The sex hormone system in carriers of BRCA1/2 mutations: a case-control study

Antiprogestins for breast cancer treatment: We are almost ready

The development of antiprogestins was initially a gynecological purpose. However, since mifepristone was developed, its application for breast cancer treatment was immediately proposed. Later, new compounds with lower antiglucocorticoid and antiandrogenic effects were developed to be applied to different pathologies, including breast cancer. We describe herein the studies performed in the breast cancer field with special focus on those reported in recent years, ranging from preclinical biological models to those carried out in patients. We highlight the potential use of antiprogestins in breast cancer prevention in women with BRCA1 mutations, and their use for breast cancer treatment, emphasizing the need to elucidate which patients will respond. In this sense, the PR isoform ratio has emerged as a possible tool to predict antiprogestin responsiveness. The effects of combined treatments of antiprogestins together with other drugs currently used in the clinic, such as tamoxifen, CDK4/CDK6 inhibitors or pembrolizumab in preclinical models is discussed since it is in this scenario that antiprogestins will be probably introduced. Finally, we explain how transcriptomic or proteomic studies, that were carried out in different luminal breast cancer models and in breast cancer samples that responded or were predicted to respond to the antiprogestin therapy, show a decrease in proliferative pathways. Deregulated pathways intrinsic of each model are discussed, as well as how these analyses may contribute to a better understanding of the mechanisms involved.

Gynecological Cancers and Microbiota Dynamics: Insights into Pathogenesis and Therapy

In recent years, the relationship between the microbiota and various aspects of health has become a focal point of scientific investigation. Although the most studied microbiota concern the gastrointestinal tract, recently, the interest has also been extended to other body districts. Female genital tract dysbiosis and its possible impact on pathologies such as endometriosis, polycystic ovary syndrome (PCOS), pelvic inflammatory disease (PID), and gynecological cancers have been unveiled. The incursion of pathogenic microbes alters the ecological equilibrium of the vagina, triggering inflammation and compromising immune defense, potentially fostering an environment conducive to cancer development. The most common types of gynecological cancer include cervical, endometrial, and ovarian cancer, which occur in women of any age but especially in postmenopausal women. Several studies highlighted that a low presence of lactobacilli at the vaginal level, and consequently, in related areas (such as the endometrium and ovary), correlates with a higher risk of gynecological pathology and likely contributes to increased incidence and worse prognosis of gynecological cancers. The complex interplay between microbial communities and the development, progression, and treatment of gynecologic malignancies is a burgeoning field not yet fully understood. The intricate crosstalk between the gut microbiota and systemic inflammation introduces a new dimension to our understanding of gynecologic cancers. The objective of this review is to focus attention on the association between vaginal microbiota and gynecological malignancies and provide detailed knowledge for future diagnostic and therapeutic strategies.

ELF5: A Molecular Clock for Breast Aging and Cancer Susceptibility

Breast cancer is predominantly an age-related disease, with aging serving as the most significant risk factor, compounded by germline mutations in high-risk genes like BRCA1/2. Aging induces architectural changes in breast tissue, particularly affecting luminal epithelial cells by diminishing lineage-specific molecular profiles and adopting myoepithelial-like characteristics. ELF5 is an important transcription factor for both normal breast and breast cancer development. This review focuses on the role of ELF5 in normal breast development, its altered expression throughout aging, and its implications in cancer. It discusses the lineage-specific expression of ELF5, its regulatory mechanisms, and its potential as a biomarker for breast-specific biological age and cancer risk.

Navigating a plethora of progesterone receptors: Comments on the safety/risk of progesterone supplementation in women with a history of breast cancer or at high-risk for developing breast cancer

Progesterone and progestin agonists are potent steroid hormones. There are at least three major types of progesterone receptor (PR) families that interact with and respond to progesterone or progestin ligands. These receptors include ligand-activated transcription factor isoforms (PR-A and PR-B) encoded by the PGR gene, often termed classical or nuclear progesterone receptor (nPR), membrane-spanning progesterone receptor membrane component proteins known as PGRMC1/2, and a large family of progestin/adipoQreceptors or PAQRs (also called membrane PRs or mPRs). Cross-talk between mPRs and nPRs has also been reported. The complexity of progesterone actions via a plethora of diverse receptors warrants careful consideration of the clinical applications of progesterone, which primarily include birth control formulations in young women and hormone replacement therapy following menopause. Herein, we focus on the benefits and risk of progesterone/progestin supplementation. We conclude that progesterone-only supplementation is considered safe for most reproductive-age women. However, women who currently have ER + breast cancer or have had such cancer in the past should not take sex hormones, including progesterone. Women at high-risk for developing breast or ovarian cancer, either due to their family history or known genetic factors (such as BRCA1/2 mutation) or hormonal conditions, should avoid exogenous sex hormones and proceed with caution when considering using natural hormones to mitigate menopausal symptoms and/or improve quality of life after menopause. These individuals are urged to consult with a qualified OB-GYN physician to thoroughly assess the risks and benefits of sex hormone supplementation. As new insights into the homeostatic roles and specificity of highly integrated rapid signaling and nPR actions are revealed, we are hopeful that the benefits of using progesterone use may be fully realized without an increased risk of women's cancer.

Physical Activity During Adolescence and Early-adulthood and Ovarian Cancer Among Women with a BRCA1 or BRCA2 Mutation

In the general population, physical activity has been associated with a lower risk of several cancers; however, the evidence for ovarian cancer is not clear. It is suggested that early-life physical activity may differentially impact risk. Whether this is true among women at high risk due to a pathogenic variant (mutation) in the BRCA1 or BRCA2 genes has not been evaluated. Thus, we performed a matched case-control study to evaluate the association between adolescent and early-adulthood physical activity and ovarian cancer. BRCA mutation carriers who completed a research questionnaire on various exposures and incident disease and with data available on physical activity were eligible for inclusion. Self-reported activity at ages 12-13, 14-17, 18-22, 23-29, and 30-34 was used to calculate the average metabolic equivalent of task (MET)-hours/week for moderate, vigorous, and total physical activity during adolescence (ages 12-17) and early-adulthood (ages 18-34). Conditional logistic regression was used to estimate the OR and 95% confidence intervals (CI) of invasive ovarian cancer associated with physical activity. This study included 215 matched pairs (mean age = 57.3). There was no association between total physical activity during adolescence (ORhigh vs. low = 0.91; 95% CI: 0.61-1.36; Ptrend = 0.85), early-adulthood (ORhigh vs. low = 0.78; 95% CI: 0.51-1.20; Ptrend = 0.38) and overall (ORhigh vs. low = 0.81; 95% CI: 0.54-1.23; Ptrend = 0.56) and ovarian cancer. Findings were similar for moderate (Ptrend ≥ 0.25) and vigorous (Ptrend ≥ 0.57) activity. These findings do not provide evidence for an association between early-life physical activity and BRCA-ovarian cancer; however, physical activity should continue to be encouraged to promote overall health.

SIGNIFICANCE

In this matched case-control study, we observed no association between physical activity during adolescence or early-adulthood and subsequent risk of ovarian cancer. These findings do not provide evidence for an association between early-life physical activity and BRCA-ovarian cancer; however, being active remains important to promote overall health and well-being.

Reevaluating the Role of Progesterone in Ovarian Cancer: Is Progesterone Always Protective?

Ovarian cancer (OC) represents a collection of rare but lethal gynecologic cancers where the difficulty of early detection due to an often-subtle range of abdominal symptoms contributes to high fatality rates. With the exception of BRCA1/2 mutation carriers, OC most often manifests as a post-menopausal disease, a time in which the ovaries regress and circulating reproductive hormones diminish. Progesterone is thought to be a "protective" hormone that counters the proliferative actions of estrogen, as can be observed in the uterus or breast. Like other steroid hormone receptor family members, the transcriptional activity of the nuclear progesterone receptor (nPR) may be ligand dependent or independent and is fully integrated with other ubiquitous cell signaling pathways often altered in cancers. Emerging evidence in OC models challenges the singular protective role of progesterone/nPR. Herein, we integrate the historical perspective of progesterone on OC development and progression with exciting new research findings and critical interpretations to help paint a broader picture of the role of progesterone and nPR signaling in OC. We hope to alleviate some of the controversy around the role of progesterone and give insight into the importance of nPR actions in disease progression. A new perspective on the role of progesterone and nPR signaling integration will raise awareness to the complexity of nPRs and nPR-driven gene regulation in OC, help to reveal novel biomarkers, and lend critical knowledge for the development of better therapeutic strategies.

