CXCL16 and breast carcinoma: However, fibroblast-secreted CXCL16 not only orchestrates paracrine pro-tumorigenic signaling to the adjacent breast cancer cells, but it can also modulate intrinsic characteristics of activated fibroblasts in an autocrine manner, since a significant inhibition in the proliferative, motile, and invasive capabilities of activated PDE5-overexpressing fibroblasts was evident in the presence of a CXCL16 neutralizing antibody.