Risk Of Breast Cancer In Women Research Articles

Urinary artificial sweeteners and breast cancer risk in women from the Moli-sani Study

Abstract Background Artificial sweeteners (AS) are chemical substances developed by the food industry to reduce sugar and calories while maintaining sweetness. Cohort studies suggested an increased risk of certain cancers, including breast cancer (BC), associated with AS intake, however evidence exclusively relied on self-reported dietary data rather than objectively measured AS. We examined the association of urinary biomarkers denoting AS intake with BC risk in women from the large Moli-sani Study. Methods Using a case-cohort design, a sample of 987 middle-aged women (mean age 55±12 y) was randomly selected as sub-cohort and compared with 273 women with incident BC (26 of them also belong to the sub-cohort). A total of 6 commonly used AS (i.e. aspartame, acesulfame, saccharine, sucralose, cyclamate, and steviol glycosides) were measured through liquid chromatography-mass spectrometry in urinary samples (creatinine-adjusted concentrations; µg/mg) collected at baseline (2005-2010). The multivariable hazard ratios (HRs) were estimated through Cox regression models using the Prentice method, where each AS was dichotomized as absence/presence, independent of concentrations. Results The main urinary AS was saccharine (E954), contributing to 71% of total AS, followed by steviol glycosides (E960;11%). During a median follow-up of 13.2 y we identified 38 premenopausal and 235 postmenopausal incident BC cases. In multivariable-adjusted Cox analyses, none of the individual AS was associated with overall BC risk, nor was the total urinary AS (HR = 0.93; 95%CI 0.63-1.37 for 1-unit increment). Compared to absence, presence of sucralose (E955) in urine was linked to premenopausal BC (HR = 4.23: 95%CI 1.23-14.51; p = 0.022). Conclusions Urinary artificial sweeteners were not associated with BC risk. However, sucralose presence in urine was linked to a higher risk of premenopausal BC. Prospective, dose-related studies with larger sample size are warranted to possibly confirm our findings. Key messages • The presence in the urine of commonly used artificial sweeteners was not associated with breast cancer risk. • Presence of urinary sucralose was linked to higher risk of premenopausal breast cancer.

Traditional Chinese Medicine Herbs for Breast Cancer Prevention and Survival: A Narrative Review of Epidemiological Studies from Taiwan.

This review aims to describe the association of integrating traditional Chinese medicine (TCM) herbs into conventional medicine (CM) in preventing breast cancer and improving survival rates among breast cancer patients of Taiwan. Of 7 relevant studies, spanning 2014-2023, 4 investigated breast cancer risk in women with menopausal symptoms and other comorbidities. All 4 reported that TCM herbal use was associated with lower risks of developing breast cancer. Three studies investigated survival in newly-diagnosed breast cancer patients receiving CM. All reported that adjunctive TCM users had lower mortality rates than CM-only patients. However, the heterogeneity of study designs, populations, and interventions may limit the generalizability and robustness of the findings. TCM herbs may promote breast cancer prevention and survival when used alongside CM. More rigorous observational research and clinical trials in specific patient populations are needed to guide clinical decision-making.

Are women's breast cancer risk appraisals in line with updated clinical risk estimates communicated? Results from a UK Family History Risk and Prevention Clinic.

The incorporation of breast density and a polygenic risk score (PRS) into breast cancer risk prediction models can alter previously communicated risk estimates. Previous research finds that risk communication does not usually change personal risk appraisals. This study aimed to examine how women from the Family History Risk (FH-Risk) study appraise their breast cancer risk following communication of an updated risk estimate. In the FH-Risk study 323 women attended a consultation to receive an updated breast cancer risk estimate. A subset (n=190) completed a questionnaire, assessing their subjective breast cancer risk appraisals, satisfaction with the information provided and cancer related worry. One hundred and three were notified of a decrease risk, 34 an increase and 53 an unchanged risk. Women's subjective risk appraisals were in line with the updated risk estimates provided, with age, a PRS and breast density explaining most of the variance in these appraisals. Those notified of an increased risk demonstrated higher subjective risk perceptions compared to those whose risk remained unchanged or decreased. Women's subjective breast cancer risk appraisals are amenable to change following updated risk feedback, with new information breast density and a PRS accepted and integrated into existing risk appraisals. Trust in the service, the analogies and visual communication strategies used may have positively influenced the integration of this new information. Further research is warranted to assess whether similar patterns emerge for other illnesses and in different clinical contexts to determine the best strategies for communicating updated risk estimates.

