Breast Adipose Tissue Research Articles

Combined mammographic breast density and breast arterial calcification is incrementally predictive of coronary artery disease beyond traditional risk factors

Abstract Background Coronary artery disease (CAD) risk is underestimated in women using current risk stratification tools. The mammographic finding of breast arterial calcification (BAC) associates with CAD. Furthermore, breast adipose tissue, measured through breast density (BD) on mammography (low breast density indicates high adiposity) has shown potential to act as a pro-inflammatory, pro-atherogenic fat deposit. Given its uptake in screening programs, mammography may therefore represent a novel risk stratification tool for cardiovascular disease in women. Purpose To evaluate the association between the combined mammographic features of BD and BAC, with CAD. Methods Single-centre, retrospective, cross-sectional study, including 153 women, mean age 62±10, who had both clinically indicated mammography, and coronary computed tomography angiogram (CCTA) for suspected CAD. CAD risk was identified by the CAD Consortium Score, with a 15% threshold for low and high risk. BD was visually assessed and categorised by 4-level BI-RADS grade with grade A-B representing low density, and C-D representing high density (Figure 1). BAC was visually assessed and categorised as present/absent (Figure 1). CAD was categorised as presence/absence of coronary artery plaque on CCTA. Logistic regression was performed with results presented as Odds Ratio (OR) and [95% Confidence Intervals]. Receiver operator characteristic area under the curve (AUC) was used for model discrimination. Results Low BD (n=103 (67%)) was associated with CAD (OR 3.20 [1.58-6.53], p=0.001, as was BAC presence (n=37 (24%), OR 4.36 [1.58-12], p=0.004). There were 51 (33%) with elevated CAD risk. Participants were categorised into 4 subgroups based on low/high BD and presence/absence of BAC: 29 (19%) had low BD and BAC, 74 (48%) had low BD and no BAC, 8 (5%) had high BD and BAC and 42 (27%) had high BD and no BAC. Significantly higher proportions of CAD were noted with low BD and BAC alone, as well as combined low BD and BAC (Figure 2). Compared with high BD/BAC negative, the presence of low BD and BAC independently associated with CAD (OR 5.27 [1.19-23.3], p=0.03). Significant incremental benefit was seen after adding BD/BAC status to CAD Consortium Score (AUC 0.65 vs. 0.72, p=0.004). Conclusions Combined, and individual mammographic features of low BD and BAC presence are associated with CAD and improve risk prediction beyond standard coronary risk probabilities. Standardised reporting of these features to inform risk identification may be of further benefit and should be tested in prospective screening studies.

The association between mammographic breast density, epicardial adipose tissue volume and coronary artery disease

Abstract Background Dysfunctional adipose tissue is strongly linked to cardiometabolic disease. Epicardial adipose tissue (EAT) which is measurable on cardiac computed tomography (CT) is well correlated with cardiovascular disease (CVD), however it is not reported clinically. Breast mammography mandates reporting of breast density (BD), which is also a marker of breast adipose tissue quantity with less dense breasts indicating greater adipose tissue volume. Given the widespread use of screening mammography, this presents an opportunity to employ BD as a possible surrogate for CVD risk. Purpose To evaluate the correlation between BD, EAT and coronary artery disease (CAD). Methods Single-centre, retrospective, cross-sectional study, including women who had both clinically indicated coronary computed tomography angiogram (CCTA) and mammography. Epicardial adipose tissue volume (EATv) was quantified using semi-automated software (QFAT 2.0). BD was visually assessed by standard 4-level Breast Imaging-Reporting and Data System (BI-RADS) grade with grade A-B representing low density, and C-D representing high density. CAD was categorised as presence/absence of any coronary artery plaque, and CAD severity was quantified using the Coronary Artery Disease Reporting and Data Systems (CAD-RADS) score, with CAD-RADS 1-2 representing mild disease, CAD-RADS 3 moderate disease and CAD-RADS 4 severe disease. CAD analyses were adjusted for modifiable (hypertension, dyslipidaemia, diabetes, body mass index) and non-modifiable (age, past smoking, family history, breast cancer) risk factors. Logistic regression was performed with results presented as Odds Ratio (OR) and [95% Confidence Intervals]. Results Among 153 patients (mean age 62±10), 103 (67.3%) had low BD (high breast adiposity). Compared with high BD, low BD patients were older, had greater rates of hypertension, had significantly higher mean EAT (106.6 ± 43.0 vs 81.0 ± 31.6ml, p<0.001) (Figure 1), and body mass index (30.5 ± 6.3 vs 26.4 ± 5.4kg/m², p<0.001). Adjusted for age and hypertension, EATv remained independently predictive of low BD (OR:1.02 [1.01-1.03], p=0.006). Low BD made up a higher proportion of mild (76.5%), moderate (73.9%) and severe (80.0%) disease. Low BD was strongly associated with presence of CAD (prevalence 75% vs 48%, OR 3.21 [1.58-6.53], p=0.001) independent of EATv (p=0.25), and independent of modifiable (OR: 2.69 [1.24-5.92], p=0.012) and non-modifiable (OR: 2.42 [1.04-5.85], p=0.047) risk factors (Figure 2). Conclusions Low breast density is associated with higher EATv and independently associated with CAD presence beyond EATv and other risk factors. Consequently, mammographic breast density may act as an early risk identification tool for CAD in women.