The RANK-RANKL-OPG System: A Multifaceted Regulator of Homeostasis, Immunity, and Cancer

The RANK-RANKL-OPG system is a complex signaling pathway that plays a critical role in bone metabolism, mammary epithelial cell development, immune function, and cancer. RANKL is a ligand that binds to RANK, a receptor expressed on osteoclasts, dendritic cells, T cells, and other cells. RANKL signaling promotes osteoclast differentiation and activation, which leads to bone resorption. OPG is a decoy receptor that binds to RANKL and inhibits its signaling. In cancer cells, RANKL expression is often increased, which can lead to increased bone resorption and the development of bone metastases. RANKL-neutralizing antibodies, such as denosumab, have been shown to be effective in the treatment of skeletal-related events, including osteoporosis or bone metastases, and cancer. This review will provide a comprehensive overview of the functions of the RANK-RANKL-OPG system in bone metabolism, mammary epithelial cells, immune function, and cancer, together with the potential therapeutic implications of the RANK-RANKL pathway for cancer management.

DNA methylation at quantitative trait loci (mQTLs) varies with cell type and nonheritable factors and may improve breast cancer risk assessment

To individualise breast cancer (BC) prevention, markers to follow a person's changing environment and health extending beyond static genetic risk scores are required. Here, we analysed cervical and breast DNA methylation (n = 1848) and single nucleotide polymorphisms (n = 1442) and demonstrate that a linear combination of methylation levels at 104 BC-associated methylation quantitative trait loci (mQTL) CpGs, termed the WID™-qtBC index, can identify women with breast cancer in hormone-sensitive tissues (AUC = 0.71 [95% CI: 0.65-0.77] in cervical samples). Women in the highest combined risk group (high polygenic risk score and WID™-qtBC) had a 9.6-fold increased risk for BC [95% CI: 4.7-21] compared to the low-risk group and tended to present at more advanced stages. Importantly, the WID™-qtBC is influenced by non-genetic BC risk factors, including age and body mass index, and can be modified by a preventive pharmacological intervention, indicating an interaction between genome and environment recorded at the level of the epigenome. Our findings indicate that methylation levels at mQTLs in relevant surrogate tissues could enable integration of heritable and non-heritable factors for improved disease risk stratification.

Tamoxifen and the risk of breast cancer in women with a BRCA1 or BRCA2 mutation

PURPOSE

Chemoprevention with a selective estrogen receptor modulator (tamoxifen or raloxifene) is a non-surgical option offered to high-risk women to reduce the risk of breast cancer. The evidence for tamoxifen benefit is based on trials conducted among predominantly postmenopausal women from the general population and on studies of contralateral breast cancer in women with a pathogenic variant (mutation hereafter) in BRCA1 or BRCA2. Tamoxifen has not been assessed as a primary prevention agent in women with an inherited BRCA mutation.

METHODS

We conducted a prospective analysis of tamoxifen chemoprevention and the risk of breast cancer in women with a BRCA1 or BRCA2 mutation. Data on tamoxifen (and raloxifene) use was collected by questionnaire and updated biennially. Information on incident cancers was collected by self-report and was confirmed by medical record review. In a matched analysis, we estimated the hazard ratio (HR) and 95% confidence intervals (CI) for developing a first primary breast cancer associated with tamoxifen or raloxifene use, using Cox proportional hazards analysis.

RESULTS

There were 4578 unaffected women in the cohort, of whom 137 reported tamoxifen use (3%), 83 reported raloxifene use (2%) and 12 used both drugs (0.3%). Women who used tamoxifen or raloxifene were matched 1:3 with women who used neither drug on year of birth, country of residence, year of study entry and gene (BRCA1 or BRCA2). We generated 202 matched pairs. After a mean follow-up of 6.8 years, there were 22 incident breast cancers diagnosed among tamoxifen/raloxifene users (10.9% of users) and 71 cases diagnosed among non-users (14.3% of non-users; HR = 0.64; 95% CI 0.40-1.03; P = 0.07).

CONCLUSION

Chemoprevention may be an effective risk-reduction option for BRCA mutation carriers, but further studies with longer follow-up are necessary.

Progress and prospects in research and clinical practice of hormone receptor-positive, HER-2-negative breast cancer with BRCA1/2 mutations

Breast cancer (BC) is a heterogeneous disease that is the most common cancer in women worldwide. However, precise subtyping and corresponding treatments have improved patient outcomes. Hormone receptor (HR)-positive, human epidermal growth factor receptor type 2 (HER2)-negative (HR+/HER2-) BC with BRCA1 and/or BRCA2 mutations (BRCA1/2m) is a unique BC subset with dual drivers: homologous recombination deficiency and hormone receptor signaling. Wild-type BRCA1/2 suppresses estrogen receptor-mediated signaling. Loss-of-function mutations in BRCA1/2 release estrogen receptor suppression, leading to reduced sensitivity to endocrine therapy. Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPis) exert antitumor effects against this subtype and can be used in combination with endocrine therapy. Although PARPis have been evaluated in metastatic triple-negative breast cancer, their efficacy against HR+/HER2- BC has not been clearly established. The present review summarizes recent advances and prospects in the progress of the HR+/HER2-/BRCA1/2m subgroup. As such, this article provides theoretical guidance for future research and promotes the use of PARPis for the treatment of HR+/HER2-/BRCA1/2m BC.

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.

[Therapeutic strategies for the treatment of endocrine resistant hormone receptor positive advanced breast cancer]

HR+ breast cancers are defined by the prominence of signaling pathways dependent on the estrogen receptor. Endocrine therapy is the standard treatment for these advanced diseases. Resistance to these treatments, called hormone resistance, appears invariably with biological mechanisms that have led to the development of therapeutic opportunities. An exhaustive literature review was carried out concerning the biology of the hormone resistance pathways, the therapeutic options before the era of CDK4/6 inhibitors, the rise of CDK4/6 inhibitors and the therapeutic prospects in a situation of hormone resistance. Various biological abnormalities have been identified in the mechanisms of hormone resistance such as changes in the estrogen receptor, mutations in the ESR1 gene, aberrant activation of the PI3K pathway or cell cycle deregulations. Historical strategies for circumventing this hormone resistance have been based on hormonal manipulation, on the development of new endocrine therapy such as fulvestrant (selective estrogen receptor inhibitor, SERD), on combinations of treatments such as everolimus, a mTOR inhibitor. This strategy combining endocrine therapy and targeted therapy has led to the development of combinations with CDK4/6 inhibitors which have now become a standard treatment in the hormone resistance phase. The future of this therapeutic era remains to be written with new combinations of hormone therapy and targeted therapy such as PI3K inhibitors or even with the positioning of new SERDs in clinical development.

Physical Activity in Young BRCA Carriers and Reduced Risk of Breast Cancer

INTRODUCTION

A systematic literature review was conducted to determine whether physical activity levels during adolescent and young adult years were associated with a reduced lifetime risk of breast cancer among carriers of deleterious mutations in BRCA1 and BRCA2 genes.

METHODS

Ovid/MEDLINE, Embase, CENTRAL, WOS, and CINAHL were searched for articles including information about adolescent and young adult physical activity and breast cancer incidence among women carrying deleterious BRCA1 and BRCA2 gene mutations (search was initiated in October 2019; last update and full analyses were in March 2021). Independent reviewers screened articles at the title/abstract and full-text levels, resolving differences by consensus with lead authors. The NIH Quality Assessment Tools were used to assess sources of bias.