Cohort profile: a nationwide study in Dutch CHEK2 c.1100delC families using the infrastructure of the HEreditary Breast and Ovarian cancer study Netherlands – Hebon-CHEK2

PurposeCHEK2 c.1100delC is associated with an increased breast cancer risk in women. While this variant is prevalent in the Netherlands (1% in the general population), knowledge of aetiology and prognosis...

Abstract A021: Development of cross-ancestry polygenic risk. scores for breast cancer in women of African ancestry

Abstract Introduction: Polygenic risk scores (PRSs) predict breast cancer (BC) risk and have shown utility for screening in European ancestry women (EUR). However, PRSs developed for non-European ancestry, particularly African American (AA) women, have limited predictive accuracy. Methods: We analyzed data from 17,454 BC cases and 19,093 controls in the African American Breast Cancer Genetics (AABCG) consortium, split into training (70%), tuning (10%), and testing (20%) sets. Genome-wide association analyses for overall BC, ER-positive BC, ER- negative BC and triple-negative BC (TNBC) were performed in the training dataset, controlling for age, genotyping platform, and the top 10 principal components. We built single-ancestry PRS models using forward stepwise selection (FSS), PRSice-2, PLINK C+T, Lassosum2, and LDpred2-auto. These were combined with published EUR 313-SNP models (330-SNP for TNBC) in the tuning set to obtain cross-ancestry models. Genome-wide cross-ancestry PRS methods, including CT-SLEB and PRScsx, were also used. We created an ensemble model by combining different PRS models across subtypes using ensemble-based approaches. All developed PRS models were then evaluated in the independent testing set. Additional validation was performed using the All of Us (AoU) study with 834 BC cases and 29,122 controls from the AA population. Results: The observed-scale SNP-based heritability was estimated at 0.29 (SE: 0.12) for overall BC risk, 0.43 (SE: 0.18) for ER-positive BC, 0.44 (SE: 0.24) for ER-negative BC, and 1.13 (SE: 0.40) for TNBC. The best models showed good discriminating capacity: ensemble-based models for overall (AUC=0.626) and ER-positive BC (AUC=0.626), and combined cross-subtype and cross-ancestry FSS models for ER-negative (AUC=0.647) and TNBC (AUC=0.654). The odds ratio per standard deviation was 1.63 (95% CI: 1.55, 1.71) for the ensemble-based PRS of overall BC risk, with an estimated life risk of 28% for the top 1%. The cross-ancestry model using CT-SLEB combined with the EUR 313-SNP model was validated (AUC=0.61) among AA women in the AoU study. Conclusion: We developed PRSs with improved discriminating ability for BC risk in women with African ancestry. Cross- ancestry and subtype learning enhanced model performance. These findings indicate common variation has a larger role in BC in AA women than previously reported, warranting further validation in external AA populations and clinical evaluation. Citation Format: James L. Li, Haoyu Zhang, Julian C McClellan, Guimin Gao, Kevin Wang, Julie R. Palmer, Olufunmilayo I. Olopade, Christopher A. Haiman, Dezheng Huo. Development of cross-ancestry polygenic risk. scores for breast cancer in women of African ancestry [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr A021.

Pregnancy-Related Factors and Breast Cancer Risk for Women Across a Range of Familial Risk

Few studies have investigated whether the associations between pregnancy-related factors and breast cancer (BC) risk differ by underlying BC susceptibility. Evidence regarding variation in BC risk is critical to understanding BC causes and for developing effective risk-based screening guidelines. To examine the association between pregnancy-related factors and BC risk, including modification by a of BC where scores are based on age and BC family history. This cohort study included participants from the prospective Family Study Cohort (ProF-SC), which includes the 6 sites of the Breast Cancer Family Registry (US, Canada, and Australia) and the Kathleen Cuningham Foundation Consortium (Australia). Analyses were performed in a cohort of women enrolled from 1992 to 2011 without any personal history of BC who were followed up through 2017 with a median (range) follow-up of 10 (1-23) years. Data were analyzed from March 1992 to March 2017. Parity, number of full-term pregnancies (FTP), age at first FTP, years since last FTP, and breastfeeding. BC diagnoses were obtained through self-report or report by a first-degree relative and confirmed through pathology and data linkages. Cox proportional hazards regression models estimated hazard ratios (HR) and 95% CIs for each exposure, examining modification by PARS of BC. Differences were assessed by estrogen receptor (ER) subtype. The study included 17 274 women (mean [SD] age, 46.7 [15.1] years; 791 African American or Black participants [4.6%], 1399 Hispanic or Latinx participants [8.2%], and 13 790 White participants [80.7%]) with 943 prospectively ascertained BC cases. Compared with nulliparous women, BC risk was higher after a recent pregnancy for those women with higher PARS (last FTP 0-5 years HR for interaction, 1.53; 95% CI, 1.13-2.07; P for interaction < .001). Associations between other exposures were limited to ER-negative disease. ER-negative BC was positively associated with increasing PARS and increasing years since last FTP (P for interaction < .001) with higher risk for recent pregnancy vs nulliparous women (last FTP 0-5 years HR for interaction, 1.54; 95% CI, 1.03-2.31). ER-negative BC was positively associated with increasing PARS and being aged 20 years or older vs less than 20 years at first FTP (P for interaction = .002) and inversely associated with multiparity vs nulliparity (P for interaction = .01). In this cohort study of women with no prior BC diagnoses, associations between pregnancy-related factors and BC risk were modified by PARS, with greater associations observed for ER-negative BC.

