CXCL9 and pterygium: In active pterygium, genes involved with immune and inflammatory response (CXCL9 and PLA2G2D), angiogenesis (SERPINB5 and BM4), keratinization (DSG1), response to UV light (TYR) and negative regulation of apoptotic process (PIM1) are up regulated in relation to atrophic pterygium.