High BMI Is Associated with Changes in Peritumor Breast Adipose Tissue That Increase the Invasive Activity of Triple-Negative Breast Cancer Cells

Breast cancer is the most common cancer in women with multiple risk factors including smoking, genetics, environmental factors, and obesity. Smoking and obesity are the top two risk factors for the development of breast cancer. The effect of obesity on adipose tissue mediates the pathogenesis of breast cancer in the context of obesity. Triple-negative breast cancer (TNBC) is a breast cancer subtype within which the cells lack estrogen, progesterone, and HER2 receptors. TNBC is the deadliest breast cancer subtype. The 5-year survival rates for patients with TNBC are 8–16% lower than the 5-year survival rates for patients with estrogen-receptor-positive breast tumors. In addition, TNBC patients have early relapse rates (3–5 years after diagnosis). Obesity is associated with an increased risk for TNBC, larger TNBC tumors, and increased breast cancer metastasis compared with lean women. Thus, novel therapeutic approaches are warranted to treat TNBC in the context of obesity. In this paper, we show that peritumor breast adipose-derived secretome (ADS) from patients with a high (>30) BMI is a stronger inducer of TNBC cell invasiveness and JAG1 expression than peritumor breast ADS from patients with low (<30) BMI. These findings indicate that patient BMI-associated changes in peritumor AT induce changes in peritumor ADS, which in turn acts on TNBC cells to stimulate JAG1 expression and cancer cell invasiveness.

Randomized dose-response trial of n-3 fatty acids in hormone receptor negative breast cancer survivors- impact on breast adipose oxylipin and DNA methylation patterns.

Increasing evidence suggests the unique susceptibility of estrogen receptor and progesterone receptor negative (ERPR-) breast cancer to dietary fat amount and type. Dietary n-3 polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), may modulate breast adipose fatty acid profiles and downstream bioactive metabolites to counteract pro-inflammatory, pro-carcinogenic signaling in the mammary microenvironment. To determine effects of ~1 to 5 g/d EPA+DHA over 12 months on breast adipose fatty acid and oxylipin profiles in women with ERPR(-) breast cancer, a high-risk molecular subtype. We conducted a 12-month randomized controlled, double-blind clinical trial of ~5g/d vs ~1g/d DHA+EPA supplementation in women within 5 years of completing standard therapy for ERPR(-) breast cancer Stages 0-III. Blood and breast adipose tissue specimens were collected every 3 months for biomarker analyses including fatty acids by gas chromatography, oxylipins by LC-MS/MS, and DNA methylation by reduced-representation bisulfite sequencing (RRBS). A total of 51 participants completed the 12-month intervention. Study treatments were generally well-tolerated. While both doses increased n-3 PUFAs from baseline in breast adipose, erythrocytes, and plasma, the 5g/d supplement was more potent (n =51, p <0.001). The 5g/d dose also reduced plasma triglycerides from baseline (p =0.008). Breast adipose oxylipins at 0, 6, and 12 months showed dose-dependent increases in unesterified and esterified DHA and EPA metabolites (n =28). Distinct DNA methylation patterns in adipose tissue after 12 months were identified, with effects unique to the 5g/d dose group (n =17). Over the course of 1 year, EPA+DHA dose-dependently increased concentrations of these fatty acids and their derivative oxylipin metabolites, producing differential DNA methylation profiles of gene promoters involved in metabolism-related pathways critical to ERPR(-) breast cancer development and progression. These data provide evidence of both metabolic and epigenetic effects of n-3 PUFAs in breast adipose tissue, elucidating novel mechanisms of action for high-dose EPA+DHA-mediated prevention of ERPR(-) breast cancer.

Characterization of Commercial and Custom-Made Printing Filament Materials for Computed Tomography Imaging of Radiological Phantoms

In recent years, material extrusion-based additive manufacturing, particularly fused filament fabrication (FFF), has gained significant attention due to its versatility and cost-effectiveness in producing complex geometries. This paper presents the characterization of seven novel materials for FFF and twenty-two commercially available filaments in terms of X-ray computed tomography (CT) numbers, as tissue mimicking materials for the realization of 3D printed radiological phantoms. Two technical approaches, by 3D printing of cube samples and by producing cylinders of melted materials, are used for achieving this goal. Results showed that the CT numbers, given in Hounsfield unit (HU), of all the samples depended on the beam kilovoltage (kV). The CT numbers ranged from +411 HU to +3071 HU (at 80 kV), from −422 HU to +3071 HU (at 100 kV), and from −442 HU to +3070 HU (at 120 kV). Several commercial and custom-made filaments demonstrated suitability for substituting soft and hard human tissues, for realization of 3D printed phantoms with FFF in CT imaging. For breast imaging, an anthropomorphic phantom with two filaments could be fabricated using ABS-C (conductive acrylonitrile butadiene styrene) as a substitute for breast adipose tissue, and ASA-A (acrylic styrene acrylonitrile) for glandular breast tissue.

Understanding tissue-resident macrophages unlocks the potential for novel combinatorial strategies in breast cancer.