Exposure to Light at Night and Risk of Cancer: A Systematic Review, Meta-Analysis, and Data Synthesis.

Emerging interest surrounds the role of environmental factors, notably exposure to light at night (LAN), as a potential cause of cancer. The aim of this study was to conduct a systematic review and, if possible, meta-analysis of observational studies on LAN and cancer risk of multiple types. A systematic literature search in PubMed, Web of Science, and Embase, spanning from inception to May 2023, was conducted. Studies focusing on the association between LAN exposure and cancer risk in adult populations were included. We used random effects models to calculate pooled risk estimates (RR) and 95% confidence intervals (CI). We assessed study quality using the Risk of Bias in Non-randomized Studies of Interventions. Among 8492 initially identified studies, 26 met the inclusion criteria (13 were case-control and 13 were cohort studies). These studies were published from 2001 to 2023 and assessed diverse cancer types in North America, Asia, Europe, and Australia. Except for breast cancer, there was a paucity of site-specific cancer studies. In the meta-analysis of 19 breast cancer studies, higher exposure to indoor (summary RR, 1.08; 95% CI 1.01-1.15) and outdoor (summary RR, 1.10; 95% CI, 1.04-1.15) LAN were associated with increased risk. After excluding one low-quality study, the results were unchanged. We found a positive association between LAN exposure and breast cancer risk in women. However, data are lacking for other cancer types, and further studies are required to better understand the role of LAN on cancer.

Associations between serum uric acid and breast cancer incidence: A systematic review and meta-analysis

BackgroundSerum uric acid (SUA) may be involved in the development of cancer by inhibiting oxidative stress, but its relationship with breast cancer remains unclear. Materials and MethodsThe PubMed, Embase, and Web of Science databases were searched systematically for studies on SUA levels in women with breast cancer and the effect of SUA levels on the risk of breast cancer. The Newcastle‒Ottawa Quality Assessment Scale (NOS) was used to assess the quality of all relevant studies included. ResultsA total of 19 studies were included, including 75,827 women with breast cancer and 508,528 healthy controls. A meta-analysis found that SUA levels were negatively correlated with breast cancer risk in women (HR = 0.94, 95% CI: 0.89 - 0.99, p = 0.003). SUA levels in female breast cancer patients were not significantly different from those in healthy controls (SMD = 0.49, 95% CI = -0.09 - 1.08, p = 0.10), while SUA levels were increased in female breast cancer patients in articles published after 2010, SUA concentration detected by spectrophotometry, and non-Asian populations, regardless of menopausal state and treatment state. ConclusionHigh levels of SUA may reduce the risk of breast cancer in women, suggesting that SUA was a protective factor in women.

Causal relationship between endometrial cancer and risk of breast cancer: A 2-sample Mendelian randomization study.

Several studies have confirmed the important role of endometrial cancer (EC) in the development and progression of breast cancer (BC), and this study will explore the causal relationship between EC and BC by 2-sample Mendelian randomization analysis. Pooled data from published genome-wide association studies were used to assess the association between EC and BC risk in women using 5 methods, namely, inverse variance weighting (IVW), MR-Egger, weighted median (WME), simple multimaximetry (SM) and weighted multimaximetry (WM) with the EC-associated genetic loci as the instrumental variables (IV) and sensitivity analyses were used to assess the robustness of the results. The statistical results showed a causal association between EC and BC (IVW: OR = 1.07, 95% CI = 1.01-1.32, P = .02; MR-Egger: OR = 1.21, 95% CI = 0.71-1.51, P = .11; weighted median: OR = 1.05, 95% CI = 0.97-1.31, P = .19; simple plurality method: OR = 0.98, 95% CI = 0.81-1.15, P = .78; weighted plurality method: OR = 0.98, 95% CI = 0.81-1.14, P = .75), and the results of the sensitivity analyses showed that there was no significant heterogeneity or multiplicity, and the results were stable. EC is associated with an increased risk of developing BC. The results of this MR analysis can be used as a guideline for screening for BC in women with EC and to help raise awareness of screening for early detection and treatment.

