Evaluating Therapeutic Efficacy against Cancer Stem Cells: New Challenges Posed by a New Paradigm

Current measures of anticancer drug efficacy reflect bulk cell killing and are poorly suited to detect activity against cancer stem cells (CSCs), which sustain tumor growth. The CSC paradigm necessitates a reexamination of methodologies used to evaluate clinical efficacy of anticancer therapies, as well as strategies employed during preclinical drug development.