Estrogen Receptor-negative Cancer Research Articles

Abstract PO1-10-02: Breast cancer among transgender and non-binary patients on gender affirming hormone therapy: a single institution experience

Abstract Background: Estrogen exposure is a known risk factor for the development of breast cancer in women. Less clear is the risk posed by gender affirming hormone therapy (GAHT) in both transgender men and transgender women. We aimed to characterize the breast cancers that have arisen in our institution’s transgender patient population including biomarker profile, method of diagnosis, and stage at diagnosis. Methods: For this retrospective cohort study, patients from the Mount Sinai Health System were identified using the electronic medical record from 2016-2023. A cohort of transgender or non-binary patients with breast cancer was established by using ICD-10 codes for carcinoma in situ of breast (D-05) and malignant neoplasm of breast (C-50) and a diagnosis or medical history encompassing gender identity disorders (ICD-10-CM: F64) or a chief complaint related to transgender health. Chart review enabled selection of patients who have a history of GAHT. Patients with incomplete medical records were excluded from analysis. Results: 14 patients met criteria and were included for final analysis. Mean age at diagnosis was 51.7 (31-65) years and 86% (12/14) were at or above 40 years of age at diagnosis and eligible for routine screening mammography. The cohort encompassed six trans men (assigned female at birth), seven trans women (assigned male at birth), and one genderqueer person (assigned female at birth). Family history was not significant for most of the cohort. Two patients had a first-degree relative with a history of breast cancer; both were BRCA negative. Four patients (29%) were diagnosed via screening mammography; six patients (43%) were diagnosed after palpating a breast or axillary mass; and four patients (29%) had not undergone screening but were diagnosed via breast imaging mandated prior to planned chest masculinization surgery. At time of initial presentation, the diagnostic stage was DCIS in five patients (36%); LCIS in one patient (7%); stage 1 cancer in four patients (29%); stage 2 cancer in three patients (21%); and breast implant-associated anaplastic large cell lymphoma in one patient (7%). 50% (7/14) of patients had an active or past prescription for testosterone-based GAHT, and 50% (7/14) patients had an active or past prescription for estrogen-based GAHT. Mean duration of all GAHT prior to diagnosis was 16.6 years (mean duration of estrogen-based GAHT was 27.6 years and mean duration for testosterone-based GAHT was 5.7 years). Biomarker profiles were available for twelve patients; 8/12 (67%) patients were diagnosed with estrogen receptor (ER) positive cancer, four (33%) with ER negative cancers. Of patients on estrogen-based GAHT, three presented with ER+ and four presented with ER- cancers. 10/14 patients had bilateral mastectomies and 4/14 had lumpectomies. Discussion/Conclusion: The mode of cancer detection suggests that screening mammography is under-utilized among transgender and non-binary patients who use GAHT. This represents a health care disparity involving a vulnerable patient population. The biomarker profile among this population demonstrates that both estrogen-responsive and estrogen-nonresponsive cancers can arise in the setting of prior or ongoing gender affirming estrogen or testosterone. Citation Format: Nithya Krishnamurthy, Ethan Ravetch, Christina Weltz. Breast cancer among transgender and non-binary patients on gender affirming hormone therapy: a single institution experience [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 PO1-10-02.

Abstract PS04-06: Breast cancer recurrence among women with pre-diagnostic major depression and co-existing substance abuse disorder: A retrospective study in the United States Veterans Health Administration Cohort

Abstract Background: Our prior study observed a 34% higher risk of breast cancer (BC) recurrence among women with major depressive disorder (MDD) at the time of their BC diagnosis compared to women without MDD after adjusting for sociodemographic, clinical, and prognostic factors. Given the high prevalence of substance abuse disorders among individuals with MDD and the positive association between alcohol use and mortality among BC survivors, we were interested to examine whether the risk of BC recurrence was compounded for women with both conditions. Objective: To investigate whether pre-diagnostic substance abuse disorders modify the association between MDD and BC recurrence. Methods: We established a retrospective cohort of women (age ≥ 18 years) with incident, early-stage BC diagnosed from 2010 through 2019 using the VHA’s electronic medical record database. A two-year window was used to identify women with MDD and co-existing substance abuse disorders prior to their BC diagnosis. We examined potential interactions between MDD and alcohol abuse and MDD and other substance abuse using multivariable proportional hazards regression, accounting for competing risk of death. Our outcome of interest was BC recurrence. The reference group for all analyses was women with BC alone. The models were adjusted for patient characteristics including age, race, ethnicity, marital status, rurality of primary residence, priority group rating (proxy for socioeconomic status), any homelessness or economic problems, comorbidity burden, body mass index, smoking status, receipt of a screening mammography, year of BC diagnosis, cancer stage, cancer subtype, and cancer treatment. Subgroup analyses were conducted by cancer subtype. Results: Our cohort comprised 6,045 women with BC, of whom 1,754 (29%) had a pre-diagnostic MDD diagnosis and 1,509 (25%) had a substance abuse disorder. Among women with MDD, 386 (22%) abused alcohol and 336 (19%) abused other substances. The median length of follow-up from BC diagnosis was 4.5 years (IQR=4.8 years). The average age at BC diagnosis was 57 years (SD=11 years) overall, 56 years (SD=10 years) among women with MDD, and 57 years (SD=9 years) among women with substance abuse disorders. On multivariable analysis, MDD (HR=1.33; 95% CI: 1.14, 1.53), alcohol abuse disorder (HR=1.37; 95% CI: 1.12, 1.68), and other substance abuse disorders (HR=1.33; 95% CI: 1.13, 1.56) were independent risk factors for BC recurrence. Further, there was a statistically significant interaction between pre-diagnostic MDD and alcohol abuse disorder (p-interaction=0.003). Women with BC who had both pre-diagnostic MDD and alcohol abuse disorder were at a 65% (HR=1.65; 95% CI: 1.29, 2.11) higher risk of BC recurrence compared to women with BC alone. A statistically significant interaction was also observed between pre-diagnostic MDD and other substance abuse disorders (p-interaction < 0.001). Women with BC who had both pre-diagnostic MDD and other substance abuse disorders were at a 90% (HR=1.90; 95% CI: 1.50, 2.42) higher risk of BC recurrence compared to women with BC alone. In subgroup analyses, the interaction between MDD and alcohol abuse disorders (p-interaction=0.001) and MDD and other substance abuse disorders (p-interaction < 0.001) was limited to women with estrogen receptor positive cancer but not estrogen receptor negative cancer. Conclusion: Women with incident BC who have prior diagnoses of both MDD and substance abuse disorder are at higher risk of recurrence than women with either exposure independently. Further research is needed to examine the etiology of our findings and to evaluate whether this newly defined risk group would benefit from closer monitoring and more tailored treatment options. Citation Format: Maya Aboumrad, Kala Visvanathan. Breast cancer recurrence among women with pre-diagnostic major depression and co-existing substance abuse disorder: A retrospective study in the United States Veterans Health Administration Cohort [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 PS04-06.

