CXCL1 and neoplasm: Given the potential role for CXCR2 in the inflammatory niche–mediated tolerance and because IL1B expression was up-regulated in tumor biopsies from patients after 10–14 d of treatment with BRAF and MEKi’s, we analyzed these tumors for CXCR2 and its ligands GROα and IL8. We observed an increase in CXCR2 and GROα expression (Fig. 8 D).