Our observation that media conditioned from pancreatic cancer cells, as well as the individual cytokines TGF-β and TNF-α, induced the expression of S100A8 and S100A9 proteins in HL-60 cells and primary monocytes supports the concept of a paracrine feedback loop, whereby cancer cells induce monocytic S100A8/A9 expression through cytokine secretion and the S100 proteins in turn induce cytokine secretion. Here, S100A9 is linked to cancer.