The utility of aqueous humor liquid biopsy in retinoblastoma genetic analysis: a systematic review of concordance and influencing factors

BACKGROUND: Current diagnostic methods in Retinoblastoma (RB) rely on clinical and radiological examinations, which remain suboptimal, as there are non-RB cases with clinical and radiological features mimicking RB, leading to enucleation, which significantly affects patients' lives. As direct tumor biopsy is contraindicated due to the risk of metastasis, cell-free DNA (cfDNA) genetic analysis using aqueous humor (AH) liquid biopsy emerged as a promising minimally invasive alternative. MATERIALS AND METHODS: A systematic literature search was conducted by the PRISMA 2020 guidelines across PubMed/MEDLINE, Embase, Scopus, and Web of Science up to March 6, 2025. Studies comparing genetic and molecular findings in matched AH and RB tumor samples were included, and of 436 initial records identified, 14 studies met the inclusion criteria after screening and eligibility assessment and were included in the analysis. RESULTS: Concordance analysis from published evidence revealed generally high concordance between AH cfDNA and tumor tissue for RB1 gene variants, SCNAs, and DNA methylation patterns. However, low cfDNA yield post-treatment, tumor heterogeneity, and differing genetic testing modality may affect the rate of detection. AH liquid biopsy demonstrates high comparability with direct tumor tissue analysis in examining key RB genetic and epigenetic alterations. CONCLUSION: This review highlights the potential of AH liquid biopsy as a reliable surrogate for RB tumor biopsy, offering a minimally invasive approach to obtain crucial molecular information for RB diagnosis, treatment monitoring, and prognostication.