CXCL12 and colorectal carcinoma: The concentrations of CXCL2, CCL17, CCL21, and CXCL12 in the CRC cell line culture supernatant were lower than those in patients’ peripheral blood (Student’s t-test, CXCL2, p = 0.0271; CCL17, p = 0.0283; CCL21, p < 0.0001; CXCL12, p = 0.0002), indicating that these cytokines were partially secreted by CRC cells (Figures 6I, J).