RESULTS

A total of 1,957 unique articles were identified; 5 met inclusion criteria. Samples size ranged from 68 to 1,185. All studies relied on self-reported adolescent and young adult physical activity. One study measured sports involvement; the others measured recreational activity. One large study was null, whereas 4 others showed a reduction in breast cancer incidence later in life with higher adolescent and young adult physical activity (p≤0.05). However, the protection was limited to premenopausal breast cancer in 1 of the studies (OR=0.62; 95% CI=0.40, 0.96; p-trend=0.01). In addition, adolescent and young adult physical activity was associated with older age at breast cancer diagnosis in 1 study (p=0.03).

CONCLUSIONS

A limited number of studies suggest that adolescent and young adult physical activity may reduce or delay the risk of breast cancer incidence among carriers of deleterious mutations in BRCA1 and BRCA2 genes.

What’s beyond BRCA Mutational Status in High Grade Serous Ovarian Cancer? The Impact of Hormone Receptor Expression in a Large BRCA-Profiled Ovarian Cancer Patient Series: A Retrospective Cohort Study

Simple Summary

Ovarian hormones are involved in ovarian cancer pathogenesis. However, few reports have investigated the hormone receptor pattern according to BRCA mutational status. The aim of this single-center, observational, retrospective study was to explore the relationship between hormone receptor status and BRCA1/2 mutation in a cohort of 207 high-grade serous ovarian carcinoma (HGSOC) patients. Interesting differences emerged between BRCA-mutated and BRCA wild-type women, in terms of pattern of receptor expression and its association to the outcome. On the whole, our findings, though needing further validation, extend our understanding of the complex interplay between BRCA1/2 protein and hormone signaling, suggesting new pathways to be exploited in order to develop future personalized therapy.

Abstract

Several studies have explored the prognostic role of hormone receptor status in high-grade serous ovarian cancer (HGSOC) patients. However, few reports have investigated their expression according to BRCA mutational status. The aim of this single-center, observational, retrospective study was to explore the hormone receptor pattern and its potential prognostic role in a cohort of 207 HGSOC women stratified for BRCA mutational status. To this end, ERα, ERβ1, ERβ2, ERβ5, PR, and AR expression were assessed by immunohistochemistry in 135 BRCA-wild type (BRCA-wt) and 72 BRCA1/2 mutation carriers (BRCA-mut). No significant difference emerged in hormone receptor expression between the two sub-samples, except for a significantly lower ERα expression observed in pre-menopausal BRCA1/2-mut as compared to BRCA-wt patients (p = 0.02). None of the examined hormone receptors has revealed a significant prognostic role in the whole sample, apart from the ratio ERα/ERβ5 nuclear, for which higher values disclosed a positive role on the outcome in BRCA-wt subgroup (HR 0.77; CI 0.61–0.96; p = 0.019). Conversely, it negatively affected overall survival in the presence of BRCA1/2-mut (HR 1.41; CI 1.06–1.87; p = 0.020). Finally, higher PR levels were associated with platinum sensitivity in the whole sample (p = 0.019). Our data, though needing further validation, suggest a potential role of oestrogen-mediated pathways in BRCA1/2-associated HGSOC tumorigenesis, thus revealing a possible therapeutic potential for targeting this interaction.

Antiprogestins reduce epigenetic field cancerization in breast tissue of young healthy women

Background

Breast cancer is a leading cause of death in premenopausal women. Progesterone drives expansion of luminal progenitor cells, leading to the development of poor-prognostic breast cancers. However, it is not known if antagonising progesterone can prevent breast cancers in humans. We suggest that targeting progesterone signalling could be a means of reducing features which are known to promote breast cancer formation.

Methods

In healthy premenopausal women with and without a BRCA mutation we studied (i) estrogen and progesterone levels in saliva over an entire menstrual cycle (n = 20); (ii) cancer-free normal breast-tissue from a control population who had no family or personal history of breast cancer and equivalently from BRCA1/2 mutation carriers (n = 28); triple negative breast cancer (TNBC) biopsies and healthy breast tissue taken from sites surrounding the TNBC in the same individuals (n = 14); and biopsies of ER+ve/PR+ve stage T1–T2 cancers and healthy breast tissue taken from sites surrounding the cancer in the same individuals (n = 31); and (iii) DNA methylation and DNA mutations in normal breast tissue (before and after treatment) from clinical trials that assessed the potential preventative effects of vitamins and antiprogestins (mifepristone and ulipristal acetate; n = 44).

Results

Daily levels of progesterone were higher throughout the menstrual cycle of BRCA1/2 mutation carriers, raising the prospect of targeting progesterone signalling as a means of cancer risk reduction in this population. Furthermore, breast field cancerization DNA methylation signatures reflective of (i) the mitotic age of normal breast epithelium and (ii) the proportion of luminal progenitor cells were increased in breast cancers, indicating that luminal progenitor cells with elevated replicative age are more prone to malignant transformation. The progesterone receptor antagonist mifepristone reduced both the mitotic age and the proportion of luminal progenitor cells in normal breast tissue of all control women and in 64% of BRCA1/2 mutation carriers. These findings were validated by an alternate progesterone receptor antagonist, ulipristal acetate, which yielded similar results. Importantly, mifepristone reduced both the TP53 mutation frequency as well as the number of TP53 mutations in mitotic-age-responders.

Conclusions

These data support the potential usage of antiprogestins for primary prevention of poor-prognostic breast cancers.

Trial registration

Clinical trial 1 Mifepristone treatment prior to insertion of a levonorgestrel releasing intrauterine system for improved bleeding control – a randomized controlled trial, clinicaltrialsregister.eu, 2009-009014-40; registered on 20 July 2009.

Clinical trial 2 The effect of a progesterone receptor modulator on breast tissue in women with BRCA1 and 2 mutations, clinicaltrials.gov, NCT01898312; registered on 07 May 2013.

Clinical trial 3 A pilot prevention study of the effects of the anti- progestin Ulipristal Acetate (UA) on surrogate markers of breast cancer risk, clinicaltrialsregister.eu, 2015-001587-19; registered on 15 July 2015.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13073-022-01063-5.

Beyond the pill: contraception and the prevention of hereditary ovarian cancer

BRCA1 and BRCA2 mutation carriers face an elevated lifetime risk of developing ovarian cancer. Oral contraceptives have been shown to significantly decrease the risk of ovarian cancer by approximately 50% in this high-risk population. Changes in contraceptive formulations and patterns of use over time have introduced lower hormonal dosages, different steroid types and non-oral routes of administration. Specifically, there has been a considerable shift in patterns of contraceptive use and the increase in the uptake of non-oral, long-acting, reversible contraception (e.g., intrauterine devices, implants, injections) has corresponded to a decline in oral contraceptive pill use. Whether or not these other methods confer a protective effect against ovarian cancer in the general population is not clear. To our knowledge, there have been no such studies conducted among BRCA mutation carriers. Furthermore, the impact of these changes on the risk of developing ovarian cancer is not known. In this article, we will review the existing epidemiologic evidence regarding the role of contraceptives and the risk of ovarian cancer with a focus on women with a BRCA1 or BRCA2 mutation. We will discuss recent findings and gaps in the knowledge while extrapolating from studies conducted among women from the noncarrier population.

A human breast atlas integrating single-cell proteomics and transcriptomics

The breast is a dynamic organ whose response to physiological and pathophysiological conditions alters its disease susceptibility, yet the specific effects of these clinical variables on cell state remain poorly annotated. We present a unified, high-resolution breast atlas by integrating single-cell RNA-seq, mass cytometry, and cyclic immunofluorescence, encompassing a myriad of states. We define cell subtypes within the alveolar, hormone-sensing, and basal epithelial lineages, delineating associations of several subtypes with cancer risk factors, including age, parity, and BRCA2 germline mutation. Of particular interest is a subset of alveolar cells termed basal-luminal (BL) cells, which exhibit poor transcriptional lineage fidelity, accumulate with age, and carry a gene signature associated with basal-like breast cancer. We further utilize a medium-depletion approach to identify molecular factors regulating cell-subtype proportion in organoids. Together, these data are a rich resource to elucidate diverse mammary cell states.

