The present invention is directed to siRNA molecules which specifically target and cause RNAi-induced degradation of mRNA from TPTE genes, so that the protein product of the TPTE gene is not produced or is produced in reduced amounts. The siRNA compounds and compositions of the invention are useful for treating diseases which require inhibition of TPTE expression for their treatment, in particular cancer pathologies. The present invention also includes methods which make possible to assess and/or prognose the metastatic behaviour of a cancer disease and/or the occurrence of a relapse of cancer.