Pharmacogenomics and cancer stem cells

In oncology, Pharmacogenomics is still considered to be the best strategy to personalize cancer therapy. Although, its clinical application is still limited to a few genes, And also in a number of cancers, the correlation between genotype and clinical outcome have been promising. However, since the current pharmacogenomic studies do not take into account the emerging role of cancer stem cells (CSCs) in drug sensitivity and resistance, Favorable results were not achieved. CSCs are the only tumor-initiating cells within a malignancy; due to this CSCs are at the apex of human cancer hierarchy system. But genetic variants affecting their activity in some specific signal-transduction pathways are generally neglected in current pharmacogenomic studies. Moreover, in several malignancies, CSCs represent a rare sub-population; therefore, whole tumor profiling might mask CSC gene expression patterns. This article reviews current evidence on CSC chemoresistance and shows how common genetic variations in CSC-related genes may predict individual response to anticancer agents. Furthermore, this article provides insights into the design of pharmacogenomic studies to address the clinical usefulness of CSC genetic profiling.