Using your colors to mark different concepts (I noticed you used for disease concept RGB: 209,243,255; for genes concept RGB: 209, 255,221; for treatments RGB: 255, 209, 220) is a little bit  difficult to distinguish marks between diseases and genes. I suggest to use "stronger" colors  (for instance  RGB: 1,255,50;  1,200,255; 255,100,200 or what else) unless there are motivations I don't know to have those colors.