Breast Cancer Multicellular Spheroid Models—A Tool for Studying Cancer Biology; a Possible Platform for Drug Screening and Personalized Medicine

There is a growing pressure for further breast cancer treatment development to improve patient quality of life and clinical effectiveness while reducing drug resistance and side effects. Clinical research, however, remains both expensive and time-consuming, highlighting the importance of advancing preclinical studies. The ability of a model to accurately replicate the biological environment is essential for generating reliable data. Although research on two-dimensional in vitro cell culture systems has been conducted for over a century, their limited complexity hinders further development of cancer treatments. Consequently, the response to tested medications is artificial, since some drugs appear to be effective only in the two-dimensional model and not in clinical settings. A multicellular spheroid (MCS) is a three-dimensional assembly of cancer cells, used in oncology to study cancer biology and drug sensitivity. MCSs serve as valuable in vitro models in preclinical drug development. They can also be used in a clinical setting as a personalized tool for drug susceptibility screening. The objective of this review is to highlight new possibilities for improved anticancer drug screening and the development of personalized treatment regimens with multicellular spheroids.