POSTN and neoplasm: To further address the role of CAF-derived POSTN in papillary thyroid tumor growth, CAFs were isolated from Postn+/+Rag1-/- (WT CAFs) or Postn-/-Rag1-/- (KO CAFs) mouse orthotopic thyroid tumors and we orthotopically co-injected tumor cells alone or together with WT CAFs or KO CAFs into Postn-/-Rag1-/- mice.