PTGS2 and neoplasm: A wide range of growth factors, immune mediators and receptors are known to be involved in the cross communication between PC and endothelium, and to regulate leukocyte migration and activation, such as CCL2, CCL5, CXCR1 and CCR3 [5, 6], or tumor vascularization, such as matrix metalloproteinases (MMPs) [7], hypoxia inducible factor (HIF)-1 [8], vascular endothelial growth factor (VEGF), VEGF tyrosine kinase receptor (VEGFR)-1 [9, 10], transforming growth factor β (TGFβ) [11] and cyclooxygenase 2 (COX2) [12].