. It gained attention due to its high chances of human exposure and predisposing individuals at extremely low doses to diseases, including cancer. It enters the human body via oral, inhaled, and dermal routes as leach-out products. BPA may be anticipated as a probable human carcinogen. Studies using in vitro cell lines, rodent models, and epidemiological analysis have convincingly shown the increasing susceptibility to cancer at doses below the oral reference dose set by the Environmental Protection Agency for BPA. Furthermore, BPA exerts its toxicological effects at the genetic and epigenetic levels, influencing various cell signaling pathways. The present review summarizes the available data on BPA and its potential impact on cancer and its clinical outcome.

In-Vitro Fertilization Impact on the Risk of Breast Cancer: A Review Article

Background

Due to the increasing prevalence of infertility, the number of referrals to infertility treatment centers has also increased. Nowadays, assisted reproductive technology (ART), including in vitro fertilization (IVF), is a treatment for infertility or genetic problems. Considering the possible consequences of this method among women undergoing in vitro fertilization (IVF) and kids conceived by IVF, extensive research has been conducted in this regard.

Methods

Overall, 100 articles were entered into the study, and relevant articles were searched and extracted from PubMed, Springer, and Google Scholar databases. In IVF procedure, medications such as Clomiphene citrate and gonadotropins are used to stimulate and mature follicles and thus increase ovulation.

Results

There are conflicting opinions on this issue. Some findings report a slight increase in cancer risk for hormone-sensitive cancers including breast cancer. The long-term use of IVF medications can increase estrogen hormones and cause excessive expression of genes, resulting in an increased risk of breast cancer, which is one of the most frequent cancers among women.

Conclusion

There are some risks to be aware of, which followed the hypothesis that long IVF treatment process may lead to breast cancer among IVF candidates. Furthermore, the risk of breast cancer may be increased in those women with a positive family history and related inherited genes. Therefore, women candidates for IVF should be informed of the probable implications of the reproductive therapy techniques.

Association of Interactions Between Mammographic Density Phenotypes and Established Risk Factors With Breast Cancer Risk, by Tumor Subtype and Menopausal Status

Previous studies suggest that the association between mammographic density (MD) and breast cancer risk might be modified by other breast cancer risk factors. In this study, we assessed multiplicative interactions between MD measures and established risk factors on the risk of invasive breast cancer overall and according to menopausal and estrogen receptor status. We used data on 2,137 cases and 4,346 controls from a nested case-control study within the Nurses' Health Study (1976-2004) and Nurses' Health Study II (1989-2007), whose data on percent mammographic density (PMD) and absolute area of dense tissue and nondense tissue (NDA) were available. No interaction remained statistically significant after adjusting for number of comparisons. For breast cancer overall, we observed nominally significant interactions (P < 0.05) between nulliparity and PMD/NDA, age at menarche and area of dense tissue, and body mass index and NDA. Individual nominally significant interactions across MD measures and risk factors were also observed in analyses stratified by either menopausal or estrogen receptor status. Our findings help provide further insights into potential mechanisms underlying the association between MD and breast cancer.

A methylation signature at the CpG island promoter of estrogen receptor beta (ER-β) in breasts of women may be an early footmark of lack of breastfeeding and nulliparity

Although little is known regarding the mechanisms behind the onset of breast cancer (BC) through reproductive risk factors, new researches have highlighted some early tumor-related methylation footmarks in the breast tissue of apparently clinically healthy women as their potential epigenetic mechanism. Previous evidence supports that the estrogen receptor beta (ER-β), whose anti-cancer roles had already been revealed in BC, is downregulated in the breasts of healthy nulliparous women. Nevertheless, data on such a link about its methylation alterations have not been reported. The goal of current study was to determine possible methylation alterations at CpG island promoter of the ER-β gene, including promoter 0 N and exon 0 N, in relation to aspects of reproductive history in the healthy breasts. The DNA was extracted from the breasts of 120 subjects undergoing cosmetic mammoplasty. Thereafter, the methylation levels of targeted regions in ER-β gene were determined by using MeDIP-qPCR assay. The results revealed that ER-β exon 0 N had no methylation in 84.2 % of the women, whereas the rest, comprising 2.5 % and 13.3 % of the samples, showed a lower and higher of its methylation, respectively. Interestingly, nulliparous women were found to have an elevated methylation level of the ER-β exon 0 N than parous women (P = 0.036). Moreover, we observed a high methylation of the ER-β exon 0 N in the breasts of non-breastfeeding women compared to breastfeeding subgroup (P = 0.048). Likewise, the non-breastfeeding subgroup showed exon 0N high methylation in comparison to women with breastfeeding >24 months (P = 0.023). Finally, although we found that 6.67 % of the samples had a high methylation level at the promoter 0N, no any relationship was found between its methylation and reproductive history. These results may provide key clues to revealing the epigenetic mechanism through which the nulliparity and lack of breastfeeding influencing the risk factor of BC as well as introducing the potential new early prediction and prevention strategies. Although further investigations need to be done in order to gain a better understanding the roles of these epigenetic signatures.

