Abstract P1-08-10: A web-based Patient Decision Aid Toolkit for unaffected BRCA mutation carriers

Women with a pathogenic mutation in the BRCA1 or BRCA2 genes have an elevated lifetime risk of developing breast and ovarian cancer. To address this risk, women are managed with a combination of surveillance and/or risk-reduction strategies. Decisions about risk management strategies can be complex, personal and multifactorial. Women often struggle with the decision-making process. In addition, within the clinical environment, there may be variations in recommendations between clinicians that can leave women uncertain and less able to choose a risk management pathway. The overall aim of this project is the development of a web-based patient decision aid toolkit for BRCA mutation carriers that will improve the decision-making process by providing the user with information about their cancer risk, options for risk management and potential benefits and side effects. Development of the patient decision aid was guided by the International Patient Decision Aid Standards (IPDAS). With appropriate ethical approval, a mixed methods approach was used to identify suitable content for the decision aid. A decision-making needs assessment was conducted to identify the information needs of women with a BRCA mutation. Semi-structured interviews were held with cancer unaffected BRCA mutation carriers (n = 16) and key stakeholders including healthcare professionals, policy makers and patient group representatives (n= 10). Data were analysed by thematic analysis. Systematic scoping reviews were conducted to synthesise relevant evidence on risk-management options, benefits, harms and the development and testing of patient decision aids in general. Content for the decision aid was refined using a Delphi process to build consensus on items for inclusion in the decision aid amongst a diverse panel of experts (n=13). A prototype patient decision aid was developed which included written information as well as visual depictions of risk, videos and photographs to enhance the patient’s information experience. A ‘values clarification’ activity was included to enable women to work through their own values and preferences relating to risk management interventions and their associated benefits and side-effects. Initial ‘sandpit’ testing of the decision aid prototype was performed by the research team and advisory group. Usability testing was conducted with BRCA mutation carries (n = 8) and healthcare professionals (n = 8) using both qualitative interviews and quantitative surveys. The research team made final revisions to the decision aid based on participant feedback and committee consensus. This evidence-based patient decision aid can be used by BRCA mutation carriers unaccompanied or during a clinical consultation. We envisage that this decision aid will improve the decision-making process by assisting women and clinicians during shared decision-making regarding cancer risk management.

Citation Format: Sarah A. McGarrigle, Carol Spillane, Niamh Byrne, Manria Polus, Geraldine Prizeman, Amanda Drury, Elizabeth Connolly, Anne-Marie Brady, Yvonne Hanhauser. A web-based Patient Decision Aid Toolkit for unaffected BRCA mutation carriers [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-08-10.

Decision aids for female BRCA mutation carriers: a scoping review protocol

INTRODUCTION

Women who inherit a pathogenic mutation in Breast Cancer Susceptibility Genes 1 or 2 (BRCA1 or BRCA2) are at substantially higher risk of developing breast and ovarian cancer than the average woman. Several cancer risk management strategies exist to address this increased risk. Decisions about which risk management strategies to choose are complex, personal and multifactorial for these women. This scoping review will map evidence relevant to cancer risk management decision making in BRCA mutation carriers without a personal history of cancer. The objective is to identify and describe the features of patient decision aids that have been developed for BRCA mutation carriers. This information may be beneficial for designing new decision aids or adapting existing decision aids to support decision making in this population.

METHODS AND ANALYSIS

This scoping review will be conducted according to the Joanna Briggs Institute's scoping review methodological framework. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews checklist will be used for guidance. Studies on decision aids for women with a BRCA mutation who are unaffected by breast or ovarian cancer will be considered for inclusion. Five electronic databases will be searched (MEDLINE, EMBASE, Cochrane Library, CINAHL, Web of Science) with no restrictions applied for language or publication date. Studies for inclusion will be selected independently by two review authors. Data will be extracted using a predefined data extraction form. Findings will be presented in tabular form. A narrative description of the evidence will complement the tabulated results.

