STAT1 and neoplasm: Notably, following systemic chemotherapy, PSCs secrete large amounts of the ELR+ CXCL chemokines through chronic activation of the STAT-1 and NF-κB transcriptional activities, which stimulated CXCR-2 signaling in cancer cells to elicit their transdifferentiation into CSCs and thereby promoted post-treatment tumor aggression and treatment failure [38].