Elevation of S100 calcium-binding protein A7 in recurrent pterygium

Recurrent pterygium, a common ophthalmic disease, is difficult to treat as its pathogenesis is unclear. To investigate the key genes responsible for the recurrence of pterygium, tissue samples were collected from six patients with primary pterygium (primary group), six patients with recurrent pterygium (recurrent group) and six patients with ocular trauma (control group) who underwent surgery between December 2014 and June 2017. The differentially expressed genes amongst these tissues were detected using expression profiling microarrays and verified by reverse transcription-quantitative PCR (RT-qPCR). Comparing the primary and control groups, 10 genes, including PP7080, small proline-rich protein 2A, keratin 24, small proline-rich protein 2F, defensin β4A, serpin family A member 3, S100 calcium-binding protein A7 (S100A7), Fc fragment of IgG binding protein and BPI Fold Containing Family A Member 1, were identified to be consistently upregulated in recurrent pterygium tissues, whilst two genes (H19 imprinted maternally expressed transcript and secretoglobin family 2A member 1) were consistently downregulated. Following RT-qPCR verification, it was identified that that S100A7 gene was significantly upregulated in recurrent pterygium tissues compared with the other groups. Protein-protein interaction and Gene Ontology analysis further revealed that all genes interacting with S100A7 were mainly involved in the regulation of defense mechanisms against bacteria, mitogen-activated protein kinase (MAPK) pathway activation and receptor for advanced glycation end-products receptor binding. The present findings confirmed that elevation of S100A7 expression in recurrent pterygium may be associated with the inflammatory response and activation of the MAPK signaling pathway.