ETHICS AND DISSEMINATION

Ethical approval for conducting this scoping review is not required as this study will involve secondary analysis of existing literature. Findings will be published in a peer-reviewed journal and presented at relevant conferences.

Circulating tumour cell enumeration does not correlate with Miller-Payne grade in a cohort of breast cancer patients undergoing neoadjuvant chemotherapy

Purpose

The association between pathological complete response (pCR) in patients receiving neoadjuvant chemotherapy (NAC) for breast cancer and Circulating Tumour Cells (CTCs) is not clear. The aim of this study was to assess whether CTC enumeration could be used to predict pathological response to NAC in breast cancer as measured by the Miller–Payne grading system.

Methods

Twenty-six patients were recruited, and blood samples were taken pre- and post-NAC. CTCs were isolated using the ScreenCell device and stained using a modified Giemsa stain. CTCs were enumerated by 2 pathologists and classified as single CTCs, doublets, clusters/microemboli and correlated with the pathological response as measured by the Miller–Payne grading system. χ² or ANOVA was performed in SPSS 24.0 statistics software for associations.

Results

89% of patients had invasive ductal carcinoma (IDC) and 11% invasive lobular carcinoma (ILC). At baseline 85% of patients had CTCs present, median 7 (0–161) CTCs per 3 ml of whole blood. Post-chemotherapy, 58% had an increase in CTCs. This did not correlate with the Miller–Payne grade of response. No significant association was identified between the number of CTCs and clinical characteristics; however, we did observe a correlation between pre-treatment CTC counts and body mass index, p < 0.05.

Conclusions

Patients with a complete response to NAC still had CTCs present, suggesting enumeration is not sufficient to aid surgery stratification. Additional characterisation and larger studies are needed to further characterise CTCs isolated pre- and post-chemotherapy. Long-term follow-up of these patients will determine the significance of CTCs in NAC breast cancer patients.

Electronic supplementary material

The online version of this article (10.1007/s10549-020-05658-7) contains supplementary material, which is available to authorized users.

Abstract P1-02-07: Breast density, metabolic syndrome and body composition in breast cancer

Background- The metabolic syndrome (MetS) is prevalent among post-menopausal breast cancer patients and is associated with increased breast cancer risk. Mammographic breast density (BD) is also positively associated with increased breast cancer risk. The relationship between MetS and mammographic BD is unclear and requires further investigation.

Aim- The aim of this study was to examine the relationship between the MetS and its component features with breast density.

Methods - 112 post-menopausal women with breast cancer were recruited. Body composition (Body Mass Index (BMI), waist circumference (WC)) was measured objectively in participants prior to surgery. Metabolic profiles were measured in blood taken from participants prior to surgery. MetS was defined according to the International Diabetes Federation (IDF) criteria. BD was classified according to the Breast Imaging Reporting and Data System (BI-RADS). Participants were categorised into those with 'Dense' (BI-RADS score 3 or 4) or 'Less Dense' (BI-RADS score 1 or 2) breasts. Group means were compared using unpaired t-tests for parametric or Mann Whitney tests for non-parametric data. Categorical data was analysed using Fisher's exact test or Chi squared test as appropriate.

Results - An inverse relationship was observed between measures of adiposity and BD. Participants with 'dense' (BI-RADS 3/4) breasts had significantly lower BMI(p=0.0034), waist circumference(p=0.0007), systolic blood pressure(p= 0.03), circulating insulin level(p=0.009) and glycated haemoglobin(p=0.008) than those with 'less dense' (BI-RADS 1/2) breasts. HDL was significantly higher in those with 'dense' versus those with 'less dense' breasts(p= 0.03). participants with 'less dense' breasts were significantly more likely to be insulin resistant (HOMA-IR ≥2) than those with 'dense breasts' (50.6% versus 20% respectively); p=0.01.

Other components of the MetS (Serum triglycerides, glucose and diastolic blood pressure) did not differ significantly between participants with 'dense' and 'less dense' breasts. No differences in overall survival were observed between participants with 'Dense' versus those with 'Less Dense' breasts (P=0.93).

