CD44 and cancer: In OC, the acquisition of invasiveness is accompanied by a shift from epithelial to mesenchymal phenotype, also called the epithelial-to-mesenchymal transition (EMT), which endows cancer cells with increased motility and invasiveness to seed metastasis and with stem cell-like properties, such as upregulation of stem cell genes (CD44 and CD133) and self-renewal ability [3, 4].