CXCL1 and neoplasm: CAF release of chemokine (C-X-C motif) ligand 1 and 2 (CXCL1 and CXCL2) also increases tumor invasion, with CXCL12 further increasing macrophage recruitment, and CXCL1 increasing tumor invasion via activation of matrix-metallopeptidase 1 (MMP1), also known as interstitial collagenase [10].