Similar to observations in hemorrhagic areas of the tumor, the presence of RBCs increased mRNA expression of Cxcl1 (KC), Cxcl2 (MIP-2), and Csf1 (M-CSF) (Figure 4E), suggesting that the activation of macrophages by heme/iron may trigger recruitment of myeloid cells. Here, CXCL1 is linked to neoplasm.