Citations

Abstract Background: Women with benign breast disease (BBD) have increased breast cancer risk, and histologic features of the lesion stratify individual risk. We hypothesized that the concentration and type of terminal duct lobular units in BBD tissue is associated with future breast cancer risk. Methods: A nested case-control series of 770 breast cancer cases and 1273 age- and year of biopsy-matched controls was identified within a cohort of 13,647 women with BBD from 1967-2001 (median follow-up 15.3 years). One representative H&E slide from each biopsy was reviewed by a single pathologist, who recorded total # of lobules present, and # of fibrocystic lobules (total and # with epithelial proliferation). Samples were also evaluated for lobular involution and primary BBD histology. Lobule density (LD) was calculated as # of lobules/cm2 in each tissue section. Breast cancer associations with LD's (total, fibrocystic, proliferative) were examined with conditional logistic regression. Odds ratios are reported per 1 SD increase in LD. Results: Each LD measure was significantly associated with involution and primary BBD histology (p<0.0001 for each). Fibrocystic (OR 1.17, 95% CI 1.06-1.28) and proliferative (OR 1.37, 95% CI 1.16-1.61) LD were each associated with case status (p≤0.001) but total LD did not reach significance (OR 1.09, 95% CI 1.0-1.20; p=0.06). LD associations were somewhat attenuated after adjusting for involution (total OR 1.04 p=0.41; fibrocystic OR 1.13 p=0.02; proliferative OR 1.28 p=0.002) and primary BBD histology (total OR 1.04 p=0.49; fibrocystic OR 1.08 p=0.15; proliferative OR 1.18 p=0.07). Conclusions: The density of proliferative lobules in benign breast biopsy tissue is related to other BBD histologic features but may provide additional breast cancer risk stratification among women with proliferative BBD. Additional research will more fully evaluate the ability of this promising novel measure to predict breast cancer risk. Lobule Density Measures (lobules per square cm) All values are Medians Total Lobule Density Fibrocystic Lobule Density Proliferative Lobule Density Overall 17.5 4.5 0.7 Cases 18.1 4.9 1.3 Controls 17.0 4.2 0.4 Primary BBD Histology Nonproliferative disease 16 3.3 0 Proliferative disease 18.6 5.8 2.7 Atypical hyperplasia 20.9 6.2 3.3 Involution Category None 28.7 5.3 1.0 Partial 19.0 5 1.2 Complete 8.5 2.1 0 Citation Format: Amy C. Degnim, Lynn C. Hartmann, Tanya L. Hoskin, Marlene H. Frost, V Shane Pankratz, Derek C. Radisky, Lorelle L. Benetti, Celine M. Vachon, Teresa M. Allers, Robert A. Vierkant, Daniel W. Visscher. Density of breast lobules in benign breast tissue and association with future breast cancer risk. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 155. doi:10.1158/1538-7445.AM2013-155

Abstract Background: Age-related lobular involution (LI) is a physiological process, usually accelerated with menopause, in which the epithelial tissue of the breast gradually regresses. Our previous analysis of a cohort of more than 14,000 women who had a benign breast biopsy at the Mayo Clinic revealed that women who had undergone LI were at significantly reduced risk of subsequent breast cancer development. In our studies of postmenopausal women specifically, we found that more than 40% had not completed the process of LI, and that the increased breast cancer incidence in older women was strongly associated with incomplete LI. We sought to determine the potential protective mechanistic effects of lobular involution. Methods: We generated primary human mammary epithelial cell lines (HMECs) from breast biopsies of women who showed no LI (N = 6), partial LI (N = 7), or complete LI (N = 6). These cell lines were analyzed for proliferation in culture and profiled for genomic signatures using Affymetrix gene arrays. We also analyzed RNA isolated from a cohort of archived formalin-fixed, paraffin-embedded (FFPE) benign breast biopsy samples from postmenopausal women who had either completed the process of LI (N = 4) or who had not initiated LI (N = 8) for genomic signatures using Whole-Genome DASL Assays. Results: We found that LI was associated with decreased cellular proliferation and inhibition of processes associated with tumor development and progression. Specifically, we found that HMECs derived from benign breast biopsies in which LI was not evident showed increased proliferation and elevated expression of Twist (p = 0.002), a transcription factor associated with epithelial-mesenchymal transition (EMT) and breast cancer development. We are assessing differentially expressed genes for association with breast cancer risk using a nested case:control group of benign breast biopsies from women in our cohort who subsequently developed breast cancer (N = 85) vs those who did not (N = 142) and for whom LI status at the time of initial biopsy was known. Conclusions: LI may decrease cancer risk through inhibition of key tumorigenic processes. Identification of processes associated with the physiologic risk reduction seen with LI may provide insight into novel avenues for risk reduction. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-06-01.