Conclusion - Although both MetS and BD are positively associated with breast cancer risk; it is unlikely that the MetS is related to an increase in breast cancer risk through a mechanism involving BD. Further work on this study is currently underway and will involve adjusting for potential confounders including age and BMI as well as examining the relationship between MetS and BD in pre-menopausal breast cancer patients.

Citation Format: Shokuhi P, McGarrigle SA, Sullivan CJ, Boyle T, Al-azawi D, O'Keeffe S, Kennedy J, Connolly EM. Breast density, metabolic syndrome and body composition in breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-02-07.

Abstract P3-09-02: Unhealthy lifestyle patterns are prevalent in unaffected BRCA mutation carriers & are associated with increased oxidative stress and telomere length alterations

The lifetime-risk of breast-cancer is greatly increased in women carrying a deleterious mutation in the BRCA1 or BRCA2 genes. Recently, there has been increased penetrance of BRCA1 and BRCA2 mutations which may be due to lifestyle influences.

There is a need to identify approaches to reduce the penetrance of BRCA 1/2 mutations. Understanding how modifiable lifestyle-factors affect cancer-risk in BRCA-mutation carriers may have implications for risk-reduction in this group. At the molecular level, oxidative-stress and telomere dysfunction are early events in cancer development and these processes may be considered surrogate markers of cancer-risk. It has been reported that BRCA-mutation carriers are more susceptible to these pro-carcinogenic processes that non-carriers.

The aim of this pilot study was to objectively measure lifestyle factors in unaffected BRCA-mutation carriers and to assess the impact of these lifestyle-factors on oxidative-stress profiles and telomere length.

Participants (n=75) were recruited from breast-cancer family-risk clinics and cancer-genetics clinics. Body-composition (BMI, waist-circumference), metabolic profiles and physical-activity (triaxial accelerometry) were measured for each participant. Serum levels of the oxidative-stress markers 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-DG) and 4-hydroxynonenal (4-HNE) were measured in a subset of participants (n=30) by ELISA. Telomere length was measured in a subset of participants (n=30) by quantitative PCR (qPCR).

Participants demonstrated poor adherence to physical-activity guidelines with 94% not reaching physical-activity levels recommended by the American College of Sports Medicine. The majority of participants were overweight (39%) or obese (32%) with 73% exhibiting abdominal obesity. 21% of participants had the metabolic syndrome (MetS) at the time of study enrolment with the majority of participants (80%) presenting with at least one feature of the MetS. Circulating levels of 8-oxo-DG did not appear to be affected by body composition or MetS status, however, serum levels of the lipid peroxidation marker 4-HNE were significantly higher in participants with the MetS (p &lt; 0.0001). Correlation of serum 4-HNE levels with individual features of the MetS and related parameters revealed significant direct correlations with waist circumference (p = 0.02), number of features of MetS (p = 0.0007), insulin (p = 0.02) insulin resistance score (HOMA-IR) (p = 0.01), HBA1c (p = 0.006), glucose (p = 0.048) and triglycerides (p &lt;0.0001). Age-adjusted telomere length was not influenced by anthropometric measurements or MetS status in this group. Moderate physical activity levels were inversely associated with age-adjusted telomere length; particularly, among post-menopausal participants (p =0.009).

This work has provided compelling evidence that in this cohort of BRCA-mutation carriers, unhealthy lifestyle-patterns are prevalent. In addition, these results suggest that the potential may exist to modify pro-carcinogenic processes in this cohort by modifying physical activity levels and targeting the metabolic syndrome and its component features lifestyle interventions and/or medication.The lifetime-risk of breast-cancer is greatly increased in women carrying a deleterious mutation in the BRCA1 or BRCA2 genes. Recently, there has been increased penetrance of BRCA1 and BRCA2 mutations which may be due to lifestyle influences.