Development of near-infrared lysosomal pH-activatable fluorescent probe for real-time visualization of autophagy progression

As the central role in maintaining physiological homeostasis, tracking the autophagy in living cells is highly desired in biological research and pharmacologic development. Herein, a lysosome-targeted pH-activatable probe (Lyso-QL) with emission at near-infrared region (NIR) was developed for monitoring the progression of autophagy. During autophagy progress, the double-membraned autophagosomes are engulfed into lysosomes to provide autolysosomes, exhibiting significantly enhanced acidification. Based on the characteristic, the real-time monitoring of autophagic flux were realized by evaluating the pH changes in these acidic compartments with Lyso-QL under nutrient-deprivation conditions as well as pharmacological induction. Importantly, through the NIR changes, the modulation of tamoxifen on autophagic levels in estrogen receptor-negative cancer cells was disclosed. Further, the elevated hepatic autophagy in mice during acetaminophen-induced liver injury was revealed, and the N-acetylcysteine pretreatment was demonstrated with a certain protective effect to restore the autophagic levels. The study demonstrates probe Lyso-QL would provide an edge for mechanistic insights into autophagy and evaluating the activities of autophagy modulators.

HER2-positive/ER-low breast carcinoma shows a response to neoadjuvant chemotherapy similar to that of HER2-positive/ER-negative breast carcinoma

Negative expression of estrogen receptor (ER) predicts response to chemotherapy in breast cancers (BCs). ER negative cancers are those with less than 1 % of nuclear staining. Tumors with 1–10 % staining are sub-classified as “low-positive” (ER-low). HER2 negative tumors with ER low staining are considered biologically and clinically equivalent to ER negative tumors. This study investigates whether ER low expression in HER2-positive (HER2+) BCs has different clinical behavior than ER negative HER2-positive tumors. We used a sample of 171 patients with HER2+ BCs to compare risk of residual cancer after neoadjuvant chemotherapy by different ER expression strength. Patients were classified into 3 groups: ER-negative (ER <1 %); ER-low (ER <10 %, any intensity or <33 % staining, weak intensity); and ER-high (ER = 10–33 %, moderate to strong intensity or >33 %, any intensity). The risk of residual cancer in patients with ER-low tumors was similar to the risk in patients with ER-negative tumors (RR = 0.76, 95 % CI: 0.30–1.93). Conversely, patients with ER-high tumors had twice the risk of residual cancer than patients with ER-negative tumors (RR = 2.20, 95 % CI: 1.46–3.31). These findings persisted after adjusting for tumor grade, clinical tumor and lymph node stage, chemotherapy regimen, and progesterone receptor status. In this cohort of patients with HER2+ BCs, ER-low tumors had a similar pathologic response to chemotherapy as ER-negative tumors suggesting similar clinical behavior. Future research should address biological explanations to these similarities between ER negative and ER low breast cancers such as HER2 enriched phenomenon.

Adjuvant Capecitabine for Early Breast Cancer: 15-Year Overall Survival Results From a Randomized Trial.

