CD44 and neoplasm: For instance, SSEA-4 that was upregulated in all in vitro and in vivo models of docetaxel resistance and has been previously associated with tumorigenicity, chemoresistance, and mesenchymal features [57–59], was found to be co-expressed with mesenchymal marker CD44 in a subpopulation of tumor cells responsible for cancer stem-like cell characteristics, malignant behavior, and worse overall survival [60–62].