Pubertal mammary gland development is a key determinant of adult mammographic density

Mammographic density refers to the radiological appearance of fibroglandular and adipose tissue on a mammogram of the breast. Women with relatively high mammographic density for their age and body mass index are at significantly higher risk for breast cancer. The association between mammographic density and breast cancer risk is well-established, however the molecular and cellular events that lead to the development of high mammographic density are yet to be elucidated. Puberty is a critical time for breast development, where endocrine and paracrine signalling drive development of the mammary gland epithelium, stroma, and adipose tissue. As the relative abundance of these cell types determines the radiological appearance of the adult breast, puberty should be considered as a key developmental stage in the establishment of mammographic density. Epidemiological studies have pointed to the significance of pubertal adipose tissue deposition, as well as timing of menarche and thelarche, on adult mammographic density and breast cancer risk. Activation of hypothalamic-pituitary axes during puberty combined with genetic and epigenetic molecular determinants, together with stromal fibroblasts, extracellular matrix, and immune signalling factors in the mammary gland, act in concert to drive breast development and the relative abundance of different cell types in the adult breast. Here, we discuss the key cellular and molecular mechanisms through which pubertal mammary gland development may affect adult mammographic density and cancer risk.

Benzophenone-3 promotion of mammary tumorigenesis is diet-dependent

Benzophenone-3 is a putative endocrine disrupting chemical and common ingredient in sunscreens. The potential of endocrine disrupting chemicals to act as agonists or antagonists in critical hormonally regulated processes, such as mammary gland development and mammary tumorigenesis, demands evaluation of its potential in promoting breast cancer. This study identifies the effects of BP-3 on mammary tumorigenesis with high-fat diet during puberty versus adulthood in Trp53-null transplant BALB/c mice. Benzophenone-3 exposure yielded levels in urine similar to humans subjected to heavy topical sunscreen exposure. Benzophenone-3 was protective for epithelial tumorigenesis in mice fed lifelong low-fat diet, while promotional for epithelial tumorigenesis in mice fed adult high-fat diet. Benzophenone-3 increased tumor cell proliferation, decreased tumor cell apoptosis, and increased tumor vascularity dependent on specific dietary regimen and tumor histopathology. Even in instances of an ostensibly protective effect, other parameters suggest greater risk. Although benzophenone-3 seemed protective on low-fat diet, spindle cell tumors arising in these mice showed increased proliferation and decreased apoptosis. This points to a need for further studies of benzophenone-3 in both animal models and humans as a potential breast cancer risk factor, as well as a more general need to evaluate endocrine disrupting chemicals in varying dietary contexts.

Immune-related gene data-based molecular subtyping related to the prognosis of breast cancer patients

Background

Breast cancer (BC), which is the most common malignant tumor in females, is associated with increasing morbidity and mortality. Effective treatments include surgery, chemotherapy, radiotherapy, endocrinotherapy and molecular-targeted therapy. With the development of molecular biology, immunology and pharmacogenomics, an increasing amount of evidence has shown that the infiltration of immune cells into the tumor microenvironment, coupled with the immune phenotype of tumor cells, will significantly affect tumor development and malignancy. Consequently, immunotherapy has become a promising treatment for BC prevention and as a modality that can influence patient prognosis.

