S100A8 and neoplasm: The three monocyte subsets were characterized by the expression of either CD14 or CD16. Classical CD14+ monocytes expressed high levels of the myeloid-derived suppressor cell (MDSC)-associated markers S100A8/9 and FCN1, whereas the non-classical CD16+ subset was enriched for LST1, CFP, and AIF1. We also identified an intermediate CD14+CD16+ monocyte subset in low abundance in the tumor.