Clinical studies of chemotherapy sensitive or resistant EOC patients show significant correlation between CD44 upregulation and chemotherapeutic drug resistance (56, 57), and numerous reports further confirm the role of CD44 in promoting chemoresistance in primary ovarian tumors, spheroids and ascites, as well as human ovarian cancer cell lines in vitro (51, 53, 54, 58). This evidence concerns the gene CD44 and ovarian cancer.