PROK2 and colorectal carcinoma: Given that myeloid cells tend to regulate Bv8 at an optimal level to maximize pro-tumoral effects in our study, the delicate balance of myeloid cell-Bv8 system and Bv8-ROS-mitocondrial-metabolism system should be studied in the future; Moreover, our data demonstrated that Bv8 increased ROS in CRC cells but decreased ROS in myeloid cells.