Psychosocial stressors and breast cancer gene expression in the Black Women's Health Study

PURPOSE

Prior studies indicate that the physiologic response to stress can affect gene expression. We evaluated differential gene expression in breast cancers collected from Black women with high versus low exposure to psychosocial stressors.

METHODS

We analyzed tumor RNA sequencing data from 417 Black Women's Health Study breast cancer cases with data on early life trauma and neighborhood disadvantage. We conducted age-adjusted differential gene expression analyses and pathway analyses. We also evaluated Conserved Transcriptional Response to Adversity (CTRA) contrast scores, relative fractions of immune cell types, T cell exhaustion, and adrenergic signaling. Analyses were run separately for estrogen receptor positive (ER+; n = 299) and ER- (n = 118) cases.

RESULTS

Among ER+ cases, the top differentially expressed pathways by stress exposure were related to RNA and protein metabolism. Among ER- cases, they were related to developmental biology, signal transduction, metabolism, and the immune system. Targeted analyses indicated greater immune pathway enrichment with stress exposure for ER- cases, and possible relevance of adrenergic signaling for ER+ cases. CTRA contrast scores did not differ by stress exposure, but in analyses of the CTRA components, ER- breast cancer cases with high neighborhood disadvantage had higher pro-inflammatory gene expression (p = 0.039) and higher antibody gene expression (p = 0.006) compared to those with low neighborhood disadvantage.

CONCLUSION

There are multiple pathways through which psychosocial stress exposure may influence breast tumor biology. Given the present findings on inflammation and immune response in ER- tumors, further research to identify stress-induced changes in the etiology and progression of ER- breast cancer is warranted.

Initial validation of the Mass. General Neuropathy Exam Tool (MAGNET) for evaluation of distal small-fiber neuropathy

INTRODUCTION/AIMS

Diagnosis of small-fiber neuropathy (SFN) is hampered by its subjective symptoms and signs. Confirmatory testing is insufficiently available and expensive, so predictive examinations have value. However, few support the 2020 SFN consensus-case-definition requirements or were validated for non-diabetes neuropathies. Thus we developed the Massachusetts General Hospital Neuropathy Exam Tool (MAGNET) and measured diagnostic performance in 160 symptomatic patients evaluated for length-dependent SFN from any cause and 37 healthy volunteers.

METHODS

We compared prevalences of abnormalities (vital signs, pupil responses, lower-limb appearance, pin, light touch, vibration and position sensitivity, great-toe strength, muscle stretch reflexes), and validated diagnostic performance against objective SFN tests: lower-leg skin-biopsy epidermal neurite densities and autonomic function testing (AFT). Sensitivity/specificity, feasibility, test-retest and inter-rater reliability, and convergence with the Utah Early Neuropathy Scale were calculated.

RESULTS

Patients' ages averaged 48.5 ± 14.7 years and 70.6% were female. Causes of neuropathy varied, remaining unknown in 59.5%. Among the 46 with abnormal skin biopsies, the most prevalent abnormality was reduced pin sharpness at the toes (71.7%). Inter-rater reliability, test-retest reliability, and convergent validity excelled (range = 91.3-95.6%). Receiver operating characteristics comparing all symptomatic patients versus healthy controls indicated that a MAGNET threshold score of 14 maximized predictive accuracy for skin biopsies (0.74) and a 30 cut-off maximized accuracy for predicting AFT (0.60). Analyzing patients with any abnormal neuropathy-test results identified areas-under-the-curves of 0.87-0.89 for predicting a diagnostic result, accuracy = 0.80-0.89, and Youden's index = 0.62. Overall, MAGNET was 80%-85% accurate for stratifying patients with abnormal versus normal neuropathy test results.

DISCUSSION

MAGNET quickly generates research-quality metrics during clinical examinations.

Addition of polygenic risk score to a risk calculator for prediction of breast cancer in US Black women

BACKGROUND

Previous work in European ancestry populations has shown that adding a polygenic risk score (PRS) to breast cancer risk prediction models based on epidemiologic factors results in better discriminatory performance as measured by the AUC (area under the curve). Following publication of the first PRS to perform well in women of African ancestry (AA-PRS), we conducted an external validation of the AA-PRS and then evaluated the addition of the AA-PRS to a risk calculator for incident breast cancer in Black women based on epidemiologic factors (BWHS model).

METHODS

Data from the Black Women's Health Study, an ongoing prospective cohort study of 59,000 US Black women followed by biennial questionnaire since 1995, were used to calculate AUCs and 95% confidence intervals (CIs) for discriminatory accuracy of the BWHS model, the AA-PRS alone, and a new model that combined them. Analyses were based on data from 922 women with invasive breast cancer and 1844 age-matched controls.

RESULTS

AUCs were 0.577 (95% CI 0.556-0.598) for the BWHS model and 0.584 (95% CI 0.563-0.605) for the AA-PRS. For a model that combined estimates from the questionnaire-based BWHS model with the PRS, the AUC increased to 0.623 (95% CI 0.603-0.644).

CONCLUSIONS

This combined model represents a step forward for personalized breast cancer preventive care for US Black women, as its performance metrics are similar to those from models in other populations. Use of this new model may mitigate exacerbation of breast cancer disparities if and when it becomes feasible to include a PRS in routine health care decision-making.

Influence of alcohol consumption and alcohol metabolism variants on breast cancer risk among Black women: results from the AMBER consortium

BACKGROUND

Moderate to heavy alcohol consumption is associated with an increased risk of breast cancer. The etiologic role of genetic variation in genes involved in ethanol metabolism has not been established, with little information available among women of African ancestry.

METHODS

Our analysis from the African American Breast Cancer Epidemiology and Risk (AMBER) Consortium included 2889 U.S. Black women who were current drinkers at the time of breast cancer diagnosis (N cases = 715) and had available genetic data for four ethanol metabolism genomic regions (ADH, ALDH, CYP2E1, and ALDH2). We used generalized estimating equations to calculate genetic effects, gene* alcohol consumption (≥ 7drinks/week vs. < 7/week) interactions, and joint main plus interaction effects of up to 23,247 variants in ethanol metabolism genomic regions on odds of breast cancer.

RESULTS

Among current drinkers, 21% of cases and 14% of controls reported consuming ≥ 7 drinks per week. We identified statistically significant genetic effects for rs79865122-C in CYP2E1 with odds of ER- breast cancer and odds of triple negative breast cancer, as well as a significant joint effect with odds of ER- breast cancer (≥ 7drinks per week OR = 3.92, < 7 drinks per week OR = 0.24, p_joint = 3.74 × 10^-6). In addition, there was a statistically significant interaction of rs3858704-A in ALDH2 with consumption of ≥ 7 drinks/week on odds of triple negative breast cancer (≥ 7drinks per week OR = 4.41, < 7 drinks per week OR = 0.57, p_int = 8.97 × 10^-5).

CONCLUSIONS

There is a paucity of information on the impact of genetic variation in alcohol metabolism genes on odds of breast cancer among Black women. Our analysis of variants in four genomic regions harboring ethanol metabolism genes in a large consortium of U.S. Black women identified significant associations between rs79865122-C in CYP2E1 and odds of ER- and triple negative breast cancer. Replication of these findings is warranted.

Adherence to Cancer Prevention Lifestyle Recommendations Before, During, and 2 Years After Treatment for High-risk Breast Cancer

Importance

The American Institute for Cancer Research and American Cancer Society regularly publish modifiable lifestyle recommendations for cancer prevention. Whether these recommendations have an impact on high-risk breast cancer survival remains unknown.

Objective

To investigate whether adherence to cancer prevention recommendations before, during, and 1 and 2 years after breast cancer treatment was associated with disease recurrence or mortality.