Predicting breast cancer risk in women of African ancestry

Predicting breast cancer risk in women of African ancestry

Interaction of sedentary behaviour and educational level in breast cancer risk.

This cross-sectional study aims to analyse the relationship between sedentary behaviour and breast cancer (BC) risk from a social perspective. Women aged 45-70 who participated in the Valencia Region Breast Cancer Screening Programme (2018-2019) were included, with a total of 121,359 women analysed, including 506 with cancer and 120,853 without cancer. The response variable was BC (screen-detected) and the main explanatory variable was sedentary behaviour (≤2 / >2-≤3 / >3-≤5 / >5 hours/day, h/d). Nested logistic regression models (M) were estimated: M1: sedentary behaviour adjusted for age and family history of BC; M2: M1 + hormonal/reproductive variables (menopausal status, number of pregnancies, hormone replacement therapy; in addition, months of breastfeeding was added for a subsample of women with one or more live births); M3: M2 + lifestyle variables (body mass index, smoking habits); M4: M3 + socioeconomic variables (educational level, occupation); Final model: M4 + gender variables (childcare responsibilities, family size). Interaction between sedentary behaviour and educational level was analysed in the Final model. Moreover, for the whole sample, postmenopausal women and HR+ BC, the Final model was stratified by educational level. Sedentary behaviour was associated with an increased risk of BC with a nearly statistically significant effect in the Final model (>2-≤3 h/d: OR = 1.22 (0.93-1.61); >3-≤5 h/d: OR = 1.14 (0.86-1.52); >5: OR = 1.19 (0.89-1.60)). For women with a low educational level, sitting more than 2 h/d was associated with an increased risk of BC in the whole sample (>2-≤3 h/d OR = 1.93 (1.19-3.21); in postmenopausal women (>2-≤3 h/d, OR = 2.12 (1.18-2.96), >5h/d OR = 1.75 (1.01-3.11)) and in HR+ BC (>2-≤3h/d, OR = 2.15 (1.22-3.99)). Similar results were observed for women with one or more live births. Conclusions Sitting >2 h/d is associated with BC risk in women with low educational level, especially in postmenopausal women and those with live births.

Association of area- and volumetric-mammographic density and breast cancer risk in women of Asian descent: a case control study

BackgroundMammographic density (MD) has been shown to be a strong and independent risk factor for breast cancer in women of European and Asian descent. However, the majority of Asian studies to date have used BI-RADS as the scoring method and none have evaluated area and volumetric densities in the same cohort of women. This study aims to compare the association of MD measured by two automated methods with the risk of breast cancer in Asian women, and to investigate if the association is different for premenopausal and postmenopausal women.MethodsIn this case–control study of 531 cases and 2297 controls, we evaluated the association of area-based MD measures and volumetric-based MD measures with breast cancer risk in Asian women using conditional logistic regression analysis, adjusting for relevant confounders. The corresponding association by menopausal status were assessed using unconditional logistic regression.ResultsWe found that both area and volume-based MD measures were associated with breast cancer risk. Strongest associations were observed for percent densities (OR (95% CI) was 2.06 (1.42–2.99) for percent dense area and 2.21 (1.44–3.39) for percent dense volume, comparing women in highest density quartile with those in the lowest quartile). The corresponding associations were significant in postmenopausal but not premenopausal women (premenopausal versus postmenopausal were 1.59 (0.95–2.67) and 1.89 (1.22–2.96) for percent dense area and 1.24 (0.70–2.22) and 1.96 (1.19–3.27) for percent dense volume). However, the odds ratios were not statistically different by menopausal status [p difference = 0.782 for percent dense area and 0.486 for percent dense volume].ConclusionsThis study confirms the associations of mammographic density measured by both area and volumetric methods and breast cancer risk in Asian women. Stronger associations were observed for percent dense area and percent dense volume, and strongest effects were seen in postmenopausal individuals.

