PTGS2 and neoplasm: Cyclooxygenase 2 (COX-2) levels are low in normal tissue but are rapidly induced as an early response to growth factors, cytokines and tumor promoters associated with inflammation, abnormal proliferation, angiogenesis, invasion, and metastasis, and the existence of an association between CRC and COX-2 overexpression appears to be established [41,42,43].