Design, Setting, and Participants

The Diet, Exercise, Lifestyles, and Cancer Prognosis Study (DELCaP) was a prospective, observational cohort study designed to assess lifestyles before diagnosis, during treatment, and at 1 and 2 years after treatment completion, implemented ancillary to the Southwest Oncology Group (SWOG) S0221 trial, a multicenter trial that compared chemotherapy regimens in breast cancer. Participants were chemotherapy-naive patients with pathologic stage I to III high-risk breast cancer, defined as node-positive disease with hormone receptor-negative tumors larger than 1 cm or any tumor larger than 2 cm. Patients with poor performance status and comorbidities were excluded from S0221. The study was conducted from January 1, 2005, to December 31, 2010; mean (SD) follow-up time for those not experiencing an event was 7.7 (2.1) years through December 31, 2018. The analyses reported herein were performed from March 2022 to January 2023.

Exposure

An aggregated lifestyle index score comprising data from 4 time points and 7 lifestyles, including (1) physical activity, (2) body mass index, (3) fruit and vegetable consumption, (4) red and processed meat intake, (5) sugar-sweetened beverage consumption, (6) alcohol consumption, and (7) smoking. Higher scores indicated healthier lifestyle.

Main Outcomes and Measures

Disease recurrence and all-cause mortality.

Results

A total of 1340 women (mean [SD] age, 51.3 [9.9] years) completed the baseline questionnaire. Most patients were diagnosed with hormone-receptor positive breast cancer (873 [65.3%]) and completed some education beyond high school (954 [71.2%]). In time-dependent multivariable analyses, patients with highest vs lowest lifestyle index scores experienced a 37.0% reduction in disease recurrence (hazard ratio, 0.63; 95% CI, 0.48-0.82) and a 58.0% reduction in mortality (hazard ratio, 0.42; 95% CI, 0.30-0.59).

Conclusions and Relevance

In this observational study of patients with high-risk breast cancer, strongest collective adherence to cancer prevention lifestyle recommendations was associated with significant reductions in disease recurrence and mortality. Education and implementation strategies to help patients adhere to cancer prevention recommendations throughout the cancer care continuum may be warranted in breast cancer.

Abstract PD14-06: PD14-06 Polygenic risk score added to risk calculator improves prediction of breast cancer in U.S. Black women

We recently derived an absolute breast cancer risk prediction model, the Black Women’s Health Study (BWHS) model, for breast cancer in U.S. Black women using data from three large case-control studies and validated it in independent prospective data from the Black Women’s Health Study (Palmer 2021). The BWHS model includes epidemiologic risk factors as well as family history of breast cancer and family history of prostate cancer. It does not include genetic variants because at the time of model development breast cancer polygenic risk scores performed poorly in women of predominantly African ancestry, primarily due to differences in allele frequency and linkage disequilibrium. More recently, Gao et al. (2022) developed and tested a polygenic risk score (PRS) using 56,943 SNPs for breast cancer in women of African ancestry (AA) based on 9,235 breast cancer cases and 10,184 controls from a large pooled analysis of studies from African American and African women; the c-statistic from cross-validation was 0.581, considerably better than in previous efforts. We evaluated whether adding this AA-PRS to the BWHS risk prediction model would improve risk stratification. We conducted a nested case-control study of 901 breast cancer cases and 1,576 controls matched on age and most recent questionnaire completed from among BWHS participants for whom genome-wide association data were available and who had not been included in the collaboration from which the PRS was derived and tested. We examined discriminatory accuracy, estimated by the area under the receiver operating characteristic curve (AUC), for the risk prediction model alone, the PRS alone, and the combination of risk prediction model and PRS, controlling for the matching factor “questionnaire cycle”. We conducted the analyses within strata of 5-year age and then combined results using inverse-variance weighting. In preliminary analyses, the AUC was 0.579 for the risk prediction model alone and 0.600 for the AA-PRS alone. When the AA-PRS and the BWHS risk prediction model were both used as predictors in a logistic regression model, the AUC increased from 0.579 to 0.622. This improvement in risk stratification is similar to what Kachuri et al. (2020) obtained in an analysis of U.K. Biobank data, where adding a PRS to epidemiologic and personal risk factors showed an improvement from 0.572 to 0.635 in women of European ancestry. The present study provides external validation of a recently derived AA PRS and demonstrates the potential for improving risk stratification for U.S. Black women by adding a PRS to a breast cancer risk prediction model that already includes family history of breast cancer.

Citation Format: Gary R. Zirpoli, Kathryn L. Lunetta, Ruth M. Pfeiffer, Julie R. Palmer. PD14-06 Polygenic risk score added to risk calculator improves prediction of breast cancer in U.S. Black women [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 PD14-06.

Abstract 3225: Time since last birth in relation to breast cancer mortality

Women who develop breast cancer less than 10 years after giving birth have been shown to have a poorer prognosis than women with a longer time since their last birth. Only a few studies have examined this relation separately by molecular features of the tumor; two observed poorer outcomes for women with hormone receptor positive tumors. A better understanding of the relation between time since last birth and risk of recurrence and death could lead to targeted treatments and/or surveillance of young women who develop breast cancer within 10 years of giving birth. There has been little research on this topic among Black women, who have a higher incidence of breast cancer at young ages compared to White women. We assessed the relation of time since last birth to breast cancer mortality according to estrogen receptor (ER) status of the primary tumor among breast cancer patients who are participants in the prospective Black Women’s Health Study (BWHS).

The BWHS includes 59,000 U.S. Black women who enrolled in the study in 1995 and have been followed by biennial questionnaire since then. The present analysis was restricted to parous women diagnosed before age 50 (N=658) because older patients would have been unlikely to have given birth within the past 10 years. ER status was positive for 348 cases, negative for 199, and unknown for 111. Follow-up time was from time of diagnosis to death or the end of 2018, whichever came first. Cox regression analysis, adjusted for age and stage at diagnosis, was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for breast cancer specific death for women diagnosed &lt;10 years since last birth relative to women diagnosed ≥10 years since last birth.

The median age at diagnosis was 44, with 41% of cancers diagnosed at stage I, 43% at stage II, and 16% at stage III. About a third (31%) had given birth &lt10 years before diagnosis. During follow-up, there were 159 total deaths, 132 of which were due to breast cancer. Among women diagnosed with ER-positive breast cancer, the HR for breast cancer death for women who gave birth &lt10 years prior to diagnosis relative to women who had not had a recent birth was 2.45 (95% 1.07-5.58). The association was even stronger among women who survived the first five years, with an HR of 3.38 (95% CI 1.34-8.51). Time since last birth was not associated with ER-negative breast cancer mortality (HR 1.06, 95% CI 0.46-2.46).

Late recurrences are a particular problem with ER-positive breast cancer. The present findings suggest a relatively short interval (e.g., &lt10 years) between childbirth and a breast cancer diagnosis may increase risk of a late recurrence and death from ER-positive breast cancer. Greater awareness of this association may lead to improved surveillance of survivors of early-onset breast cancer.

Citation Format: Gary R. Zirpoli, Nelsy Castro-Webb, Kimberly A. Bertrand, Julie R. Palmer. Time since last birth in relation to breast cancer mortality [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3225.

Neighborhood disadvantage and individual-level life stressors in relation to breast cancer incidence in US Black women

BACKGROUND

Research on psychosocial stress and risk of breast cancer has produced conflicting results. Few studies have assessed this relation by breast cancer subtype or specifically among Black women, who experience unique chronic stressors.

METHODS

We used prospective data from the Black Women's Health Study, an ongoing cohort study of 59,000 US Black women, to assess neighborhood- and individual-level psychosocial factors in relation to risk of breast cancer. We used factor analysis to derive two neighborhood score variables after linking participant addresses to US Census data (2000 and 2010) on education, employment, income and poverty, female-headed households, and Black race for all households in each residential block group. We used Cox proportional hazards regression to estimate hazard ratios (HR) and 95% confidence intervals (CI) adjusted for established breast cancer risk factors.