Few data are available regarding the influence of adjuvant capecitabine on long-term survival of patients with early breast cancer. The Finland Capecitabine Trial (FinXX) is a randomized, open-label, multicenter trial that evaluates integration of capecitabine to an adjuvant chemotherapy regimen containing a taxane and an anthracycline for the treatment of early breast cancer. Between January 27, 2004, and May 29, 2007, 1,500 patients with axillary node-positive or high-risk node-negative early breast cancer were accrued. The patients were randomly allocated to either TX-CEX, consisting of three cycles of docetaxel (T) plus capecitabine (X) followed by three cycles of cyclophosphamide, epirubicin, and capecitabine (CEX, 753 patients), or to T-CEF, consisting of three cycles of docetaxel followed by three cycles of cyclophosphamide, epirubicin, and fluorouracil (CEF, 747 patients). We performed a protocol-scheduled analysis of overall survival on the basis of approximately 15-year follow-up of the patients. The data collection was locked on December 31, 2020. By this date, the median follow-up time of the patients alive was 15.3 years (interquartile range, 14.5-16.1 years) in the TX-CEX group and 15.4 years (interquartile range, 14.8-16.0 years) in the T-CEF group. Patients assigned to TX-CEX survived longer than those assigned to T-CEF (hazard ratio 0.81; 95% CI, 0.66 to 0.99; P = .037). The 15-year survival rate was 77.6% in the TX-CEX group and 73.3% in the T-CEF group. In exploratory subgroup analyses, patients with estrogen receptor-negative cancer and those with triple-negative cancer treated with TX-CEX tended to live longer than those treated with T-CEF. Addition of capecitabine to a chemotherapy regimen that contained docetaxel, epirubicin, and cyclophosphamide prolonged the survival of patients with early breast cancer.

Abstract 2571: Paternal epigenetic regulation contributes to the prevention of estrogen receptor-negative mammary cancer with combined broccoli sprouts and green tea polyphenols consumption in transgenic mice

Abstract Breast cancer is one of the leading causes of cancer-related death among women in the United States. It is widely appreciated that abnormal epigenetic alterations act as one of the primary contributors to breast cancer initiation and progression. Parental, including maternal and paternal, nutritional interventions have shown considerable impact on fetal development leading to different susceptibility of offspring to various chronic diseases. Moreover, combinatorial dietary administration to parents could be more efficacious in ameliorating epigenetic aberrations and changing cancer risk in an individual's later life. The bioactive dietary broccoli sprouts (BSp) and green tea polyphenol (GTP) are important epigenetic modulators that can prevent various cancers. Our study focusses on investigating the effect of paternal dietary BSp and GTP administration on mammary cancer prevention of their offspring. Two spontaneous breast cancer transgenic mouse models, C3(1)/SV40 and Her2/neu, were employed in this study. Male C3(1)/SV40 or Her2/neu transgenic mice were randomly assigned into four groups and treated with: control AIN-93G diet, 26% BSp (w/w) in food pellets, 0.5% GTPs (w/v) in drinking water or combined BSp and GTPs from 3 wks of age until 10 wks of age. Treated male mice of different groups were then mated with non-treated female mice. Female pups were selected after their weaning and tumor growth was monitored weekly until the termination of the experiment. Tumor- and epigenetic-related protein expression and histone modifications (methylation and acetylation) were measured. Our study indicated that paternal BSp or/and GTPs administration suppressed tumor growth, decreased tumor incidence, and delayed tumor latency compared with the control in both mouse models. Overall, paternal dietary intervention displayed more efficacy for mammary tumor prevention in C3(1)/SV40 mice and the combination group in this model also showed synergistically effects. Subsequent analysis with the C3(1)/SV40 mouse tumors demonstrated that paternal BSp or/and GTPs treatments upregulated the expression of tumor suppressor proteins, such as P16 and P53, and down-regulated tumor promoting proteins, such as MYC and BMI1. Moreover, altered DNA methylation, histone methylation and acetylation levels were also observed. These results suggested that paternal exposure to BSp and GTPs may contribute to ER-negative mammary tumor prevention in their offspring through epigenetic regulations and the combined addition of bioactive botanicals could be a more promising approach for coping with breast cancer initiation and progression in humans. Citation Format: Shizhao Li, Huixin Wu, Trygve Tollefsbol. Paternal epigenetic regulation contributes to the prevention of estrogen receptor-negative mammary cancer with combined broccoli sprouts and green tea polyphenols consumption in transgenic mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2571.

Impact of Adjuvant Treatment on Heparanase Concentration in Invasive, Unilateral Breast Cancer Patients: Results of a Prospective Single-Centre Cohort Study.

Background: In recent years, great progress has been made in the treatment of breast cancer, but it is still one of the ten leading causes of death in women. The aim of the study was to evaluate the heparanase concentration of invasive breast cancer (IBrC) patients, before and after cancer adjuvant treatment. Methods: Eighty patients with stage IA to IIB IBrC receiving adjuvant treatment were included prospectively in this study. The heparanase concentrations were determined by an enzyme-linked immunosorbent assay. A univariate analysis was used to estimate the factors influencing the low or high pre-treatment concentration of heparanase and the low or high numerical decrease in heparanase concentration after completion of adjuvant treatment. Results: Treatment reduced the concentration of heparanase by almost four times in the general IBrC cohort. Higher levels of pre- and post-treatment heparanase were noted in oestrogen receptor-negative cancers than in positive ones. A higher post-treatment concentration of heparanase was found in patients with a triple-negative tumour compared to patients with a luminal B HER2 negative type of IBrC. Overweight IBrC subjects and those with a tumour diameter of ≥2 cm demonstrated a lower chance of a lower pre-treatment heparanase concentration. Interestingly, a pre-treatment heparanase concentration is the main predictor of the changes in heparanase concentration after adjuvant treatment. Follow-up revealed significantly lower progression-free survival (PFS) rates in IBrC patients with a pre-treatment concentration of heparanase higher than 181.46 pg/mL (PFS = 80%). Conclusions: Our findings provide supporting evidence that IBrC therapy reduced the heparanase levels, regardless of treatment patterns and a pre-treatment concentration of heparanase may serve as a prognostic indicator for future outcomes.

