Abstract 165: Suppressed immunity and macrophages characterize high risk high grade DCIS

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Background: High grade in situ (DCIS) features associated with high recurrence include large size (>5cm), comedo necrosis, palpable mass, hormone receptor (HR) negativity, and HER2 positivity. Given that high grade, HR-neg invasive breast cancers have an inflammatory component (significant macrophage infiltration) we sought to characterize the immune microenvironment of DCIS to assess patterns of immune cell infiltrates associated with high risk lesions. Methods: 48 cases of high grade DCIS were age matched with 64 cases of non-high grade DCIS. Immunohistochemical analyses were performed as single color stains for the following antigens: CD115, FoxP3, ALDH, Ki-67, HER2. Two color IHC was performed for the following antigen pairs: CD68/PCNA; CD68/Mac 387; CD8/HLA-DR; CD68/MRC1, and CD24/CD44. HR status was determined from ER and PR staining results in pathology reports. For each case, 3 hot spots were identified and marked on 10 consecutive sections. Nuance multispectral imaging software was used to image each hot spot. Protocols for automated image analysis were developed using CellProfiler software. Clinical parameters of interest included tumor palpability, recurrence, and Van Nuys score, (12 point scale-margins, age, size, grade). Associations were identified with non-parametric Spearman correlation test. Results: High numbers of macrophages were associated with high Van Nuys score, palpability, and high Ki-67. High CD115 (CSF-1 receptor/c-fms) was associated with HER2+, high Ki-67, and recurrence. Mac387+ cells and FoxP3+ regulatory T cells (Treg) were significantly associated with high Van Nuys score, comedo necrosis, high Ki-67, HR- and HER2+. Interestingly, both Mac387 and CD115 were expressed on tumor cells as well as macrophages and high CD115 staining on tumor cells was associated with recurrence. The presence of CD8+HLA-DR negative T cells throughout a section was associated with high Van Nuys score, HR-, HER2+, and recurrence. In contrast, CD8+ T cells within the nests of tumor cells were negatively associated with Van Nuys score, palpability, and comedo necrosis. Conclusions: Suppressed immunity (high Treg and CD8+HLA-DR neg T cells) and upregulated CD115 and Mac387 expression on both tumor cells and macrophages were strongly correlated with high risk DCIS features (increased recurrence, palpability, high Van Nuys scores, high proliferation, HR- and HER2+). These results suggest that manipulation of the immune microenvironment in DCIS, via local stimulation of the immune system, depletion of Treg, and/or manipulation of macrophages could potentially alter disease progression. Targeted agents are in trials and could be tested in preoperative window trials using these biomarkers to monitor the impact of presurgical immunotherapy. Citation Format: Michael J. Campbell, Rita Mukhtar, Ekene Obi-Okoye, Booyeon Han, Vick Tandon, Sarah Zheng, Zelos Zhu, Max Endicott, Max Wicha, Linda Lindstrom, Alfred Au, Frederick Baehner, Joe Gray, Laura Esserman. Suppressed immunity and macrophages characterize high risk high grade DCIS. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 165. doi:10.1158/1538-7445.AM2014-165