tumor_volume_x_1 -> 0
endothelial_volume_x_2 -> 0
0 -> endothelial_volume_x_2
endothelial_volume_x_2 -> 0
endothelial_volume_x_2 -> 0
concentration_of_administrated_inhibitor_x_3 -> 0
0 -> concentration_of_administrated_inhibitor_x_3