Tissue-resident macrophages (TRMs) are an integral part of the innate immune system, but their biology is not well understood in the context of cancer. Distinctive resident macrophage populations are identified in different organs in mice using fate mapping studies. They develop from the yolk sac and self-maintain themselves lifelong in specific tissular niches. Similarly, breast-resident macrophages are part of the mammary gland microenvironment. They reside in the breast adipose tissue stroma and close to the ductal epithelium and help in morphogenesis. In breast cancer, TRMs may promote disease progression and metastasis; however, precise mechanisms have not been elucidated. TRMs interact intimately with recruited macrophages, cytotoxic T cells, and other immune cells along with cancer cells, deciding further immunosuppressive or cytotoxic pathways. Moreover, triple-negative breast cancer (TNBC), which is generally associated with poor outcomes, can harbor specific TRM phenotypes. The influence of TRMs on adipose tissue stroma of the mammary gland also contributes to tumor progression. The complex crosstalk between TRMs with T cells, stroma, and breast cancer cells can establish a cascade of downstream events, understanding which can offer new insight for drug discovery and upcoming treatment choices. This review aims to acknowledge the previous research done in this regard while exploring existing research gaps and the future therapeutic potential of TRMs as a combination or single agent in breast cancer.

Breast volume in non-obese females is related to breast adipose cell hypertrophy, inflammation, and COX2 expression.

Breast hypertrophy seems to be a risk factor for breast cancer and the amount and characteristics of breast adipose tissue may play important roles. The main aim of this study was to investigate associations between breast volume in normal weight women and hypertrophic adipose tissue and inflammation. Fifteen non-obese women undergoing breast reduction surgery were examined. Breast volume was measured with plastic cups and surgery was indicated if the breast was 800 ml or larger according to Swedish guidelines. We isolated adipose cells from the breasts and ambient subcutaneous tissue to measure cell size, cell inflammation and other known markers of risk of developing breast cancer including COX2 gene activation and MAPK, a cell proliferation regulator. Breast adipose cell size was characterized by cell hypertrophy and closely related to breast volume. The breast adipose cells were also characterized by being pro-inflammatory with increased IL-6, IL-8, IL-1β, CCL-2, TNF-a and an increased marker of cell senescence GLB1/β-galactosidase, commonly increased in hypertrophic adipose tissue. The prostaglandin synthetic marker COX2 was also increased in the hypertrophic cells and COX2 has previously been shown to be an important marker of risk of developing breast cancer. Interestingly, the phosphorylation of the proliferation marker MAPK was also increased in the hypertrophic adipose cells. Taken together, these findings show that increased breast volume in non-obese women is associated with adipose cell hypertrophy and dysfunction and characterized by increased inflammation and other markers of increased risk for developing breast cancer. Projektdatabasen FoU i VGR, project number: 249191 (https://www.researchweb.org/is/vgr/project/249191).

Oxylipins in Breast Implant-Associated Systemic Symptoms.

A subset of females with breast implants have reported a myriad of nonspecific systemic symptoms collectively termed systemic symptoms associated with breast implants (SSBI). SSBI symptoms are similar to manifestations associated with autoimmune and connective tissue disorders. Breast tissue is rich in adipose cells, comprised of lipids. Insertion of an implant creates an oxidative environment leading to lipid oxidation. Oxylipins can influence immune responses and inflammatory processes. In this study we explored the abundance of a spectrum of oxylipins in the periprosthetic tissue surrounding the breast implant. Because oxylipins are immunogenic, we sought to determine if they were associated with the SSBI patients. We have also attempted to determine if the common manifestations exhibited by such patients have any association with oxylipin abundance. The study included 120 patients divided into 3 cohorts. We analyzed 46 patients with breast implants exhibiting manifestations associated with SSBI; 29 patients with breast implants not exhibiting manifestations associated with SSBI (control cohort I, non-SSBI); and 45 patients without implants (control cohort II, no-implant tissue). Lipid extraction and oxylipin quantification were performed with liquid chromatography mass spectrometry (LC-MS/MS). LC-MS/MS targeted analysis of the breast adipose tissue was performed. Of the 15 oxylipins analyzed, 5 exhibited increased abundance in the SSBI cohort when compared to the non-SSBI and no-implant cohorts. The study documents the association of the oxylipins with each manifestation reported by the patient. This study provides an objective assessment of the subjective questionnaire, highlighting which symptoms may be more relevant than the others.

Characterization of selected additive manufacturing materials for synchrotron monochromatic imaging and broad-beam radiotherapy at the Australian synchrotron-imaging and medical beamline

Objective. This study aims to characterize radiological properties of selected additive manufacturing (AM) materials utilizing both material extrusion and vat photopolymerization technologies. Monochromatic synchrotron x-ray images and synchrotron treatment beam dosimetry were acquired at the hutch 3B and 2B of the Australian Synchrotron-Imaging and Medical Beamline. Approach. Eight energies from 30 keV up to 65 keV were used to acquire the attenuation coefficients of the AM materials. Comparison of theoretical, and experimental attenuation data of AM materials and standard solid water for MV linac was performed. Broad-beam dosimetry experiment through attenuated dose measurement and a Geant4 Monte Carlo simulation were done for the studied materials to investigate its attenuation properties specific for a 4 tesla wiggler field with varying synchrotron radiation beam qualities. Main results. Polylactic acid (PLA) plus matches attenuation coefficients of both soft tissue and brain tissue, while acrylonitrile butadiene styrene, Acrylonitrile styrene acrylate, and Draft resin have close equivalence to adipose tissue. Lastly, PLA, co-polyester plus, thermoplastic polyurethane, and White resins are promising substitute materials for breast tissue. For broad-beam experiment and simulation, many of the studied materials were able to simulate RMI457 Solid Water and bolus within ±10% for the three synchrotron beam qualities. These results are useful in fabricating phantoms for synchrotron and other related medical radiation applications such as orthovoltage treatments. Significance and conclusion. These 3D printing materials were studied as potential substitutes for selected tissues such as breast tissue, adipose tissue, soft-tissue, and brain tissue useful in fabricating 3D printed phantoms for synchrotron imaging, therapy, and orthovoltage applications. Fabricating customizable heterogeneous anthropomorphic phantoms (e.g. breast, head, thorax) and pre-clinical animal phantoms (e.g. rodents, canine) for synchrotron imaging and radiotherapy using AM can be done based on the results of this study.

