S100A8 and neoplasm: Together suggest that although IRISOE tumor cells normally secrete CCL2, entrainment by hypoxia and/or MSC contact exacerbates the secretion leading to recruitment of macrophages to the vicinity of IRISOE tumor cells, most likely within the aggressiveness niche, in vivo, through upregulating the expression of CCR2 on macrophages, and activating them to secrete S100A8.