CCL5 and neoplasm: Th1 cell activation of CTLs and macrophages to facilitate antitumor immunity is supplanted by Th2 cell–mediated fibrogenesis and stimulation of tumor-supporting macrophages.25 The role of Th17 cells in tumor immunity is controversial as they can be both tumor-restrictive and tumor-promoting.26 Treg cells are recruited to tumors via secreted factors such as C-C motif ligand (CCL)2 and CCL5,27,28 where they induce CTL suppression and cytolysis via expressed and secreted molecules (eg, IL-10, TGF-β, CTLA-4, granzyme B).