Abstract Background: Fibroadenoma (FA) is a relatively common benign breast tumor that can occur in women of any age, with a peak incidence during the second and third decades. The only previous study of this lesion reported that FAs are associated with a 2.2 times increased risk of developing invasive breast cancer (BC) compared to matched controls [1]. This relative risk may increase to 3.1 among patients with complex FA, and remains elevated for decades after diagnosis. However, this study did not thoroughly account for other forms of concomitant risk factors. Our investigative team sought to examine breast cancer risk among women with non-complex and complex FA, overall and stratified by other BC risk factors. Materials and Methods: The study cohort included women between ages 18 to 85 in the Mayo Benign Breast Disease (BBD) Cohort who underwent excisional breast biopsy between 1967and1991 and were found to have a FA. FA was defined histologically as a combination of epithelial and stromal proliferation. Complex FA was defined as FA associated with any of the following features: sclerosing adenosis, epithelial calcifications, papillary apocrine change, and microcysts greater than 3.0 mm. The primary endpoint was a diagnosis of BC, determined using the Mayo medical record and questionnaire information from study participants. A single breast pathologist, blinded to the initial diagnosis and clinical outcome, performed pathology review. Observed vs. expected BC risk across levels of FA was assessed via standardized incidence ratios (SIRs), using age-stratified incidence rates from the Iowa Surveillance, Epidemiology, and End Results (SEER) registry. Analyses were carried out overall and within subgroups of involution status (none, partial, complete) and overall histology (non-proliferative disease [NP], proliferative disease without atypia [PDWA] or atypical hyperplasia [AH]). Results: Of 9097 women in the Mayo BBD Cohort, FA were identified in 2139- non-complex in 1903 (20.9%) and complex in 236 (2.6%). The greatest proportion of FA occurred in the 40–69 age range. The mean ages for women with non-complex FA and complex FA were 45.7 and 50.2 years respectively. The SIR of breast cancer in the overall BBD cohort was 1.5 (95% CI [1.4–1.6]). The SIR among women with non-complex FA was 1.5 (95% CI [1.3–1.8]), and for complex FA increased to 2.41 (95% CI [1.7–3.4]). However, women with complex FA were more likely to have other concomitant high-risk histologic features such as PDWA and incomplete involution. In stratified analyses accounting for involution status and PDWA, complex FA did not demonstrate an independent increase in BC risk. Conclusion: Complex FA does not confer an increased risk for BC beyond other established histologic features. Therefore, women with complex FA should be managed based upon a risk level consistent with the major histologic category of PDWA and/or AH. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-01-08.

Abstract Background: Optimal early detection and prevention strategies for breast cancer are predicated on our ability to accurately identify women at increased risk for disease. Current breast cancer risk prediction models rely on clinical and epidemiologic features. As demonstrated with other cancers, such as those of the cervix and colon, cancer risk assessment is enhanced when the tissue at risk is examined for evidence of premalignant abnormalities. Here, we present a multivariate model for individualized breast cancer risk prediction that incorporates tissue features identified from biopsies from women with benign breast disease (BBD). Methods: We used our cohort of more than 9000 women diagnosed with BBD at the Mayo Clinic from 1967–1991, and identified a nested case:control series of 377 women who developed cancer (cases) matched with 734 women who did not (controls). We identified a set of variables that either alone or in two-way interactions contributed to a multivariable risk prediction model. We combined this relative risk model with the baseline incidence of breast cancer and the baseline hazard of death from our full BBD cohort to develop a risk prediction tool that computes absolute risk estimates for breast cancer. We calculated 5-year risk predictions for these cases and controls using our model and using the Gail model and compared c-statistics from these risk predictions. We validated our model using an independent set of 378 breast cancer cases and 728 matched controls drawn from our BBD cohort. Results: Cases and controls in the model development data set differed significantly on a number of features when examined individually. Those included in a multivariable relative risk model for breast cancer among women with BBD are shown below. After including interactions between lobular involution, and histologic impression, with age at first live birth/number of children, and degree of involution with sclerosing adenosis, we devised a model that predicts the absolute risk of breast cancer. Predicted five-year risks in the model development series, we observed a c-statistic of 0.66, higher than the c-statistic of 0.61 for the Gail model. With risk prediction estimates from our validation series of cases and matched controls, the c-statistic of our model decreased to 0.59 and the c-statistic for the Gail model was 0.55. Conclusion: We have identified an initial risk prediction model for breast cancer in women with BBD. The identified model includes basic demographic information as well as a number of histologic features of the tissue samples. Its initial performance is promising, providing improved discrimination over the Gail model in our replication data set. Further work is needed to identify features which might provide additional predictive information for breast cancer risk. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-12-03.

