Table 1. Experimental model systems for analyzing cell–cell interactions.

	Cell: 2D culture	Cell: 3D culture	Spheroids	Organoids	Tissue slices	Xenografts	PDX	Syngeneic models	Patient tumors
Physiologicalrelevance						+++	+++	+++	+++
Tissue architecture				+	+++	+++	+++	+++	+++
Human-derived stromal cells				++	+++		+		+++
Tightly packed cells		+	++	++	++	+++	+++	+++	+++
Complex cell types		+	+	++	+++	+++	+++	+++	+++
Sample availability (reproducibility)	+++	++	++	+	+	+
Molecular intervention	+++	++	+	+	+	+

+++ denotes strong relevance; ++ denotes moderate relevance; + denotes low relevance.