Inadequate DNA Damage Repair Promotes Mammary Transdifferentiation, Leading to BRCA1 Breast Cancer.

Loss of BRCA1 p220 function often results in basal-like breast cancer (BLBC), but the underlying disease mechanism is largely opaque. In mammary epithelial cells (MECs), BRCA1 interacts with multiple proteins, including NUMB and HES1, to form complexes that participate in interstrand crosslink (ICL) DNA repair and MEC differentiation control. Unrepaired ICL damage results in aberrant transdifferentiation to a mesenchymal state of cultured, human basal-like MECs and to a basal/mesenchymal state in primary mouse luminal MECs. Loss of BRCA1, NUMB, or HES1 or chemically induced ICL damage in primary murine luminal MECs results in persistent DNA damage that triggers luminal to basal/mesenchymal transdifferentiation. In vivo single-cell analysis revealed a time-dependent evolution from normal luminal MECs to luminal progenitor-like tumor cells with basal/mesenchymal transdifferentiation during murine BRCA1 BLBC development. Growing DNA damage accompanied this malignant transformation.

Exposure to per- and polyfluoroalkyl substances and breast cancer risk: a systematic review and meta-analysis of epidemiologic studies.

We synthesized the epidemiologic evidence on the associations between per- and polyfluoroalkyl substances (PFAS) exposure and breast cancer risk. Our systematic review and meta-analysis included 18 and 11 articles, respectively, covering studies up to February 2023. The summary relative risks (RRs) estimated by random-effects meta-analyses did not support an association between PFAS and overall breast cancer risk (eg, a natural log (ln)-unit increase in serum/plasma concentrations [ng/mL] for perfluorooctanoate [PFOA] RR = 0.95; 95% CI, 0.77-1.18; perfluorooctane sulfonate [PFOS] RR = 0.98; 95% CI, 0.87-1.11). However, when limiting to studies that assessed exposures prior to a breast cancer diagnosis, we observed a positive association with PFOA (a ln-unit increase, RR = 1.16; 95% CI, 0.96-1.40). We also observed some possible heterogeneous associations by tumor estrogen and progesterone receptor status among postmenopausal breast cancer cases. No meaningful changes were observed after excluding the studies with high risk of bias (Tier 3). Based on the evaluation tool developed by the National Toxicology Program, given the heterogeneity across studies and the variability in timing of exposure measurements, the epidemiologic evidence needed to determine the association between PFAS exposure and breast cancer remains inadequate. Our findings support the need for future studies with improved study designs to determine this association.

Germline predictors for bevacizumab induced hypertensive crisis in ECOG-ACRIN 5103 and BEATRICE.

BACKGROUND: Bevacizumab is a beneficial therapy in several advanced cancer types. Predictive biomarkers to better understand which patients are destined to benefit or experience toxicity are needed. Associations between bevacizumab induced hypertension and survival have been reported but with conflicting conclusions. METHODS: We performed post-hoc analyses to evaluate the association in 3124 patients from two phase III adjuvant breast cancer trials, E5103 and BEATRICE. Differences in invasive disease-free survival (IDFS) and overall survival (OS) between patients with hypertension and those without were compared. Hypertension was defined as systolic blood pressure (SBP) ≥ 160 mmHg (n = 346) and SBP ≥ 180 mmHg (hypertensive crisis) (n = 69). Genomic analyses were performed to evaluate germline genetic predictors for the hypertensive crisis. RESULTS: Hypertensive crisis was significantly associated with superior IDFS (p = 0.015) and OS (p = 0.042), but only IDFS (p = 0.029; HR = 0.28) remained significant after correction for prognostic factors. SBP ≥ 160 mmHg was not associated with either IDFS or OS. A common single-nucleotide polymorphism, rs6486785, was significantly associated with hypertensive crisis (p = 8.4 × 10-9; OR = 5.2). CONCLUSION: Bevacizumab-induced hypertensive crisis is associated with superior outcomes and rs6486785 predicted an increased risk of this key toxicity.

Menopausal hormone therapy and breast cancer risk: a population-based cohort study of 1.3 million women in Norway.