Perinatal and postnatal exposures and risk of young-onset breast cancer

BackgroundPerinatal factors have been associated with some adult health outcomes, but have not been well studied in young-onset breast cancer. We aimed to evaluate the association between young-onset breast cancer and perinatal exposures and to explore etiologic heterogeneity in the relationship between associated perinatal factors and estrogen receptor status of the tumor.MethodsWe addressed this in a sister-matched case-control study. Cases were women who had been diagnosed with ductal carcinoma in situ or invasive breast cancer before the age of 50. Each case had a sister control who was free of breast cancer up to the same age at which her case sister developed the disease. The factors considered were self-reported and included the mother’s preeclampsia in that pregnancy, mother’s smoking in that pregnancy, gestational hypertension, prenatal diethylstilbestrol use, and gestational diabetes, as well as low birth weight (less than 5.5 pounds), high birth weight (greater than 8.8 pounds), short gestational length (less than 38 completed weeks), and being breastfed or being fed soy formula.ResultsIn conditional logistic regression analyses, high birth weight (odds ratio [OR] = 1.59, 95% confidence interval [CI] 1.07–2.36) and preeclampsia (adjusted OR = 1.92, CI 0.824–4.5162) were positively associated with risk. The association with preeclampsia was stronger when the analysis was restricted to invasive breast cancer (OR = 2.87, CI 1.08–7.59). We also used case-only analyses to assess etiologic heterogeneity for estrogen receptor (ER)-positive versus estrogen receptor-negative cancer. Women who were born to a preeclamptic pregnancy and later developed young-onset breast cancer were at increased odds for the ER-negative type (OR = 2.27; CI 1.05–4.92).ConclusionThese results suggest that being born to a preeclamptic pregnancy may increase risk for young-onset breast cancer, especially for the ER-negative subtype.

Mendelian randomisation analysis of circulating adipokines and C-reactive protein on breast cancer risk.

Circulating adipokines and C‐reactive protein (CRP) have been linked to breast cancer risk in observational epidemiological studies. The causal nature of these associations is unclear because of the susceptibility of conventional observational designs to residual confounding, reverse causation and other forms of bias. Mendelian randomisation (MR) uses genetic variants as proxies for risk factors to strengthen causal inference in observational settings. We performed a MR analysis to evaluate the causal relevance of six previously reported circulating adipokines [adiponectin, hepatocyte growth factor (HGF), interleukin‐6, leptin receptor, plasminogen activator inhibitor‐1 and resistin] and CRP in risk of overall and oestrogen receptor‐stratified breast cancer in up to 122,977 cases and 105,974 controls of European ancestry. Genetic instruments were constructed from single‐nucleotide polymorphisms robustly (p < 5 × 10−8) associated with risk factors in genome‐wide association studies. Colocalisation was performed as a sensitivity analysis to examine whether findings reflected shared causal variants or genomic confounding. In MR analyses, there was evidence for an association of HGF with oestrogen receptor‐negative cancer (odds ratio per standard deviation increase: 1.17, 95% confidence interval: 1.01–1.35; p = 0.035) but little evidence for associations of other adipokines or CRP with overall or oestrogen receptor‐stratified breast cancer. Colocalisation analysis suggested that the association of HGF with oestrogen receptor‐negative breast cancer was unlikely to reflect a causal association. Collectively, these findings do not support an important aetiological role of various adipokines or CRP in overall or oestrogen receptor‐specific breast cancer risk.

Association Between Organic Food Consumption and Breast Cancer Risk: Findings from the Sister Study (P18-038-19)

ObjectivesDiet is a source of exposure to pesticides. Organic food consumption may lower cancer risk, possibly due to decreased exposure to pesticides. Few studies have investigated the association between organic food consumption and cancer risk and evidence on the risk of breast cancer is limited. MethodsWe used data from 39,563 Sister Study participants aged 35 to 74 years who enrolled in 2003–2009 and had information available on frequency of organic food consumption. Participants reported their consumption of organic produce, meat, and dairy during the past 12 months as never, less than half the time, about half the time, and more than half the time. An organic diet score was calculated by assigning scores of 0, 1, 2 and 3 for increasing consumption proportions and summing across foods (maximum score 9). We used Cox proportional hazards models to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for breast cancer associated with ever consuming organic foods and organic diet scores, adjusting for potential confounders, including known risk factors for breast cancer. ResultsAt baseline, 61.8% of women reported ever eating organic produce, meat, or dairy. We identified 2336 incident breast cancers diagnosed at least 1 year after enrollment (mean follow-up 9.0 years). Any organic food consumption was inversely associated with breast cancer (HR: 0.87 [95% CI, 0.80–0.95]), especially estrogen receptor negative cancer (HR: 0.77 [95% CI, 0.61–0.98]). There was no trend with increasing organic diet score based on all organic food types. Consumption of organic produce half or more than half the time was associated with reduced risk of breast cancer compared to no organic produce consumption (HR: 0.87 [95% CI, 0.77–0.99]). There was no trend for organic dairy or meat consumption. In stratified analyses, associations did not differ by demographics, obesity, menopausal status, lifestyle characteristics, cancer screening, or degree of family history. ConclusionsAlthough unmeasured factors associated with consuming organic foods may explain these results, organic produce consumption was associated with reduced breast cancer risk. Funding SourcesNational Institute of Environmental Health Sciences.

Abstract CS1-1: Polygenic risk scores for breast cancer: Ready or not?

