PPBP and colorectal cancer: PPBP, also known as NAP-2/CXCL7, belongs to the CXCL subgroup, which is released by activated platelets and associated with the initiation and development of various tumors; therefore, serum levels of PPBP can be regarded as an auxiliary diagnostic marker of colorectal cancer (CRC) and obstructive colorectal cancer (OCRC) (39, 40).