The invention relates to the identification of genes involved in resistance of cancer cells to therapy, to short nucleic acid molecules which inhibit the expression of these genes by RNA interference and to their use as adjuvant in cancer therapy, to sensitize cancer cells to conventional anticancer agents; the short nucleic acid molecules are double-stranded short interfering nucleic acid molecules including a sense and an antisense region, wherein the sense region includes a nucleotide sequence that is selected from the group consisting of: the sequences SEQ ID NO: 15, 11, 13, 14, 30, 31, 38, 46, 64 and 70 and the sequences having at least 70% identity, preferably at least 80% identity, more preferably at least 90% identity with the sequences, and the antisense region includes a nucleotide sequence that is complementary to the sense region.