Abstract There are increasing attempts to try to stratify cancer risks to enable more targeted early detection and prevention strategies and in particular to balance the risks and benefits of population screening for breast cancer. An increasing number of common genetic variants called Single Nucleotide Polymorphisms (SNPs) have been identified which alter breast cancer risk. Although individually their effect sizes are small they can be used multiplicatively to provide a polygenic risk score (PRS) that accurately predicts risk in both the familial and population setting. Although the first 18 SNPs produce a highly calibrated PRS that is ready for use there are now PRSs of 143 or even 313 SNPs that increase risk stratification although with some loss of calibration. Using data from 9362 women in the Predicting the Risk Of Cancer At Screening (PROCAS) study (500 prospective cancers) and 2000 women in the FH-Risk familial cohort (500 prospective cancers) we have validated the PRS alongside mammographic density (density residual-DR) and standard risk factors to assess future risk of different types of breast cancer. The combined score accurately predicts breast cancers rates with 18-21% of women being predicted in the moderate or high risk categories (≥5% 10 year risk) that developed 41.5-45% of the stage 2+ cancers. In contrast SNP143 is able to identify alongside density and standard risk factors 21% of the general population at &amp;lt;1.4% 10-year risk aged 46-73 years who develop only 9% of the breast cancers. These are also more likely to be potentially 'overdiagnosed' grade 1 and DCIS. The SNP143 is also predictive for oestrogen receptor negative cancers using a 20 SNP PRS. Conclusions: A combined approach using Tyrer-Cuzick, mammographic density and a PRS provides accurate risk stratification not only overall but also for worse prognosis cancers. This provides support for reducing screening intervals in the high and increasing them in the low risk groups. It is high time these highly informative tests were used in risk stratification Citation Format: Evans D. Polygenic risk scores for breast cancer: Ready or not? [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr CS1-1.

Association Between Postpartum Breast Cancer Diagnosis and Metastasis and the Clinical Features Underlying Risk

In women 45 years or younger, breast cancer diagnosis after childbirth increases the risk for metastasis and death, yet limited data exist to define this window of risk and associated prognostic factors. To assess the window of elevated risk for metastasis following a postpartum breast cancer (PPBC) diagnosis and whether clinical prognostic factors are associated with the increased risk. This multicenter cohort study conducted using cases from the Colorado Young Women's Breast Cancer Cohort diagnosed between January 1, 1981, and December 31, 2014, included 701 women 45 years or younger with stage I to III invasive breast cancer for whom parity data, including time of last childbirth, were available. Data analysis was conducted from July 1 to September 30, 2017. This study involved a tertiary care academic hospital-based breast center and its regional affiliates with cases from the greater Rocky Mountain region. Primary exposures were prior childbirth or no childbirth, time between most recent childbirth and breast cancer diagnosis, and time between breast cancer diagnosis and metastasis. The primary outcome was distant metastasis-free survival. A total of 701 women 45 years or younger from the greater Rocky Mountain states region were included in the analysis; mean (SD) age at diagnosis was 37.9 (5.1) years. Breast cancer diagnosis within 10 years after parturition was associated with elevated risk for metastasis, particularly in women with stage I or II disease. In addition, women with PPBC diagnosed within 10 years of a completed pregnancy that was estrogen receptor-positive showed distant metastasis-free survival similar to that of nulliparous patients with estrogen receptor-negative cancer, and women with estrogen receptor-negative PPBC had further reduced metastasis-free survival. Moreover, women with PPBC had increased lymphovascular invasion and lymph node involvement. In addition, tumor-associated Ki67 positivity identified 129 patients with luminal B cancer in the cohort that, independent of parity status, had poorer prognosis compared with patients with luminal A cancer, although it did not reach statistical significance. Diagnosis of PPBC within 10 years post partum appears to be associated with an increased risk for metastasis. This increased risk was highest in stages I and II cancer at diagnosis and present in both patients with estrogen receptor-positive and estrogen receptor-negative cancer, persisting in estrogen receptor-positive cases for up to 15 years after diagnosis. Postpartum breast cancer diagnoses were not associated with increased Ki67 index but were associated with increased lymphovascular invasion and lymph node involvement compared with breast cancer in nulliparous patients.

Antigen Specificity and Clinical Significance of IgG and IgA Autoantibodies Produced in situ by Tumor-Infiltrating B Cells in Breast Cancer

An important role for tumor infiltrating B lymphocytes (TIL-B) in the immune response to cancer is emerging; however, very little is known about the antigen specificity of antibodies produced in situ. The presence of IgA antibodies in the tumor microenvironment has been noted although their biological functions and clinical significance are unknown. This study used a 91-antigen microarray to examine the IgG and IgA autoantibody repertoires in breast cancer (BC). Tumor and adjacent breast tissue supernatants and plasma from BC patients together with normal breast tissue supernatants and plasma from healthy controls (patients undergoing mammary reduction and healthy blood donors) were analyzed to investigate relationships between autoantibodies and the clinical, histological and immunological features of tumors. Our data show that >84% of the BC samples tested contain autoantibodies to one or more antigens on the array, with ANKRD30BL, COPS4, and CTAG1B being most frequently reactive. Ex vivo TIL-B responses were uncoupled from systemic humoral responses in the majority of cases. A comparison of autoantibody frequencies in supernatants and plasma from patients and controls identified eight antigens that elicit BC-associated autoantibody responses. The overall prevalence of IgG and IgA autoantibodies was similar and while IgG and IgA responses were not linked they did correlate with distinct clinical, pathological and immunological features. Higher levels of ex vivo IgG responses to BC-associated antigens were associated with shorter recurrence-free survival (RFS), HER2 overexpression and lower tumor-infiltrating CD8+ T cell counts. Higher IgA levels were associated with estrogen and progesterone receptor-negative cancers but were not significantly associated with RFS. Furthermore, ex vivo IgA but not IgG autoantibodies reactive to BC-associated antigens were linked with germinal center and early memory B cell maturation and the presence of tertiary lymphoid structures suggesting that these TIL-B are activated in the tumor microenvironment. Overall, our results extend the current understanding of the antigen specificity, the biological and the clinical significance of IgG and IgA autoantibodies produced by BC TIL-B in situ.

