On the contrary, ABCC3 clustered with claudin-3 and claudin-4 in the co-culture Transwell experiment with human primary astrocytes/pericytes (Fig. 7) as well as in the well-plate experiment (Fig. 2) just like claudin-5 with claudin-18 tv2a, whereas ABCB1 clustered together with ZO-1 in the co-culture set-up with glioma C6 cells (Fig. 5) and the well-plate experiment (Fig. 2). Here, CLDN3 is linked to central nervous system cancer.