Abstract P3-02-02: CD68-positive Crown-Like Structures of the Breast Are Independently Associated with Adverse Survival: A Retrospective Analysis of Cases from a Prospective Cohort

Abstract Introduction: The association of breast cancer (BC) with obesity is complex and multifactorial, depending partly on diet and related metabolic imbalances. Previous reports have shown that local inflammation in adipocytes can be seen in tissue sections as rings of macrophages of macrophages around necrotic adipocytes (“Crown-Like Structures of the Breast”, CLS-B). We and others have shown that CLS-B have higher prevalence and density within the adipose tissue of obese patients. Our goal was to examine the association of CLS-B with survival in participants enrolled at one center (Mount Sinai Hospital, Toronto) of a multicenter prospective cohort study designed to investigate obesity-related prognostic factors in early stage BC. Design: Archived H&E sections of breast adipose tissue were retrieved from Mount Sinai (Toronto) participants (N=163). All specimens were from breast excisions for invasive carcinoma. A CLS-B was defined as a ring of macrophages surrounding an adipocyte in otherwise normal breast tissue. In a subset (N=119), immunostains for CD68 were performed on a representative block to highlight macrophages. Sections containing tumor, fat necrosis, and mastitis were excluded. Slides were pathologist-reviewed, recording the number of CLS-B, slides containing CLS-B, and slides with normal tissue. Serologic markers of metabolism and inflammation were previously performed in a central laboratory. Correlations with clinical and serologic markers were examined using descriptive statistics and Wilcoxon tests. Survival analysis was performed with Cox proportional hazards models. Results: CLS-B were identified in routine H&E sections of normal fat in 59 out of 163 cases (36%). In the representative subset stained for CD68 (N=119), 22 cases were identified as positive for CLS-B by both H&E and CD68, 15 cases by CD68 alone and 24 by H&E alone, giving a CLS-B prevalence of 39% as detected by H&E, 31% by CD68 and 51% when combining the two. Both i) CD68-positive and ii) H&E-positive CLS-B showed similar positive relationships with BMI (median BMI 27 versus 24 kg/m2, P<0.01 for CLS-B present versus absent); however the relationship with insulin was stronger for CD68-positive CLS-B (median insulin 49 vs 35 pmol/L, P=0.009) than for H&E-positive CLS-B (insulin 39 vs 35 pmol/L, P=0.39). Univariable Cox model hazard ratios (HRs) for CD68-positive CLS-B were 2.79 (95% confidence interval (CI) 1.31-5.95) and 3.74 (CI 1.73-8.07) for disease-free and overall survival respectively, and after adjustment for age, nodal status, tumour grade, stage, ER/PR status, adjuvant treatment and BMI, HRs were 2.43 (CI 1.01-5.81) and 3.19 (CI 1.3-7.79). In the same subset, H&E-positive CLS-B had univariable HRs of 0.66 (CI 0.29-1.52) and 1.18 (CI 0.55-2.54) respectively and adjusted HRs of 0.31 (CI 0.11-0.82) and 0.57 (CI 0.23-1.39). Combining H&E and CD68 did not improve prediction over using CD68 alone. Conclusion: CLS-B visualized by the macrophage immunostain CD68 were associated with poor outcome, independent of patient BMI and tumour characteristics. Detection of CLS-B using H&E alone was not associated with poor outcome. Our results demonstrate that although CLS-B are a phenotype of obesity, they may also reflect a tissue-specific risk of adverse BC outcome. This risk may relate to localized tissue inflammation with higher prevalence in obese individuals. Although we do not advocate the clinical use of the CD68 stain, further work is warranted to clarify the connection between tissue inflammation and poor breast cancer outcome. Acknowledgement: The authors wish to acknowledge the Hold'Em For Life Charity Challenge for Cancer Research for their generous support. Citation Format: Martin C. Chang, Marguerite Ennis, Zohreh Eslami, Pamela J. Goodwin. CD68-positive crown-like structures of the breast are independently associated with adverse survival: A retrospective analysis of cases from a prospective cohort [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-02-02.