RESULTS

During follow-up from 1995 to 2017, there were 2167 incident invasive breast cancer cases (1259 estrogen receptor positive (ER +); 687 ER negative (ER-)). For ER- breast cancer, HRs were 1.26 (95% CI 1.00-1.58) for women living in the highest quartile of neighborhood disadvantage relative to women in the lowest quartile, and 1.24 (95% CI 0.98-1.57) for lowest versus highest quartile of neighborhood socioeconomic status (SES). For ER+ breast cancer, living in the lowest quartile of neighborhood SES was associated with a reduced risk of ER+ breast cancer (HR = 0.83, 95% CI 0.70-0.98). With respect to individual-level factors, childhood sexual abuse (sexual assault ≥ 4 times vs. no abuse: HR = 1.35, 95% CI 1.01-1.79) and marital status (married/living together vs. single: HR = 1.29, 95% CI 1.08-1.53) were associated with higher risk of ER+, but not ER- breast cancer.

CONCLUSION

Neighborhood disadvantage and lower neighborhood SES were associated with an approximately 25% increased risk of ER- breast cancer in this large cohort of Black women, even after control for multiple behaviors and lifestyle factors. Further research is need to understand the underlying reasons for these associations. Possible contributing factors are biologic responses to the chronic stress/distress experienced by individuals who reside in neighborhoods characterized by high levels of noise, crime and unemployment or the direct effects of environmental toxins.

Genetic Variants in COX2 and ALOX Genes and Breast Cancer Risk in White and Black Women

COX and ALOX genes are involved in inflammatory processes and that may be related to breast cancer risk differentially between White and Black women. We evaluated distributions of genetic variants involved in COX2 and ALOX-related pathways and examined their associations with breast cancer risk among 1,275 White and 1,299 Black cases and controls who participated in the Women’s Circle of Health Study. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable-adjusted logistic regression models. Our results showed differential associations of certain genetic variants with breast cancer according to menopausal and ER status in either White or Black women. In White women, an increased risk of breast cancer was observed for COX2-rs689470 (OR: 2.02, P = 0.01) in the dominant model, and was strongest among postmenopausal women (OR: 2.72, P = 0.02) and for estrogen receptor positive (ER+) breast cancers (OR: 2.60, P = 0.001). A reduced risk was observed for ALOX5-rs7099874 (OR: 0.75, P = 0.01) in the dominant model, and was stronger among postmenopausal women (OR: 0.68, P = 0.03) and for ER+ cancer (OR: 0.66, P = 0.001). Four SNPs (rs3840880, rs1126667, rs434473, rs1042357) in the ALOX12 gene were found in high LD (r² >0.98) in White women and were similarly associated with reduced risk of breast cancer, with a stronger association among postmenopausal women and for ER− cancer. Among Black women, increased risk was observed for ALOX5-rs1369214 (OR: 1.44, P = 0.003) in the recessive model and was stronger among premenopausal women (OR: 1.57, P = 0.03) and for ER+ cancer (OR: 1.53, P = 0.003). Our study suggests that genetic variants of COX2 and ALOX genes are associated with breast cancer, and that these associations and genotype distributions differ in subgroups defined by menopausal and ER status between White and Black women. Findings may provide insights into the etiology of breast cancer and areas for further research into reasons for breast cancer differences between races.

Physical Activity Before, During, and After Chemotherapy for High-Risk Breast Cancer: Relationships With Survival

BACKGROUND

Although physical activity has been consistently associated with reduced breast cancer mortality, evidence is largely based on data collected at one occasion. We examined how pre- and postdiagnosis physical activity was associated with survival outcomes in high-risk breast cancer patients.

METHODS

Included were 1340 patients enrolled in the Diet, Exercise, Lifestyle and Cancer Prognosis (DELCaP) Study, a prospective study of lifestyle and prognosis ancillary to a SWOG clinical trial (S0221). Activity before diagnosis, during treatment, and at 1- and 2-year intervals after enrollment was collected. Patients were categorized according to the Physical Activity Guidelines for Americans as meeting the minimum guidelines (yes/no) and incrementally as inactive, low active, moderately active (meeting the guidelines), or high active.

RESULTS

In joint-exposure analyses, patients meeting the guidelines before and 1 year after diagnosis experienced statistically significant reductions in hazards of recurrence (hazard ratio [HR] = 0.59, 95% confidence interval [CI] = 0.42 to 0.82) and mortality (HR = 0.51, 95% CI = 0.34-0.77); associations were stronger at 2-year follow-up for recurrence (HR = 0.45, 95% CI = 0.31 to 0.65) and mortality (HR = 0.32, 95% CI = 0.19 to 0.52). In time-dependent analyses, factoring in activity from all time points, we observed striking associations with mortality for low- (HR = 0.41, 95% CI = 0.24 to 0.68), moderate- (HR = 0.42, 95% CI = 0.23 to 0.76), and high-active patients (HR = 0.31, 95% CI = 0.18 to 0.53).

CONCLUSIONS

Meeting the minimum guidelines for physical activity both before diagnosis and after treatment appears to be associated with statistically significantly reduced hazards of recurrence and mortality among breast cancer patients. When considering activity from all time points, including during treatment, lower volumes of regular activity were associated with similar overall survival advantages as meeting and exceeding the guidelines.

Epidemiology of Basal-like and Luminal Breast Cancers among Black Women in the AMBER Consortium

BACKGROUND

Evidence suggests etiologic heterogeneity among breast cancer subtypes. Previous studies with six-marker IHC classification of intrinsic subtypes included small numbers of black women.

METHODS

Using centralized laboratory results for estrogen receptor (ER), progesterone receptor, HER2, proliferation marker, Ki-67, EGFR, and cytokeratin (CK)5/6, we estimated case-only and case-control ORs for established breast cancer risk factors among cases (n = 2,354) and controls (n = 2,932) in the African American Breast Cancer Epidemiology and Risk (AMBER) consortium. ORs were estimated by ER status and intrinsic subtype using adjusted logistic regression.

RESULTS

Case-only analyses by ER status showed etiologic heterogeneity by age at menarche, parity (vs. nulliparity), and age at first birth. In case-control analyses for intrinsic subtype, increased body mass index and waist-to-hip ratio (WHR) were associated with increased risk of luminal A subtype, whereas older age at menarche and parity, regardless of breastfeeding, were associated with reduced risk. For basal-like cancers, parity without breastfeeding and increasing WHR were associated with increased risk, whereas breastfeeding and age ≥25 years at first birth were associated with reduced risk among parous women. Basal-like and ER^-/HER2⁺ subtypes had earlier age-at-incidence distribution relative to luminal subtypes.

CONCLUSIONS

Breast cancer subtypes showed distinct etiologic profiles in the AMBER consortium, a study of more than 5,000 black women with centrally assessed tumor biospecimens.

IMPACT

Among black women, high WHR and parity without breastfeeding are emerging as important intervention points to reduce the incidence of basal-like breast cancer.

Racial differences in CD8+ T cell infiltration in breast tumors from Black and White women

Background

African American/Black women with breast cancer have poorer survival than White women, and this disparity persists even after adjusting for non-biological factors. Differences in tumor immune biology have been reported between Black and White women, and the tumor immune milieu could potentially drive racial differences in breast cancer etiology and outcome.

Methods

We examined the association of CD8⁺ cytotoxic T cells with clinical-pathological variables in the Women’s Circle of Health Study (WCHS) population of predominantly Black breast cancer patients. We evaluated 688 invasive breast tumor samples (550 Black, 138 White) using immunohistochemical staining of tissue microarray slides. CD8⁺ T cells were scored for each patient tumor sample with digital image analysis.

