Comparative study of droplet-digital PCR and absolute Q digital PCR for ctDNA detection in early-stage breast cancer patients.

Clinica chimica acta; international journal of clinical chemistry 2024 Jan 01

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Analysis of circulating tumor DNA (ctDNA) is increasingly used for clinical decision-making in oncology. However, ctDNA could represent ≤ 0.1 % of cell-free DNA in early-stage tumors and its detection requires high-sensitive techniques such as digital PCR (dPCR). In 46 samples from patients with early-stage breast cancer, we compared two leading dPCR assays for ctDNA analysis: QX200 droplet digital PCR (ddPCR) system from Bio-Rad which is the gold-standard in the field, and Absolute Q plate-based digital PCR (pdPCR) system from Thermo Fisher Scientific which has not been reported before. We analyzed 5 mL of baseline plasma samples prior to any treatment. Both systems displayed a comparable sensitivity with no significant differences observed in mutant allele frequency. In fact, ddPCR and pdPCR possessed a concordance > 90 % in ctDNA positivity. Nevertheless, ddPCR exhibited higher variability and a longer workflow. Finally, we explored the association between ctDNA levels and clinicopathological features. Significantly higher ctDNA levels were present in patients with a Ki67 score > 20 % or with estrogen receptor-negative or triple-negative breast cancer subtypes. Both ddPCR and pdPCR may constitute sensitive and reliable tools for ctDNA analysis with an adequate agreement in early-stage breast cancer patients. Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.

Citation

Victoria Sánchez-Martín, Esperanza López-López, Diego Reguero-Paredes, Ana Godoy-Ortiz, Maria Emilia Domínguez-Recio, Begoña Jiménez-Rodríguez, Alfonso Alba-Bernal, Maria Elena Quirós-Ortega, María Dunia Roldán-Díaz, Jesús Velasco-Suelto, Noelia Linares-Valencia, Alicia Garrido-Aranda, Rocío Lavado-Valenzuela, Martina Álvarez, Javier Pascual, Emilio Alba, Iñaki Comino-Méndez. Comparative study of droplet-digital PCR and absolute Q digital PCR for ctDNA detection in early-stage breast cancer patients. Clinica chimica acta; international journal of clinical chemistry. 2024 Jan 01;552:117673