CD44 and ovarian cancer: Epithelial cell adhesion molecule is a type I transmembrane glycoprotein regulating intercellular adhesionEpCAM+ cells show greater tumor-initiating potentialEpCAM/Bcl-2 pathway prevents platinum-dependent apoptosis of cancer cellsEpCAM+CD45+ cells constitute the chemoresistant phenotype in the ascitic fluid of patients with ovarian cancer. These cells overexpress SIRT1, ABCA1, and BCL2 genes. EpCAM+CD45+ population is highly invasive with signature mesenchymal gene expression and also consists of CD133+ and CD117+CD44+ OCSCs