BACKGROUND: It is important to monitor the association between menopausal hormone therapy (HT) use and breast cancer (BC) risk with contemporary estimates, and specifically focus on HT types and new drugs. METHODS: We estimated hazard ratios (HR) of BC risk according to HT type, administration route and individual drugs, overall and stratified by body mass index (BMI), molecular subtype and detection mode, with non-HT use as reference. RESULTS: We included 1,275,783 women, 45+ years, followed from 2004, for a median of 12.7 years. Oral oestrogen combined with daily progestin was associated with the highest risk of BC (HR 2.42, 95% confidence interval (CI) 2.31-2.54), with drug-specific HRs ranging from Cliovelle®: 1.63 (95% CI 1.35-1.96) to Kliogest®: 2.67 (2.37-3.00). Vaginal oestradiol was not associated with BC risk. HT use was more strongly associated with luminal A cancer (HR 1.97, 95% CI 1.86-2.09) than other molecular subtypes, and more strongly with interval (HR 2.00, 95% CI: 1.83-2.30) than screen-detected (HR 1.33, 95% CI 1.26-1.41) BC in women 50-71 years. HRs for HT use decreased with increasing BMI. CONCLUSIONS: The use of oral and transdermal HT was associated with an increased risk of BC. The associations varied according to HT type, individual drugs, molecular subtype, detection mode and BMI.

A polygenic-score-based approach for identification of gene-drug interactions stratifying breast cancer risk.

An individual's genetics can dramatically influence breast cancer (BC) risk. Although clinical measures for prevention do exist, non-invasive personalized measures for reducing BC risk are limited. Commonly used medications are a promising set of modifiable factors, but no previous study has explored whether a range of widely taken approved drugs modulate BC genetics. In this study, we describe a quantitative framework for exploring the interaction between the genetic susceptibility of BC and medication usage among UK Biobank women. We computed BC polygenic scores (PGSs) that summarize BC genetic risk and find that the PGS explains nearly three-times greater variation in disease risk within corticosteroid users compared to non-users. We map 35 genes significantly interacting with corticosteroid use (FDR < 0.1), highlighting the transcription factor NRF2 as a common regulator of gene-corticosteroid interactions in BC. Finally, we discover a regulatory variant strongly stratifying BC risk according to corticosteroid use. Within risk allele carriers, 18.2% of women taking corticosteroids developed BC, compared to 5.1% of the non-users (with an HR = 3.41 per-allele within corticosteroid users). In comparison, there are no differences in BC risk within the reference allele homozygotes. Overall, this work highlights the clinical relevance of gene-drug interactions in disease risk and provides a roadmap for repurposing biobanks in drug repositioning and precision medicine.

Polypharmacy, over-the-counter medications, and aromatase inhibitor adherence in early-stage breast cancer.

PURPOSE: Polypharmacy is associated with negative health outcomes and decreased medication adherence. Polypharmacy is common in cancer populations, but few studies have evaluated the relationship between polypharmacy and aromatase inhibitor (AI) adherence. No studies have evaluated the relationship between over-the-counter (OTC) supplements and AI adherence. Our primary hypothesis was that polypharmacy would be associated with increased risk of premature AI discontinuation. METHODS: This exploratory analysis used data from the Exemestane and Letrozole Pharmacogenetics (ELPh) trial, a prospective, multicenter, randomized controlled trial that enrolled participants from 2005 to 2009. Included patients were female, postmenopausal, with stage 0-III breast cancer, who had completed indicated chemotherapy, surgery, and radiation. Participants were randomized to adjuvant exemestane or letrozole and completed serial clinical examinations and questionnaires for two years. Concomitant medication data were collected prospectively. Cox proportion models were used for statistical analysis of the relationship between polypharmacy, OTCs, medication class, and AI adherence. RESULTS: In the 490 analyzed participants, use of any prescription medications at baseline was associated with decreased risk of premature AI discontinuation (HR 0.56, p = 0.02). Use of selective serotonin reuptake inhibitors (SSRIs) or selective serotonin and norepinephrine reuptake inhibitors (SNRIs) at baseline was associated with decreased risk of premature AI discontinuation (HR 0.67, p = 0.04). Use of any OTCs was not associated with AI discontinuation. CONCLUSION: Baseline use of prescription medications but not OTCs was associated with increased AI persistence. Future research is needed to understand how this can be utilized to promote AI adherence.

Benzo[a]pyrene promotes an epithelial-to-mesenchymal transition process in MCF10A cells and mammary tumor growth and brain metastasis in female mice.