There is a need to identify approaches to reduce the penetrance of BRCA 1/2 mutations. Understanding how modifiable lifestyle-factors affect cancer-risk in BRCA-mutation carriers may have implications for risk-reduction in this group. At the molecular level, oxidative-stress and telomere dysfunction are early events in cancer development and these processes may be considered surrogate markers of cancer-risk. It has been reported that BRCA-mutation carriers are more susceptible to these pro-carcinogenic processes that non-carriers.

The aim of this pilot study was to objectively measure lifestyle factors in unaffected BRCA-mutation carriers and to assess the impact of these lifestyle-factors on oxidative-stress profiles and telomere length.

Participants (n=75) were recruited from breast-cancer family-risk clinics and cancer-genetics clinics. Body-composition (BMI, waist-circumference), metabolic profiles and physical-activity (triaxial accelerometry) were measured for each participant. Serum levels of the oxidative-stress markers 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-DG) and 4-hydroxynonenal (4-HNE) were measured in a subset of participants (n=30) by ELISA. Telomere length was measured in a subset of participants (n=30) by quantitative PCR (qPCR).

Participants demonstrated poor adherence to physical-activity guidelines with 94% not reaching physical-activity levels recommended by the American College of Sports Medicine. The majority of participants were overweight (39%) or obese (32%) with 73% exhibiting abdominal obesity. 21% of participants had the metabolic syndrome (MetS) at the time of study enrolment with the majority of participants (80%) presenting with at least one feature of the MetS. Circulating levels of 8-oxo-DG did not appear to be affected by body composition or MetS status, however, serum levels of the lipid peroxidation marker 4-HNE were significantly higher in participants with the MetS (p &lt; 0.0001). Correlation of serum 4-HNE levels with individual features of the MetS and related parameters revealed significant direct correlations with waist circumference (p = 0.02), number of features of MetS (p = 0.0007), insulin (p = 0.02) insulin resistance score (HOMA-IR) (p = 0.01), HBA1c (p = 0.006), glucose (p = 0.048) and triglycerides (p &lt;0.0001). Age-adjusted telomere length was not influenced by anthropometric measurements or MetS status in this group. Moderate physical activity levels were inversely associated with age-adjusted telomere length; particularly, among post-menopausal participants (p =0.009).

This work has provided compelling evidence that in this cohort of BRCA-mutation carriers, unhealthy lifestyle-patterns are prevalent. In addition, these results suggest that the potential may exist to modify pro-carcinogenic processes in this cohort by modifying physical activity levels and targeting the metabolic syndrome and its component features lifestyle interventions and/or medication.

Citation Format: McGarrigle SA, Guinan EM, Hussey J, O'Sullivan J, Boyle T, Hanhauser Y, Al-azawi D, Kennedy MJ, Gallagher DJ, Connolly EM. Unhealthy lifestyle patterns are prevalent in unaffected BRCA mutation carriers & are associated with increased oxidative stress and telomere length alterations [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-09-02.

The characterization of an intestine-like genomic signature maintained during Barrett's-associated adenocarcinogenesis reveals an NR5A2-mediated promotion of cancer cell survival

Barrett’s oesophagus (BO), an intestinal-type metaplasia (IM), typically arising in conjunction with gastro-oesophageal reflux disease, is a prominent risk factor for the development of oesophageal adenocarcinoma (OAC). The molecular similarities between IM and normal intestinal tissues are ill-defined. Consequently, the contribution of intestine-enriched factors expressed within BO to oncogenesis is unclear. Herein, using transcriptomics we define the intestine-enriched genes expressed in meta-profiles of BO and OAC. Interestingly, 77% of the genes differentially expressed in a meta-profile of BO were similarly expressed in intestinal tissues. Furthermore, 85% of this intestine-like signature was maintained upon transition to OAC. Gene networking analysis of transcription factors within this signature revealed a network centred upon NR5A2, GATA6 and FOXA2, whose over-expression was determined in a cohort of BO and OAC patients. Simulated acid reflux was observed to induce the expression of both NR5A2 and GATA6. Using siRNA-mediated silencing and an NR5A2 antagonist we demonstrate that NR5A2-mediated cancer cell survival is facilitated through augmentation of GATA6 and anti-apoptotic factor BCL-XL levels. Abrogation of NR5A2-GATA6 expression in conjunction with BCL-XL co-silencing resulted in synergistically increased sensitivity to chemotherapeutics and photo-dynamic therapeutics. These findings characterize the intestine-like signature associated with IM which may have important consequences to adenocarcinogenesis.

