CXCL1 and neoplasm: Serum levels of CXCL1 and CXCR1, as well as CEA and CRP concentrations, were elevated in intermediate and high grades (G2 and G3) of CRC in comparison to the low grade (G1) of this tumor; however, the statistical differences were found only for CEA (p = 0.005) and CRP (p < 0.001) levels via the Kruskal–Wallis test (Table 4).