Results

Black women had a significantly higher percentage of high-grade, estrogen receptor (ER)-negative, and triple-negative tumors than White women and significantly higher CD8⁺ T cell density (median 87.6/mm² vs. 53.1/mm²; p < 0.001). Within the overall population and in the population of Black women only, CD8⁺ T cell density was significantly higher in younger patients and patients with high-grade and ER/PR-negative tumors. No significant associations were observed between CD8⁺ T cell density and overall survival or breast cancer-specific survival in the overall population, or when Black patients were analyzed as a separate group. However, when stratified by subtype, Black women with triple-negative breast cancer and high CD8⁺ T cell density showed a trend towards better overall survival in comparison with patients with low CD8⁺ T cell density (HR = 0.51; 95% CI 0.25–1.04).

Conclusions

Our data raise the possibility that distinct mechanisms of immune cell action may occur in different racial groups.

Abstract D101: Breast cancer in Black women: Do risk factors differ for those who have a family history of breast cancer?

Background: Women who have at least one first-degree relative diagnosed with breast cancer have an almost two-fold risk of developing breast cancer themselves. Therefore, there is particular interest in identifying modifiable factors that can reduce risk. To date, most studies of breast cancer risk in women with a family history of breast cancer have focused on White women. Methods: We pooled questionnaire data on Black women from three case-control studies (Women’s Contraceptive and Reproductive Experiences, Carolina Breast Cancer Study, and Women’s Circle of Health Study) and nested case-control data from the prospective Black Women’s Health Study for an analytic sample of 5,015 invasive breast cancer cases and 15,354 controls; 15.9% of cases and 9.4% of controls reported a first-degree family history of breast cancer (“family history”). We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for risk of breast cancer overall, and by estrogen receptor (ER) status, within strata of family history. All models were adjusted for age and study. Additional covariates were body mass index (recent and at age 18), adult height, smoking, alcohol consumption, parity, breastfeeding, age at first birth, age at menarche, interval between menarche and first birth, age at menopause, and history of benign breast disease. Results: ORs were consistent among women with and without a family history for most factors. However, associations of parity and breastfeeding with risk of ER negative breast cancer were stronger among women with a positive family history: the OR for ever parous vs. nulliparous was 1.63 (1.11-2.39) among women with a family history and 1.31 (1.13-1.53) among those without. In both groups, the elevated OR associated with parity was reduced if the women had breastfed at least one child. The ORs for ER negative breast cancer associated with parity without breastfeeding were 1.86 (1.25-2.77) and 1.43 (1.22-1.67), among women with and without a family history of breast cancer, respectively (p-interaction &gt;0.05). Additional control for other reproductive factors did not materially change the estimates. Breastfeeding was not associated with risk of ER positive breast cancer in either group. Conclusion: As has been shown previously, parous women were found to be at increased risk of ER negative breast cancer, with the increase attenuated by breastfeeding. Stratification by family history of breast cancer indicated that the associations may be stronger among women with a first-degree family history, although interactions were not statistically significant. Findings from the present study demonstrate that Black women who already have a higher than average baseline risk of ER negative breast cancer due to their familial history may favorably modify their risk by breastfeeding.

Citation Format: Gary R Zirpoli, Traci N Bethea, Leslie Bernstein, Melissa A Troester, Christine B Ambrosone, Julie R Palmer. Breast cancer in Black women: Do risk factors differ for those who have a family history of breast cancer? [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr D101.

Dietary Supplement Use During Chemotherapy and Survival Outcomes of Patients With Breast Cancer Enrolled in a Cooperative Group Clinical Trial (SWOG S0221)

PURPOSE

Despite reported widespread use of dietary supplements during cancer treatment, few empirical data with regard to their safety or efficacy exist. Because of concerns that some supplements, particularly antioxidants, could reduce the cytotoxicity of chemotherapy, we conducted a prospective study ancillary to a therapeutic trial to evaluate associations between supplement use and breast cancer outcomes.

METHODS

Patients with breast cancer randomly assigned to an intergroup metronomic trial of cyclophosphamide, doxorubicin, and paclitaxel were queried on their use of supplements at registration and during treatment (n =1,134). Cox proportional hazards regression adjusting for clinical and lifestyle variables was used. Recurrence and survival were indexed at 6 months after enrollment using a landmark approach.

RESULTS

There were indications that use of any antioxidant supplement (vitamins A, C, and E; carotenoids; coenzyme Q10) both before and during treatment was associated with an increased hazard of recurrence (adjusted hazard ratio [adjHR], 1.41; 95% CI, 0.98 to 2.04; P = .06) and, to a lesser extent, death (adjHR, 1.40; 95% CI, 0.90 to 2.18; P = .14). Relationships with individual antioxidants were weaker perhaps because of small numbers. For nonantioxidants, vitamin B12 use both before and during chemotherapy was significantly associated with poorer disease-free survival (adjHR, 1.83; 95% CI, 1.15 to 2.92; P < .01) and overall survival (adjHR, 2.04; 95% CI, 1.22 to 3.40; P < .01). Use of iron during chemotherapy was significantly associated with recurrence (adjHR, 1.79; 95% CI, 1.20 to 2.67; P < .01) as was use both before and during treatment (adjHR, 1.91; 95% CI, 0.98 to 3.70; P = .06). Results were similar for overall survival. Multivitamin use was not associated with survival outcomes.

CONCLUSION

Associations between survival outcomes and use of antioxidant and other dietary supplements both before and during chemotherapy are consistent with recommendations for caution among patients when considering the use of supplements, other than a multivitamin, during chemotherapy.

Smoking, Sex, and Non-Small Cell Lung Cancer: Steroid Hormone Receptors in Tumor Tissue (S0424)

Background

To what extent steroid hormones contribute to lung cancer in male and female never smokers and smokers is unclear. We examined expression of hormone receptors in lung tumors by sex and smoking.

Methods

Patients with primary non-small cell lung cancer were recruited into an Intergroup study in the United States and Canada, led by SWOG (S0424). Tumors from 813 cases (450 women and 363 men) were assayed using immunohistochemistry for estrogen receptor (ER)-α, ER-β, progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Linear regression was used to examine differences in expression by sex and smoking status. Cox proportional hazard models were used to estimate survival associated with the receptors. All statistical tests were two-sided.

Results

In ever smokers, postmenopause and oral contraceptive use were associated with lower nuclear ER-β (P = .02) and total (nuclear + cytoplasmic) PR expression (P = .02), respectively. Women had lower cytoplasmic ER-α (regression coefficient [β], or differences in H-scores = -15.8, P = .003) and nuclear ER-β (β = -12.8, P = .04) expression than men, adjusting for age, race, and smoking. Ever smokers had both higher cytoplasmic ER-α (β = 45.0, P < .001) and ER-β (β = 25.9, P < .001) but lower total PR (β = -42.1, P < .001) than never smokers. Higher cytoplasmic ER-α and ER-β were associated with worse survival (hazard ratio = 1.73, 95% confidence interval [CI] = 1.15 to 2.58, and HR = 1.59, 95% CI = 1.08 to 2.33, respectively; quartiles 4 vs 1).

Conclusions

Lower expression of nuclear ER-β in women supports the estrogen hypothesis in lung cancer etiology. Increasing cytoplasmic ER-α and ER-β and decreasing PR protein expression may be mechanisms whereby smoking disrupts hormone pathways.

