CD44 and cancer: Up- and down-regulated genes in all three putative CSCs (A549 CD166+/CD44+, A549 CD166+/EpCAM+, and H2170 CD166+/EpCAM+) were found to be involved in several biological cancer processes, including angiogenesis, apoptosis, anti-apoptosis, induction of apoptosis, cell death, and cell migration.