The problem of molecules interaction based on the spatial structure is central to many fields of biology. Methods of building libraries that contain vast numbers of different molecules offer new appro- ach in ligand-oriented research. One of these methods is phage display technology using libraries of peptides displayed on filamentous phage particles. Among many applications of the technique, structural peptide mimicry seems to be particularly important, since it opens a possibility for cancer immunothera- py to utilise peptide epitopes instead of glycolipid ones.

Cancer immunotherapy is not a standard in clinical treatment of tumors, while first attempts were made several years ago. The appearance of tumor specific antigens (TSA) e.g. Bcr/abl, or tumor associated antigens (TAA) in cancer cells may be used theoreticaly in cancer therapy. Tumor cells in transformation process accumulate products of oncogenes and/or loss the functional products of tumor suppressor genes. This processes change intracellular signaling roads regulating cell proliferation and/or apoptosis of cancer cells and effect the tumor growth progression.