The present invention concerns products containing (i) at least one nucleic acid sequence coding for the human somatostatin 2 receptor protein (sst2), (ii) at least one nucleic acid sequence coding for the human deoxycytidine kinase protein (dck), (iii) at least one nucleic acid sequence coding for the human uridine monophosphate kinase protein (umk) and (iv) gemcitabine, as a combined preparation for simultaneous, separate, or sequential use for treating cancer in a subject.