Breast cancer is the most frequent neoplasia in developed countries and the leading cause of death in women worldwide. Epithelial-to-mesenchymal transition (EMT) is a cellular process through which epithelial cells decrease or lose their epithelial characteristics and gain mesenchymal properties. EMT mediates tumor progression, because tumor cells acquire the capacity to execute the multiple steps of invasion and metastasis. Benzo[a]pyrene (B[a]P) is an environmental organic pollutant generated during the burning of fossil fuels, wood, and other organic materials. B[a]P exposition increases the incidence of breast cancer, and induces migration and/or invasion in MDA-MB-231 and MCF-7 breast cancer cells. However, the role of B[a]P in the induction of an EMT process and metastasis of mammary carcinoma cells has not been studied in detail. In this study, we demonstrate that B[a]P induces an EMT process in MCF10A mammary non-tumorigenic epithelial cells. In addition, B[a]P promotes the formation of larger tumors in Balb/cJ mice inoculated with 4T1 cells than in untreated mice and treated with dimethyl sulfoxide (DMSO). B[a]P also increases the number of mice with metastasis to brain and the total number of brain metastatic nodules in Balb/cJ mice inoculated with 4T1 cells compared with untreated mice and treated with DMSO. In conclusion, B[a]P induces an EMT process in MCF10A cells and the growth of mammary tumors and metastasis to brain in Balb/cJ mice inoculated with 4T1 cells.

Heavy-metal associated breast cancer and colorectal cancer hot spots and their demographic and socioeconomic characteristics.

PURPOSE: Cancer registries offer an avenue to identify cancer clusters across large populations and efficiently examine potential environmental harms affecting cancer. The role of known metal carcinogens (i.e., cadmium, arsenic, nickel, chromium(VI)) in breast and colorectal carcinogenesis is largely unknown. Historically marginalized communities are disproportionately exposed to metals, which could explain cancer disparities. We examined area-based metal exposures and odds of residing in breast and colorectal cancer hotspots utilizing state tumor registry data and described the characteristics of those living in heavy metal-associated cancer hotspots. METHODS: Breast and colorectal cancer hotspots were mapped across Kentucky, and area-based ambient metal exposure to cadmium, arsenic, nickel, and chromium(VI) were extracted from the 2014 National Air Toxics Assessment for Kentucky census tracts. Among colorectal cancer (n = 56,598) and female breast cancer (n = 77,637) diagnoses in Kentucky, we used logistic regression models to estimate Odds Ratios (ORs) and 95% Confidence Intervals to examine the association between ambient metal concentrations and odds of residing in cancer hotspots, independent of individual-level and neighborhood risk factors. RESULTS: Higher ambient metal exposures were associated with higher odds of residing in breast and colorectal cancer hotspots. Populations in breast and colorectal cancer hotspots were disproportionately Black and had markers of lower socioeconomic status. Furthermore, adjusting for age, race, tobacco and neighborhood factors did not significantly change cancer hotspot ORs for ambient metal exposures analyzed. CONCLUSION: Ambient metal exposures contribute to higher cancer rates in certain geographic areas that are largely composed of marginalized populations. Individual-level assessments of metal exposures and cancer disparities are needed.

Ambient polycyclic aromatic hydrocarbon exposure and breast cancer risk in a population-based Canadian case-control study.

PURPOSE: Polycyclic aromatic hydrocarbons (PAHs) represent a class of ubiquitous pollutants recognized as established human carcinogens and endocrine-disrupting chemicals. PAHs have seldom been modeled at the population-level in epidemiological studies. Fluoranthene is a prevalent PAH in urban settings and correlates with the occurrence of other PAHs. The purpose of this study was to evaluate associations between long-term residential exposure to ambient PAHs and breast cancer risk, both pre- and post-menopausal, in Canada. METHODS: Using the National Enhanced Cancer Surveillance System (NECSS), a national-scale Canadian population-based case-control study, annual fluoranthene exposures were estimated using the GEM-MACH-PAH chemical transport model on the basis of geocoded residential histories throughout a 20-year exposure window. Odds ratios (ORs) and 95% confidence intervals (CIs) controlling for potential confounders were estimated using logistic regression. Separate analyses were conducted for Ontario and national samples given a finer-resolution exposure surface and additional risk factor information available for Ontario. RESULTS: Positive associations were observed between fluoranthene exposure and premenopausal breast cancer, with inconsistent findings for postmenopausal breast cancer. For premenopausal breast cancer, adjusted ORs of 2.48 (95% CI: 1.29, 4.77) and 1.59 (95% CI: 1.11, 2.29) were observed when comparing the second highest category of exposure to the lowest, among the Ontario and national samples, respectively. For postmenopausal breast cancer, adjusted ORs were 1.10 (95% CI: 0.67, 1.80) and 1.33 (95% CI: 1.02, 1.73). Associations for the highest level of exposure, across both samples and menopausal strata, were non-significant. CONCLUSION: This study provides support for the hypothesis that ambient PAH exposures increase the risk of premenopausal breast cancer.