Abstract PO3-19-02: White Button Mushroom and Biomarkers of Immune Cell and Inflammatory Responses in Obese Postmenopausal Women at High Risk of Breast Cancer

Abstract Background: White Button Mushroom (WBM), Agaricus bisporus, has anti-tumor and anti-inflammatory effects. Oral WBM mitigated the effects of a high fat diet on hepatic steatosis and insulin resistance in ovariectomized mice. A Phase I trial of WBM in men with prostate cancer demonstrated decreased myeloid derived suppressor cells (MDSC) in those with decreased PSA; MDSC have been linked to different cancers, including breast, and conditions of chronic inflammation. Design: This is a preliminary evidence trail in postmenopausal, obese women at high risk of breast cancer with a single intervention arm of 14g of WBM taken as 28 tablets daily for 3 months to assess effects on inflammation. Participants undergo a physical exam, measuring height, weight, and waist circumference, an optional fine needle aspiration (FNA) of breast tissue, a blood draw, a food frequency questionnaire and a 24-hour food recall at baseline and final visits. Participants are contacted monthly for tolerance and adherence. Blood samples and FNA adipose are used for metabolic measurements and processed for biomarkers of inflammation and immune response. Peripheral blood mononuclear cells (PBMC) will be used for RNA single-cell analysis to assess for immune cell profiles and expression with an interest in evaluating MDSC. Red blood cells will be assessed for fatty acid profiles. Eligibility: Postmenopausal, obese (BMI ≥30, Asian ≥25) women with high risk for breast cancer who can swallow pills are eligible. Patients are high risk if their relative risk of breast cancer is ≥2 times that of the general population; this includes women with a strong family history, a genetic mutation associated with hereditary breast cancer, a high-risk breast histology, Gail model 5-year risk &amp;gt;1.67, or a previous history of stage I-II breast cancer. Participants are excluded for an active malignancy within 5 years, ongoing active or preventative cancer treatment, or lab abnormalities of serum creatinine and total bilirubin &amp;gt;1.5 the upper limit of normal, hemoglobin of &amp;lt; 9.0 g/dL, platelets of &amp;lt; 100,000/mm3, or a total white blood cell count of &amp;lt; 3,500/mm3. Participants cannot be taking mushroom supplements, immunosuppressants, or non-steroidal anti-inflammatories. Specific Aims: This study aims to evaluate the effects of WBM on regulating immune response and inflammation in obese women at high risk for breast cancer. Our primary objective is the assessment of PBMC, specifically MDSC immune profiles before and after treatment. Our secondary objective is to evaluate changes in biomarkers of inflammation, immune cell profiles in breast adipose tissue, BMI, waist circumference, and metabolic biomarkers. Additionally, the study aims to assess tolerability of the WBM dose and effects on diet quality. Statistical Methods: 26 patients will provide 80% power to detect a change in %MDSC of -0.67, assuming a standard deviation of 1.15, and a 2-sided type I error of 5%. We will have similar power to evaluate changes in other immune subsets, inflammatory markers, metabolic markers, anthropometric measurements, and diet quality. FNA adipose tissue analysis will be used as a safety signal to evaluate the potential for unwanted inflammation with taking WBM. 13 patients with FNA will provide 80% power to detect a change of 85% of the standard deviation of the difference in the measure of biomarkers such as Interleukin-6 with a 2-sided type I error of 5%. As a safety signal, the signal will be reported without adjustment for multiple comparisons. Any conclusions based on such secondary endpoints will make note of the multiple comparison issue. Accrual: The accrual target is 26 evaluable patients with an estimated need to enroll 31. The study has enrolled 27 patients, 14 completed the study and 5 are currently on treatment. 8 participants were removed; 3 never started treatment, 1 was diagnosed with breast cancer, and 4 had other medical issues preventing continuation. Contact: Jessica Dzubnar, MD: jdzubnar@coh.org Citation Format: Jessica Dzubnar, Lisa Yee, Shiuan Chen. White Button Mushroom and Biomarkers of Immune Cell and Inflammatory Responses in Obese Postmenopausal Women at High Risk of Breast Cancer [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 PO3-19-02.