Changes in mitochondrial stability during the progression of the Barrett's esophagus disease sequence

Background

Barrett’s esophagus follows the classic step-wise progression of metaplasia-dysplasia-adenocarcinoma. While Barrett’s esophagus is a leading known risk factor for esophageal adenocarcinoma, the pathogenesis of this disease sequence is poorly understood. Mitochondria are highly susceptible to mutations due to high levels of reactive oxygen species (ROS) coupled with low levels of DNA repair. The timing and levels of mitochondria instability and dysfunction across the Barrett’s disease progression is under studied.

Methods

Using an in-vitro model representing the Barrett’s esophagus disease sequence of normal squamous epithelium (HET1A), metaplasia (QH), dysplasia (Go), and esophageal adenocarcinoma (OE33), random mitochondrial mutations, deletions and surrogate markers of mitochondrial function were assessed. In-vivo and ex-vivo tissues were also assessed for instability profiles.

Results

Barrett’s metaplastic cells demonstrated increased levels of ROS (p < 0.005) and increased levels of random mitochondrial mutations (p < 0.05) compared with all other stages of the Barrett’s disease sequence in-vitro. Using patient in-vivo samples, Barrett’s metaplasia tissue demonstrated significantly increased levels of random mitochondrial deletions (p = 0.043) compared with esophageal adenocarcinoma tissue, along with increased expression of cytoglobin (CYGB) (p < 0.05), a gene linked to oxidative stress, compared with all other points across the disease sequence. Using ex-vivo Barrett’s metaplastic and matched normal patient tissue explants, higher levels of cytochrome c (p = 0.003), SMAC/Diablo (p = 0.008) and four inflammatory cytokines (all p values <0.05) were secreted from Barrett’s metaplastic tissue compared with matched normal squamous epithelium.

Conclusions

We have demonstrated that increased mitochondrial instability and markers of cellular and mitochondrial stress are early events in the Barrett’s disease sequence.

Levels of oxidative stress and telomeres in Lynch syndrome-associated malignancies

582

Background: Lynch Syndrome (LS) is caused by germline mutations in mismatch repair genes (MMR) genes which are critical in maintaining cellular integrity. Failure of the MMR pathway in LS culminates in the hypermutable phenotype of Microsatellite Instability. LS confers an increased risk of malignancy of which colorectal cancer (CRC) is most common. Carriers exhibit significant phenotypic variation in the age of onset of malignancy which cannot be predicted. Telomere length attrition is considered an early step in carcinogenesis and may be accelerated by oxidative stress. We investigated an association between relative telomere length (RTL) and levels of DNA oxidative damage in LS affected carriers (AC), unaffected carriers (UAC) and in patients with MMR- proficient colorectal cancer (MPC). Methods: Peripheral blood mononuclear cells were isolated from patients within each group. DNA was extracted and RTL measured by quantitative polymerase chain reaction (PCR). Real-Time PCR was used to quantitate expression levels of TERT, TERC and DKC1 (telomerase components) from RNA. Serum levels of 8-hydroxydeguanosine (8-OHdG) were measured from patients using the ELISA technique. Pearson’s correlation was used to compare mean RTL, telomerase levels and 8-OHdG between groups. Results: RTL and telomerase components were measured in 27 AC (median age 50yrs) 27 UAC (median age 40yrs) and 27 MPC (median age 66yrs). Corresponding RTLs were 0.89, 0.91 and 1.69 respectively. AC had significantly shorter RTL compared to UAC (p = 0.03) and MPC (p < 0.0001). There we no differences in the mean expression of TERT, TERC or DKC between groups. Younger age of tumour onset was associated with shorter telomere length in both AC (p = 0.0006) and MPC (p < 0.0001). 8-OHdG levels have been measured in 17 AC, 19 UAC and 14 MPC. The mean levels of AC and UAC were not statistically different. However the mean MPC level was significantly less than UAC (p = 0.03) and AC (p < 0.0001). Conclusions: Shortened telomere length is an important step in carcinogenesis. Affected LS patients have shorter telomeres and evidence of higher levels of DNA oxidative stress than patients with MMR-proficient CRC.