Methods

In this study, samples collected from The Cancer Genome Atlas (TCGA) and ImmPort databases were analyzed to investigate specific immune-related genes that affect the prognosis of BC patients. In all, 64 immune-related genes related to prognosis were screened, and the 17 most representative genes were finally selected to establish the prognostic prediction model of BC (the RiskScore model) using the Lasso and StepAIC methods. By establishing a training set and a test set, the efficiency, accuracy and stability of the model in predicting and classifying the prognosis of patients were evaluated. Finally, the 17 immune-related genes were functionally annotated, and GO and KEGG signal pathway enrichment analyses were performed.

Results

We found that these 17 genes were enriched in numerous BC- and immune microenvironment-related pathways. The relationship between the RiskScore and the clinical characteristics of the sample and signaling pathways was also analyzed.

Conclusions

Our findings indicate that the prognostic prediction model based on the expression profiles of 17 immune-related genes has demonstrated high predictive accuracy and stability in identifying immune features, which can guide clinicians in the diagnosis and prognostic prediction of BC patients with different immunophenotypes.

Electronic supplementary material

The online version of this article (10.1007/s12282-020-01191-z) contains supplementary material, which is available to authorized users.

Protective Effects of Epigallocatechin Gallate (EGCG) on Endometrial, Breast, and Ovarian Cancers

Green tea and its major bioactive component, (-)-epigallocatechin gallate (EGCG), possess diverse biological properties, particularly antiproliferation, antimetastasis, and apoptosis induction. Many studies have widely investigated the anticancer and synergistic effects of EGCG due to the side effects of conventional cytotoxic agents. This review summarizes recent knowledge of underlying mechanisms of EGCG on protective roles for endometrial, breast, and ovarian cancers based on both in vitro and in vivo animal studies. EGCG has the ability to regulate many pathways, including the activation of nuclear factor erythroid 2-related factor 2 (Nrf2), inhibition of nuclear factor-κB (NF-κB), and protection against epithelial-mesenchymal transition (EMT). EGCG has also been found to interact with DNA methyltransferases (DNMTs) and histone deacetylases (HDACs), which affect epigenetic modifications. Finally, the action of EGCG may exert a suppressive effect on gynecological cancers and have beneficial effects on auxiliary therapies for known drugs. Thus, future clinical intervention studies with EGCG will be necessary to more and clear evidence for the benefit to these cancers.

Preclinical Evaluation of the Oncolytic Vaccinia Virus TG6002 by Translational Research on Canine Breast Cancer

Oncolytic virotherapy is a promising therapeutic approach for the treatment of cancer. TG6002 is a recombinant oncolytic vaccinia virus deleted in the thymidine kinase and ribonucleotide reductase genes and armed with the suicide gene FCU1, which encodes a bifunctional chimeric protein that efficiently catalyzes the direct conversion of the nontoxic 5-fluorocytosine into the toxic metabolite 5-fluorouracil. In translational research, canine tumors and especially mammary cancers are relevant surrogates for human cancers and can be used as preclinical models. Here, we report that TG6002 is able to replicate in canine tumor cell lines and is oncolytic in such cells cultured in 2D or 3D as well as canine mammary tumor explants. Furthermore, intratumoral injections of TG6002 lead to inhibition of the proliferation of canine tumor cells grafted into mice. 5-fluorocytosine treatment of mice significantly improves the anti-tumoral activity of TG6002 infection, a finding that can be correlated with its conversion into 5-fluorouracil within infected fresh canine tumor biopsies. In conclusion, our study suggests that TG6002 associated with 5-fluorocytosine is a promising therapy for human and canine cancers.

Expression and clinicopathological significance of AOC4P, PRNCR1, and PCAT1 lncRNAs in breast cancer

Long none coding RNAs (lncRNAs) AOC4P, PRNCR1, and PCAT-1 are dysregulated in various types of malignancies. However, their expression and clinicopathological significances are uncertain in breast cancer (BC). Quantitative real-time polymerase chain reaction (RT- qPCR) was used to measure the expression levels of the selected lncRNAs in tumor tissues obtained from 50 BC patients compared to the normal adjacent tissues (NATs) and 50 clinically healthy normal tissues. Our results revealed a significant downregulation of AOC4P, however, upregulated PRNCR1 and PCAT1 were found in tumor tissues compared to NATs and clinically healthy normal tissues (P < 0.05). Interestingly, remarkable decreased expression of AOC4P was observed in NATs than clinically healthy normal tissues. Dysregulation of the lncRNAs was correlated with worse outcomes of patients. Furthermore, our data showed that the altered expression levels of lncRNAs AOC4P, PRNCR1, and PCAT1 might be occurred through the function of demographic and reproductive variables. Taken together, the altered regulation of AOC4P, PRNCR1, and PCAT1 may highlight their crucial roles in BC development and pathogenesis. Our findings also proposed demographic and reproductive variables as risk factors in BC through the possible influence on the expression of the studied lncRNAs. Nevertheless, further explorations are required to elucidate the more detailed functions of these lncRNAs in BC.