A plain language summary of the TROPiCS-02 study in patients with breast cancer (HR-positive/HER2-negative).

WHAT IS THIS SUMMARY ABOUT?: Sacituzumab govitecan (brand name: TRODELVY®) is a new treatment for certain types of advanced or metastatic breast cancer. One common type of breast cancer has at least 1 of 2 hormone receptors (HR positive) and does not have human epidermal growth factor 2 (HER2 negative). The HR and HER2 receptors are known to influence how severe a case of breast cancer is. Certain treatments will only work if a specific receptor is present on breast cancer cells. HR-positive/HER2-negative advanced or metastatic breast cancer can be treated with sacituzumab govitecan. This is a summary of the results of the TROPiCS-02 study. This study compared sacituzumab govitecan with standard chemotherapy in participants with HR-positive/HER2-negative advanced or metastatic breast cancer. WHAT WERE THE RESULTS?: The study showed that participants treated with sacituzumab govitecan lived significantly longer without their cancer getting worse than participants treated with chemotherapy. Participants also survived significantly longer and their tumors became significantly smaller in more participants treated with sacituzumab govitecan than with chemotherapy. In general, participants treated with sacituzumab govitecan were more likely to have side effects and had more severe side effects. These side effects included low levels of a type of white blood cell known as neutrophils and diarrhea. Oncologists (doctors that treat cancer) know of these side effects as they are common among people being treated for cancer. Doctors can control these side effects by following standard treatment guidelines and the package insert for sacituzumab govitecan. Participants treated with sacituzumab govitecan maintained their sense of well-being and ability to do daily activities (quality of life) longer than participants treated with chemotherapy. It also took longer for fatigue and other symptoms of cancer to worsen in participants treated with sacituzumab govitecan compared with chemotherapy. WHAT DO THE RESULTS MEAN?: Sacituzumab govitecan is more effective than standard chemotherapies for people who have already received multiple treatments for HR-positive/ HER2-negative advanced breast cancer. The side effects from sacituzumab govitecan could generally be managed well by doctors. Although there were more side effects with sacituzumab govitecan than with chemotherapy, they were generally mild to moderate.

Trajectories of long-term exposure to PCB153 and Benzo[a]pyrene (BaP) air pollution and risk of breast cancer.

BACKGROUND: While genetic, hormonal, and lifestyle factors partially elucidate the incidence of breast cancer, emerging research has underscored the potential contribution of air pollution. Polychlorinated biphenyls (PCBs) and benzo[a]pyrene (BaP) are of particular concern due to endocrine-disrupting properties and their carcinogenetic effect. OBJECTIVE: To identify distinct long term trajectories of exposure to PCB153 and BaP, and estimate their associations with breast cancer risk. METHODS: We used data from the XENAIR case-control study, nested within the ongoing prospective French E3N cohort which enrolled 98,995 women aged 40-65 years in 1990-1991. Cases were incident cases of primary invasive breast cancer diagnosed from cohort entry to 2011. Controls were randomly selected by incidence density sampling, and individually matched to cases on delay since cohort entry, and date, age, department of residence, and menopausal status at cohort entry. Annual mean outdoor PCB153 and BaP concentrations at residential addresses from 1990 to 2011 were estimated using the CHIMERE chemistry-transport model. Latent class mixed models were used to identify profiles of exposure trajectories from cohort entry to the index date, and conditional logistic regression to estimate their association with the odds of breast cancer. RESULTS: 5058 cases and 5059 controls contributed to the analysis. Five profiles of trajectories of PCB153 exposure were identified. The class with the highest PCB153 concentrations had a 69% increased odds of breast cancer compared to the class with the lowest concentrations (95% CI 1.08, 2.64), after adjustment for education and matching factors. The association between identified BaP trajectories and breast cancer was weaker and suffered from large CI. CONCLUSIONS: Our results support an association between long term exposure to PCB153 and the risk of breast cancer, and encourage further studies to account for lifetime exposure to persistent organic pollutants.

