**9. Future development and prospective applications**

Recently, complexes of bovine -lactoglobulin and pike parvalbumin with OA were produced and classified as HAMLET-type complexes [39]. These proteins are neither structurally related to -lactalbumins nor to lysozymes. Nevertheless, their complexes with OA displayed cytotoxic activity that bears a resemblance to the cytotoxic activity of HAMLET [39]. This suggests that protein self-assembly may be mediated by oleic acid and more oleic acid-protein complexes can be discovered in future. Their putative ability to eliminate specifically rapidly divided cells, such as cancer cells, has a significant therapeutic potential. The mechanisms of their toxic activity are still debated. Our research provides first insight at a single cell level that ELOA interactions with the cellular membrane play critical role in cytotoxicity, leading to membrane permeability and even rupture. There are obvious differences in the composition and structure of protein-oleic acid complexes arising due to differences in the structure and dynamics of the protein component and differences in the conditions of complex formation. The common feature of these complexes can be

related to the fact that they all serve as cargo vessels delivering oleic acid to the cells and facilitating its penetration into cell membrane and cell interior. HAMLET is the first example of proteinaceous complexes with oleic acid effectively used in combating various cancer conditions and other complexes can be also potentially used for this purpose if their properties will be well-understood and controlled.
