Mimicking breast cancer tissue—3D bioprinted models in accurate drug sensitivity tests

Three‐dimensional (3D) cell culture models derived from patient tumors are currently under development to recapitulate in vivo physiological conditions and assess therapeutic responses. In vitro models often fail to replicate the drug sensitivity observed in humans. In this study, a standardized in vitro culturing method using a 3D bioprinted breast cancer tumor model was established. We compared traditional two‐dimensional (2D), spheroid, and 3D bioprinted in vitro models as well as in vivo growing syngeneic or xenograft tumors. Our aim was to determine whether 3D bioprinted in vitro cultures can represent tissue heterogeneity, growth capacity, and/or drug response as potential tools for personalized drug sensitivity tests. Our findings demonstrated that 3D bioprinted models closely mimic in vivo tumor morphology and drug responses, outperforming 2D cultures and patient‐derived xenografts (PDX) in severe combined immunodeficiency mice. Additionally, 3D bioprinted models showed similar drug sensitivity to syngeneic tumors regrown in BALB/c mice, highlighting their potential for better therapeutic response predictions. Our results support the use of 3D bioprinted tumor models for personalized oncology. The presented approach could significantly advance personalized cancer therapy by using 3D bioprinted tumor tissues, offering a more accurate representation of tumor behavior and treatment efficacy compared to currently used PDX models.