Risk of venous thromboembolism in pregnant patients with active malignancy: A systematic review and meta-analysis.

INTRODUCTION: Cancer currently occurs in about 1 in 1000 pregnancies. Both active malignancy and pregnancy are individual risk factors for venous thromboembolism (VTE). The purpose of this systematic review/meta-analysis was to evaluate the rate of VTE in pregnant patients with active malignancy compared with pregnant patients without malignancy. MATERIAL AND METHODS: Embase, Medline/PubMed, Cochrane Database, and clinicaltrial.gov were search by a trained librarian from inception until June 2021, and limited to English and French language human studies using keywords related to pregnancy, neoplasm, and thrombosis. This study was prospectively registered with PROSPERO (CRD42021245886). Title, abstract, and full-text review was performed using the Covidence data management system. Two authors reviewed the studies independently. Of the 3821 articles screened, seven cohort studies were included that reported VTE rate in patients with active malignancy in pregnancy. RESULTS: A total of 5928 individuals had active malignancy and pregnancy. Active malignancy in pregnancy significantly increased the odds of a VTE (odds ratio [OR] 6.8, 95% confidence interval [CI] 3.8-12.1). Specifically, patients with thyroid (OR 2.7, 95% CI 1.3-6.3), cervix (OR 6.6, 95% CI 2.4-18.0), or other gynecological (OR 10.6, 95% CI 4.4-25.8) cancers; Hodgkin's lymphoma (OR 8.7, 95% CI 3.3-23.4); or acute leukemia (OR 17.1, 95% CI 10.9-26.8) all had increased odds, whereas those with brain cancer (OR 6.1, 95% CI 0.4-98.2), breast cancer (OR 2.5, 95% CI 0.3-17.4), malignant melanoma (OR 5.5, 95% CI 0.3-88.1), or non-Hodgkin's lymphoma (OR 3.2, 95% CI 0.8-12.9) malignancies did not have statistically significant increased odds for VTE. No studies reported whether prophylactic anticoagulation was used during pregnancy in this population; nor did they report timing in pregnancy of the VTE. The absolute risk for VTE in those with active malignancy was 0.9% compared with 0.2% in those without active malignancy in pregnancy. CONCLUSIONS: Pregnancy with active malignancy confers a significant increased risk for VTE compared with pregnancy alone. Given this finding, prophylactic anticoagulation during pregnancy and postpartum could be considered in this patient population. Data are underpowered to make firm recommendations per cancer type.

Elevated aerobic glycolysis driven by p62-mTOR axis promotes arsenic-induced oncogenic phenotypes in human mammary epithelial cells.

Chronic arsenic exposure is considered to increase the risk of breast cancer. p62 is a multifunctional adaptor protein that controls myriad cellular processes and is overexpressed in breast cancer tissues. Although previous studies have indicated the involvement of p62 accumulation in arsenic tumorigenesis, the underlying mechanism remains obscure. Here, we found that 0.1 µM or 0.5 µM arsenite exposure for 24 weeks induced oncogenic phenotypes in human mammary epithelial cells. Elevated aerobic glycolysis, cell proliferation capacity, and activation of p62-mTOR pathway, as indicated by increased protein levels of p62, phosphorylated-mTOR (p-mTOR) and hypoxia-inducible factor 1α (HIF1α), were observed in chronically arsenite-exposed cells, and of note in advance of the onset of oncogenic phenotypes. Moreover, p62 silencing inhibited acquisition of oncogenic phenotypes in arsenite-exposed cells. The protein levels of p-mTOR and HIF1α, as well as aerobic glycolysis and cell proliferation, were suppressed by p62 knockdown. In addition, re-activation of p­mTOR reversed the inhibitory effects of p62 knockdown. Collectively, our data suggest that p62 exerts an oncogenic role via mTORC1 activation and acts as a key player in glucose metabolism during arsenite-induced malignant transformation, which provides a new mechanistic clue for the arsenite carcinogenesis.

Quantitative analysis of the effect of docetaxel-induced edema on quality of life in patients with breast cancer and related factors: a prospective cohort study.

