Figure 1.

2D cell cultures and animal models vs. 3D cell cultures. On one hand, 2D monolayers do not retain the tissue-specific structure and mechanical/biochemical properties. On the other hand, in vivo models are very expensive and associated with ethical issues. Importantly, 3D systems can overcome these limitations by accurately reproducing cell polarity and shape, tissue stiffness, oxygen/nutrient diffusion gradients and cell-stroma communication.