Targeting cancer-initiating cell drug-resistance: a roadmap to a new-generation of cancer therapies?

The occurrence of drug resistance in oncology accounts for treatment failure and relapse of diverse tumor types. Cancers contain cells at various stages of differentiation together with a limited number of 'cancer-initiating cells' able to self-renew and divide asymmetrically, driving tumorigenesis. Cancer-initiating cells display a range of self-defense systems that include almost all mechanisms of drug-resistance. Different molecular pathways and markers, identified in this malignant sub-population, are becoming targets for novel compounds and for monoclonal antibodies, which may be combined with conventional drugs. These interventions might eliminate drug-resistant cancer-initiating cells and lead to remission or cure of cancer patients.