LRP6 and neoplasm: The ability of tetra-branched polypeptides (NT4) to bind with sulphated glycosaminoglycans and endocytic receptor tumour markers, such as low-density lipoprotein receptor-related protein 1 (LRP1) and low-density lipoprotein receptor-related protein 6 (LRP6), makes it a potential target molecule for cancer cells [63].