The present invention provides an oligopeptidic compound comprising a PCNA interacting motif, or a nucleic acid molecule comprising a sequence encoding said oligopeptidic compound, for use in treatment of a hyperproliferative disorder, wherein the PCNA interacting motif is [R/K]-[W/F/Y]-[L/I/V/A/M]-[V/L/I/A/M]-[K/R] (SEQ ID NO. 28), wherein the oligopeptidic compound has less than 70 subunits and comprises a cell penetrating peptide comprising an oligomer of 5 to 20 basic amino acids. In certain aspects the compounds of the invention may be used as cytostatic agents in their own right. In other aspects of the invention oligopeptidic compounds comprising such a motif may be used in conjunction with cytostatic agents or with radiotherapy.
