In this context, recent studies have demonstrated that the CRT response is mediated by cancer stem cells (CSCs), expressing ALDH1, Sox2, Oct-4, Lgr5, CD24, CD26, CD29, CD44, CD51, CD133, CD166, Nanog and EpCAM surface markers, which are a subpopulation of RC tumor cells distinguished by their stemness properties and self-renewal capacities [2,19,20,21]. The gene discussed is CD44; the disease is neoplasm.