Women's brain aging: Effects of sex-hormone exposure, pregnancies, and genetic risk for Alzheimer's disease

Sex hormones such as estrogen fluctuate across the female lifespan, with high levels during reproductive years and natural decline during the transition to menopause. Women's exposure to estrogen may influence their heightened risk of Alzheimer's disease (AD) relative to men, but little is known about how it affects normal brain aging. Recent findings from the UK Biobank demonstrate less apparent brain aging in women with a history of multiple childbirths, highlighting a potential link between sex-hormone exposure and brain aging. We investigated endogenous and exogenous sex-hormone exposure, genetic risk for AD, and neuroimaging-derived biomarkers for brain aging in 16,854 middle to older-aged women. The results showed that as opposed to parity, higher cumulative sex-hormone exposure was associated with more evident brain aging, indicating that i) high levels of cumulative exposure to sex-hormones may have adverse effects on the brain, and ii) beneficial effects of pregnancies on the female brain are not solely attributable to modulations in sex-hormone exposure. In addition, for women using hormonal replacement therapy (HRT), starting treatment earlier was associated with less evident brain aging, but only in women with a genetic risk for AD. Genetic factors may thus contribute to how timing of HRT initiation influences women's brain aging trajectories.

A case-control study of the joint effect of reproductive factors and radiation treatment for first breast cancer and risk of contralateral breast cancer in the WECARE study

Objective

To examined the impact of reproductive factors on the relationship between radiation treatment (RT) for a first breast cancer and risk of contralateral breast cancer (CBC).

Methods

The Women’s Environmental Cancer and Radiation Epidemiology (WECARE) Study is a multi-center, population-based case-control study where cases are women with asynchronous CBC (N = 1521) and controls are women with unilateral breast cancer (N = 2211). Rate ratios (RR) and 95% confidence intervals (CI) were estimated using conditional logistic regression to assess the independent and joint effects of RT (ever/never and location-specific stray radiation dose to the contralateral breast [0, >0-<1Gy, ≥1Gy]) and reproductive factors (e.g., parity).

Results

Nulliparous women treated with RT (≥1Gy dose) were at increased risk of CBC compared with nulliparous women not treated with RT, although this relationship did not reach statistical significance (RR = 1.34, 95% CI 0.87, 2.07). Women treated with RT who had an interval pregnancy (i.e., pregnancy after first diagnosis and before second diagnosis [in cases]/reference date [in controls]) had an increased risk of CBC compared with those who had an interval pregnancy with no RT (RR = 4.60, 95% CI 1.16, 18.28). This was most apparent for women with higher radiation doses to the contralateral breast.

Conclusion

Among young female survivors of breast cancer, we found some evidence suggesting that having an interval pregnancy could increase a woman’s risk of CBC following RT for a first breast cancer. While sampling variability precludes strong interpretations, these findings suggest a role for pregnancy and hormonal factors in radiation-associated CBC.

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Radiation treatment is associated with increased contralateral breast cancer risk in some women.

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Reproductive status at the time of treatment may modify this relationship.

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Some evidence that pregnancy after radiation treatment increases contralateral breast cancer risk.

Women's views about breast cancer prevention at mammography screening units and well women's clinics

Background

Women attending mammography screening units (msus) and well women's clinics (wwcs) represent a motivated cohort likely to engage in interventions aimed at primary breast cancer (bca) prevention.

Methods

We used a feasibility questionnaire distributed to women (40-49 or 50-74 years of age) attending msus and wwcs in Halifax, Nova Scotia, to examine■ women's views about bca primary prevention and sources of health care information,■ prevalence of lifestyle-related bca risk factors, and■ predictors of prior mammography encounters within provincial screening guidelines.Variables examined included personal profiling, comorbidities, prior mammography uptake, lifestyle behaviours, socioeconomic status, health information sources, and willingness to discuss or implement lifestyle modifications, or endocrine therapy, or both. A logistic regression analysis examined associations with prior mammography encounters.