Polymorphisms near TBX5 and GDF7 are associated with increased risk for Barrett's esophagus

BACKGROUND & AIMS

Barrett's esophagus (BE) increases the risk of esophageal adenocarcinoma (EAC). We found the risk to be BE has been associated with single nucleotide polymorphisms (SNPs) on chromosome 6p21 (within the HLA region) and on 16q23, where the closest protein-coding gene is FOXF1. Subsequently, the Barrett's and Esophageal Adenocarcinoma Consortium (BEACON) identified risk loci for BE and esophageal adenocarcinoma near CRTC1 and BARX1, and within 100 kb of FOXP1. We aimed to identify further SNPs that increased BE risk and to validate previously reported associations.

METHODS

We performed a genome-wide association study (GWAS) to identify variants associated with BE and further analyzed promising variants identified by BEACON by genotyping 10,158 patients with BE and 21,062 controls.

RESULTS

We identified 2 SNPs not previously associated with BE: rs3072 (2p24.1; odds ratio [OR] = 1.14; 95% CI: 1.09-1.18; P = 1.8 × 10(-11)) and rs2701108 (12q24.21; OR = 0.90; 95% CI: 0.86-0.93; P = 7.5 × 10(-9)). The closest protein-coding genes were respectively GDF7 (rs3072), which encodes a ligand in the bone morphogenetic protein pathway, and TBX5 (rs2701108), which encodes a transcription factor that regulates esophageal and cardiac development. Our data also supported in BE cases 3 risk SNPs identified by BEACON (rs2687201, rs11789015, and rs10423674). Meta-analysis of all data identified another SNP associated with BE and esophageal adenocarcinoma: rs3784262, within ALDH1A2 (OR = 0.90; 95% CI: 0.87-0.93; P = 3.72 × 10(-9)).

CONCLUSIONS

We identified 2 loci associated with risk of BE and provided data to support a further locus. The genes we found to be associated with risk for BE encode transcription factors involved in thoracic, diaphragmatic, and esophageal development or proteins involved in the inflammatory response.

Abstract P2-09-16: Pre-clinical evaluation of novel anti-angiogenic agents as breast cancer therapeutics

Background

There is a need to develop novel drugs that will improve survival in breast cancer patients. Angiogenesis is essential for breast tumour progression. To date, the most promising approach to inhibit angiogenesis in breast cancer patients has been the drug bevacizumab which targets the pro-angiogenic factor Vascular Endothelial Growth Factor (VEGF). Recently, there has been controversy regarding the efficacy of bevacizumab for breast cancer treatment. In clinical trials, bevacizumab failed to establish an overall-survival benefit and was associated with serious toxicities. This resulted in the FDA revoking approval for the drug for the first line treatment of advanced breast cancer. Due to this uncertainty surrounding the efficacy of bevacizumab for the treatment of breast cancer it is clear that there is a clinical need for more effective novel anti-angiogenic drugs with better toxicity profiles for the treatment of breast cancer.

Aim

This study aimed to identify novel small-molecule anti-angiogenic agents with therapeutic potential in human breast cancer.

Methods

Compounds with physiochemical properties consistent with drug-like compounds were screened for anti-angiogenic activity by high-throughput screening involving zebrafish larvae. Human breast tumour explants were treated with the lead compound and secretion of angiogenic factors was assessed by ELISA.

