Universita di Milano 1 article published in JoVE Cancer Research Isolation of Primary Cancer-Associated Fibroblasts from a Syngeneic Murine Model of Breast Cancer for the Study of Targeted Nanoparticles Marta Truffi*1, Leopoldo Sitia*2, Marta Sevieri2, Arianna Bonizzi2, Maria Antonietta Rizzuto3, Serena Mazzucchelli2, Fabio Corsi1,2 1Istituti Clinici Scientifici Maugeri IRCCS, 2Dipartimento di Scienze Biomediche e Cliniche “L. Sacco”, Università di Milano, 3Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca This paper aims to provide a protocol for the isolation and culture of primary cancer-associated fibroblasts from a syngeneic murine model of triple-negative breast cancer and their application for the preclinical study of novel nanoparticles designed to target the tumor microenvironment.