Current address for M. Sansó: Genomics for Precision Oncology Group Leader, Oncohematology Department at the Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain.
Cristina Saura, Carolina Ortiz, Judit Matito, Enrique J. Arenas, Anna Suñol, Ágatha Martín, Octavi Córdoba, Alex Martínez-Sabadell, Itziar García-Ruiz, Ignacio Miranda, Clara Morales-Comas, Estela Carrasco, Cristina Viaplana, Vicente Peg, Paolo Nuciforo, Neus Bayó-Puxan, Alberto Gonzalez-Medina, Josep M. Miquel, Marina Gómez-Rey, Guillermo Villacampa, Silvia Arévalo, Martín Espinosa-Bravo, Judith Balmaña, Rodrigo Dienstmann, Joaquin Arribas, Josep Tabernero, Ana Vivancos, Miriam Sansó; Early-Stage Breast Cancer Detection in Breast Milk. Cancer Discov 2023; https://doi.org/10.1158/2159-8290.CD-22-1340
Breast cancer occurring during pregnancy (PrBC) and postpartum (PPBC) is usually diagnosed at more advanced stages compared with other breast cancer, worsening its prognosis. PPBC is particularly aggressive, with increased metastatic risk and mortality. Thus, effective screening methods to detect early PrBC and PPBC are needed. We report for the first time that cell-free tumor DNA (ctDNA) is present in breast milk (BM) collected from patients with breast cancer. Analysis of ctDNA from BM detects tumor variants in 87% of the cases by droplet digital PCR, while variants remain undetected in 92% of matched plasma samples. Retrospective next-generation sequencing analysis in BM ctDNA recapitulates tumor variants, with an overall clinical sensitivity of 71.4% and specificity of 100%. In two cases, ctDNA was detectable in BM collected 18 and 6 months prior to standard diagnosis. Our results open up the potential use of BM as a new source for liquid biopsy for PPBC detection.