Results

We have identified a novel small-molecule agent ‘SMG1’ that significantly inhibited inter-segmental blood-vessel development in zebrafish and showed no toxicity. Treatment of breast tumour explants with SMG1 significantly inhibited secretion of the potent pro-angiogenic cytokine VEGF (p = 0.01). Furthermore, SMG1 inhibited VEGF secretion more than the standard targeted breast cancer therapies tamoxifen and Herceptin® which have been reported to inhibit angiogenesis.

Conclusion

Continuing pre-clinical work will determine if SMG1 has potential as a therapeutic agent for human breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-09-16.

A prospective investigation of predictive and modifiable risk factors for breast cancer in unaffected BRCA1 and BRCA2 gene carriers

Background

Breast cancer is the most common female cancer worldwide. The lifetime risk of a woman being diagnosed with breast cancer is approximately 12.5%. For women who carry the deleterious mutation in either of the BRCA genes, BRCA1 or BRCA2, the risk of developing breast or ovarian cancer is significantly increased. In recent years there has been increased penetrance of BRCA1 and BRCA2 associated breast cancer, prompting investigation into the role of modifiable risk factors in this group. Previous investigations into this topic have relied on participants recalling lifetime weight changes and subjective methods of recording physical activity. The influence of obesity-related biomarkers, which may explain the link between obesity, physical activity and breast cancer risk, has not been investigated prospectively in this group. This paper describes the design of a prospective cohort study investigating the role of predictive and modifiable risk factors for breast cancer in unaffected BRCA1 and BRCA2 gene mutation carriers.

Methods/design

Participants will be recruited from breast cancer family risk clinics and genetics clinics. Lifestyle risk factors that will be investigated will include body composition, metabolic syndrome and its components, physical activity and dietary intake. PBMC telomere length will be measured as a potential predictor of breast cancer occurrence. Measurements will be completed on entry to the study and repeated at two years and five years. Participants will also be followed annually by questionnaire to track changes in risk factor status and to record cancer occurrence. Data will be analysed using multiple regression models. The study has an accrual target of 352 participants.

Discussion

The results from this study will provide valuable information regarding the role of modifiable lifestyle risk factors for breast cancer in women with a deleterious mutation in the BRCA gene. Additionally, the study will attempt to identify potential blood biomarkers which may be predictive of breast cancer occurrence.

Abstract P6-01-02: Adipose tissue from breast cancer patients with the metabolic syndrome promotes proliferation and invasion of tumor cells and influences expression of genes involved in carcinogenesis

Background: Obesity is a public health issue of global proportions and is recognised as a risk factor for post-menopausal breast cancer. Similarly, the metabolic syndrome (MetS) is recognised as a high risk state for cancer in general. Previously we have shown that the MetS is common in postmenopausal breast cancer patients and is associated with a more aggressive tumor biology. However, the molecular mechanisms by which obesity and/or the MetS promote breast cancer remain unclear. Adipose tissue, including mammary fat, is a functionally active endocrine organ. The aims of this study were to determine whether factors secreted by mammary adipose tissue could affect tumor cell biology and to assess the effect of the MetS on this adipose depot and its subsequent effect on tumor cells.

Methods: Adipose tissue from fresh mastectomy specimens was cultured in serum free media for 72 h to produce adipose conditioned media (ACM). MCF-7 and MDA-MB 231 cell lines were treated with ACM for 24–48 h. Tumor cell function was then assessed by measuring cell proliferation (BrDU assay) and cell invasion. In addition, expression of 84 genes implicated in pathways involved in carcinogenesis was examined in these cell lines following ACM treatment, using quantitative PCR arrays.