Delineating the role of osteoprotegerin as a marker of breast cancer risk among women with a BRCA1 mutation

Women with a pathogenic germline mutation in the BRCA1 gene face a very high lifetime risk of developing breast cancer, estimated at 72% by age 80. Prophylactic bilateral mastectomy is the only effective way to lower their risk; however, most women with a mutation opt for intensive screening with annual MRI and mammography. Given that the BRCA1 gene was identified over 20 years ago, there is a need to identify a novel non-surgical approach to hereditary breast cancer prevention. Here, we provide a review of the emerging preclinical and epidemiologic evidence implicating the dysregulation of progesterone-mediated receptor activator of nuclear factor κB (RANK) signaling in the pathogenesis of BRCA1-associated breast cancer. Experimental studies have demonstrated that RANK inhibition suppresses Brca1-mammary tumorigenesis, suggesting a potential target for prevention. Data from studies conducted among women with a BRCA1 mutation further support this pathway in BRCA1-associated breast cancer development. Progesterone-containing (but not estrogen-alone) hormone replacement therapy is associated with an increased risk of breast cancer in women with a BRCA1 mutation. Furthermore, BRCA1 mutation carriers have significantly lower levels of circulating osteoprotegerin (OPG), the decoy receptor for RANK-ligand (RANKL) and thus endogenous inhibitor of RANK signaling. OPG levels may be associated with the risk of disease, suggesting a role of this protein as a potential biomarker of breast cancer risk. This may improve upon current risk prediction models, stratifying women at the highest risk of developing the disease, and further identify those who may be targets for anti-RANKL chemoprevention. Collectively, the evidence supports therapeutic inhibition of the RANK pathway for the primary prevention of BRCA1-associated breast cancer, which may generate unique prevention strategies (without prophylactic surgery) and enhance quality of life.

A BRCA1 Splice Site Variant Responsible for Familial Ovarian Cancer in a Han-Chinese Family

OBJECTIVE

Ovarian cancer (OC) is one of the most common and most lethal gynecological malignancies. OC has an age-dependent incidence and occurs more commonly in females older than 50 years old. Most OC patients are diagnosed at an advanced stage and have a poor prognosis. Germline mutations in the BRCA1 DNA repair associated gene (BRCA1) and the BRCA2 DNA repair associated gene (BRCA2) account for 20%-25% of epithelial ovarian cancer (EOC). BRCA1 germline mutations are more common in Chinese EOC patients.

METHODS

This study reported a three-generation Han-Chinese family containing four EOC patients and a rectal adenocarcinoma patient. Whole-exome sequencing was performed on two EOC patients and an unaffected individual. Variant validation was also performed in all available members by Sanger sequencing.

RESULTS

A heterozygous splice site variant, c.4358-2A>G in the BRCA1 gene, was identified. Bioinformatic analysis showed that the variant may change the splicing machinery.

CONCLUSION

The BRCA1 splice site variant, c.4358-2A>G was identified as the likely genetic cause for EOC, and may also be associated with the increased risk of rectal adenocarcinoma in the family. The findings were beneficial for genetic counseling, helpful for cancer prevention in other family members, and may facilitate therapy decision-making in the future to reduce cancer lethality.

Susceptibility to hormone-mediated cancer is reflected by different tick rates of the epithelial and general epigenetic clock

Background

A variety of epigenetic clocks utilizing DNA methylation changes have been developed; these clocks are either tissue-independent or designed to predict chronological age based on blood or saliva samples. Whether discordant tick rates between tissue-specific and general epigenetic clocks play a role in health and disease has not yet been explored.

Results

Here we analyze 1941 cervical cytology samples, which contain a mixture of hormone-sensitive cervical epithelial cells and immune cells, and develop the WID general clock (Women’s IDentification of risk), an epigenetic clock that is shared by epithelial and immune cells and optimized for cervical samples. We then develop the WID epithelial clock and WID immune clock, which define epithelial- and immune-specific clocks, respectively. We find that the WID-relative-epithelial-age (WID-REA), defined as the difference between the epithelial and general clocks, is significantly reduced in cervical samples from pre-menopausal women with breast cancer (OR 2.7, 95% CI 1.28-5.72). We find the same effect in normal breast tissue samples from pre-menopausal women at high risk of breast cancer and show that potential risk reducing anti-progesterone drugs can reverse this. In post-menopausal women, this directionality is reversed. Hormone replacement therapy consistently leads to a significantly lower WID-REA in cancer-free women, but not in post-menopausal women with breast or ovarian cancer.

Conclusions

Our findings imply that there are multiple epigenetic clocks, many of which are tissue-specific, and that the differential tick rate between these clocks may be an informative surrogate measure of disease risk.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13059-022-02603-3.

The WID-BC-index identifies women with primary poor prognostic breast cancer based on DNA methylation in cervical samples

Genetic and non-genetic factors contribute to breast cancer development. An epigenome-based signature capturing these components in easily accessible samples could identify women at risk. Here, we analyse the DNA methylome in 2,818 cervical, 357 and 227 matched buccal and blood samples respectively, and 42 breast tissue samples from women with and without breast cancer. Utilising cervical liquid-based cytology samples, we develop the DNA methylation-based Women’s risk IDentification for Breast Cancer index (WID-BC-index) that identifies women with breast cancer with an AUROC (Area Under the Receiver Operator Characteristic) of 0.84 (95% CI: 0.80–0.88) and 0.81 (95% CI: 0.76–0.86) in internal and external validation sets, respectively. CpGs at progesterone receptor binding sites hypomethylated in normal breast tissue of women with breast cancer or in BRCA mutation carriers are also hypomethylated in cervical samples of women with poor prognostic breast cancer. Our data indicate that a systemic epigenetic programming defect is highly prevalent in women who develop breast cancer. Further studies validating the WID-BC-index may enable clinical implementation for monitoring breast cancer risk.

Breast cancer is most commonly diagnosed via a needle biopsy. In this study, the authors show that cervical samples from women with breast cancer have a methylation signature different to that of healthy controls.

BRCA1: An Endocrine and Metabolic Regulator

The breast and ovarian cancer susceptibility gene (BRCA1) is a tumor suppressor whose mutation has been associated with the development of breast, ovarian and, probably, other malignancies at young ages. The BRCA1 gene product participates in multiple biological pathways including the DNA damage response, transcriptional control, cell growth and apoptosis. Inactivating germline mutations of the BRCA1 gene can be detected in a substantial portion of families with inherited breast and/or ovarian cancer. While the genomic and cancer-related actions of BRCA1 have been extensively investigated, not much information exists regarding the cellular and circulating factors involved in regulation of BRCA1 expression and action. The present review article dissects the emerging role of BRCA1 as an important regulator of various endocrine and metabolic axes. Experimental and clinical evidence links BRCA1 with a number of peptide and steroid hormones. Furthermore, comprehensive analyses identified complex interactions between the insulin/insulin-like growth factor-1 (IGF1) signaling axis and BRCA1. The correlation between metabolic disorders, including diabetes and the metabolic syndrome, and BRCA1 mutations, are discussed in this article.

New Generation of Meso and Antiprogestins (SPRMs) into the Osteoporosis Approach

Receptor activator of nuclear factor κB (RANK) and its ligand (RANKL) play key roles in bone metabolism and the immune system. The RANK/RANKL complex has also been shown to be critical in the formation of mammary epithelia cells. The female hormones estradiol and progesterone closely control the action of RANKL with RANK. Blood concentration of these sex hormones in the postmenopausal period leads to an increase in RANK/RANKL signaling and are a major cause of women's osteoporosis, characterized by altered bone mineralization. Knowledge of the biochemical relationships between hormones and RANK/RANKL signaling provides the opportunity to design novel therapeutic agents to inhibit bone loss, based on the anti-RANKL treatment and inhibition of its interaction with the RANK receptor. The new generation of both anti- and mesoprogestins that inhibit the NF-κB-cyclin D1 axis and blocks the binding of RANKL to RANK can be considered as a potential source of new RANK receptor ligands with anti-RANKL function, which may provide a new perspective into osteoporosis treatment itself as well as limit the osteoporosis rise during breast cancer metastasis to the bone.