Storage Conditions and Immunoreactivity of Breast Cancer Subtyping Markers in Tissue Microarray Sections

Loss of immunoreactivity in tissue sections has been shown to occur when slide sections are stored at room temperature for prolonged periods of time. We conducted a systematic investigation to determine the extent of staining loss in various storage conditions to determine an optimal storage method. We investigated 6 antibodies that are commonly used for breast cancer subtyping in research studies with immunohistochemistry (ER, PR, HER2, CK5/6, EGFR, and Ki67) in formalin-fixed paraffin-embedded breast tissue microarrays consisting of 148 patients. Tissue microarrays were sectioned at various time points: fresh, 1 week, 1 month, 6 months, and 12 months before staining. Slides sectioned at each time point were stored in 5 storage conditions: desiccator, paraffin dipped, 4°C, -20°C, and -80°C. Immunohistochemistry scores were assessed over time with McNemar Test and Bowker Test of Symmetry. Desiccator storage was the only storage condition that did not show any loss in immunoreactivity for any antibody or time point in our study. Paraffin coated slides were the most difficult storage method operationally and also showed the most loss in immunoreactivity. Storing sections in a desiccator was the most effective method for minimizing immunoreactivity loss. Cold storage at 4°C is an intermediate option that is not as protective as a desiccator, but offers the advantage of being accessible to virtually all research labs.

Supplement Use and Chemotherapy-Induced Peripheral Neuropathy in a Cooperative Group Trial (S0221): The DELCaP Study

Background

Chemotherapy-induced peripheral neuropathy (CIPN) can interfere with daily function and quality of life, and there are no known preventive approaches. In a cohort of breast cancer patients receiving paclitaxel as part of a clinical trial (SWOG 0221), we examined the use of dietary supplements both before diagnosis and during treatment in relation to CIPN.

Methods

At registration to S0221, 1225 breast cancer patients completed questionnaires regarding the use of multivitamins and supplements before and at diagnosis. A second questionnaire at six months queried use during treatment. Supplement use was evaluated in relation to CIPN, assessed via the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE v. 3.0) and the self-reported Functional Assessment of Cancer Therapy/Gynecologic Oncology Group Neurotoxicity (FACT/GOG-Ntx) subscale. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed with logistic regression for the CTCAE analyses and ordinal regression for the FACT/GOG-Ntx analyses.

Results

Multivitamin use before diagnosis was associated with reduced symptoms of CIPN (CTCAE-adjusted OR = 0.60, 95% CI = 0.42 to 0.87; FACT/GOG-Ntx-adjusted OR = 0.78, 95% CI = 0.61 to 1.00). Use during treatment was marginally inversely associated with CIPN (CTCAE-adjusted OR = 0.73, 95% CI = 0.49 to 1.08; FACT/GOG-Ntx-adjusted OR = 0.77, 95% CI = 0.60 to 0.99). Other supplement use, either before diagnosis or during treatment, was not statistically significantly associated with CIPN.

Conclusions

Multivitamin use may be associated with reduced risk of CIPN, although individual dietary supplement use did not appreciably affect risk. Multivitamin use could be a surrogate for other related behaviors that are the actual drivers of the association with reduced CIPN. Without prospective randomized trials of vitamin supplementation, recommendations for use or changes to clinical practice are clearly not warranted.

Associations between self-reported diet during treatment and chemotherapy-induced peripheral neuropathy in a cooperative group trial (S0221)

Background

The pathophysiology of chemotherapy-induced peripheral neuropathy (CIPN) is not well understood. Currently, dose reduction is the only recommendation for alleviating symptoms, often leading to premature treatment cessation. The primary aim of this analysis was to determine the association between components of diet during taxane treatment for breast cancer and change in CIPN symptoms over treatment.

Methods

Women with stage II or III invasive breast cancer were enrolled into an ancillary study to the North American Breast Cancer Intergroup phase III trial (S0221) led by the Southwest Oncology Group (SWOG). Questionnaires including a food frequency questionnaire and the Functional Assessment of Cancer Treatment Gynecologic Oncology Group—Neurotoxicity were administered to assess diet and neuropathic conditions at baseline and during chemotherapy. Ordinal regression was used to estimate odds ratios (ORs) for associations between various food groups and change in neuropathy score (< 10%, 10–30%, > 30%) (n = 900).

Results

The odds of worse neuropathy decreased by 21% for each increase in tertile of grain consumption (OR = 0.79, 95% CI 0.66–0.94, p = 0.009). We also observed a nominal 19% increase with higher consumption of citrus fruits (OR = 1.19, 95% CI 1.01–1.40, p = 0.05).

Conclusions

Distinguishing between those who experienced a moderate and a severe change in neuropathy, we found that citrus fruit and grain consumption may play a role in the severity of symptoms. Since there are no existing dietary recommendations for the management of CIPN, further research is needed to investigate whether there may be certain foods that could worsen or alleviate neuropathy symptoms associated with treatment for breast cancer.

Trial registration

ClinicalTrials.gov, NCT03413761. Registered retrospectively on 29 January 2018.

Biology and Etiology of Young-Onset Breast Cancers among Premenopausal African American Women: Results from the AMBER Consortium

Background: African American (AA) women have higher incidence of aggressive, young-onset (<40 years) breast cancers. Young- and older-onset disease may have distinct tumor biologies and etiologies; however, studies investigating age differences among AA women have been rare and generally underpowered.Methods: We examined tumor characteristics and breast cancer risk factors associated with premenopausal young (<40) vs. older (≥40) AA women's breast cancer in the African American Breast Cancer Epidemiology and Risk Consortium (2,008 cases and 5,144 controls). Unconditional logistic regression models assessed heterogeneity of tumor biology and risk factor associations by age, overall, and by estrogen receptor status.Results: Premenopausal AA women <40 years had higher frequency of poorer-prognosis tumor characteristics compared with older women, including negative estrogen and progesterone receptor status, triple-negative subtype, higher grade, higher stage, and larger tumors. Adiposity (i.e., waist-to-hip ratio) and family history of breast cancer were more strongly associated with young-onset disease [case-control OR = 1.46, 95% confidence interval (CI) = 1.04-2.05; OR = 3.10, 95% CI = 2.08-4.63, respectively] compared with older-onset disease (OR = 1.11, 95% CI = 0.91-1.35; OR = 1.57, 95% CI = 1.26-1.94). Breastfeeding showed a slight inverse risk association among young women (OR = 0.70, 95% CI = 0.43-1.16). Oral contraceptive use was associated with increased risk regardless of age. Considering various cutoff points for young age (<40, <45, <50), age-related heterogeneity was greatest when <40 was used.Conclusions: Among premenopausal AA women, diagnosis before age 40 is associated with more aggressive breast tumor biology and some etiologic differences.Impact: Modifiable risk factors including breastfeeding, adiposity, and oral contraceptive use may be important targets for mitigating harms of young-onset breast cancer. Cancer Epidemiol Biomarkers Prev; 26(12); 1722-9. ©2017 AACR.

