Cell‐free DNA profiling in retinoblastoma patients with advanced intraocular disease: An MSKCC experience

Abstract

Purpose The enucleation rate for retinoblastoma has dropped from over 95% to under 10% in the past 10 years as a result of improvements in therapy. This reduces access to tumor tissue for molecular profiling, especially in unilateral retinoblastoma, and hinders the confirmation of somatic RB1 mutations necessary for genetic counseling. Plasma cell‐free DNA (cfDNA) has provided a platform for noninvasive molecular profiling in cancer, but its applicability in low tumor burden retinoblastoma has not been shown. We analyzed cfDNA collected from 10 patients with available tumor tissue to determine whether sufficient tumorderived cfDNA is shed in plasma from retinoblastoma tumors to enable noninvasive RB1 mutation detection. Methods Tumor tissue was collected from eye enucleations in 10 patients diagnosed with advanced intra‐ocular unilateral retinoblastoma, three of which went on to develop metastatic disease. Tumor RB1 mutation status was determined using an FDA‐cleared tumor sequencing assay, MSK‐IMPACT. Plasma samples were collected before eye enucleation and analyzed with a customized panel targeting all exons of RB1. Results Tumor‐guided genotyping detected 10 of the 13 expected somatic RB1 mutations in plasma cfDNA in 8 of 10 patients (average variant allele frequency 3.78%). Without referring to RB1 status in the tumor, de novo mutation calling identified 7 of the 13 expected RB1 mutations (in 6 of 10 patients) with high confidence. Conclusion Plasma cfDNA can detect somatic RB1 mutations in patients with unilateral retinoblastoma. Since intraocular biopsies are avoided in these patients because of concern about spreading tumor, cfDNA can potentially offer a noninvasive platform to guide clinical decisions about treatment, follow‐up schemes, and risk of metastasis.

Establishing the Clinical Utility of ctDNA Analysis for Diagnosis, Prognosis, and Treatment Monitoring of Retinoblastoma: The Aqueous Humor Liquid Biopsy

“…In terms of diagnostic value, this workflow can identify pathogenic RB1 variants that induce tumorigenesis in both heritable and sporadic cases, whereas commonly utilized blood-based biopsies are only capable of identifying germline, heritable mutations [ 17 ]. However, it should be noted that the detection of somatic RB1 mutations in the plasma has recently been described and is an active area of research [ 32 ]. Furthermore, our RB workflow detects prognostic molecular biomarkers, specifically 6p gain and MYCN amplification, that objectively predict the likelihood of therapeutic response and eye salvage [ 16 , 19 ].…”

“…Other liquid biopsy platforms have been described for retinoblastoma. The detection of ctDNA based on RB1 SNVs in the AH has been described by Gerrish et al [ 14 ] and Kothari et al first described RB1 SNVs detected from the plasma of patients with advanced intraocular disease requiring enucleation [ 32 ]. To the authors’ knowledge, blood based liquid biopsy platforms are actively being investigated at Memorial Sloan Kettering Cancer Center as well as Institut Curie, while development of AH platforms is ongoing at Birmingham Women’s, Children’s NHS Trust, and CHLA.…”

Recurrent Somatic Chromosomal Abnormalities in Relapsed Extraocular Retinoblastoma

“…A prospective study correlating the presence of HRPF with CNA and outcome should confirm these observations. As proposed for other pediatric tumors, CNA may also be detected by the evaluation of circulating free tumor DNA [36,37].…”

Retinoblastoma: Etiology, Modeling, and Treatment

“…However, understanding risk profiles of tumor biopsies is essential before the findings can be translated clinically. Given the prohibition to biopsy in this cancer there has been progress using both blood and the aqueous humor, however none are used clinically at this time [ 166 , 167 , 168 , 169 ].…”