Results

Of the 244 responses obtained during 1.5 months from women aged 40-49 years (n = 75) and 50-74 years (n = 169), 56% and 75% respectively sought or would prefer to receive health information from within, as opposed to outside, health care. Lifestyle-related bca risk factors were prevalent, and most women were willing to discuss or implement lifestyle modifications (93%) or endocrine therapy (67%). Of the two age groups, 49% and 93% respectively had previously undergone mammography within guidelines. Increasing age and marital status (single, separated, or divorced vs. married or partnered) were independent predictors of prior mammography encounters within guidelines for women 40-49 years of age; no independent predictors were observed in the older age group.

Conclusions

Women attending msus and wwcs seem to largely adhere to mammography guidelines and appear motivated to engage in bca primary prevention strategies, including lifestyle modifications and endocrine therapy. Women's views as observed in this study provide a rationale for the potential incorporation of bca risk assessment within the "mammogram point of care" to engage motivated women in bca primary prevention strategies.

Long Noncoding RNAs Involved in the Endocrine Therapy Resistance of Breast Cancer

Long noncoding RNAs (lncRNAs) are defined as RNAs longer than 200 nucleotides that do not encode proteins. Recent studies have demonstrated that numerous lncRNAs are expressed in humans and play key roles in the development of various types of cancers. Intriguingly, some lncRNAs have been demonstrated to be involved in endocrine therapy resistance for breast cancer through their own mechanisms, suggesting that lncRNAs could be promising new biomarkers and therapeutic targets of breast cancer. Here, we summarize the functions and mechanisms of lncRNAs related to the endocrine therapy resistance of breast cancer.

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.

Clinical and epidemiologic factors associated with breast cancer and its subtypes among Northeast Chinese women

The incidence of breast cancer has increased dramatically in China. We evaluated the clinical and epidemiologic factors associated with breast cancer, and its stage in a case‐control study of Northeast Chinese women. We also examined whether these factors were differentially distributed among molecular subtypes of breast cancer in a case‐only analysis. We identified 1118 breast cancer patients and 2284 healthy women from Cancer Hospital of Medical University between January 2014 and December 2017. Logistic regression models were used to calculate the odds ratios (ORs) and corresponding 95% confidence intervals (CIs). We found that postmenopausal women had a decreased risk of breast cancer (multivariate‐adjusted OR = 0.33, 95% CI:0.25‐0.43), and tended to have breast cancer of human epidermal growth factor receptor 2 (HER2)‐overexpressing (multivariate‐adjusted OR = 2.99, 95% CI: 1.49‐5.97) and triple‐negative (multivariate‐adjusted OR = 2.16, 95% CI: 1.02‐4.56) subtypes, compared with the luminal B subtype. Women with history of abortion had an increased risk of breast cancer (multivariate‐adjusted OR = 4.70, 95% CI: 3.60‐6.14). Women with high breast density and high Breast Imaging Reporting and Data System (BIRADS) scores of lesions tended to have breast cancer of advanced stage, but were not differentially distributed among its molecular subtypes. In conclusion, postmenopausal women had decreased risk of breast cancer, and tended to have nonluminal subtype, while women with history of abortion had increased risk of breast cancer. Women with high breast density and BIRADS scores of lesions tended to have advanced stage breast cancer. We provide evidence on the epidemiologic factors for breast cancer and its subtypes, which may help with breast cancer risk stratification.

Longitudinal study of age of menarche in association with childhood concentrations of persistent organic pollutants

BACKGROUND

Age at female puberty is associated with adult morbidities, including breast cancer and diabetes. Hormonally active chemicals are suspected of altering pubertal timing. We examined whether persistent organic pollutants (POPs) are associated with age at menarche in a longitudinal study.

METHODS

We analyzed data for females enrolled at age 6-8 years in the Breast Cancer and Environment Research Program from California and Ohio. Participants were followed annually 2004-2013 and provided serum (mean age 7.8 years) for measurement of polychlorinated biphenyl (PCB), organochlorine pesticide (OCP), and polybrominated diphenyl ether (PBDE) concentrations. Age of menarche was assigned based on parental and participant reported dates and ages of menarche. Adjusted hazard ratios (aHRs) for menarchal onset were calculated with Cox proportional regression. Body mass index (BMI), potentially on the causal pathway, was added to parallel analyses.