Trends in Cruciferous Vegetable Consumption and Associations with Breast Cancer Risk: A Case-Control Study

Background: The chemopreventive activities of cruciferous vegetables were recognized in the early 1990s, followed by a growth of evidence in various cancer models, including breast cancer. To our knowledge, no studies have examined whether consumption of cruciferous vegetables has changed accordingly, and what impact, if any, on breast cancer risk may have resulted. Objective: The time trend in cruciferous vegetable intake was investigated between 1982 and 1998, and its associations with breast cancer risk were examined. Methods: In a hospital-based case-control study in 1491 patients with breast cancer and 1482 controls, loess curves were constructed to describe the relation between median consumption of cruciferous vegetables and year of admission. ORs and 95% CIs were calculated with unconditional logistic regression, adjusting for age, year of admission, family income, body mass index, cigarette smoking, age at menarche, parity, age at first birth, family history of breast cancer, hormone replacement therapy, and total meat intake. Results: Consumption patterns differed between cases and controls. A slow but steady increase in cruciferous vegetable intake was observed in the cases, although among controls, cruciferous vegetable consumption increased from 1982 to 1987, reached a plateau during 1988-1992, and then declined from 1993 to 1998. Accordingly, although an overall inverse association with breast cancer risk was observed for cruciferous vegetable intake (highest compared with lowest quartile-OR: 0.68; 95% CI: 0.55, 0.86; P-trend = 0.0006), the inverse association tended to be more pronounced within more recent-year strata, with an OR of 0.52 (95% CI: 0.33, 0.83) for 1993-1998 compared with an OR of 0.89 (95% CI: 0.64, 1.23) for 1982-1987. Conclusions: The consumption of cruciferous vegetables increased during the past 2 decades, showing different trends in cases and controls. The subtle but sustained increase in cruciferous vegetable intake reported by the cases could influence association studies with breast cancer risk.

Abstract 4998: Breast tumor FOXA1 protein expression and reproductive characteristics among African-American and European-American women

Background: Forkhead box protein A1 (FOXA1) plays a key role in determining estrogen receptor (ER) function and mammary ductal development and may repress the basal cell phenotype during differentiation of breast epithelium. While reproductive factors are known to influence breast cancer risk depending on the subtypes, data on the association of tumor FOXA1 protein expression and reproductive characteristics are very limited.

Methods: Tissue microarrays comprising surgical tumors from 638 women (466 African-American [AA] and 172 European-American [EA], aged 20-75 years) with primary breast cancer in the Women’s Circle of Health Study (WCHS) were analyzed for FOXA1 expression by immunohistochemistry and automated image analysis. In-person interviews were conducted to obtain data on demographics, medical and family histories, and reproductive and menstrual histories. Logistic regression was performed for FOXA1 positivity (&gt;10% cells with strong staining) with menopausal status, age at menarche, age at first live birth, parity, and breastfeeding, adjusting for age at diagnosis, family history of breast cancer, and history of benign breast disease.

Results: FOXA1 expression was higher in tumors from EA compared to those from AA women (80% vs. 70% positivity, P=0.011). FOXA1 expression was highly correlated with ER positivity (88% positive in ER+ and 26% in ER- breast cancer among AA women; 90% and 29% respectively among EA women; both P&lt;0.001). Among AA women, a higher number of live births was associated with lower FOXA1 expression (odds ratio [OR]=0.45, 95% confidence interval [CI]=0.22-0.91 for 2 live births and OR=0.44, 95% CI=0.20-0.91 for ≥3 live births, versus nulliparous). However, the inverse association was not observed among EA women, potentially due to the small sample size.

Conclusion: In AA women, a higher number of live births, which has been related to greater risk of ER- breast cancer, is associated with lower FOXA1 expression. Because FOXA1 promotes luminal and represses the basal differentiation, respectively, the effects of parity on expression of FOXA1 may be the link whereby it increases risk of ER- breast cancer. (Funding: NIH P01CA151135, R01CA100598, R01CA185623, P30CA072720, K07CA201334; US Army Medical Research and Material Command DAMD-17-01-1-0334; the Breast Cancer Research Foundation; and the Philip L. Hubbell family)

Citation Format: Ting-Yuan David Cheng, Rochelle Payne Ondracek, Song Yao, Wiam Bshara, Thaer Khoury, Gary R. Zirpoli, Warren Davis, Elisa V. Bandera, Michael Higgins, Christine B. Ambrosone. Breast tumor FOXA1 protein expression and reproductive characteristics among African-American and European-American women [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4998. doi:10.1158/1538-7445.AM2017-4998

Single nucleotide variants in metastasis-related genes are associated with breast cancer risk, by lymph node involvement and estrogen receptor status, in women with European and African ancestry

Single nucleotide polymorphisms (SNPs) in pathways influencing lymph node (LN) metastasis and estrogen receptor (ER) status in breast cancer may partially explain inter-patient variability in prognosis. We examined 154 SNPs in 12 metastasis-related genes for associations with breast cancer risk, stratified by LN and ER status, in European-American (EA) and African-American (AA) women. Two-thousand six hundred and seventy-one women enrolled in the Women's Circle of Health Study were genotyped. Pathway analyses were conducted using the adaptive rank truncated product (ARTP) method, with p_ARTP  ≤ 0.10 as significant. Multi-allelic risk scores were created for the ARTP-significant gene(s). Single-SNP and risk score associations were modeled using logistic regression, with false discovery rate (FDR) P-value adjustment. Although single-SNP associations were not significant at p_FDR  < 0.05, several genes were significant in the ARTP analyses. In AA women, significant ARTP gene-level associations included CDH1 with LN+ (p_ARTP  = 0.10; multi-allelic OR = 1.13, 95%CI 1.07-1.19, p_FDR  = 0.0003) and SIPA1 with ER- breast cancer (p_ARTP  = 0.10; multi-allelic OR = 1.16, 95%CI 1.02-1.31, p_FDR  = 0.03). In EA women, MTA2 was associated with overall breast cancer risk (p_ARTP  = 0.004), regardless of ER status, and with LN- disease (p_ARTP  = 0.01). Also significant were SATB1 in ER- (p_ARTP  = 0.03; multi-allelic OR = 1.12, 95%CI 1.05-1.20, p_FDR  = 0.003) and KISS1 in LN- (p_ARTP  = 0.10; multi-allelic OR = 1.18, 95%CI 1.08-1.29, p_FDR  = 0.002) analyses. Among LN+ cases, significant ARTP associations were observed for SNAI1, CD82, NME1, and CTNNB1 (multi-allelic OR = 1.09, 95%CI 1.04-1.14, p_FDR  = 0.001). Our findings suggest that variants in several metastasis genes may affect breast cancer risk by LN or ER status, although verification in larger studies is required. © 2016 Wiley Periodicals, Inc.

Intratumoral heterogeneity as a source of discordance in breast cancer biomarker classification

BACKGROUND

Spatial heterogeneity in biomarker expression may impact breast cancer classification. The aims of this study were to estimate the frequency of spatial heterogeneity in biomarker expression within tumors, to identify technical and biological factors contributing to spatial heterogeneity, and to examine the impact of discordant biomarker status within tumors on clinical record agreement.

METHODS

Tissue microarrays (TMAs) were constructed using two to four cores (1.0 mm) for each of 1085 invasive breast cancers from the Carolina Breast Cancer Study, which is part of the AMBER Consortium. Immunohistochemical staining for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) was quantified using automated digital imaging analysis. The biomarker status for each core and for each case was assigned using clinical thresholds. Cases with core-to-core biomarker discordance were manually reviewed to distinguish intratumoral biomarker heterogeneity from misclassification of biomarker status by the automated algorithm. The impact of core-to-core biomarker discordance on case-level agreement between TMAs and the clinical record was evaluated.

RESULTS

On the basis of automated analysis, discordant biomarker status between TMA cores occurred in 9 %, 16 %, and 18 % of cases for ER, PR, and HER2, respectively. Misclassification of benign epithelium and/or ductal carcinoma in situ as invasive carcinoma by the automated algorithm was implicated in discordance among cores. However, manual review of discordant cases confirmed spatial heterogeneity as a source of discordant biomarker status between cores in 2 %, 7 %, and 8 % of cases for ER, PR, and HER2, respectively. Overall, agreement between TMA and clinical record was high for ER (94 %), PR (89 %), and HER2 (88 %), but it was reduced in cases with core-to-core discordance (agreement 70 % for ER, 61 % for PR, and 57 % for HER2).

