Abstract 5142: Correlation of peripheral blood S100A9+ myeloid-derived suppressor cells and tumor-associated macrophages in lung adenocarcinoma patient

Abstract

Abstract Background: Peripheral blood S100A9+ monocytic myeloid derived suppressor cells (MDSCs) is a predictive factor for treatment response of chemotherapy and epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) of lung adenocarcinoma patients. Tumor associated macrophages (TAMs), which might derived from peripheral blood monocyte, is also a predictive factor to treatment response of EGFR-TKI. However, the correlation of S100A9+ monocytic MDSCs and TAMs is not well understood in lung adenocarcinoma patients. Methods: Stage IV lung adenocarcinoma patients with paired formalin fixed paraffin embedded (FFPE) tumor tissue and peripheral blood mononuclear cell (PBMCs) were enrolled. CD68+ cells were calculated in 3 different 200X microscopic field of FFPE as TAMs, and S100A9+ cells also calculated with same method as MDSCs in tumor microenvironment. S100A9+ MDSCs percentage was calculated by flow cytometry from CD14+S100A9+ in PBMC. Results: Twenty-four lung adenocarcinoma patients with paired FFPE tissue and PBMC data were enrolled. PBMC S100A9+ MDSCs percentage is 17.9± 13.6; average number of S100A9+ cells and CD68+ TAMs in tumor tissue is 96.8±45.7 and 79.3±13.3, respectively. The correlation between S100A9+ MDSCs percentage and tissue S100A9+ cells and CD68+ TAMs is significant (Spearman r = 0.54, p = 0.003 for S100A9+; Spearman r = 0.03, p = 0.03 for CD68; n = 24) CD68+ and S100A9+ cells were also correlated (Spearman r = 0.41, p = 0.04, n = 24). Clinically, high or low (cutoff value as median number) tissue S100A9+ cells and CD68+ TAMs were both predictive factors for treatment PFS for EGFR-TKI. (For CD68, median: 56, high vs low TAM PFS = 7.4 vs 15.4 months, p = 0.04; For S100A9+ cells, median: 76, high vs low S100A9+ cells PFS = 7.2 vs 13.6 months, p = 0.05) Conclusion: Peripheral blood S100A9+ MDSCs is well correlated to tumor tissue S100A9+ cells and CD68+ TAMs. Both tissue S100A9+ cells and CD68+ TAMs were predictive factors for EGFR-TKI PFS. Our study suggests that peripheral blood S100A9+ monocytic MDSC might be one of the origin of tumor tissue CD68+ TAMs. Citation Format: Kang-Yun Lee, Po-Hao Feng. Correlation of peripheral blood S100A9+ myeloid-derived suppressor cells and tumor-associated macrophages in lung adenocarcinoma patient. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5142.