MAY 20, 2020
This study compared the use of blood and aqueous humor as source of tumor-derived cell-free DNA (cfDNA) for retinoblastoma.
Samples were collected from 20 eyes of 17 patients diagnosed with retinoblastoma between August 2018 and February 2019. Aqueous humor specimens were collected at diagnosis or immediately before intravitreal injection. Blood samples were obtained by venipuncture. The authors compared the genome-wide somatic copy number alteration (SCNA) profiles from aqueous humor and blood samples.
This study demonstrated that the aqueous humor yielded more cfDNA than blood based on both the size distribution and the presence of SCNAs.
Liquid biopsy yield is limited by tumor burden. Since retinoblastoma patients often present with disease in the eye, DNA detection in the blood is limited. Going forward, it will be important to understand the exact tumor burden at which the DNA is accurately detected within the aqueous humor.
Liquid biopsy is quickly becoming an important diagnostic and therapeutic marker in the treatment of many types of cancers. Understanding its role in retinoblastoma will help with diagnosis, prognosis and assessing response to treatment. This study, among others, have shown that the aqueous humor holds a higher yield than blood for detecting tumor-derived cfDNA.