The properties of these cells expressing the OCSC markers (CD44+/CD133+) (Fig. 2e, f) and the mRNA level of CD44 and CD133 were also significantly increased in the microenvironment of chemotherapy-challenged cells (Fig. 3a, b), which confirmed again that the chemotherapy treatment can significantly increase the CSC properties of ovarian cancer cells. The gene discussed is CD44; the disease is ovarian cancer.