CCR1 and colorectal carcinoma: Mmp7 and Ifitm3 are known to promote metastasis in human CRC (Zeng et al., 2002; Li et al., 2011), and Ccl9 expression by epithelial cells promotes tumor invasion through recruitment of Ccr1+ myeloid cells to the tumor’s invasive front in a mouse model of CRC (Kitamura et al., 2007).