CXCL8 and colorectal carcinoma: In this study, we found that IL-8 was enriched in conditioned medium derived from hypoxic CRC cells (Fig. 3a), and hypoxia-treated tumors expressed much higher levels of IL-8 than normoxic tumors (Fig. 5b, c), which is in line with our observations of human primary CRC tumors (Fig. S5E).