Abstract Background: Current options to prevent ovarian and breast cancer recurrence are limited. However, signs of anti-tumor immunity are associated with improved survival in patients who have experienced a number of different malignancies. After identifying folate receptor alpha (FR)-derived class II-binding peptides recognized by lymphocytes from patients who previously had breast or ovarian cancer, we developed a multi-peptide vaccine with five peptides, each of which was recognized by more than 25% of the patients. We combined this vaccine with metronomic cyclophosphamide in an attempt to selectively reduce T regulatory cells in the periphery and the tumor microenvironment. Methods: We obtained an Investigational New Drug approval from the Food and Drug Administration to perform a phase I study in 22 patients who were currently in remission from their breast or ovarian cancer. Participants were required to be at least 90 days past any treatment for their disease (other than hormonal treatment, if applicable) and show no current evidence of disease. After 28 days of metronomic cyclophosphamide, six monthly intradermal injections of the vaccine were given. The primary endpoints of the trial are safety and immunogenicity. Results: To date, 15 of 22 patients have enrolled (7 breast and 8 ovarian cancer patients). 4 breast and 2 ovarian cancer patients are available for toxicity evaluation. No serious major adverse events have been observed, with the expected injection site reactions being the primary toxicity experienced by most participants; grade 2 decreased white blood cell counts were observed in 3 patients at completion of cyclophosphamide. Two patients went off study prior to completing all six vaccinations, one for vision changes, and one for disease progression. Immune monitoring is underway, with major assays being ELISAs for high-affinity IgG targeting the FR and FR-peptide specific ELIspots. These data will be presented at the meeting. Conclusions: Metronomic cyclophosphamide followed by intradermal vaccinations with a multi-peptide vaccine targeting the tumor antigen FR appears to be a tolerable regimen at this preliminary point of the study. With the exception of vision changes in one patient, no serious safety concerns have arisen. Pursuit of this strategy in further clinical study will require demonstration of FR-specific immune responses, an acceptable toxicity profile, and demonstration that T regulatory cells are altered in the periphery. Citation Format: Kimberly R. Kalli, Courtney L. Erskine, James W. Krempski, Linda M. Benson, Vera J. Suman, Douglas J. Padley, Allan B. Dietz, Timothy J. Hobday, Amy C. Degnim, Lynn C. Hartmann, Matthew S. Block, Keith L. Knutson. Metronomic cyclophosphamide followed by a multi-peptide folate receptor vaccine for ovarian and breast cancer immunotherapy in the setting of minimal residual disease - a feasibility study. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr A82.

Abstract Atypical hyperplasia is a high-risk premalignant lesion of the breast, but its biology is poorly understood. Many believe that atypical ductal hyperplasia (ADH) is a direct precursor for low-grade ductal breast cancer, whereas atypical lobular hyperplasia (ALH) serves as a risk indicator. These assumptions underlie current clinical recommendations. We tested these assumptions by studying the characteristics of the breast cancers that develop in women with ADH or ALH. Using the Mayo Benign Breast Disease Cohort, we identified all women with ADH or ALH from 1967 to 2001 and followed them for later breast cancers, characterizing side of breast cancer versus side of atypia; time to breast cancer; type, histology, and grade of breast cancer, looking for patterns consistent with precursors versus risk indicators. A total of 698 women with atypical hyperplasia were followed a mean of 12.5 years; 143 developed breast cancer. For both ADH and ALH, there is a 2:1 ratio of ipsilateral to contralateral breast cancer. The ipsilateral predominance is marked in the first 5 years, consistent with a precursor phenotype for both ADH and ALH. For both, there is a predominance of invasive ductal cancers with 69% of moderate or high grade. Twenty-five percent are node positive. Both ADH and ALH portend risk for ductal carcinoma in situ and invasive breast cancers, predominantly ductal, with two thirds moderate or high grade. The ipsilateral breast is at especially high risk for breast cancer in the first 5 years after atypia, with risk remaining elevated in both breasts long term. ADH and ALH behave similarly in terms of later breast cancer endpoints. Cancer Prev Res; 7(2); 211–7. ©2014 AACR.