Breast Cancer Risk After Bariatric Surgery and Influence of Insulin Levels

Obesity and insulin are risk factors for breast cancer, and retrospective studies suggest bariatric surgery reduces breast cancer risk in women. However, long-term prospective data on breast cancer risk after bariatric surgery and the role of baseline insulin levels are lacking. To examine if bariatric surgery is associated with breast cancer incidence in women and if treatment benefit is modified by baseline insulin levels. The Swedish Obese Subjects (SOS) study was a nonrandomized intervention trial designed to investigate the long-term effects of bariatric surgery on obesity-related mortality and morbidity. Study recruitment took place between 1987 and 2001, and median (IQR) follow-up time was 23.9 years (20.1-27.1) years. The study was conducted at 25 public surgical departments and 480 primary health care centers in Sweden and included 2867 women aged 37 to 60 years and with body mass index 38 or greater (calculated as weight in kilograms divided by height in meters squared). In the surgery group (n = 1420), 260 women underwent gastric banding, 970 vertical banded gastroplasty, and 190 gastric bypass. The remaining contemporaneously matched control individuals (n = 1447) received usual obesity care. Breast cancer, the main outcome of this secondary report, was not a predefined outcome in the SOS study. Breast cancer events were identified in the Swedish National Cancer Registry. The study population comprised 2867 women with a mean (SD) age of 48.0 (6.2) years. During follow-up, there were 154 breast cancer events, 66 in the surgery group and 88 in the usual care group, and a decreased risk of breast cancer was observed in the bariatric surgery group (hazard ratio [HR], 0.68; 95% CI, 0.49-0.94; P = .019; adjusted HR, 0.72; 95% CI, 0.52-1.01; P = .06). The surgical treatment benefit on breast cancer risk was greater in women with baseline insulin levels above the median 15.8 μIU/L (HR, 0.48; 95% CI, 0.31-0.74; P = .001; adjusted HR, 0.55; 95% CI, 0.35-0.86; P = .008) compared to those below (HR, 0.95; 95% CI, 0.59-1.53; P = .84; adjusted HR, 1.01; 95% CI, 0.61-1.66; P = .97; interaction P = .02). This prospective clinical trial indicated a reduced risk of breast cancer after bariatric surgery in women with obesity. The surgical treatment benefit was predominantly seen in women with hyperinsulinemia. ClinicalTrials.gov Identifier: NCT01479452.

Abstract PS10-01: Hormonal Contraception and Breast Cancer Risk for Carriers of Germline Pathogenic Variants in BRCA1 and BRCA2

Abstract BACKGROUND: Current use of hormonal contraception is associated with a 20-30% relative increase in the risk of breast cancer (BC) for women in the general population compared with never using. Longer duration of use is associated with higher risk, and the risk remains elevated above that of never users for at least 5 years after cessation. Most published data are for various formulations of the combined oral contraceptive pill, but associations are similar for progestogen-only contraceptives, including intrauterine devices. For women in the general population who use hormonal contraceptives in their 20s and 30s, when baseline BC risk for most women is low, these increased relative risks translate into only small increases in absolute risk. It is unclear whether use of hormonal contraceptives increases BC risk for women carrying a germline BRCA1 or BRCA2 pathogenic variant (PV). These women are at markedly higher risk of early-onset BC, so even slightly increased relative risks could translate to important increases in their absolute risk of BC. This study assessed the association between use of any hormonal contraception and BC risk for BRCA1 and BRCA2 PV carriers using individual participant data from four prospective cohorts. METHODS: Data from females born after 1920 with a PV in BRCA1 or BRCA2 and no history of cancer or bilateral mastectomy at cohort entry were analyzed. Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for BC (invasive disease or ductal carcinoma in situ) associated with use of hormonal contraceptives for at least 1 year, with age as the timescale, entry at cohort enrolment, and censoring at the earlier of bilateral mastectomy, death, diagnosis of another cancer or last follow-up. Analyses were adjusted for study, birth cohort, first-degree family history of BC, parity, premenopausal bilateral oophorectomy and menopausal status. Current use of hormonal contraceptives was defined as use within the previous year, to account for cessation of use due to BC symptoms or clinical investigation. RESULTS: Of 3,882 BRCA1 and 1,509 BRCA2 PV carriers, 53% and 71%, respectively had ever used hormonal contraceptives (for at least one year). The median cumulative duration of hormonal contraceptive use was 4.8 and 5.7 years, respectively. Overall, 488 BRCA1 and 191 BRCA2 PV carriers developed incident BC during a median of 5.9 and 5.6 years of follow-up, respectively. For BRCA1 PV carriers, use of hormonal contraceptives for at least 1 year was associated with increased BC risk (HR [95% CI]: 1.29 [1.04-1.60] p=0.019). BC risk increased with longer cumulative duration of hormonal contraceptive use (HR [95% CI]: 1.13 [0.88-1.45] p=0.35, 1.48 [1.11-1.96] p=0.007 and 1.56 [1.13-2.17] p=0.007 for 1-5, 6-10 and &amp;gt;10 years of use, respectively), with an estimated proportional increase in risk of 3% (1%-5%, p=0.002) for each additional year of use. For BRCA2 PV carriers, there was no evidence that current or past use, or cumulative duration of use, were associated with increased risk of BC, but confidence intervals on the HRs were wide. CONCLUSION: Hormonal contraceptive use is associated with an increased risk of BC for women carrying PVs in BRCA1 and risk increases with cumulative duration of use. Hormonal contraceptives are an important healthcare option for women; they provide excellent contraceptive efficacy and reduce risks of ovarian and endometrial cancer. Decisions about use of hormonal contraceptives in women at increased risk for BC due to BRCA1 PVs need to carefully weigh the risks and benefits; while shorter-term use may result in only small increases, prolonged cumulative use may result in larger increases in absolute BC risk that may not be acceptable to some women. Citation Format: Kelly-Anne Phillips, Joanne Kotsopoulos, Susan Domchek, James Chamberlain, Julie Bassett, Amber Aeilts, Irene Andrulis, Saundra Buys, Wanda Cui, Mary Daly, Andrea Eisen, William Foulkes, Michael Friedlander, Jacek Gronwald, John Hopper, Esther John, Beth Karlan, Raymond Kim, Jan Lubiński, Kelly Metcalfe, Katherine Nathanson, Christian F. Singer, Heather Symecko, Nadine Tung, Steven Narod, Mary Beth Terry, Roger Milne. Hormonal Contraception and Breast Cancer Risk for Carriers of Germline Pathogenic Variants in BRCA1 and BRCA2 [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS10-01.