BACKGROUND: Systemic edema is an adverse effect of docetaxel chemotherapy and causes distress to patients, including those receiving this agent for breast cancer. However, its characteristics and factors related to its effect on quality of life (QoL) have not been adequately investigated. In this study, we assessed systemic edema quantitatively, explored related factors, and evaluated QoL in patients receiving docetaxel for breast cancer. METHODS: The study had a prospective cohort design and included 37 patients with no known history of swelling who were treated with docetaxel between September 2019 and April 2022. Patients were examined at the start, middle, and end of their course of treatment and 1 and 2 months later. Body water content, body mass, fat mass, and muscle mass were quantified using bioelectrical impedance analysis. Systemic edema was evaluated with reference to the Common Terminology Criteria for Adverse Events. The timing of development of systemic edema at any anatomical site that was grade 2 or worse was recorded. QoL was assessed using the Quality of Life-Anti Cancer Drug scale. Nutrition was evaluated using the Brief-type self-administered diet history questionnaire. Multivariable logistic regression analysis was performed to identify related factors. QoL was also compared between patients with edema and those without edema. RESULTS: Systemic edema developed in 67% of the study participants and was most prevalent at the end of treatment. Body fat mass (adjusted odds ratio [aOR] 0.802, 95% confidence interval [CI] 0.651-0.988, p = 0.038), disease stage (aOR 3.279, 95% CI 0.493-21.793, p = 0.219), and history of alcohol consumption (aOR 0.141, 95% CI 0.013-1.521, p = 0.106) were identified as risk factors for docetaxel-induced edema. Participants who developed systemic edema experienced more physical, vital, and emotional distress 1 month after treatment than those who did not. There was no association between systemic edema and nutrition. CONCLUSIONS: Systemic edema may develop after treatment with docetaxel and increase distress in patients with a high body fat mass. Patients at risk of systemic edema should be informed in advance about the potential frequency, location, and timing of its onset and encouraged to self-manage this condition.

Thrombosis of acute superior mesenteric artery in a patient with breast cancer receiving toremifene therapy: a case report and literature review.

It is widely recognized that cancer itself is related to increased risk of thromembolism. Venous thromboembolism is relatively common in breast cancer patients, but arterial thrombosis, especially acute superior mesenteric artery thrombosis (SMAT) associated with chemotherapy or endocrinotherapy, rarely occurs in breast cancer patients. There were few reports about acute SMAT in cancer patients who underwent chemotherapy, but no reports of acute SMAT caused by endocrine-therapy. We reported a 54-year-old patient with acute SMAT during toremifene treatment after breast cancer surgery. She underwent 4 cycles chemotherapy of TC regimen, then accepted toremifen endocrinotherapy because of positive estrogen receptor. She suffered from acute SMAT after 2 months toremifen treatment. Therefore, we consider that this case of acute SMAT may be a rare adverse event of toremifen. In view of the high risk and rarity of acute SMAT caused by toremifene, we suggest that except for venous thrombosis, arterial thrombosis in special position (ATSP) should be kept in mind during use of toremifene. Once a thrombotic event occurs, toremifene should be stopped immediately.

Breast cancer, alcohol, and phosphate toxicity.

Alcohol consumption is associated with an increased risk of breast cancer, even at low alcohol intake levels, but public awareness of the breast cancer risk associated with alcohol intake is low. Furthermore, the causative mechanisms underlying alcohol's association with breast cancer are unknown. The present theoretical paper uses a modified grounded theory method to review the research literature and propose that alcohol's association with breast cancer is mediated by phosphate toxicity, the accumulation of excess inorganic phosphate in body tissue. Serum levels of inorganic phosphate are regulated through a network of hormones released from the bone, kidneys, parathyroid glands, and intestines. Alcohol burdens renal function, which may disturb the regulation of inorganic phosphate, impair phosphate excretion, and increase phosphate toxicity. In addition to causing cellular dehydration, alcohol is an etiologic factor in nontraumatic rhabdomyolysis, which ruptures cell membranes and releases inorganic phosphate into the serum, leading to hyperphosphatemia. Phosphate toxicity is also associated with tumorigenesis, as high levels of inorganic phosphate within the tumor microenvironment activate cell signaling pathways and promote cancer cell growth. Furthermore, phosphate toxicity potentially links cancer and kidney disease in onco-nephrology. Insights into the mediating role of phosphate toxicity may lead to future research and interventions that raise public health awareness of breast cancer risk and alcohol consumption.

Elucidating the mechanism of plasticizers inducing breast cancer through network toxicology and molecular docking analysis.

