Single-Cell Rna-Sequencing Reveals The Immune Contexture Of Triple-Negative Breast Cancer Tumors

Triple-negative breast cancer (TNBC) is aggressive and associated with a higher risk of early relapse. The lack of estrogen receptor, progesterone receptor, and HER2 expression precludes the use of targeted therapies, and the high level of immune cell infiltration suggests that TNBC patients may benefit from immunotherapy. The design of immunomodulatory strategies for the TNBC treatment will tremendously benefit from a comprehensive understanding of the tumor infiltrated immune cell landscape of this cancer. To this end, we performed deep single cell RNA sequencing to 7,066 immune cells collected from 8 TNBC patients using the MIRALCS platform. We identified 13 immune cell subsets according to their transcriptome features. We found that the frequency of identified T cells and macrophages varied greatly across patients. We explored the diversity of tumor-infiltrating T lymphocytes and their functional states, and described the complicated and patient specific macrophage phenotypes. We also examined the single-cell expression level of immunotherapeutic target molecules in different immune cell subgroups. Our study gives an insight into the heterogeneity of the immune cell contexture of TNBC tumors, provides a valuable resource to understand the immune ecosystem of TNBC and may accelerate immunotherapies development on this breast cancer subtype. Citation Format: Si Qiu, Ruoxi Hong, Zhenkun Zhuang, Shusen Wang. Single-cell RNA-sequencing reveals the immune contexture of triple-negative breast cancer tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1763A.