RESULTS

Age of menarche was later with higher summed PCB levels (median 11.9 years in quartile 1 [Q1] versus 12.7 in quartile 4 [Q4]) and OCP levels (12.1 years versus 12.4, respectively). When adjusting for all covariates except BMI, higher POP concentrations were associated with later age at menarche (Q4 versus Q1 aHRs: PBDEs 0.75 [95% CI 0.58, 0.97], PCBs 0.67 [95% CI 0.5, 0.89], and OCPs 0.66 [95% CI 0.50, 0.89]). Additional adjustment for BMI attenuated aHRs; PCB aHR approached the null.

CONCLUSION

Findings revealed later onset of menarche with higher concentrations of certain POPs, possibly through an association with BMI. Altered pubertal timing may have long lasting effects on reproductive health and disease risk, so continued attention is important for understanding the biological processes affected by hormonally active chemicals.

Reproductive factors associated with breast cancer risk in Li-Fraumeni syndrome

Li-Fraumeni syndrome (LFS) is a rare autosomal dominant cancer predisposition syndrome with exceptionally high lifetime cancer risks, caused primarily by germline TP53 variants. Early-onset breast cancer is the most common cancer in women with LFS. Associations between female reproductive factors and breast cancer risk have been widely studied in the general population and BRCA1/2 mutation carriers but not in LFS. We evaluated whether reproductive factors are associated with breast cancer in LFS. Questionnaire data were collected for 152 women with confirmed germline TP53 variants enrolled in the National Cancer Institute's LFS study (NCT01443468); of which, 85 had breast cancer, confirmed by pathology/medical reports. Fisher's exact test and Cox proportional hazards were used to calculate the effect of reproductive factors on breast cancer risk. Lifetime breastfeeding for at least 7 months was associated with lower breast cancer risk (hazard ratio [HR] 0.57, p = 0.05). Parity did not independently change breast cancer risk (HR 1.08, p = 0.8) but suggested an increased risk with older age at first live birth (HR 2.14, p = 0.05). Age at menarche (HR 1.09, p = 0.24) and use of oral contraceptives (HR 0.88; p = 0.7) did not significantly affect breast cancer risk. In this first study of reproductive factors and breast cancer in women with LFS, breastfeeding was observed to be protective against breast cancer risk, especially with at least 7 months of lifetime breastfeeding. Older age at first live birth was suggested to slightly increase breast cancer risk. Larger prospective studies of reproductive factors are warranted in women with LFS before making definitive clinical recommendations.

A Pooled Analysis of Breastfeeding and Breast Cancer Risk by Hormone Receptor Status in Parous Hispanic Women

BACKGROUND

Data on breastfeeding and breast cancer risk are sparse and inconsistent for Hispanic women.

METHODS

Pooling data for nearly 6,000 parous Hispanic women from four population-based studies conducted between 1995 and 2007 in the United States and Mexico, we examined the association of breastfeeding with risk of breast cancer overall and subtypes defined by estrogen receptor (ER) and progesterone receptor (PR) status, and the joint effects of breastfeeding, parity, and age at first birth. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using logistic regression.

RESULTS

Among parous Hispanic women, older age at first birth was associated with increased breast cancer risk, whereas parity was associated with reduced risk. These associations were found for hormone receptor positive (HR+) breast cancer only and limited to premenopausal women. Age at first birth and parity were not associated with risk of ER- and PR- breast cancer. Increasing duration of breastfeeding was associated with decreasing breast cancer risk (≥25 vs. 0 months: OR = 0.73; 95% CI = 0.60, 0.89; Ptrend = 0.03), with no heterogeneity by menopausal status or subtype. At each parity level, breastfeeding further reduced HR+ breast cancer risk. Additionally, breastfeeding attenuated the increase in risk of HR+ breast cancer associated with older age at first birth.

CONCLUSIONS

Our findings suggest that breastfeeding is associated with reduced risk of both HR+ and ER- and PR- breast cancer among Hispanic women, as reported for other populations, and may attenuate the increased risk in women with a first pregnancy at older ages.