Abstract PO4-27-11: Fat grafting is oncologically safe during implant-based breast reconstruction and mastectomy after radiotherapy for breast cancer or Hodgkin Lymphoma: results of a multicentric study

Abstract Background. Fat grafting during or after mastectomy could promote the regeneration of irradiated tissues, thus improving tissue softness, increasing patient comfort and ameliorating quality of life. However, there are no conclusive data about the oncological safety of fat grafting, especially in terms of risk of tumor recurrences. The most appropriate timing of adipose tissue transplant is also debated, especially in patients with locoregional breast cancer (BC) recurrence undergoing salvage mastectomy and implant-based breast reconstruction after breast conserving surgery and radiotherapy. Methods. We conducted a prospective, multicentric Italian study to investigate the oncological safety of fat grafting between June 2007 and March 2022. One hundred sixty-three patients who had previously received radiotherapy, either as adjuvant treatment after breast conservative surgery (N=154), or as a treatment of Hodgkin Lymphoma (N=9), underwent mastectomy (simple mastectomy, NAC-sparing and skin-sparing mastectomy) and implant-based, two-stage breast reconstruction. Inclusion criteria were: age between 25 and 75 years, absence of concomitant malignancies, grade 2 or 3 of Breast post Radiotherapy Reconstruction with ExpAnder Score Test (B.R.R.E.A.S.T. score) (Tab 1). Patient BMI, hypertension, smoking history, diabetes and having received neoadjuvant chemotherapy were not considered as exclusion criteria. Contextual mastectomy and expander positioning were performed during first stage (stage I), while substitution of the expander with definitive implant occurred during second stage (stage II). Fat grafting could be performed during stage I, between stage I and II surgery, or during stage II. Results. One hundred sixty-nine mastectomy procedures (six bilateral) and first-stage implant-based reconstructions with expander were performed either as prophylactic surgery (N=23) or for the treatment of primary or recurrent BC (N=146). Thirty-four patients had ductal carcinoma in situ, whereas 112 patients had invasive disease, including: 17 patients with Luminal A BC, 67 patients with Luminal B HER2-negative BC, 3 patients with Luminal B HER-2 positive BC, 7 patients with HER-2 positive BC and 18 patients had triple-negative BC. One hundred thirty-six (80.5%) patients received at least one fat grafting. Eighty-six patients (52.8%) have received second-stage definitive implant. With a median time of observation of 25.1 months, we observed four locoregional cancer recurrences (2.4%), one of which in axillary lymph nodes. All tumor recurrences occurred in patients who had received fat grafting. Eight patients (4.9%) developed distant metastases (liver, lung, lymph nodes, and bone metastases); of these, four patients (50%) had received fat grafting. No death events occurred. Conclusion. Fat grafting after radiotherapy of the breast is associated with a low incidence of locoregional tumor recurrences and distant metastases. Although our findings need to be confirmed in larger, multicentric clinical studies, fat grafting is a safe and useful technique that can be proposed for breast reconstruction after irradiation. Table. Breast post Radiotherapy Reconstruction with ExpAnder Score Test, B.R.R.E.A.S.T score. Based on our experience, we thought to include two tissue characteristics (Pinch test ≥ 0.5 cm and presence/absence of skin teleangectasia or severe dyscromia) in a pre-operative, clinically useful, and ready-to-use score to assess soft tissue adequacy as recommended by NCCN guidelines, that we called Breast post Radiotherapy Reconstruction with ExpAnder Score Test (B.R.R.E.A.S.T. score). In our study, two-stage implant-based breast reconstruction and adipose tissue transplant with regenerative intent were performed in patients with Pinch test ≥ 0.5 cm but moderate skin teleangectasia or dyscromia (B.R.R.E.A.S.T. score 2) and in patients with Pinch test ≥ 0.5 cm and absence of skin teleangectasia or severe dyscromia (B.R.R.E.A.S.T. score 3). Patients with skin teleangectasia or dyscromia and Pinch test &amp;lt; 0.5 cm (B.R.R.E.A.S.T. score 1) were not enrolled in our study as they did not undergo alloplastic breast reconstruction but they underwent autologous reconstruction (data not shown). Citation Format: Chiara Listorti, Claudio Vernieri, Francesco Barretta, Chiara Osio, Ilaria Maugeri, Federica Pilotta, Cristina Ferraris, Massimiliano Gennaro, Gabriele Martelli, Marco Visaggio, Giulia Valeria Bianchi, Serena Di Cosimo, Gianfranco Scaperrotta, Maria Carmen De Santis, Daniela Tognali, Antonino Romeo, Matteo Mingozzi, Francesco Marongiu, Annalisa Curcio, Secondo Folli. Fat grafting is oncologically safe during implant-based breast reconstruction and mastectomy after radiotherapy for breast cancer or Hodgkin Lymphoma: results of a multicentric study [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 PO4-27-11.

Breast Adiposity: Menopausal Status Impact and its Influence on Glycemic and Anthropometric Metabolic Parameters.