CONCLUSIONS

Intratumoral biomarker heterogeneity may impact breast cancer classification accuracy, with implications for clinical management. Both manually confirmed biomarker heterogeneity and misclassification of biomarker status by automated image analysis contribute to discordant biomarker status between TMA cores. Given that manually confirmed heterogeneity is uncommon (<10 % of cases), large studies are needed to study the impact of heterogeneous biomarker expression on breast cancer classification and outcomes.

Chronic Recreational Physical Inactivity and Epithelial Ovarian Cancer Risk: Evidence from the Ovarian Cancer Association Consortium

BACKGROUND

Despite a large body of literature evaluating the association between recreational physical activity and epithelial ovarian cancer (EOC) risk, the extant evidence is inconclusive, and little is known about the independent association between recreational physical inactivity and EOC risk. We conducted a pooled analysis of nine studies from the Ovarian Cancer Association Consortium to investigate the association between chronic recreational physical inactivity and EOC risk.

METHODS

In accordance with the 2008 Physical Activity Guidelines for Americans, women reporting no regular, weekly recreational physical activity were classified as inactive. Multivariable logistic regression was utilized to estimate the ORs and 95% confidence intervals (CI) for the association between inactivity and EOC risk overall and by subgroups based upon histotype, menopausal status, race, and body mass index.

RESULTS

The current analysis included data from 8,309 EOC patients and 12,612 controls. We observed a significant positive association between inactivity and EOC risk (OR = 1.34; 95% CI, 1.14-1.57), and similar associations were observed for each histotype.

CONCLUSIONS

In this large pooled analysis examining the association between recreational physical inactivity and EOC risk, we observed consistent evidence of an association between chronic inactivity and all EOC histotypes.

IMPACT

These data add to the growing body of evidence suggesting that inactivity is an independent risk factor for cancer. If the apparent association between inactivity and EOC risk is substantiated, additional work via targeted interventions should be pursued to characterize the dose of activity required to mitigate the risk of this highly fatal disease. Cancer Epidemiol Biomarkers Prev; 25(7); 1114-24. ©2016 AACR.

Performance of Three-Biomarker Immunohistochemistry for Intrinsic Breast Cancer Subtyping in the AMBER Consortium

BACKGROUND

Classification of breast cancer into intrinsic subtypes has clinical and epidemiologic importance. To examine accuracy of IHC-based methods for identifying intrinsic subtypes, a three-biomarker IHC panel was compared with the clinical record and RNA-based intrinsic (PAM50) subtypes.

METHODS

Automated scoring of estrogen receptor (ER), progesterone receptor (PR), and HER2 was performed on IHC-stained tissue microarrays comprising 1,920 cases from the African American Breast Cancer Epidemiology and Risk (AMBER) consortium. Multiple cores (1-6/case) were collapsed to classify cases, and automated scoring was compared with the clinical record and to RNA-based subtyping.

RESULTS

Automated analysis of the three-biomarker IHC panel produced high agreement with the clinical record (93% for ER and HER2, and 88% for PR). Cases with low tumor cellularity and smaller core size had reduced agreement with the clinical record. IHC-based definitions had high agreement with the clinical record regardless of hormone receptor positivity threshold (1% vs. 10%), but a 10% threshold produced highest agreement with RNA-based intrinsic subtypes. Using a 10% threshold, IHC-based definitions identified the basal-like intrinsic subtype with high sensitivity (86%), although sensitivity was lower for luminal A, luminal B, and HER2-enriched subtypes (76%, 40%, and 37%, respectively).

CONCLUSION

Three-biomarker IHC-based subtyping has reasonable accuracy for distinguishing basal-like from nonbasal-like, although additional biomarkers are required for accurate classification of luminal A, luminal B, and HER2-enriched cancers.

IMPACT

Epidemiologic studies relying on three-biomarker IHC status for subtype classification should use caution when distinguishing luminal A from luminal B and when interpreting findings for HER2-enriched cancers.

Abstract 2789: Associations between insertional polymorphisms of human endogenous retrovirus K113 and K115 and breast cancer risk in African American and European American women

Background: Human endogenous retroviruses (HERVs) are remnants of ancient virus infection. The majority of them are disabled due to mutation and/or deletion. However, HERV K113 and K115 have been shown to have full-length insertion in human genome and retain the ability to encode functional virus proteins in some individuals. Considering the potential role of HERVs in carcinogenesis and a high genetic homology between HERV K and mouse mammary tumor virus, the study is designed to investigate the distribution of HERV K113 and K115 in African American (AA) and European American (EA) women, and their association with breast cancer risk.

Methods: Built on a funded multi-center case-control study, the Women's Circle of Health Study, the study included 1242 cases (608 AA and 634 EA) and 1422 controls (783 AA and 639 EA). PCR followed by fragment analysis was used for insertional polymorphism assay. For each HERV, three PCRs were performed to determine whether the insertion is partial or full length. Indeed, a subset of individuals showed insertion of long terminal repeat (LTR) of HERV, instead of whole virus insertion. The distribution of insertional polymorphisms was compared between AA and EA as well as between cases and controls. Logistic regression was used to calculate odds ratio (OR) and 95% confidence interval (CI) with adjustment for age at diagnosis and proportion of European ancestry.

Results: For both K113 and K115, with or without including LTR insertion, the distribution was significantly different between AA and EA women. A two-fold higher prevalence of HERVs was observed in AA women, showing 51.5% of individuals with at least one copy of either K113 or K115 compared to 23.3% in EA women among controls. The prevalence of HERVs was inversely associated with proportions of European ancestry, showing a decrease from averagely 66% European ancestry in individuals without insertion to 42.9%, 23.2%, 13.3% with one, two, or more insertions of HERV K113 or K115, respectively.

Between cases and controls, the prevalence of K113 was slightly higher in controls, but not for K115. Furthermore, both K113 and K115 insertion were significantly associated with the reduced risk of breast cancer in both AA and EA women. Near 50% reduction of breast cancer risk was observed in AA and EA women with homozygous insertion of K113 (combined OR, 0.45; 95% CI, 0.25-0.80).

A trend of a reduction in breast cancer risk with an increase of copy number of HERV K insertion was observed in both AA and EA women. However, there was no association with breast cancer subtypes.

Conclusion: This is the first study to document the prevalence of HERV K113 and K115 in AA and EA population, and to report an inverse association with breast cancer risk. Validation of the findings in a relatively large study is warranted in the future.

Funded by 5R03CA156645, K07CA148888, P01151135, and R01CA100598.

Citation Format: Li Tang, Steven R. Gregory, David Tritchler, Gary R. Zirpoli, Song Yao, Warren Davis, Gregory L. Ciupak, Yasmin Thanavala, Elisa V. Bandera, Christine B. Ambrosone. Associations between insertional polymorphisms of human endogenous retrovirus K113 and K115 and breast cancer risk in African American and European American women. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2789. doi:10.1158/1538-7445.AM2015-2789

Associations between estrogen receptor-negative breast cancer and timing of reproductive events differ between African American and European American women

The effects of reproductive factors on breast cancer risk seem to differ by estrogen receptor (ER) status. Menarche and first live birth (FLB) tend to occur at younger ages in African Americans (AA) than European Americans (EA), and could play a role in breast cancer disparities. In the Women's Circle of Health Study, a case-control study of breast cancer in EA and AA women, in-person interviews were conducted to collect epidemiologic data, including reproductive histories. Data on ER status, abstracted from pathology reports, were available for 814 AA and 538 EA breast cancer cases, and were analyzed with 1015 AA and 715 EA controls, to evaluate associations between subgroups and age at menarche, age at FLB, and the interval between those ages. Among AA women, later age at menarche (≥14 years) was associated with reduced risk of both ER(+) and ER(-) breast cancer, with ORs strongest for ER(-) disease [OR = 0.57; 95% confidence interval (CI), 0.37-0.88]; associations were weaker and nonsignificant for EA women. There were no significant associations with age at FLB, but AA women with a FLB within 15 years of menarche had increased risk of ER(-) disease (OR = 2.26; 95% CI, 1.29-3.95), with no significant associations among EAs. In our data, earlier age at menarche and shorter intervals until FLB are associated with ER(-) breast cancer in AA women; differential distributions by race of these and other reproductive risk factors could contribute to the higher prevalence of ER(-) breast cancer in AA women. Cancer Epidemiol Biomarkers Prev; 23(6); 1115-20. ©2014 AACR.

