Central nervous system tumors and three-dimensional cell biology: Current and future perspectives in modeling

Table 1 Comparison between two-dimensional and three-dimensional tumor cell culture systems[14-18]

	2D tumor cell cultures	3D tumor cell cultures
Time required	Few days	Few weeks
Physiological relevance	Does not simulate in vivo tumor	Simulates in vivo tumor
Cell-cell and cell-ECM interactions	Low to no interactions	High level of interactions
Cell morphology	Flat cells expanding on 2D surface	Preserved in vivo cell shapes and growth patterns; multilayer growth
Oxygen and nutrients perfusion	Homogeneous	Heterogeneous due to the three-dimensional geometry
Response to drugs	More susceptible to drug actions	More resistant to drugs with a similar drug penetration profile to in vivo tumor counterparts
Gene expression	Many differences compared to in vivo tumor counterparts	Similar to in vivo tumor counterparts
Differentiation	Poor	Well differentiated cells
Cost	Cheap	Expensive
Technique difficulty	Low	High

2D: Two-dimensional; 3D: Three-dimensional; ECM: Extracellular matrix.