Use of antipsychotics and risk of breast cancer: a Danish nationwide case-control study.

Some antipsychotics increase prolactin levels, which might increase the risk of breast cancer. Existing evidence is conflicting and based on sparse data, especially for the increasingly used second-generation antipsychotics. We conducted a nationwide case-control study of the association between antipsychotic use and incident breast cancer. From the Danish Cancer Registry, we identified women with a first-time diagnosis of breast cancer 2000-2015 (n=60 360). For each case, we age-matched 10 female population controls. Using conditional logistic regression, we calculated odds ratios (ORs) for breast cancer associated with use of antipsychotics. We stratified antipsychotics by first- and second-generation status and by ability to induce elevation of prolactin. In total, 4951 cases (8.1%) and 47 643 controls (7.9%) had ever used antipsychotics. Long-term use (≥10 000mg olanzapine equivalents) was associated with breast cancer, with an adjusted OR of 1.18 [95% confidence interval (CI), 1.06, 1.32]. A weak dose-response pattern was seen, with ORs increasing to 1.27 (95% CI 1.01, 1.59) for ≥50 000mg olanzapine equivalents. Associations were similar for first- and second-generation antipsychotics (ORs 1.17 vs. 1.11), but also for nonprolactin inducing-antipsychotics (OR 1.17). Stratifying by oestrogen receptor status, positive associations were seen for oestrogen receptor-positive cancers (long-term use: OR 1.29; 95% CI 1.13, 1.47) while no associations were observed for oestrogen receptor-negative cancers. Overall, our results do not suggest a clinically important association between antipsychotic use and risk of breast cancer. The importance of drug-induced prolactin elevation is unclear but may lead to a slightly increased risk of oestrogen receptor-positive breast cancer.

Abstract B28: Development of estrogen-dependent and estrogen receptor-negative cervical cancer in HPV transgenic mice

Abstract Estradiol (E2) and human papillomavirus (HPV) cooperate to cause cervical cancer. The role of estrogen receptor α (ERα) in cervical cancer has been underappreciated. Chronic treatment with E2 promotes the development of cervical cancer in K14E7 transgenic mice expressing HPV16 E7 oncoprotein. In the present study, we bred K14E7 to mice with conditional ablation of Esr1 (ERα-coding gene) in the cervical epithelial cells (Wnt7aCre/Esr1f/f; Esr1ed/ed). We found that E2 promoted the development of ERα cervical cancer in K14E7/Esr1ed/ed mice. In addition, proliferation and apoptotic indices of ERα cancer in K14E7/Esr1ed/ed mice were similar to those of ERα+ cancer in K14E7/Esr1f/f mice. We also found that E2 increased the epithelium thickness and epithelial cell proliferation in the cervix of Esr1ed/ed mice. Our published results have demonstrated that deletion of Esr1 in the cervical stroma promotes the regression of cervical precancer lesions in K14E7 mice. In patients, ERα is expressed in the cancer stroma but not cancer epithelial cells. These observations support that stromal ERα, rather than epithelial ERα, mainly mediates oncogenic E2 signaling for cervical cancer. They also suggest that stromal ERα might be an effective therapeutic target for cervical cancer. Note: This abstract was not presented at the conference. Citation Format: Jieun Son, Sang-Hyuk Chung. Development of estrogen-dependent and estrogen receptor-negative cervical cancer in HPV transgenic mice [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr B28.

Phase II study of neoadjuvant anthracycline combined with nanoparticle albumin‑bound paclitaxel for human epidermal growth factor receptor 2‑negative breast cancer

Neoadjuvant chemotherapy (NAC) with anthracyclines followed by taxane chemotherapy has become the standard treatment for patients with locally advanced, operable breast cancer. Recently, the efficacy of nanoparticle albumin-bound paclitaxel (nab-PTX) for metastatic breast cancer was reported. However, there are still few studies of a neoadjuvant regimen including nab-PTX. Thus, the present phase II study evaluated the efficacy and safety of 5-fluorouracil, epirubicin and cyclophosphamide (FEC regimen) followed by nab-PTX as neoadjuvant treatment for operable human epidermal growth factor receptor 2 (HER2)-negative breast cancer. Women with operable HER2-negative breast cancer (clinical stage T1a-4N1-3) received 4 cycles of FEC (5-fluorouracil 500 mg/m2, epirubicin 100 mg/m2 and cyclophosphamide 500 mg/m2 every 21 days), followed by 4 cycles of nab-PTX at 260 mg/m2 every 21 days. The patients then underwent mastectomy or breast-conserving surgery (BCS). The primary endpoint was pathological complete response (pCR) rate. The secondary endpoints included clinical response rate, pathological response rate, BCS rate and safety. A total of 16 patients were evaluated and 3 patients (18%) achieved pCR (1 patient with estrogen receptor-positive cancer and 2 with estrogen receptor-negative cancer). The pCR rate was 12 and 25% in patients with estrogen receptor-positive and -negative cancers, respectively. The clinical response rate was 100% (clinical complete and partial response in 6 and 10 patients, respectively). The BCS rate was 31.25%. Three patients experienced grade 3 neutropenia during FEC therapy, and no grade 3/4 events occurred during nab-PTX therapy. Thus, neoadjuvant therapy with FEC followed by nab-PTX for operable HER2-negative breast cancer was found to be a safe and effective option.