Breast Cancer Risk for Women With a TP53 Pathogenic Variant.

The article highlights that breast cancer risk for women with TP53 mutations depends on family history.

Statin use as a moderator on the association between metformin and breast cancer risk in women with type 2 diabetes mellitus

IntroductionMetformin and statins are considered as potential agents for prevention of breast cancer, however, existing evidence does not uniformly substantiate this claim, and the data is scarce concerning their interaction in relation to breast cancer risk. This study aims to investigate whether the effect of metformin on breast cancer incidence varied by statin use among women with type 2 diabetes mellitus (T2DM).MethodsThis study included women with T2DM, without a history of cancers, and followed up for more than one year from the Zwolle Outpatient Diabetes project Integrating Available Care (ZODIAC) for the period 1998–2014. The dataset was structured using a person-time approach, where the cumulative medication usage was annually updated for each person. The extended Cox proportional hazards models were employed, reporting adjusted hazard ratios (HR) with 95% confidence intervals (CI).ResultsDuring a median follow-up of 5 years, 515 of 29,498 women received a breast cancer diagnosis. Each additional year of metformin or statins use corresponded to a decrease in breast cancer incidence, while the magnitude attenuated over time. Noteworthily, statin use modified the effect of metformin on breast cancer incidence. For instance, after 5 years of follow-up, one-year increase of metformin use among women who used statins for 3 years was linked to a substantially reduced breast cancer risk (HR, 95% CI: 0.88, 0.84–0.93), however, there was no significant decrease in risk for those non-statins users (HR, 95% CI: 0.96, 0.89–1.04).ConclusionsExtending metformin or statin usage by one year conferred breast cancer protection in women with T2DM. Enhanced protective effect of metformin was observed among those who also use statins. These results suggest the potential of combined metformin and statin therapy as promising breast cancer prevention strategies.

Abstract 6141: Genetic risk, health-associated lifestyle, and risk of early-onset total cancer and breast cancer: A prospective cohort study

