To discriminate between cytokine production from tumor and surrounding stroma to the myeloid populations, we examined G-CSF expression in the CD45− population representing tumor and stromal cells, and CD11b+Gr1hi population representing myeloid cells, and showed increased G-CSF in Rip2-deficient compared to wild-type CD11b+Gr1hi cells, suggesting an autocrine and paracrine regulation of MDSCs in absence of Rip2 (Fig 4D). Here, RIPK2 is linked to neoplasm.