Results: In the estrogen receptor (ER) positive MCF-7 cell line, ACM from MetS breast cancer patients promoted significantly greater proliferation compared to ACM from normal weight patients (203.6 ± 34.23 vs 136.8 ± 11.58%, p = 0.022). Similarly, ACM from MetS patients significantly increased invasion of MCF-7 cells compared to ACM from normal weight patients (153.4 ± 6.027 vs 126.3 ± 6.03% RFU, p = 0.006). No differences in cell proliferation or invasion between cells treated with ACM from MetS patients compared to ACM from normal weight patients were found in the ER negative MDA-MB-231 cell line. Treatment of MCF-7 cells with ACM from MetS patients resulted in significant alterations (&gt;2 fold up/down regulation) in expression of 11 genes involved in carcinogenesis. Primarily, genes implicated in invasion/metastasis and adhesion were differentially expressed between ACM-treated cells and cells treated with control media. On the other hand, when MDA-MB-231 cells were treated with ACM from the same patients only one gene, SERPIN B5 was significantly up-regulated &gt; 2 fold.

Conclusions: These data demonstrate that factors secreted from mammary adipose tissue from metabolically unhealthy patients promote proliferation and invasion of ER positive tumor cells and influence expression of genes involved in carcinogenesis in these cells. These effects were not observed in ER negative tumor cells suggesting that they may be mediated, at least in part by the estrogen receptor. These results have provided insight into how mammary adipose tissue may act via a paracrine mechanism to influence aspects of carcinogenesis and into how the metabolic syndrome may modulate this.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-01-02.

MMP9 expression in oesophageal adenocarcinoma is upregulated with visceral obesity and is associated with poor tumour differentiation

Overweight and obesity is linked to increased incidence and mortality of many cancer types. Of all cancers, oesophageal adenocarcinoma (OAC) displays one of the strongest epidemiological links with obesity, accounting for up to 40% of cases, but molecular pathways driving this association remain largely unknown. This study aimed to elucidate mechanisms underpinning the association of obesity and cancer, and to determine if visceral obesity is associated with aggressive tumour biology in OAC. Following co-culture with visceral adipose tissue explants, expression of genes involved in tumour cell invasion and metastasis (matrix metalloproteinase (MMP)2 and MMP9) were upregulated between 10-fold (MMP2) and 5000-fold (MMP9), and expression of tumour suppressor p53 was downregulated 2-fold in OAC cell lines. Western blotting confirmed these results at the protein level, while zymographic analysis detected increased activity of MMPs in OAC cell lines following co-culture with adipose tissue explants. When OAC cell lines were cultured with adipose tissue conditioned media (ACM) from visceral adipose tissue, increased proliferative, migratory and invasive capacity of tumour cells was observed. In OAC patient tumour biopsies, elevated gene expression of MMP9 was associated with visceral obesity, measured by visceral fat area, while increased gene expression of MMP9 and decreased gene expression of tumour suppressor p53 was associated with poor tumour differentiation. These novel data highlight an important role for visceral obesity in upregulation of pro-tumour pathways contributing to aggressive tumour biology, and may ultimately lead to development of stratified treatment for viscerally obese OAC patients.

Pro-inflammatory and tumour proliferative properties of excess visceral adipose tissue

Obesity has been associated with increased incidence and mortality of oesophageal and colorectal adenocarcinoma. Excess central adiposity may drive this association through an altered inflammatory milieu. Utilising a unique adipose tissue bioresource we aimed to determine the pro-tumour properties of visceral adipose tissue. Comparing subcutaneous and visceral adipose tissue depots, we observed significantly higher levels of VEGF and IL-6, along with significantly higher proportions of CD8(+) T cells and NKT cells in visceral adipose tissue. Significantly higher levels of VEGF were observed in the conditioned media from visceral adipose tissue of centrally obese compared to non-obese patients. We also report a significant increase in oesophageal and colorectal tumour cell proliferation following culture with conditioned media from visceral adipose tissue of centrally obese patients. Neutralising VEGF in the conditioned media significantly decreased tumour cell proliferation. This novel report highlights a potential mechanism whereby visceral adipose tissue from centrally obese cancer patients may drive tumour progression.