Ectopic fat depots are related to the deregulation of energy homeostasis, leading to diseases related to obesity and metabolic syndrome (MetS). Despite significant changes in body composition over women's lifespans, little is known about the role of breast adipose tissue (BrAT) and its possible utilization as an ectopic fat depot in women of different menopausal statuses. We aimed to assess the relationship between BrAT and metabolic glycemic and lipid profiles and body composition parameters in adult women. In this cross-sectional study, we enrolled adult women undergoing routine mammograms and performed history and physical examination, body composition assessment, semi-automated assessment of breast adiposity (BA) from mammograms, and fasting blood collection for biochemical analysis. Correlations and multivariate regression analysis were used to examine associations of BA with metabolic and body composition parameters. Of the 101 participants included in the final analysis, 76.2% were in menopause, and 23.8% were in premenopause. The BA was positively related with fasting plasma glucose, glycated hemoglobin, homeostasis model assessment of insulin resistance, body mass index, waist circumference, body fat percentage, and abdominal visceral and subcutaneous fat when adjusted for age among women in postmenopause. Also, the BA was an independent predictor of hyperglycemia and MetS. These associations were not present among women in premenopause. The BA was related to different adverse body composition and metabolic factors in women in postmenopause. The results suggest that there might be a relevant BrAT endocrine role during menopause, with mechanisms yet to be clarified, thus opening up research perspectives on the subject and potential clinical implications.

Abstract 3935: Involvement of nanoscale physical communication in obesity-associated breast cancer severity

Abstract Obesity is a risk factor for several cancers, including breast cancer, and contributes up to 20% of cancer-related deaths. Growing evidence from both clinical and preclinical studies indicates that increased obesity is associated with increases in cancer incidence, progression, metastasis, and therapeutic resistance. According to the Centers for Disease Control and Prevention (CDC), more than 70% and 40% of American adults can be classified as overweight and obese, respectively. However, treatment strategies for dealing with cancer in obese patients have not advanced apart from lifestyle interventions. However, several signaling mechanisms have been proposed related to the inflammatory and metabolic impact of obese adipocytes in promoting cancer progression. However, a lack of mechanistic understanding led to no specific treatment strategies have been proposed which can specifically downregulate the key regulator by which obese adipocytes promote cancer progression. Thus, translational research initiatives are immediately needed to provide mechanistic justifications for these striking statistics in order to better serve this growing segment of the population. Here, we have shown the role of nanoscale physical communication between breast cancer cells and adipose tissue in promoting cancer progression. Using high-resolution optical and electron microscopy, we have found that breast cancer cells form nanoscale tubular communications with obese adipocytes. Moreover, the cancer cells hijack mitochondria from obese adipocytes. However, coculturing cancer cells and obese adipocytes in the Boyden chamber, allowing exosomal and paracrine communication but blocking direct physical communication, revealed negligible mitochondria transfer. This observation indicates an active transfer of mitochondria via nanotube. A significantly higher rate of mitochondria transfer from obese adipocytes to cancer cells has been observed than non-differentiated pre-adipocytes. The transfer of mitochondria results in an increase in the metabolism of the cancer cells. The mechanistic investigation of the nanotube formation revealed actin's presence as the major component in the nanotube. The exocyst-GTPase protein complex has a prime contribution in actin remodeling and nanotube formation. Inhibition of exocyst-GTPase using a pharmacological inhibitor results in a significant reduction in nanotube-mediated mitochondria transfer. Conclusion: Our goal is to (i) investigate the direct physical connection between adipocytes and cancer cells and the effect on cancer progression and (ii) eliminate mortality related to obesity-associated breast cancer severity by introducing a new therapeutic strategy. Here, we have shown how cancer cells communicate with obese adipocytes and receive additional metabolic power for proliferation. The in vivo investigation of the same is under progress. Citation Format: Tanmoy Saha, Balaaji Baanupriya Srinivasan, Shiladitya Sengupta. Involvement of nanoscale physical communication in obesity-associated breast cancer severity [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 3935.

PPARγ antagonists induce aromatase transcription in adipose tissue cultures

Aromatase is the rate-limiting enzyme in the biosynthesis of estrogens and a key risk factor for hormone receptor-positive breast cancer. In postmenopausal women, estrogens synthesized in adipose tissue promotes the growth of estrogen receptor positive breast cancers. Activation of peroxisome proliferator-activated receptor gamma (PPARγ) in adipose stromal cells (ASCs) leads to decreased expression of aromatase and differentiation of ASCs into adipocytes. Environmental chemicals can act as antagonists of PPARγ and disrupt its function. This study aimed to test the hypothesis that PPARγ antagonists can promote breast cancer by stimulating aromatase expression in human adipose tissue.Primary cells and explants from human adipose tissue as well as A41hWAT, C3H10T1/2, and H295R cell lines were used to investigate PPARγ antagonist-stimulated effects on adipogenesis, aromatase expression, and estrogen biosynthesis. Selected antagonists inhibited adipocyte differentiation, preventing the adipogenesis-associated downregulation of aromatase. NMR spectroscopy confirmed direct interaction between the potent antagonist DEHPA and PPARγ, inhibiting agonist binding. Short-term exposure of ASCs to PPARγ antagonists upregulated aromatase only in differentiated cells, and a similar effect could be observed in human breast adipose tissue explants. Overexpression of PPARG with or without agonist treatment reduced aromatase expression in ASCs.The data suggest that environmental PPARγ antagonists regulate aromatase expression in adipose tissue through two mechanisms. The first is indirect and involves inhibition of adipogenesis, while the second occurs more acutely.

The Immunohistochemical Profile of Mammary Tissue in Women With Macromastia and Its Potential Clinical Implications.

