SLC46A3 and cancer: Cyclosporin is an enzymatically stable cyclic peptide with D-amino acids and N-methyl amide groups and penetrates the membrane via passive diffusion, which suggests that special cyclic peptides with anti-cancer activity, obtained from the RaPID system, could passively cross the lysosomal membrane to the cytoplasm as a catabolite without needing transporters, such as SLC46A3.