The use of compounds is described which are capable of functionally blocking at least one of the genes chosen from the group composed of EphA1, EphA2, EphA8, EphB2, CSF1R, VEGFR2, RAMP2, RAMP3, CLRN1, MAPK4, PIK3C2A, PIK3CG, GSK3alpha, GSK3beta, IRAK3, DAPK1, JAK1, PIM1, TRB3, BTG1, LATS1, LIMK2, MYLK, PAK1, PAK2, CDC2, BTK, PNRC2, NCOA4, NR2C1, TPR, RBBP8, TRPC7, FXYD1, ERN1, PRSS16, RPS3, CCL23 and SERPINE1, for the manufacture of a medicament destined to diminish the resistance to chemotherapeutic drugs in the therapeutic treatment of epithelial tumour pathologies. Also described is a method for the determination of the drug resistance in tumour cells, as well as a method for the identification of tumour stem cells.