PDA exposure also induced epithelial–mesenchymal transition (EMT), upregulated cancer stem cell markers (CD44, CD117, CD133, Sox2, Oct4, and Nanog), and elevated expression of metastasis- and chemoresistance-associated molecules (MMP-2, MMP-9, MDR1, and MRP1). This evidence concerns the gene CD44 and Patent ductus arteriosus.