Macromastia is an excessive, rapid, or slow growth of breast tissue in 1 or both breasts. While macromastia represents a benign lesion, it may cause breast, shoulder, back, and neck pain, poor posture, infections, and loss of nipple sensation. The pathogenesis of macromastia or hypertrophy of mammary tissue remains poorly understood. The purpose of this study is to investigate the immunohistochemical expression of several hormone receptors that may potentially influence the growth of breast tissue in women with macromastia. Immunohistochemical studies performed on representative sections of breast tissue from 63 patients diagnosed with macromastia included estrogen receptor, progesterone receptor, androgen receptor (AR), prolactin receptor, growth hormone receptor, and vascular endothelial growth factor. The expression of each stain was evaluated separately in the glandular epithelium and adipose tissue and calculated as an H-score. We observed that AR expression in breast glandular and adipose tissue in women with macromastia was significantly lower than benign, nonhypertrophic breast tissue of a control group. Although the analyses were controlled for the age, the fact the mean age and hormonal status differed between the patients and the controls could have affected the results. Additional large studies will be required to further verify this finding and increase the knowledge about the etiology of this condition and then guide pharmacological treatment of juvenile and/or idiopathic gigantomastia.

Investigation of Tissue Components Impacts on Dose Enhancement Factor Using Monte Carlo Code

Despite the progress of science in cancer treatments and radiotherapy improvements, there are still several side effects that occur during tumors treatment, particularly on healthy tissues surrounded tumors. Newer treatment methods are being explored lately, one of which is the use of nanoparticles, wherein the tumor is injected with gold nanoparticles. Its aim is to enhance tumor sensitivity to radiation and reduce radiation damage to healthy tissues. Tissue type may play an effective role in enhancing the dose being received under the use of nanoparticles. This study aims to find the effect of different tissue components on dose enhancement factor through MCNP6 and GATE simulations, as well as to accurately compare the simulation results of these two code packages for dose enhancement factors. A 125I brachytherapy source was simulated in phantoms for five tissues or materials (adipose tissue, breast tissue, soft tissue, water, and brain tissue). MCNP6 simulation code was validated by comparing its results with a previous study by Cho et al. Gold nanoparticles were injected as a mixture at a concentration of 7 mg/g into tissues inside a tumor. MCNP6 and GATE simulation results were compared. It was estimated from MCNP simulations that the highest radiation dose enhancement of 2.34 occurs in adipose tissue while lowest dose enhancement of 1.69 is in brain. In comparison, from GATE results, the estimates were that the highest value of dose enhancement factor also occurred in adipose tissue at 2.01, and the lowest value in brain at 1.48. The comparison between two codes suggest that they are compatible with the percentage difference in all tissues being less than 15 %. This study confirms that both MCNP6 and GATE codes could calculate DEF for different tissues under irradiation from a low-energy source.

Presence of crown-like structures in breast adipose tissue; differences between healthy controls, BRCA1/2 gene mutation carriers and breast cancer patients.

Crown-like structures (CLS) in breast adipose tissue are associated with inflammation and a potential factor in breast cancer behaviour. Whether this effect varies between breast cancer subtypes and is influenced by BMI and BRCA mutation status is presently unknown. Therefore, we compared CLS presence between adipose tissue of healthy controls, BRCA1/2 gene mutation carriers and breast cancer patients, and assessed the relation of CLS with clinical outcome in breast cancer patients. Immunohistochemical staining for CD68 was performed on breast adipose tissue sections of 48 healthy controls, 78 BRCA1/2 gene mutation carriers and 259 breast cancer patients. CLS presence and index (CLS/cm2) were correlated with BMI, BRCA status, tumour presence, intrinsic tumour subtype and tumour characteristics. Associations with clinical outcome were assessed. CLS were more often present in breast cancer patients compared to BRCA carriers and healthy controls. CLS presence was associated with the presence of breast cancer and high BMI. CLS were more often present in Luminal-B-like tumours compared to the other subtypes. No correlations between CLS and BRCA status or age was found. In TNBC, CLS were related to lymphovascular invasion. No association with survival was found. In conclusion, CLS were more frequently present in breast adipose tissue of breast cancer patients compared to BRCA1/2 gene mutation carriers and healthy controls. Furthermore, our study provides evidence of the association between obesity and presence of CLS. The prognostic significance and impact on clinical outcome of differences in CLS numbers should be further assessed in prospective studies.

Abstract B087: Racial disparities in breast cancer survival: Examining the potential role of neighborhood deprivation and breast adipose tissue inflammation

