MicroRNAs as biomarkers and therapeutic targets in pterygia: A systematic review with quantitative synthesis

MicroRNAs (miRNAs) are emerging as important regulators in pterygium, a fibrovascular growth of the conjunctiva with high recurrence rates. This systematic review with selective quantitative synthesis aimed to identify differentially expressed miRNAs as potential biomarkers and therapeutic targets of pterygium. A comprehensive search of PubMed and Scopus (January 2010-March 2024) identified 17 eligible studies for the systematic review, of which 13 case-control studies, involving 789 pterygium patients and 546 controls, contributed quantitative data for synthesis. Following PRISMA guidelines, 4 miRNAs showed differential expression, with miR-21 and miR-199a-5p upregulated and miR-200a and miR-221-3p downregulated. Quantitative synthesis across independent studies was feasible for miR-200a, whereas miR-21, miR-199a-5p, and miR-221-3p were supported by single-study evidence. A literature review confirmed that the identified miRNAs regulate several target genes-TGF-β1, ZEB1, ZEB2, CDKN1B, and MAP3K11-which are implicated in pterygium pathogenesis. The enriched pathways identified included cell proliferation, inflammation, angiogenesis, and epithelial-mesenchymal transition, which have been associated with pterygium. Despite heterogeneity across included studies, these findings enhance understanding of pterygium pathogenesis. The identified miRNAs represent promising candidates for diagnostic and therapeutic exploration, warranting further validation in large-scale, longitudinal studies. This work lays the foundation for future miRNA-based clinical research in pterygium management.