Abstract Background Early-onset cancer (diagnosed under 50 years of age) is generally more aggressive. Its rising incidence is a global concern. The associations between genetic risk, lifestyle, and the risk of early-onset cancer may inform preventive strategies. Methods We studied the association between genetic risk, lifestyle and early-onset cancers among 66308 white British participants enrolled in the UK Biobank before age 50. Genetic risk was assessed using sex-specific composite total cancer polygenic risk scores (PRSs). We calculated composite PRSs as weighted sums of previously-developed cancer site-specific PRSs using weights obtained from lasso regression. We considered a breast cancer-specific PRS for analyses on breast cancer among women. A health-associated lifestyle score (HLS) was calculated based on baseline smoking, BMI (men only), physical activity, alcohol intake, and diet. Cox models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of early-onset total cancer and breast cancer across genetic risk and HLS groups in women and men. Results A total of 1247 incident invasive early-onset cancer cases (820 in women, 427 in men) were documented, including 386 cases of early-onset breast cancer. In multivariable-adjusted analyses with 2-year latency, higher genetic risk (highest vs. lowest tertile of PRS) was associated with significantly increased risks of early-onset total cancer in women (composite PRS HR=1.85; 95% CI, 1.50-2.29), early onset total cancer in men (composite PRS HR=1.94; 95% CI, 1.45-2.59), and early-onset breast cancer in women (breast-cancer PRS HR=3.06; 95% CI, 2.20-4.25). The HRs (95% CI) of early-onset total cancer in women and men, and early-onset breast cancer in women associated with adopting an unfavorable lifestyle (highest vs. lowest tertile of HLS) were 1.49 (0.99, 2.25), 1.14 (0.67, 1.95), and 1.78 (0.97, 3.24), respectively, in the total study population; 1.85 (1.02, 3.36), 3.27 (0.78, 13.72), and 1.67 (0.71, 3.90), respectively, in those with high genetic risk; 1.25 (0.60, 2.57), 1.11 (0.42, 2.89), and 1.66 (0.54, 5.11), respectively, in those with intermediate genetic risk; and 1.15 (0.44, 2.98), 1.16 (0.39, 3.40), and 2.10 (0.57, 7.75), respectively, in those with low genetic risk. Compared to individuals with both low genetic risk and a favorable lifestyle, those with high genetic risk and an unfavorable lifestyle had substantially increased risks of early-onset total cancer in women (3.07; 1.64-5.78) and men (2.18; 0.78-6.11), and significantly higher early-onset breast cancer risk in women (4.11; 1.56-10.85). Conclusion Genetic and lifestyle factors were independently associated with risks of early-onset total cancer and breast cancer. Compared to those with low genetic risk, individuals with a high genetic risk may benefit more from adopting a healthy lifestyle in preventing early-onset cancer. Citation Format: Yin Zhang, Yuxi Liu, Kathryn L. Penney, Sara Lindström, Peter Kraft. Genetic risk, health-associated lifestyle, and risk of early-onset total cancer and breast cancer: A prospective cohort study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6141.

Abstract 849: Deciphering the link between aging, lobular involution, and breast cancer risk: The role of LIFR/pSTAT3 signaling

Abstract Background: Age-related lobular involution (ARLI), characterized by regression of breast epithelial tissue during the peri-and post-menopausal period, plays a crucial role in breast cancer risk. Delayed or incomplete ARLI is linked with increased postmenopausal breast cancer susceptibility.This study focuses on unraveling the molecular mechanisms of ARLI, drawing parallels with the well-characterized postpartum involution (PPI). Our aim was to discover biomarkers differentiating women who progressed through ARLI from those with stagnant ARLI. Methods: We utilized the Mayo Clinic Benign Breast Disease (BBD) cohort, analyzing 108 perimenopausal women aged 45-55 who had a subsequent benign biopsy between 2-15 years later. We assessed Lobular Involution (Ll) status by comparing the number and size of lobules in initial and subsequent biopsies. RNA profiling of initial biopsies was performed using NanoString 10360 and BC360, identifying differentially expressed genes between ARLI progression and stagnation. Immunohistochemistry (IHC) mapped the expression of these biomarkers in epithelial lobules. Results: We identified 37 genes with significant differential expression, highlighting Leukemia Inhibitory Factor Receptor (LIFR) as upregulated in ARLI stagnant samples. LIFR, part of the IL-6 cytokine signaling pathway, is known for its role in the induction of apoptosis during PPI via pSTAT3 activation. Our IHC analyses of initial biopsies of women who differentially progress through ARLI confirmed differential expression of LIFR that is coordinately regulated with pSTAT3. Conclusion: Our findings reveal significant parallels between ARLI and PPI. Future research will assess how LIFR/pSTAT3 signaling is linked to induction of apoptotic markers in perimenopausal women and will investigate how anomalies in the LIFR/pSTAT3 pathway might contribute to heightened breast cancer risk in women with delayed or incomplete ARLI. This study not only sheds light on the complex biological processes of aging in breast tissue but also opens new avenues for breast cancer risk assessment and prevention strategies. Citation Format: Jaida C. Lue, Derek Radisky, Melody Stallings-Mann, Mark Sherman, Amy Degnim, Bryan McCauley, Tanya Hoskin. Deciphering the link between aging, lobular involution, and breast cancer risk: The role of LIFR/pSTAT3 signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 849.

