Editorial: molecular aspects of cancer resistance to biological and non- biological drugs and strategies to overcome resistance.

Cancer therapy represents one of the greatest challenges for medical science. Systematic knowledge of the molecular and genetic changes in cancer, acquired via –omic and functional tools, is leading to designing precise therapies. The tumor stem compartment and surrounding cells that support cancer are becoming additional targets for cancer therapy. How- ever, notwithstanding increased therapeutic options are now available for the treatment of disseminated cancers, the occurrence of intrinsic resistance and the emergence of resistant populations, limiting the effectiveness of cytotoxic and/or molecular ther- apy, remain unsolved issues. Recent advances in cancer therapy owe a great deal to the understanding that the metastatic tumor is other than the primary and must be attacked differently.