Abstract A70: Aqueous humor is superior to blood as a liquid biopsy for retinoblastoma

Abstract

Abstract Purpose: To evaluate whether blood demonstrates similar potential as aqueous humor (AH) to be used as a liquid biopsy for retinoblastoma (RB) and whether tumor-derived cell-free DNA (cfDNA) can be isolated as effectively from the blood as AH. Methods: AH was extracted via clear corneal limbal paracentesis from RB eyes at diagnosis or during intravitreal injection of chemotherapy. Matched peripheral venous blood samples were drawn. Shallow whole-genome sequencing was performed to assess for cell-free tumor DNA fractions and highly recurrent somatic copy number alterations (SCNAs) in the blood and AH samples. Results: Seven samples of AH taken at diagnosis and 13 samples at the time of intravitreal injection were compared to matched blood samples. The presence of any detectable SCNA in the AH was 11/20 and 0/20 in the blood (p=<0.001). The median size distribution of cfDNA molecules in the AH was 157.5 bp versus 181.5 bp in the blood (p=<0.001). Conclusions: The AH appears to be superior to the blood as a source of cell-free tumor DNA for retinoblastoma, thus a better target for development as a liquid biopsy for this cancer. Citation Format: Liya Xu, Jesse L Berry, Ashley Polski, Rima Jubran, Peter Kuhn, Jonathan W. Kim, James Hicks. Aqueous humor is superior to blood as a liquid biopsy for retinoblastoma [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr A70.