OBJECTIVE: The objective of this study was to elucidate the molecular mechanisms underlying the potential contribution of commonly utilized plasticizers, including Diethyl phthalate (DEP), Dimethyl phthalate (DMP), and Dioctyl phthalate (DOP), to the pathogenesis of breast cancer. This study aimed to highlight the complex interactions between these environmental chemicals and key molecular pathways implicated in tumorigenesis. METHODS: We employed network toxicology and molecular docking techniques to analyze the interactions between plasticizers and key proteins implicated in breast cancer. Utilizing databases such as the TCGA, we performed an expression analysis of selected key genes in breast cancer tissue compared to normal controls. Enrichment analysis was conducted to identify the biological pathways associated with these genes. RESULTS: Enrichment analysis highlighted the association of these plasticizer-targeted genes with pathways integral to adenocarcinoma development, suggesting a broad impact of plasticizers on hormone-dependent and other forms of cancers. Subsequent expression analysis using data from the TCGA breast cancer database indicated significant upregulation or downregulation of these genes in breast cancer tissues compared to normal controls, confirming their pivotal roles in tumor biology. Furthermore, the molecular docking analysis revealed that plasticizers, including DEP, DMP, and DOP, exhibit specific binding interactions with key proteins such as MAPK1, AKT1, SRC, ESR1, and ALB, which are crucial in the regulation of breast cancer pathogenesis. CONCLUSION: The study provides evidence that exposure to plasticizers may influence breast cancer pathogenesis through interactions with critical proteins and signaling pathways. By employing network pharmacology, protein interactions, and molecular docking, our findings highlight the potential risks posed by plasticizers. These results underscore the need for further epidemiological and clinical research to fully understand the implications of plasticizer exposure on breast cancer risk, thus informing future preventive and therapeutic strategies.

Depot medroxyprogesterone acetate and breast cancer: a systematic review.

PURPOSE: Short-acting progestin-only injectables containing depot medroxyprogesterone acetate (DMPA) are a safe method of contraception. Although DMPA has been available for several decades, there is little data on its influence on the risk of breast cancer. Hence, the aim of this paper was to provide an overview of the existing studies and create clarity regarding a possible association with breast cancer. METHODS: Literature searches were executed in MEDLINE, Embase, the Cochrane Library, ClinicalTrials.gov and ICTRP. Search terms were related to DMPA and breast cancer. After elimination of duplicates, 3'850 studies were identified and assessed according to inclusion and exclusion criteria. Finally, ten studies were selected and included in this review. RESULTS: All the selected papers were case-control-studies, except for one pooled analysis and one study comparing observed and expected number of cancer cases. Most of the included studies found no overall elevated breast cancer incidence in DMPA users, only one study found a slightly increased risk and two studies concluded with a significant increase for the overall breast cancer risk. CONCLUSION: There is little evidence that DMPA may increase the overall risk for breast cancer. However, the incidence of breast cancer is possibly increased in current and more recent users, especially in women younger than 35 years. Long-term use did not result in any risk increase. Nevertheless, further studies will be necessary to confirm these findings and weigh up the individual risks and benefits of this contraceptive method.

In Vitro and In Vivo Preventive Effects of Thymoquinone against Breast Cancer: Role of DNMT1.

Breast cancer (BC) is one of the most common cancers in women and is a major cause of female cancer-related deaths. BC is a multifactorial disease caused by the dysregulation of many genes, raising the need to find novel drugs that function by targeting several signaling pathways. The antitumoral drug thymoquinone (TQ), found in black seed oil, has multitargeting properties against several signaling pathways. This study evaluated the inhibitory effects of TQ on the MCF7 and T47D human breast cancer cell lines and its antitumor activity against BC induced by a single oral dose (65 mg/kg) of 7,12-dimethylbenzanthracene (DMBA) in female rats. The therapeutic activity was evaluated in DMBA-treated rats who received oral TQ (50 mg/kg) three times weekly. TQ-treated MCF7 and T47D cells showed concentration-dependent inhibition of cell proliferation and induction of apoptosis. TQ also decreased the expression of DNA methyltransferase 1 (DNMT1) in both cancer cell types. In DMBA-treated animals, TQ inhibited the number of liver and kidney metastases. These effects were associated with a reduction in DNMT1 mRNA expression. These results indicate that TQ has protective effects against breast carcinogens through epigenetic mechanisms involving DNMT1 inhibition.