CD44 and neoplasm: In order to study the effects of inhibiting Stat3 in vivo, we utilized human-cancer-in-mouse xenograft models, and confirmed that Stat3 inhibition not only reduced the frequency of cells expressing TIC markers as measured by flow cytometry (CD44+/CD24−, and ALDH) and MSFE, this inhibitor also significantly decreased time to tumor recurrence when compared to chemotherapy alone using a chemoresistant xenograft model.