CCL2 and malignant colon neoplasm: By further investigation of Gna13 in colon cancer cells, the authors found Gna13 to negatively regulate the expression of the chemokine Ccl2/MCP-1, resulting in an increased secretion of CCL2 upon loss of GNA13, which led to the recruitment of pro-tumor macrophages (TAMs) to the tumor microenvironment.