Generation of multicellular tumor spheroids of breast cancer cells: How to go three-dimensional

The multicellular tumor spheroid model is a widely used culture system to mimic the three-dimensionality of tumors. Several methods and an even larger number of protocols are available to prepare spheroids from regular monolayers. This paper describes the assessment of several techniques frequently used to culture spheroids of breast cancer cells. We found that some methods produced suboptimal results. Ultimately, an adapted liquid overlay technique generated tight, compact and robust spheroids of the breast cancer cells tested.