Physical activity and Mediterranean diet as potential modulators of osteoprotegerin and soluble RANKL in gBRCA1/2 mutation carriers: results of the lifestyle intervention pilot study LIBRE-1

Purpose

Emerging evidence suggests that the progesterone-mediated receptor activator of nuclear factor κB (RANK)/soluble RANK ligand (sRANKL)/osteoprotegerin (OPG) pathway plays an important role in mammary carcinogenesis and is hyperactivated in germline (g)BRCA1/2 mutation carriers. We analyzed the effects of a 3-month intensive lifestyle intervention within the LIBRE-1 study on the serum levels of OPG and sRANKL and hypothesized that the intervention program provides a beneficial impact on the biomarkers by increasing OPG and reducing sRANKL serum concentrations.

Methods

Serum levels of OPG and sRANKL of 49 gBRCA1/2 mutation carriers were quantified using enzyme-linked immunosorbent assays. We used previously collected blood samples from participants of the prospective LIBRE-1 study, who were randomized into an intervention group (IG), increasing physical activity and adherence to the Mediterranean diet (MedD) through supervised sessions from study entry to the first study visit after 3 months and a usual-care control group (CG). Differences in biomarker levels before and after the 3-month intervention were tested within and between study groups.

Results

The lifestyle intervention resulted in a significant increase in OPG for participants in both the IG (q = 0.022) and CG (q = 0.002). sRANKL decreased significantly in the IG (q = 0.0464) and seemed to decrease in the CG (q = 0.5584). An increase in the intake of Omega-3 polyunsaturated fatty acids was significantly associated with an increase in OPG (r = 0.579, q = 0.045). Baseline serum levels of sRANKL were a strong predictor for the change of sRANKL in the course of the intervention (ß-estimate = − 0.70; q = 0.0018). Baseline physical fitness (assessed as VO₂peak) might predict the change of OPG in the course of the intervention program (ß-estimate = 0.133 pg/ml/ml/min/kg; p = 0.0319; q = 0.2871).

Conclusion

Findings from this pilot study seem to confirm our hypothesis by showing an increase in OPG and decrease in sRANKL over a 3-month lifestyle intervention and suggest that increased physical activity and adherence to the MedD are potent modulators of the biomarkers OPG and potentially sRANKL.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06400-7.

Targeting steroid hormone receptors for anti-cancer therapy-A review on small molecules and nanotherapeutic approaches

The steroid hormone receptors (SHRs) among nuclear hormone receptors (NHRs) are steroid ligand-dependent transcription factors that play important roles in the regulation of transcription of genes promoted via hormone responsive elements in our genome. Aberrant expression patterns and context-specific regulation of these receptors in cancer, have been routinely reported by multiple research groups. These gave an window of opportunity to target those receptors in the context of developing novel, targeted anticancer therapeutics. Besides the development of a plethora of SHR-targeting synthetic ligands and the availability of their natural, hormonal ligands, development of many SHR-targeted, anticancer nano-delivery systems and theranostics, especially based on small molecules, have been reported. It is intriguing to realize that these cytoplasmic receptors have become a hot target for cancer selective delivery. This is in spite of the fact that these receptors do not fall in the category of conventional, targetable cell surface bound or transmembrane receptors that enjoy over-expression status. Glucocorticoid receptor (GR) is one such exciting SHR that in spite of it being expressed ubiquitously in all cells, we discovered it to behave differently in cancer cells, thus making it a truly druggable target for treating cancer. This review selectively accumulates the knowledge generated in the field of SHR-targeting as a major focus for cancer treatment with various anticancer small molecules and nanotherapeutics on progesterone receptor, mineralocorticoid receptor, and androgen receptor while selectively emphasizing on GR and estrogen receptor. This review also briefly highlights lipid-modification strategy to convert ligands into SHR-targeted cancer nanotherapeutics. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Biology-Inspired Nanomaterials > Lipid-Based Structures Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Leveraging Antiprogestins in the Treatment of Metastatic Breast Cancer

Although incurable, the prognosis for patients with metastatic breast cancer (MBC) has considerably improved with the approvals of multiple targeted and cytotoxic therapies. For hormone receptor-positive (HR+), ie, estrogen receptor and progesterone receptor positive (ER+/PgR+) and human epidermal growth factor receptor-2 negative (ie, ERBB2 gene nonamplified or HER2-) MBC, current approved treatment options include palliative endocrine therapy (ET), cyclin-dependent kinase (CDK 4/6) inhibitors, mTOR inhibitors, and PI3 kinase inhibitors. Most treatments target ER+ disease regardless of PgR status. Although the presence of PgR is crucial for ER+ cell proliferation in both normal and malignant mammary tissue, currently, there are no approved treatments that specifically target PgR. Recent literature has demonstrated the potential of antiprogestins in the treatment of MBC both in preclinical and clinical studies. Antiprogestins, including selective PgR modulators (SPRMs) that act as PgR antagonists, are a promising class of therapeutics for overcoming endocrine resistance in patients who develop activating estrogen receptor 1 (ESR1) and phosphatidylinositol 3-kinase (PI3K) gene mutations after prior endocrine therapy. Herein, we summarize the role of PgR and antiprogestins in the treatment of MBC. Other aspects on the use of functional imaging, clinical trials incorporating novel antiprogestins, and potential treatment combinations to overcome endocrine resistance will be briefly discussed.

Plasma Metabolome Signature Indicative of BRCA1 Germline Status Independent of Cancer Incidence

Individuals carrying a pathogenic germline variant in the breast cancer predisposition gene BRCA1 (gBRCA1+) are prone to developing breast cancer. Apart from its well-known role in DNA repair, BRCA1 has been shown to powerfully impact cellular metabolism. While, in general, metabolic reprogramming was named a hallmark of cancer, disrupted metabolism has also been suggested to drive cancer cell evolution and malignant transformation by critically altering microenvironmental tissue integrity. Systemic metabolic effects induced by germline variants in cancer predisposition genes have been demonstrated before. Whether or not systemic metabolic alterations exist in gBRCA1+ individuals independent of cancer incidence has not been investigated yet. We therefore profiled the plasma metabolome of 72 gBRCA1+ women and 72 age-matched female controls, none of whom (carriers and non-carriers) had a prior cancer diagnosis and all of whom were cancer-free during the follow-up period. We detected one single metabolite, pyruvate, and two metabolite ratios involving pyruvate, lactate, and a metabolite of yet unknown structure, significantly altered between the two cohorts. A machine learning signature of metabolite ratios was able to correctly distinguish between gBRCA1+ and controls in ~82%. The results of this study point to innate systemic metabolic differences in gBRCA1+ women independent of cancer incidence and raise the question as to whether or not constitutional alterations in energy metabolism may be involved in the etiology of BRCA1-associated breast cancer.

Progesterone Receptor Signaling in the Breast Tumor Microenvironment

The tumor microenvironment (TME) is a complex infrastructure composed of stromal, epithelial, and immune cells embedded in a vasculature ECM. The microenvironment surrounding mammary epithelium plays a critical role during the development and differentiation of the mammary gland, enabling the coordination of the complex multihormones and growth factor signaling processes. Progesterone/progesterone receptor paracrine signaling interactions in the microenvironment play vital roles in stem/progenitor cell function during normal breast development. In breast cancer, the female sex hormones, estrogen and progesterone, and growth factor signals are altered in the TME. Progesterone signaling modulates not only breast tumors but also the breast TME, leading to the activation of a series of cross-communications that are implicated in the genesis of breast cancers. This chapter reviews the evidence that progesterone and PR signaling modulates not only breast epitheliums but also the breast TME. Furthermore, crosstalk between estrogen and progesterone signaling affecting different cell types within the TME is discussed. A better understanding of how PR and progesterone affect the TME of breast cancer may lead to novel drugs or a therapeutic approach for the treatment of breast cancer shortly.