Abstract 2138: Understanding the link between breastfeeding and the risk of breast cancer through comparative analysis of the murine-based model of mammary gland involution

Abstract Introduction: A meta-analysis of 47 global epidemiological studies highlights a higher breast cancer risk in women who did not breastfeed or breastfed for a short time. Further studies showed this is especially true for triple-negative breast cancer (TNBC) patients. Premenopausal AA women (AAW) have a lower prevalence of breastfeeding and a higher incidence of TNBC and mortality. Our previous study compares short-term breastfeeding, abrupt involution (AI) with prolonged breastfeeding called gradual involution (GI), revealing that AI alone induces ductal hyperplasia four months postpartum. Our current investigation delves into early events during AI versus GI, employing a comprehensive approach encompassing histology, gene expression, and myeloid cell involvement. Methods: Utilizing FVB female mice, we conducted a comparative analysis of AI and GI. AI involved early pup removal, while GI was achieved through staggered weaning. The evaluation included analysis of histomorphology, gene/protein expression, and myeloid cell infiltration. Sequential mammary gland (MG) changes were monitored through H&amp;E staining, TUNEL assay, and DNA damage analysis. 3D-organoid cultures of luminal progenitors (LPs) were employed to assess the impact of AI versus GI. qRT-PCR, IHC, Western blot, and flow cytometry/multiplex imaging were employed for the differential expression analysis of molecular and cellular factors associated with AI/GI. Results: Our research showed that AI had early adipocyte repopulation, rapid cell death, DNA repair, and myeloid cell infiltration, resulting in a chronically inflamed microenvironment. In contrast, the GI triggers a controlled immune response and prolonged cell death, facilitating comprehensive remodeling of the MG. Our flow cytometric or multiplexing imaging analyses revealed that AI-affected glands exhibit an enrichment of CCL9-producing CD206+ M2-like macrophages and CD11b+Gr1+ myeloid-derived suppressor cells. Moreover, exogenous CCL9 treatment on LPs in 3D-organoid culture results in disorganized acinar-type organoids, mirroring morphological differences observed in LPs from AI mammary glands on day56 PPM. Further analysis of CCL9 treated organoids revealed the expansion of Esr1- LPs population in ex-vivo organoid culture which might indicate an increase in the putative cells of origin of TNBC. Conclusion: Our studies comparing AI and GI demonstrate that AI is producing a pro-tumorigenic environment in the breast. It is important to note that prolonged breastfeeding protects the breast, although this cannot be a singular risk factor for TNBC. Therefore, understanding the mechanism will lead to prevention strategies to improve outcomes for all women but, has the potential to have a significant benefit in AAW. Citation Format: Sanjay Mishra, Neelam Shinde, Maria Cuitino, Morgan Bauer, Dinesh Ahirwar, Vijaya Bharti, Kate Ormiston, Resham Mawalkar, Sara Alsammerai, Gautam Sarathy, Xiaoli Zhang, Anna Vilgelm, Ramesh Ganju, Sarmila Majumder, Bhuvaneswari Ramaswamy. Understanding the link between breastfeeding and the risk of breast cancer through comparative analysis of the murine-based model of mammary gland involution [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2138.

The Prognostic Quality of Risk Prediction Models to Assess the Individual Breast Cancer Risk in Women: An Overview of Reviews

Purpose. Breast cancer is the most common cancer among women globally, with an incidence of approximately two million cases in 2018. Organised age-based breast cancer screening programs were established worldwide to detect breast cancer earlier and to reduce mortality. Currently, there is substantial anticipation regarding risk-adjusted screening programs, considering various risk factors in addition to age. The present study investigated the discriminatory accuracy of breast cancer risk prediction models and whether they suit risk-based screening programs. Methods. Following the PICO scheme, we conducted an overview of reviews and systematically searched four databases. All methodological steps, including the literature selection, data extraction and synthesis, and the quality appraisal were conducted following the 4-eyes principle. For the quality assessment, the AMSTAR 2 tool was used. Results. We included eight systematic reviews out of 833 hits based on the prespecified inclusion criteria. The eight systematic reviews comprised ninety-nine primary studies that were also considered for the data analysis. Three systematic reviews were assessed as having a high risk of bias, while the others were rated with a moderate or low risk of bias. Most identified breast cancer risk prediction models showed a low prognostic quality. Adding breast density and genetic information as risk factors only moderately improved the models’ discriminatory accuracy. Conclusion. All breast cancer risk prediction models published to date show a limited ability to predict the individual breast cancer risk in women. Hence, it is too early to implement them in national breast cancer screening programs. Relevant randomised controlled trials about the benefit-harm ratio of risk-adjusted breast cancer screening programs compared to conventional age-based programs need to be awaited.