The invention relates to the fields of tumour physiology and biotechnology. The object of the invention is to develop effective and selective novel fusion proteins and fusion protein-antibody complexes against various types of leukaemia and solid tumours. Selectivity is achieved by cell-specific or tumour-specific ligands of the fusion proteins or by antibodies of the fusion protein-antibody complexes. Effectiveness is achieved on the one hand by the direct binding of the microtubules or cytoskeleton elements to the microtubule-binding regions and on the other hand by induction, as well as by the reinforcement of the immune reaction by regions that trigger the immune reaction on the target cells.