Breast Cancer Risk with Progestin Subdermal Implants: A Challenge in Patients Counseling

There is a steady global rise in the use of progestin subdermal implants, where use has increased by more than 20 times in the past two decades. BC risk has been reported with the older progestin only methods such as oral pills, injectables, and intrauterine devices, however, little is known about the risk with subdermal implants. In this review, we aim to update clinicians and researchers on the current evidence to support patient counseling and to inform future research directions. The available evidence of the association between the use of progestin subdermal implants and BC risk is discussed. We provide an overview of the potential role of endogenous progesterone in BC development. The chemical structure and molecular targets of synthetic progestins of relevance are summarized together with the preclinical and clinical evidence on their association with BC risk. We review all studies that investigated the action of the specific progestins included in subdermal implants. As well, we discuss the potential effect of the use of subdermal implants in women at increased BC risk, including carriers of BC susceptibility genetic mutations.

Targeting progesterone signaling prevents metastatic ovarian cancer

Effective cancer prevention requires the discovery and intervention of a factor critical to cancer development. Here we show that ovarian progesterone is a crucial endogenous factor inducing the development of primary tumors progressing to metastatic ovarian cancer in a mouse model of high-grade serous carcinoma (HGSC), the most common and deadliest ovarian cancer type. Blocking progesterone signaling by the pharmacologic inhibitor mifepristone or by genetic deletion of the progesterone receptor (PR) effectively suppressed HGSC development and its peritoneal metastases. Strikingly, mifepristone treatment profoundly improved mouse survival (∼18 human years). Hence, targeting progesterone/PR signaling could offer an effective chemopreventive strategy, particularly in high-risk populations of women carrying a deleterious mutation in the BRCA gene.

DNA methylation signatures to predict the cervicovaginal microbiome status

Background

The composition of the microbiome plays an important role in human health and disease. Whether there is a direct association between the cervicovaginal microbiome and the host’s epigenome is largely unexplored.

Results

Here we analyzed a total of 448 cervicovaginal smear samples and studied both the DNA methylome of the host and the microbiome using the Illumina EPIC array and next-generation sequencing, respectively. We found that those CpGs that are hypo-methylated in samples with non-lactobacilli (O-type) dominating communities are strongly associated with gastrointestinal differentiation and that a signature consisting of 819 CpGs was able to discriminate lactobacilli-dominating (L-type) from O-type samples with an area under the receiver operator characteristic curve (AUC) of 0.84 (95% CI = 0.77–0.90) in an independent validation set. The performance found in samples with more than 50% epithelial cells was further improved (AUC 0.87) and in women younger than 50 years of age was even higher (AUC 0.91). In a subset of 96 women, the buccal but not the blood cell DNA showed the same trend as the cervicovaginal samples in discriminating women with L- from O-type cervicovaginal communities.

Conclusions

These findings strongly support the view that the epithelial epigenome plays an essential role in hosting specific microbial communities.

Repurposing denosumab in breast cancer beyond prevention of skeletal related events: Could nonclinical data be translated into clinical practice?

INTRODUCTION

Denosumab is a human monoclonal antibody inhibiting the receptor activator of nuclear factor kappa-B ligand (RANKL). Initially approved as antiosteοporotic agent, denosumab is being currently pursued as a candidate for drug repurposing in oncology, especially breast cancer.

AREAS COVERED

The present review provides an overview of the therapeutic potential of denosumab in breast cancer beyond prevention of skeletal-related events (SREs), with focus on prevention of carcinogenesis in BRCA mutation carriers and on adjuvant treatment in early breast cancer patients. Study search was conducted on the following electronic databases: PubMed, Google scholar, Scopus.com, ClinicalTrials.gov, and European Union Clinical Trials Register from 2008 until June 2020.

EXPERT OPINION

Nonclinical data have established links between RANKL signaling and breast cancer initiation and progression, rationalizing exploring the potential bone-independent anticancer role of denosumab beyond SREs prevention. Preclinical and preliminary clinical data show that denosumab may inhibit carcinogenesis in BRCA mutation carriers. Denosumab adjuvant in early breast cancer has been shown, though inconsistently, to provide a disease-free survival benefit for a subgroup of patients. Despite promising results, the incorporation of denosumab in preventive and therapeutic protocols of breast cancer beyond prevention of SREs cannot be endorsed until further research consolidates its efficacy.

Personalized early detection and prevention of breast cancer: ENVISION consensus statement

The European Collaborative on Personalized Early Detection and Prevention of Breast Cancer (ENVISION) brings together several international research consortia working on different aspects of the personalized early detection and prevention of breast cancer. In a consensus conference held in 2019, the members of this network identified research areas requiring development to enable evidence-based personalized interventions that might improve the benefits and reduce the harms of existing breast cancer screening and prevention programmes. The priority areas identified were: 1) breast cancer subtype-specific risk assessment tools applicable to women of all ancestries; 2) intermediate surrogate markers of response to preventive measures; 3) novel non-surgical preventive measures to reduce the incidence of breast cancer of poor prognosis; and 4) hybrid effectiveness-implementation research combined with modelling studies to evaluate the long-term population outcomes of risk-based early detection strategies. The implementation of such programmes would require health-care systems to be open to learning and adapting, the engagement of a diverse range of stakeholders and tailoring to societal norms and values, while also addressing the ethical and legal issues. In this Consensus Statement, we discuss the current state of breast cancer risk prediction, risk-stratified prevention and early detection strategies, and their implementation. Throughout, we highlight priorities for advancing each of these areas.

Targeting the RANKL/RANK/OPG Axis for Cancer Therapy

RANKL and RANK are expressed in different cell types and tissues throughout the body. They were originally described for their essential roles in bone remodeling and the immune system but have subsequently been shown to provide essential signals from regulating mammary gland homeostasis during pregnancy to modulating tumorigenesis. The success of RANKL/RANK research serves as a paragon for translational research from the laboratory to the bedside. The case in point has been the development of Denosumab, a RANKL-blocking monoclonal antibody which has already helped millions of patients suffering from post-menopausal osteoporosis and skeletal related events in cancer. Here we will provide an overview of the pathway from its origins to its clinical relevance in disease, with a special focus on emerging evidence demonstrating the therapeutic value of targeting the RANKL/RANK/OPG axis not only in breast cancer but also as an addition to the cancer immunotherapy arsenal.

Progesterone and Breast Cancer

Synthetic progestogens (progestins) have been linked to increased breast cancer risk; however, the role of endogenous progesterone in breast physiology and carcinogenesis is less clearly defined. Mechanistic studies using cell culture, tissue culture, and preclinical models implicate progesterone in breast carcinogenesis. In contrast, limited epidemiologic data generally do not show an association of circulating progesterone levels with risk, and it is unclear whether this reflects methodologic limitations or a truly null relationship. Challenges related to defining the role of progesterone in breast physiology and neoplasia include: complex interactions with estrogens and other hormones (eg, androgens, prolactin, etc.), accounting for timing of blood collections for hormone measurements among cycling women, and limitations of assays to measure progesterone metabolites in blood and progesterone receptor isotypes (PRs) in tissues. Separating the individual effects of estrogens and progesterone is further complicated by the partial dependence of PR transcription on estrogen receptor (ER)α-mediated transcriptional events; indeed, interpreting the integrated interaction of the hormones may be more essential than isolating independent effects. Further, many of the actions of both estrogens and progesterone, particularly in "normal" breast tissues, are driven by paracrine mechanisms in which ligand binding to receptor-positive cells evokes secretion of factors that influence cell division of neighboring receptor-negative cells. Accordingly, blood and tissue levels may differ, and the latter are challenging to measure. Given conflicting data related to the potential role of progesterone in breast cancer etiology and interest in blocking progesterone action to prevent or treat breast cancer, we provide a review of the evidence that links progesterone to breast cancer risk and suggest future directions for filling current gaps in our knowledge.

