AREG and cancer: We focused on cytokines, growth factors, and hormones, and chose CCL2 and CCL7 (both previously validated as functionally important fibroblast secreted factors [17], [36]); the related factor CCL8 which, like CCL7, binds CCR1 (MIM: 601159); amphiregulin (AREG; MIM: 104640), which has been implicated in tumor stromal-interactions but as a ligand produced by cancer cells acting on fibroblasts [37]; and stanniocalcin1 (STC1; MIM: 601185), which has been shown to act as a cancer cell autonomous factor, but not as a stromally produced factor [38].