{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T20:12:39Z","timestamp":1778271159735,"version":"3.51.4"},"reference-count":35,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T00:00:00Z","timestamp":1778198400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"PRONON","award":["25000.019858\/2018-14"],"award-info":[{"award-number":["25000.019858\/2018-14"]}]},{"name":"National Science and Technology Institute for Children\u2019s Cancer Biology and Pediatric Oncology","award":["406484\/2022-8"],"award-info":[{"award-number":["406484\/2022-8"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Retinoblastoma (RB) is the most common intraocular malignancy of childhood, yet molecular assessment of disease dissemination and minimal residual disease (MRD) remains challenging due to the contraindication of intraocular biopsy. Here, we evaluate the feasibility of cell-free RNA (cfRNA)- and circulating tumor cell RNA (ctcRNA)-based liquid biopsy for the sensitive detection of disseminated retinoblastoma using digital PCR (dPCR) targeting the retina-specific markers CRX and RBP3. We analyzed 433 bone marrow (BM), peripheral blood (PB) and cerebrospinal fluid (CSF) samples collected longitudinally from 50 patients with RB. dPCR assays demonstrated high analytical sensitivity. cfRNA detection showed complete sensitivity and negative predictive value in bone marrow compared with myelogram analysis, frequently identifying molecular positivity in cytologically negative samples. In cerebrospinal fluid, cfRNA detection was highly specific but less sensitive, reflecting compartment-specific biological constraints. Longitudinal analysis revealed that changes in CRX and RBP3 ctcRNA levels closely tracked treatment response, preceded cytological evidence of bone marrow involvement in several cases, and identified molecular persistence or re-emergence during follow-up, including after hematopoietic stem cell transplantation. Together, these findings demonstrate that cfRNA- and ctcRNA-based liquid biopsy using CRX and RBP3 enables sensitive and dynamic detection of disseminated retinoblastoma, particularly in bone marrow, and supports its potential utility for MRD monitoring. Longitudinal patient analyses will be required to define prognostic thresholds and establish the clinical role of this approach in risk stratification and long-term surveillance.<\/jats:p>","DOI":"10.3390\/ijms27104177","type":"journal-article","created":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T19:10:52Z","timestamp":1778267452000},"page":"4177","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Digital PCR Quantification of a Circulating RBP3 and CRX RNA Signature Establishes a Liquid Biopsy Framework for Precision Monitoring of Retinoblastoma"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0114-4578","authenticated-orcid":false,"given":"Thais Biude","family":"Mendes","sequence":"first","affiliation":[{"name":"Genetics Laboratory, Pediatric Oncology Institute (IOP\/GRAACC), Federal University of Sao Paulo, Sao Paulo 04039-001, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Indhira Dias","family":"Oliveira","sequence":"additional","affiliation":[{"name":"Genetics Laboratory, Pediatric Oncology Institute (IOP\/GRAACC), Federal University of Sao Paulo, Sao Paulo 04039-001, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2959-8363","authenticated-orcid":false,"given":"Francine","family":"Tesser Gamba","sequence":"additional","affiliation":[{"name":"Genetics Laboratory, Pediatric Oncology Institute (IOP\/GRAACC), Federal University of Sao Paulo, Sao Paulo 04039-001, SP, Brazil"},{"name":"National Science and Technology Institute for Children\u2019s Cancer Biology and Pediatric Oncology\u2014INCT BioOncoPed, Porto Alegre 90010-150, RS, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fernanda Teresa","family":"Lima","sequence":"additional","affiliation":[{"name":"Genetics Laboratory, Pediatric Oncology Institute (IOP\/GRAACC), Federal University of Sao Paulo, Sao Paulo 04039-001, SP, Brazil"},{"name":"Department of Gynecology, Federal University of Sao Paulo, Sao Paulo 04024-002, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bruna Fernanda Silva Cardoso","family":"Morales","sequence":"additional","affiliation":[{"name":"Institute of Pediatric Oncology (IOP\/GRAACC), Sao Paulo 04023-062, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Carla Renata Pacheco Donato","family":"Macedo","sequence":"additional","affiliation":[{"name":"Institute of Pediatric Oncology (IOP\/GRAACC), Sao Paulo 04023-062, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Luiz Fernando","family":"Teixeira","sequence":"additional","affiliation":[{"name":"Institute of Pediatric Oncology (IOP\/GRAACC), Sao Paulo 04023-062, SP, Brazil"},{"name":"Ophthalmology Department, Universidade Federal de S\u00e3o Paulo, Sao Paulo 04023-062, SP, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Silvia Regina Caminada de","family":"Toledo","sequence":"additional","affiliation":[{"name":"Genetics Laboratory, Pediatric Oncology Institute (IOP\/GRAACC), Federal University of Sao Paulo, Sao Paulo 04039-001, SP, Brazil"},{"name":"National Science and Technology Institute for Children\u2019s Cancer Biology and Pediatric Oncology\u2014INCT BioOncoPed, Porto Alegre 90010-150, RS, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"15021","DOI":"10.1038\/nrdp.2015.21","article-title":"Retinoblastoma","volume":"1","author":"Dimaras","year":"2015","journal-title":"Nat. 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