Non-Surgical Cancer Risk Reduction in BRCA1 Mutation Carriers: Disabling the Remote Control

Women-specific cancers are a major health issue, particularly those associated with the BRCA1 germline mutation carrier state, which include triple-negative basal breast carcinomas and high-grade serous ovarian carcinomas (referred to as extra-uterine Müllerian carcinomas). Whereas many chronic diseases can currently be prevented (e.g., cardiovascular diseases), no recent tangible progress was made in cancer prevention of BRCA1 mutation carriers apart from surgical resections of at-risk organs. This lack of progress is largely due to (1) poor understanding of the initiating events triggered by known risk factors in the development of these cancers, (2) the fact that current preventive measures rely on evidence obtained from adjuvant breast cancer treatment that fail to protect against poor prognostic cancers, and (3) problems with using cancer incidence in high-risk women as an ethically justifiable endpoint in cancer prevention trials. Here, we propose that cancer predisposition in BRCA1 mutation carriers is driven, at least in part, by cell-nonautonomous mechanisms (i.e., driven by consequences of this carrier state on hormonal and other systemic factors controlled in organs other than those that are cancer-prone) and that biomarkers of epigenomic reprogramming, hypothesized to be a direct consequence of such cell-nonautonomous mechanisms, are attractive as intermediate surrogate endpoints to assess the efficacy of cancer risk-reducing strategies targeting these mechanisms.

BRCA1 Attenuates Progesterone Effects on Proliferation and NFκB Activation in Normal Human Mammary Epithelial Cells

Germline mutations in the breast cancer susceptibility gene BRCA1, encoding a tumor suppressor protein, greatly enhance the risk of breast and ovarian cancer. This tissue-specificity implicates the role of ovarian hormones. Indeed, BRCA1 has been demonstrated to regulate the signalling axis of the hormone, progesterone, and its receptor, the progesterone receptor (PR), and progesterone action has been implicated in BRCA1-related tumorigenesis. BRCA1 also plays important roles in oxidative stress and activating nuclear factor kappaB (NFκB) signalling pathways. Like wildtype BRCA1 function, PR signalling has also been shown to inhibit NFκB activation. Although PR and BRCA1 networks are known to interact, their interaction at the level of NFκB activation in the human breast is not understood. This study investigates the effect of reduced BRCA1 expression on proliferation and NFκB activation in human breast cells, and the impact of progesterone on these effects. The major findings are that: 1) Reduced BRCA1 levels inhibit cell growth in normal human mammary cells and breast cancer cells; 2) Reduced BRCA1 levels stimulated inflammatory targets and NFκB activity in normal human mammary cells; 3) Wildtype BRCA1 inhibited the pro-proliferative effects of progesterone in normal mammary epithelial cells, and; 4) Progesterone attenuated BRCA1-mediated NFκB activation in normal human mammary cells. These data have important implications for our understanding of progesterone action in BRCA1 mutation carriers, and how inhibition of this action may potentially delay tumorigenesis or impart a more favourable prognosis.

Mammary stem cells and progenitors: targeting the roots of breast cancer for prevention

Breast cancer prevention is daunting, yet not an unsurmountable goal. Mammary stem and progenitors have been proposed as the cells-of-origin in breast cancer. Here, we present the concept of limiting these breast cancer precursors as a risk reduction approach in high-risk women. A wealth of information now exists for phenotypic and functional characterization of mammary stem and progenitor cells in mouse and human. Recent work has also revealed the hormonal regulation of stem/progenitor dynamics as well as intrinsic lineage distinctions between mammary epithelial populations. Leveraging these insights, molecular marker-guided chemoprevention is an achievable reality.

Mendelian randomisation study of height and body mass index as modifiers of ovarian cancer risk in 22,588 BRCA1 and BRCA2 mutation carriers

BACKGROUND

Height and body mass index (BMI) are associated with higher ovarian cancer risk in the general population, but whether such associations exist among BRCA1/2 mutation carriers is unknown.

METHODS

We applied a Mendelian randomisation approach to examine height/BMI with ovarian cancer risk using the Consortium of Investigators for the Modifiers of BRCA1/2 (CIMBA) data set, comprising 14,676 BRCA1 and 7912 BRCA2 mutation carriers, with 2923 ovarian cancer cases. We created a height genetic score (height-GS) using 586 height-associated variants and a BMI genetic score (BMI-GS) using 93 BMI-associated variants. Associations were assessed using weighted Cox models.

RESULTS

Observed height was not associated with ovarian cancer risk (hazard ratio [HR]: 1.07 per 10-cm increase in height, 95% confidence interval [CI]: 0.94-1.23). Height-GS showed similar results (HR = 1.02, 95% CI: 0.85-1.23). Higher BMI was significantly associated with increased risk in premenopausal women with HR = 1.25 (95% CI: 1.06-1.48) and HR = 1.59 (95% CI: 1.08-2.33) per 5-kg/m2 increase in observed and genetically determined BMI, respectively. No association was found for postmenopausal women. Interaction between menopausal status and BMI was significant (Pinteraction < 0.05).

CONCLUSION

Our observation of a positive association between BMI and ovarian cancer risk in premenopausal BRCA1/2 mutation carriers is consistent with findings in the general population.

BRCA Genes: The Role in Genome Stability, Cancer Stemness and Therapy Resistance

Carcinogenesis is a multistep process, and tumors frequently harbor multiple mutations regulating genome integrity, cell division and death. The integrity of cellular genome is closely controlled by the mechanisms of DNA damage signaling and DNA repair. The association of breast cancer susceptibility genes BRCA1 and BRCA2 with breast and ovarian cancer development was first demonstrated over 20 years ago. Since then the germline mutations within these genes were linked to genomic instability and increased risk of many other cancer types. Genomic instability is an engine of the oncogenic transformation of non-tumorigenic cells into tumor-initiating cells and further tumor evolution. In this review we discuss the biological functions of BRCA1 and BRCA2 genes and the role of BRCA mutations in tumor initiation, regulation of cancer stemness, therapy resistance and tumor progression.

Plasma RANKL levels are not associated with breast cancer risk in BRCA1 and BRCA2 mutation carriers

Background

Aberrant progesterone/receptor activator of nuclear factor κβ (RANK) signaling has been implicated in BRCA1 breast cancer development. Furthermore, lower circulating RANKL has been reported among women with a BRCA mutation compared to non-carriers; however, there have been no reports of plasma RANKL levels and subsequent breast cancer risk. We prospectively evaluated the relationship between plasma RANKL and breast cancer risk among women with a BRCA1 or BRCA2 mutation.

Methods

An enzyme-linked immunosorbent assay was used to quantify plasma RANKL levels in 184 BRCA mutation carriers. Women were stratified into high vs. low RANKL based on the median levels of the cohort (5.24 pg/ml). Kaplan-Meier survival analysis was used to estimate the cumulative incidence of breast cancer by baseline plasma RANKL and cox proportional hazards models were used to estimate the adjusted hazard ratios (HRs) and 95% confidence intervals (CI) for the association between plasma RANKL and risk.

Results

Over a mean follow-up of 6.3 years (0.02-19.24), 15 incident breast cancers were identified. The eight-year cumulative incidence was 10% in the low RANKL group and 12% in the high RANKL group (P-log-rank = 0.85). There was no significant association between plasma RANKL levels and breast cancer risk (multivariate HR high vs. low = 1.06; 95%CI 0.34-3.28; P-trend = 0.86).

Conclusions

These findings suggest that circulating RANKL levels are not associated with breast cancer among BRCA mutation carriers. Pending validation in a larger sample, these findings suggest that RANKL is likely not a biomarker of breast cancer risk among BRCA mutation carriers.

Amount of fibroglandular tissue FGT and background parenchymal enhancement BPE in relation to breast cancer risk and false positives in a breast MRI screening program : A retrospective cohort study

Objectives

The purpose of this study is to evaluate the predictive value of the amount of fibroglandular tissue (FGT) and background parenchymal enhancement (BPE), measured at baseline on breast MRI, for breast cancer development and risk of false-positive findings in women at increased risk for breast cancer.

Methods

Negative baseline MRI scans of 1533 women participating in a screening program for women at increased risk for breast cancer between January 1, 2003, and January 1, 2014, were selected. Automated tools based on deep learning were used to obtain quantitative measures of FGT and BPE. Logistic regression using forward selection was used to assess relationships between FGT, BPE, cancer detection, false-positive recall, and false-positive biopsy.

Results

Sixty cancers were detected in follow-up. FGT was only associated to short-term cancer risk; BPE was not associated with cancer risk. High FGT and BPE did lead to more false-positive recalls at baseline (OR 1.259, p = 0.050, and OR 1.475, p = 0.003) and to more frequent false-positive biopsies at baseline (OR 1.315, p = 0.049, and OR 1.807, p = 0.002), but were not predictive for false-positive findings in subsequent screening rounds.