Abstract 4681: Effect of physician recommendation on multivitamin and antioxidant supplement use during chemotherapy in an adjuvant trial for breast cancer (SWOG S0221)

Because numerous chemotherapeutic agents exert their cytotoxic effects through generation of reactive oxygen species, the use of antioxidant supplements during treatment is controversial. There are published recommendations to suspend antioxidant supplement use during treatment, despite lack of empirical data from clinical studies; however, it is unclear if patients follow these recommendations. We examined use of multivitamins and vitamin supplements (MV/SP) during treatment for breast cancer, particularly in relation to physician recommendations.

High-risk breast cancer patients (n=855) were queried regarding physician recommendations and use of MV/SP via self-administered questionnaires in an ancillary study embedded in a phase III trial of dose-dense compared to metronomic administration of doxorubicin/cyclophosphamide + paclitaxel (SWOG S0221). Of the 658 patients who reported discussing use of supplements during treatment with their physicians, 390 (59%) received no counseling regarding MV/SP use, 85 (13%) received recommendations not to take MV/SP, and 183 (28%) received recommendations to use MV/SP.

MV/SP use during treatment was compared to use prior to diagnosis in relation to physician recommendations, with the reference group comprised of those receiving no recommendations. Of those using MV ≥ once/week before diagnosis, recommendations not to take MV/SP were associated with a tenfold reduction in MV use to &lt; once/week during treatment. (OR=10.0, 95% CI=3.7-27.0). MV use was less likely to decrease among patients receiving recommendations to use MV/SP (OR=0.23, 95% CI=0.12-0.44). Similar findings were observed among patients who reported use of vitamin C and vitamin E supplements ≥ once/week before diagnosis, with patients who were advised to take no supplements other than a MV more than 5 times as likely to decrease use of antioxidant supplements.

MV use during treatment among previous non-users increased almost sixfold among those whose physicians recommended MV/SP use during treatment (OR=5.92, 95% CI=3.29-10.6). For those reporting vitamin C or vitamin E use &lt; once/week before diagnosis, patients whose physicians recommended MV/SP during treatment were more likely to increase their use of vitamin C (OR=2.05, 95% CI=1.00-4.19) and vitamin E (OR=5.28, 95% CI=2.24-12.4).

In this study, physician recommendations were strongly associated with patient use of MV/SP during chemotherapy, regardless of the patient's frequency of use prior to diagnosis. These findings highlight the critical need to better understand the mechanisms by which antioxidants may influence chemotherapeutic outcomes, and to determine if supplement use affects toxicity and/or recurrence. Yearly follow-up in this ongoing study will allow us to assess the impact of MV/SP use treatment outcomes, providing a basis for physician recommendations.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4681. doi:10.1158/1538-7445.AM2011-4681

Intake of cruciferous vegetables modifies bladder cancer survival

BACKGROUND

Intake of cruciferous vegetables, a rich source of dietary isothiocyanates, has been inversely associated with risk of bladder cancer. Due to the potent antiproliferative effects of dietary isothiocyanates on bladder cancer in in vitro and in vivo models, cruciferous vegetable intake may also play a role in survival among patients with bladder cancer.

METHODS

Using information obtained from the Roswell Park Cancer Institute Tumor Registry, patient medical records, and routinely collected questionnaire data, we examined potential associations between intake of cruciferous vegetables and survival among bladder cancer patients. As cooking can substantially reduce or destroy isothiocyanates, consumption of raw versus cooked cruciferous vegetables was examined separately. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional hazard models.

RESULTS

A total of 239 bladder cancer patients were included in the study. After an average of 8 years of follow-up, 179 deaths occurred, with 101 deaths attributable to bladder cancer. After adjustment for other prognostic factors, a strong and significant inverse association was observed between bladder cancer mortality and broccoli intake, in particular raw broccoli intake (> or =1 versus <1 serving per month; HR for overall death, 0.57; 95% CI, 0.39-0.83; HR for disease-specific death, 0.43; 95% CI, 0.25-0.74). There were no significant associations for total vegetables, total fruits, or other individual cruciferous vegetables.

CONCLUSIONS

Considering the strong preclinical evidence, intake of broccoli may improve bladder cancer survival.

IMPACT

Further prospective investigation is warranted to confirm the potential role of cruciferous vegetables in bladder cancer prognosis.

Cruciferous vegetable intake is inversely associated with lung cancer risk among smokers: a case-control study

Background

Inverse associations between cruciferous vegetable intake and lung cancer risk have been consistently reported. However, associations within smoking status subgroups have not been consistently addressed.

Methods

We conducted a hospital-based case-control study with lung cancer cases and controls matched on smoking status, and further adjusted for smoking status, duration, and intensity in the multivariate models. A total of 948 cases and 1743 controls were included in the analysis.

Results

Inverse linear trends were observed between intake of fruits, total vegetables, and cruciferous vegetables and risk of lung cancer (ORs ranged from 0.53-0.70, with P for trend < 0.05). Interestingly, significant associations were observed for intake of fruits and total vegetables with lung cancer among never smokers. Conversely, significant inverse associations with cruciferous vegetable intake were observed primarily among smokers, in particular former smokers, although significant interactions were not detected between smoking and intake of any food group. Of four lung cancer histological subtypes, significant inverse associations were observed primarily among patients with squamous or small cell carcinoma - the two subtypes more strongly associated with heavy smoking.

Conclusions

Our findings are consistent with the smoking-related carcinogen-modulating effect of isothiocyanates, a group of phytochemicals uniquely present in cruciferous vegetables. Our data support consumption of a diet rich in cruciferous vegetables may reduce the risk of lung cancer among smokers.

Consumption of raw cruciferous vegetables is inversely associated with bladder cancer risk

Cruciferous vegetables contain isothiocyanates, which show potent chemopreventive activity against bladder cancer in both in vitro and in vivo studies. However, previous epidemiologic studies investigating cruciferous vegetable intake and bladder cancer risk have been inconsistent. Cooking can substantially reduce or destroy isothiocyanates, and could account for study inconsistencies. In this hospital-based case-control study involving 275 individuals with incident, primary bladder cancer and 825 individuals without cancer, we examined the usual prediagnostic intake of raw and cooked cruciferous vegetables in relation to bladder cancer risk. Odds ratios (OR) and 95% confidence intervals (CI) were estimated with unconditional logistic regression, adjusting for smoking and other bladder cancer risk factors. We observed a strong and statistically significant inverse association between bladder cancer risk and raw cruciferous vegetable intake (adjusted OR for highest versus lowest category = 0.64; 95% CI, 0.42-0.97), with a significant trend (P = 0.003); there were no significant associations for fruit, total vegetables, or total cruciferous vegetables. The associations observed for total raw crucifers were also observed for individual raw crucifers. The inverse association remained significant among current and heavy smokers with three or more servings per month of raw cruciferous vegetables (adjusted ORs, 0.46 and 0.60; 95% CI, 0.23-0.93 and 0.38-0.93, respectively). These data suggest that cruciferous vegetables, when consumed raw, may reduce the risk of bladder cancer, an effect consistent with the role of dietary isothiocyanates as chemopreventive agents against bladder cancer.