Abstract Background: Previous studies have found the Black-White disparity in breast cancer survival is greatest among women living in neighborhoods of high socioeconomic status (i.e., low % poverty). This study aimed to examine the association between race and breast cancer mortality according to neighborhood deprivation, a more comprehensive measure of neighborhood socioeconomic status. We also explored the association between neighborhood deprivation and the presence of breast adipose tissue inflammation as a potential biologic mechanism underlying the association. Methods: We examined Black-White disparities in breast cancer mortality overall and stratified by neighborhood deprivation status among 37,369 Black and White women in the Georgia Cancer Registry who were diagnosed with a first primary Stage I-IIIA breast cancer between 2010 and 2017 and followed until December 31, 2019. Cox proportional hazards regression models were used to calculate hazard ratios (HR) and 95% confidence intervals (CI). In a separate analysis, we examined the presence of crown-like structures in breast adipose tissue (CLS-B), detected by CD68 immunohistochemistry, among 342 women with stage I–III breast cancer who underwent mastectomy at Emory University Hospitals in Atlanta, Georgia (2007–2012). Logistic regression models were used to estimate odds ratios (OR) and 95% CIs. For both cohorts of breast cancer patients, neighborhood deprivation was assessed dichotomously using census tract at diagnosis and the neighborhood deprivation index (NDI), which was computed using American Community Survey 5-year estimates for census tracts in Georgia. Results: In Georgia, we found Black women with breast cancer had ~1.8 times higher rate of breast cancer mortality than their White counterparts (age-adj. HR=1.78, 95% CI: 1.63, 1.94). The disparity was attenuated after adjusting for stage and molecular subtype but was not eliminated (multivariable (MV)-adj. HR=1.32, 95% CI: 1.21, 1.45). When stratified by NDI, the disparity was greater among women living in neighborhoods of low deprivation (MV-adj. HR=1.44, 95% CI: 1.26, 1.64) compared to high deprivation (MV-adj. HR=1.17, 95% CI: 1.03, 1.33). Among Emory breast cancer patients, we found high neighborhood deprivation was inversely associated with CLS-B (age- and race-adj. OR=0.48, 95% CI; 0.26, 0.87). We also found Black patients were more likely than their White counterparts to have CLS-B in low deprivation neighborhoods (age-adj. OR=1.79, 95% CI: 0.98, 3.25) but not in high deprivation neighborhoods (age-adj. OR=0.73, 95% CI: 0.24, 2.20), albeit estimates were imprecise. Conclusion: Our study using a population-based cohort of breast cancer patients in Georgia adds to the evidence that racial disparities in breast cancer survival are worse among women living in higher socioeconomic (i.e., low deprivation) neighborhoods. Additionally, we provide evidence of a potential underlying mechanism, finding the prevalence of CLS-B higher for women in low rather than high deprivation neighborhoods, particularly Black women in this group. Citation Format: Maret L. Maliniak, Lauren E. Barber, Jasmine M. Miller-Kleinhenz, Leah Moubadder, Lauren E. McCullough. Racial disparities in breast cancer survival: Examining the potential role of neighborhood deprivation and breast adipose tissue inflammation [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr B087.

Breast adipose tissue-derived extracellular vesicles from obese women alter tumor cell metabolism.

Breast adipose tissue is an important contributor to the obesity-breast cancer link. Extracellular vesicles (EVs) are nanosized particles containing selective cargo, such as miRNAs, that act locally or circulate to distant sites to modulate target cell functions. Here, we find that long-term education of breast cancer cells with EVs obtained from breast adipose tissue of women who are overweight or obese (O-EVs) results in increased proliferation. RNA-seq analysis of O-EV-educated cells demonstrates increased expression of genes involved in oxidative phosphorylation, such as ATP synthase and NADH: ubiquinone oxidoreductase. O-EVs increase respiratory complex protein expression, mitochondrial density, and mitochondrial respiration in tumor cells. The mitochondrial complex I inhibitor metformin reverses O-EV-induced cell proliferation. Several miRNAs-miR-155-5p, miR-10a-3p, and miR-30a-3p-which promote mitochondrial respiration and proliferation, are enriched in O-EVs relative to EVs from lean women. O-EV-induced proliferation and mitochondrial activity are associated with stimulation of the Akt/mTOR/P70S6K pathway, and are reversed upon silencing of P70S6K. This study reveals a new facet of the obesity-breast cancer link with human breast adipose tissue-derived EVs causing metabolic reprogramming of breast cancer cells.

Investigation of test methods for QC in dual-energy based contrast-enhanced digital mammography systems: II. Artefacts/uniformity, exposure time and phantom-based dosimetry

Part II of this study describes constancy tests for artefacts and image uniformity, exposure time, and phantom-based dosimetry; these are applied to four mammography systems equipped with contrast enhanced mammography (CEM) capability. Artefacts were tested using a breast phantom that simulated breast shape and thickness change at the breast edge. Image uniformity was assessed using rectangular poly(methyl)methacrylate PMMA plates at phantom thicknesses of 20, 40 and 60 mm, for the low energy (LE), high energy (HE) images and the recombined CEM image. Uniformity of signal and of the signal to noise ratio was quantified. To estimate CEM exposure times, breast simulating blocks were imaged in automatic exposure mode. The resulting x-ray technique factors were then set manually and exposure time for LE and HE images and total CEM acquisition time was measured with a multimeter. Mean glandular dose (MGD) was assessed as a function of simulated breast thickness using three different phantom compositions: (i) glandular and adipose breast tissue simulating blocks combined to give glandularity values that were typical of those in a screening population, as thickness was changed (ii) PMMA sheets combined with polyethylene blocks (iii) PMMA sheets with spacers. Image uniformity was superior for LE compared to HE images. Two systems did not generate recombined images for the uniformity test when the detector was fully covered. Acquisition time for a CEM image pair for a 60 mm thick breast equivalent phantom ranged from 3.4 to 10.3 s. Phantom composition did not have a strong influence on MGD, with differences generally smaller than 10%. MGD for the HE images was lower than for the LE images, by a factor of between 1.3 and 4.0, depending on system and simulated breast thickness. When combined with the iodine signal assessment in part I, these tests provide a comprehensive assessment of CEM system imaging performance.