Retraction Note: Anti-cancer effects of grailsine-al-glycoside isolated from Rhizoma Sparganii

An embryonic toxicity of Rhizoma sparganii was observed in mice. This study was aimed to evaluate the anticancer effects of Grailsine-Al-glycoside, the bioactive component of Rhizoma sparganii, on estrogen receptor-positive (ER+) and estrogen receptor-negative (ER-) cancer cell lines. After A549, HeLa, HepG-2 and MCF-7 cells were treated with Grailsine-Al-glycoside, cell proliferation was analyzed by MTT, cell cycle and apoptosis by flow cytometry, and morphology with an immunofluorescence microscope. Grailsine-Al-glycoside strongly suppressed cell proliferation in a dose-dependent fashion in A549, MCF-7, HepG2, and HeLa cells, though this growth inhibitory effect on HepG2 cells was not as strong and long lasting. Compared to the control, Grailsine-Al-glycoside caused a significant increase of apoptosis in A549, MCF-7 and Hela cells. A549 and MCF-7 cells were arrested at the G2/S phase whereas HepG2 cells were arrested at the G1 phase by a high concentration of Grailsine-Al-glycoside . Cell shapes were also changed by the presence of Grailsine-Al-glycoside. Grailsine-Al-glycoside from Rhizoma sparganii inhibited the proliferation of ER+ and some ER- cancer cells. Grailsine-Al-glycoside may be used as a chemotherapeutic agent against ER+ and ERRα-expressing ER- cancers.

Abstract P1-03-02: Intratumoral heterogeneity of Ki67 expression in early breast cancers exceeds variability between individual tumours

Abstract Background Regional differences in proliferative activity are commonly seen within breast cancers, but little is known on the degree of intratumoral heterogeneity of Ki67 expression. Our aim was to study intratumoral heterogeneity of Ki67 expression in early breast cancers and its association with clinicopathological features like estrogen receptor (ER) status, grade and histological type. Methods The Ki67-labelling index (Ki67-LI) was assessed in hot, cold and intermediate spots of 233 invasive breast cancers by counting a total of 1020 cells, according to a protocol of the International Ki67 in Breast Cancer Working Group. Differences between the spots per tumor were further analyzed for clinicopathological subgroups defined by ER status, grade and histological type. Results All clinicopathological subgroups showed significant differences in Ki67-LI between hot, intermediate and cold spots (p &amp;lt;0.001). The coefficient of variance (CV) between the spots was higher in ER positive than in ER negative cancers (72.6% vs 49.2%, p &amp;lt;0.001), and was highest in grade 3 (96.12%), grade 1 (87.27%) and invasive lobular tumors (83.59%), and lowest in medullary (26.48%) cancers. Nested analysis of variance indicated that in both ER positive and ER negative cancers, variance in Ki67-LI within tumours contributed more to the total variance (56% for ER positive, 60% for ER negative cancers) than the variance between tumors. Conclusion Intratumoral heterogeneity in Ki67-LI is an ubiquitous phenomenon across various pathological subgroups of breast cancer that may impact assessment of Ki67 levels for clinical decision making, and sheds new light on recommended cut-offs. Citation Format: Focke CM, Decker T, van Diest PJ. Intratumoral heterogeneity of Ki67 expression in early breast cancers exceeds variability between individual tumours [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 P1-03-02.

Abstract P5-06-07: PTEN immunohistochemistry is a predictor of mismatch repair status in breast cancer

