CXCL1 and neoplasm: To further validate the promoting effect of CXCL1 on colon cancer growth in vivo, we transplanted three cell lines (MC38 WT, MC38CXCL1−/−, MC38CXCL1+/+) percutaneously at the right flank of C57BL/6J male mice and started assessing the tumor volume 1 week later (Fig. 5a).