Conclusions

FGT and BPE, measured on baseline MRI, are not predictive for overall breast cancer development in women at increased risk. High FGT and BPE lead to more false-positive findings at baseline.

Key Points

• Amount of fibroglandular tissue is only predictive for short-term breast cancer risk in women at increased risk.

• Background parenchymal enhancement measured on baseline MRI is not predictive for breast cancer development in women at increased risk.

• High amount of fibroglandular tissue and background parenchymal enhancement lead to more false-positive findings at baseline MRI.

Electronic supplementary material

The online version of this article (10.1007/s00330-019-06020-2) contains supplementary material, which is available to authorized users.

Women's cancers: how the discovery of BRCA genes is driving current concepts of cancer biology and therapeutics

Over the last two decades, discoveries related to the breast cancer susceptibility genes 1 and 2 (BRCA1 and BRCA2) have profoundly changed our understanding and management of hereditary breast and ovarian cancers. The concept of synthetic lethality, which arises when cells become vulnerable to a combination of deficiencies in DNA repair, has driven the expanding roles of poly (adenosine diphosphate (ADP)-ribose) polymerase inhibitors in breast and ovarian cancers, and prevention strategies are taking into account the tissue specificity, natural history (fallopian tube origin of some high-grade serous ovarian cancers) and hormone sensitivity of BRCA-associated cancers. Current research has focussed on further elucidating the roles of BRCA proteins in DNA repair, investigating other key DNA repair processes and proteins and linking aberrant DNA repair with carcinogenesis. The ultimate goal is to translate this evolving knowledge into improving the clinical care and treatment of patients with pathogenic BRCA variants or other deficiencies in homologous recombination (HR). In this review, we will discuss 1) the role of BRCA proteins in DNA repair; 2) emerging concepts in the biology of HR deficiency and 3) implications for prevention and treatment.

BRCA1 and Breast Cancer: a Review of the Underlying Mechanisms Resulting in the Tissue-Specific Tumorigenesis in Mutation Carriers

Since the first cloning of BRCA1 in 1994, many of its cellular interactions have been elucidated. However, its highly specific role in tumorigenesis in the breast tissue—carriers of BRCA1 mutations are predisposed to life-time risks of up to 80%—relative to many other tissues that remain unaffected, has not yet been fully enlightened. In this article, we have applied a universal model of tissue-specificity of cancer genes to BRCA1 and present a systematic review of proposed concepts classified into 4 categories. Firstly, tissue-specific differences in levels of BRCA1 expression and secondly differences in expression of proteins with redundant functions are outlined. Thirdly, cell-type specific interactions of BRCA1 are presented: its regulation of aromatase, its interaction with Progesterone- and receptor activator of nuclear factor-κB ligand-signaling that controls proliferation of luminal progenitor cells, and its influence on cell differentiation via modulation of the key regulators jagged 1-NOTCH and snail family transcriptional repressor 2. Fourthly, factors specific to the cell-type as well as the environment of the breast tissue are elucidated: distinct frequency of losses of heterozygosity, interaction with X inactivation specific transcript RNA, estrogen-dependent induction of genotoxic metabolites and nuclear factor (erythroid-derived 2)-like 2, and regulation of sirtuin 1. In conclusion, the impact of these concepts on the formation of hormone-sensitive and -insensitive breast tumors is outlined.

RANKL/RANK/OPG system beyond bone remodeling: involvement in breast cancer and clinical perspectives

RANKL/RANK/OPG system consists of three essential signaling molecules: i) the receptor activator of nuclear factor (NF)-kB-ligand (RANKL), ii) the receptor activator of NF-kB (RANK), and iii) the soluble decoy receptor osteoprotegerin (OPG). Although this system is critical for the regulation of osteoclast differentiation/activation and calcium release from the skeleton, different studies have elucidated its specific role in mammary gland physiology and hormone-driven epithelial proliferation during pregnancy. Of note, several data suggest that progesterone induces mammary RANKL expression in mice and humans. In turn, RANKL controls cell proliferation in breast epithelium under physiological conditions typically associated with higher serum progesterone levels, such as luteal phase of the menstrual cycle and pregnancy. Hence, RANKL/RANK system can be regarded as a major downstream mediator of progesterone-driven mammary epithelial cells proliferation, potentially contributing to breast cancer initiation and progression. Expression of RANKL, RANK, and OPG has been detected in breast cancer cell lines and in human primary breast cancers. To date, dysregulation of RANKL/RANK/OPG system at the skeletal level has been widely documented in the context of metastatic bone disease. In fact, RANKL inhibition through the RANKL-blocking human monoclonal antibody denosumab represents a well-established therapeutic option to prevent skeletal-related events in metastatic bone disease and adjuvant therapy-induced bone loss in breast cancer. On the other hand, the exact role of OPG in breast tumorigenesis is still unclear. This review focuses on molecular mechanisms linking RANKL/RANK/OPG system to mammary tumorigenesis, highlighting pre-clinical and clinical evidence for the potential efficacy of RANKL inhibition as a prevention strategy and adjuvant therapy in breast cancer settings.

BRCA Mutations and Breast Cancer Prevention

Women who inherit a deleterious BRCA1 or BRCA2 mutation face substantially increased risks of developing breast cancer, which is estimated at 70%. Although annual screening with magnetic resonance imaging (MRI) and mammography promotes the earlier detection of the disease, the gold standard for the primary prevention of breast cancer remains bilateral mastectomy. In the current paper, I review the evidence regarding the management of healthy BRCA mutation carriers, including key risk factors and protective factors, and also discuss potential chemoprevention options. I also provide an overview of the key findings from the literature published to date, with a focus on data from studies that are well-powered, and preferably prospective in nature.

Associations of Dietary Patterns and Metabolic-Hormone Profiles with Breast Cancer Risk: A Case-Control Study

Breast cancer is the most diagnosed cancer in women worldwide. Studies regarding complex breast cancer aetiology are limited and the results are inconclusive. We investigated the associations between dietary patterns (DPs), metabolic-hormone profiles (M-HPs), and breast cancer risk. This case-control study involved 420 women aged 40⁻79 years from north-eastern Poland, including 190 newly-diagnosed breast cancer cases. The serum concentration of lipid components, glucose, and hormones (oestradiol, progesterone, testosterone, prolactin, cortisol, insulin) was marked in 129 post-menopausal women (82 controls, 47 cases). The food frequency consumption was collected using a validated 62-item food frequency questionnaire. A posteriori DPs or M-HPs were derived with a Principal Component Analysis (PCA). Three DPs: 'Non-Healthy', 'Prudent', and 'Margarine and Sweetened Dairy' and two M-HPs: 'Metabolic-Syndrome' and 'High-Hormone' were identified. The 'Polish-adapted Mediterranean Diet' ('Polish-aMED') score was calculated. The risk of breast cancer risk was three-times higher (odds ratio (OR): 2.90; 95% confidence interval (95% Cl): 1.62⁻5.21; p < 0.001) in the upper tertile of the 'Non-Healthy' pattern (reference: bottom tertile) and five-times higher (OR: 5.34; 95% Cl: 1.84⁻15.48; p < 0.01) in the upper tertile of the 'High-Hormone' profile (reference: bottom tertile). There was a positive association of 'Metabolic-Syndrome' profile and an inverse association of 'Polish-aMED' score with the risk of breast cancer, which disappeared after adjustment for confounders. No significant association between 'Prudent' or 'Margarine and Sweetened Dairy' DPs and cancer risk was revealed. Concluding, a pro-healthy diet is insufficient to reduce the risk of breast cancer in peri- and postmenopausal women. The findings highlight the harmful effect of the 'High-Hormone' profile and the 'Non-Healthy' dietary pattern on breast cancer risk. In breast cancer prevention, special attention should be paid to decreasing the adherence to the 'Non-Healthy' pattern by reducing the consumption of highly processed food and foods with a high content of sugar and animal fat. There is also a need to monitor the concentration of multiple sex hormones in the context of breast cancer risk.