Abstract Phosphatase and tensin homolog (PTEN), a potent downregulator of the PI3K-Akt pathway, has been shown to mediate the interaction between poly (ADP-ribose) polymerases (PARPs) and the mismatch repair (MMR) complex in endometrial and ovarian cancer. Drugs inhibiting PARPs (iPARPs) are currently considered promising therapeutic tools in a subset of PTEN-defective tumors. Regrettably, the frequency and significance of MMR alterations in breast cancer is debated, and their relationship with PTEN status has not been investigated in the breast. Furthermore, many of the studies on the DNA damage response and its therapeutic implications in breast cancer focus on inherited syndromes (e.g. Lynch syndrome and hereditary breast-ovarian cancer syndrome). Aims: We sought to explore the interplay between PTEN and the MMR system and to define whether PTEN immunohistochemistry (IHC) is a predictor of MMR proficiency in non-familial breast cancers. Methods: 373 cases of non-familial breast cancers, including a representative number of no special (n=295) and special types (n=78), carefully characterized from clinical and pathological standpoints, were reviewed and used to construct 14 tissue microarrays (TMAs). For each case, a mean of 4.5 tumor tissue cores (range 3 to 6 cores) was sampled, incorporating distinct topographic areas of the tumor, as well as matched non-neoplastic breast tissue. Taken together, 1876 spots were generated. Each TMA was subjected to IHC for PTEN and the DNA MMR proteins MLH1, MSH2, MSH6 and PMS2. In order to minimize human-related biases, each stained slide was digitalized and two pathologists blindly analyzed each tumor spot using a dedicated software able to segment and randomize TMA cores. The pattern of expression was therefore annotated manually on a digital database using a specific add-on module to reconstruct the original topography. Results: According to clinicopathologic surrogate definition of intrinsic subtypes, PTEN protein loss or heterogeneous expression was more frequent in estrogen receptor negative cancers. Furthermore, 100% of the MMR-proficient luminal B-like (HER2+) and triple-negative breast cancers displayed strong and diffuse homogeneous PTEN expression, while PTEN-positive status identified MMR-proficient luminal A-like and luminal B (HER2-) like tumors with accuracy rates of 89.3% and 92.7%, respectively (p=0.001, Fisher's exact test). Conclusions: The present study is the first to investigate PTEN protein loss in a large set of non-familial breast carcinomas based on their DNA MMR status by IHC. Here, we demonstrated that PTEN strong and homogeneous expression by IHC is able to capture the vast majority of MMR-proficient non-familial breast cancers. Our findings broaden the understanding of the biology underpinning these tumors, suggesting that PTEN is likely play a role in the development of MMR alterations. Given that PTEN-defective breast cancers have the propensity to develop additional somatic alterations in the MMR system, our results suggest that IHC for PTEN and MMR proteins may be emplyed as an ancillary study to define new subclasses of sporadic breast cancers potentially eligible for iPARPs therapies. Citation Format: Fusco N, Gambini D, Runza L, Lopez G, Ercoli G, Despini L, Bosari S. PTEN immunohistochemistry is a predictor of mismatch repair status in breast cancer [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 P5-06-07.

Abstract S5-04: Low-fat dietary pattern and breast cancer overall survival in the women's health initiative dietary modification randomized controlled trial

Abstract Introduction: Among 48,835 postmenopausal women randomized in the Women's Health Initiative Dietary Modification (WHI DM) primary prevention trial, 1,767 women were diagnosed with breast cancer during the 8.3 years of dietary intervention. While differences were not statistically significant, there were fewer breast cancers diagnosed in the low fat dietary group women (HR 0.92 95% CI 0.84-1.01, P=0.09) with somewhat lower breast cancer mortality (HR 0.77 95% CI 0.48-1.22) than seen in control group women (JAMA 2006; 295:629). These findings were recently updated, and after 10.9 years (mean) post-diagnosis follow-up, breast cancer overall survival among these 1,767 women measured from diagnosis was greater in the dietary group (10 year survival, 82% vs 78%, 168 (2.24%) versus 319 (2.71%) deaths; HR 0.80 95% CI 0.66-0.97, P=0.02) (AACR Annual Meeting 2016, abstract CT0433, Clinical Trials Plenary Session). We now report low-fat dietary pattern influence on breast cancer overall survival in subgroups defined by breast cancer characteristics. Methods: The WHI DM trial, conducted at 40 US clinical centers, from1993-1998 enrolled 48,835 postmenopausal women, aged 50-79, without prior breast cancer, with normal mammogram and dietary fat intake &amp;gt;32% of total energy. Participants were randomly assigned to a dietary intervention group (40%, n=19,541) with goals of fat intake reduction to 20% of energy and increased fruits, vegetables and grain intake, or a usual diet control group (60%, n=29,294). As previously reported, the dietary modification program reduced fat intake, increased fruit, vegetable and grain intake and was associated with modest weight loss (all P&amp;lt; 0.001). The current secondary analysis outcome is breast cancer overall survival in subgroups defined by breast cancer characteristics for cases diagnosed during the dietary intervention period. Because of possible selection prior to breast cancer diagnosis, these analyses do not compare randomized outcomes. Therefore, careful attention is paid to control of risk factors for breast cancer in the analysis. Results: The examined subgroups included histology (ductal, lobular, other), estrogen receptor (ER) status (positive vs. negative by local laboratory), progesterone receptor (PR) status, HER2 status, triple negative (yes/no), stage (local, regional or distant), grade (well, moderately, poorly differentiated), tumor size (&amp;lt;1, 1- 2, &amp;gt;=2 cm), and nodal involvement (none, 1-3, 4+). None of the tests of interaction in subgroups were statistically significant. All subgroup hazard ratios (HR) were less than one except for ER negative cancers, triple negative cancers and those with 4+ positive lymph nodes. The results are suggestive of no influence of the low-fat dietary pattern on triple negative cancers (HR 1.64 95% CI 0.73-3.70 for triple negative vs. HR 0.73 95% CI 0.56-0.95 for other breast cancers, interaction P=0.06). Conclusion: Compared to a usual diet control group, women randomized to a dietary intervention group providing a low-fat dietary pattern had a significantly increased overall survival following a breast cancer diagnosis with the possible exception of those developing triple negative cancers. Citation Format: Chlebowski RT, Aragaki AK, Thomson CA, Anderson G, Manson JE, Simon MS, Rohan TE, Snetselar LG, Lane D, Barrington WE, Vitolins M, Womack C, Qi L, Hou L, Thomas F, Prentice RL. Low-fat dietary pattern and breast cancer overall survival in the women's health initiative dietary modification randomized controlled trial [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 S5-04.