 In the picture above, distribution of N-cadherin (red) and nuclei (blue) in human brain cancer mouse xenograft (left, human brain cancer cells grown in a mouse brain), brain cancer cells cultured by 3D magnetic levitation for 48 h. (middle), and cells cultured on a glass slide cover slip (2D, right).The 2D system shows N-cadherin in the cytoplasm and nucleus and notably absent from the membrane, while in the levitated culture and mouse, N-cadherin is clearly concentrated in the membrane, and also present in cytoplasm and cell junctions.One of the challenges in generating in vivo like cultures or tissue in vitro is the difficulty in co-culturing different cell types.