Identification of miR-20a as A Potential Discerning Biomarker for Non-Invasive versus Invasive Retinoblastoma.

Objective: Intraocular retinoblastoma (RB) is common in kids. Although the cause of this disease is a mutation in the RB1 gene, the formed cancerous mass in different patients is seen in non-invasive states, limited to the ocular cavity or in invasive states distributed to other parts of the body. Because this tumor's aggressiveness cannot be predicted early, these patients receive systemic chemotherapy with multiple drugs. Treating non-invasive and invasive tumors separately reduces chemical drug side effects. The aim of this study was to identify diagnostic biomarkers by separating miRNAs in blood serum from invasive and non-invasive RB patients.

Materials and methods: In this experimental study, selected three gene expression omnibus (GEO) datasets. Two were related to serum and tumor tissue miRNAs, and one was related to non-invasive and invasive RB gene expression. Examined RB gene-miRNA relationships. Then, we performed real-time polymerase chain reaction (PCR) on candidate miRNAs in the Y79 cell line and patient blood samples in non-invasive and invasive retinoblastoma.

Results: Fourteen high-expression and 7 low-expression miRNAs resulted. MiR-181, miR-135a, miR-20a, miR-373, and miR-191 were common genes with differential genes between invasive and non-invasive retinoblastoma. Only MiR-181 was upregulated in the Y79 RB cell line. Other candidate miRNAs expressed less. Invasive retinoblastomas increased serum miR-20a and miR-191.

Conclusion: Integrated and regular bioinformatics analyses found important miRNAs in patients' and miR-20a, miR- 191, and miR-135a can distinguish non-invasive and invasive retinoblastoma, suggesting further research.