CD44 and neoplasm: Next, in order to identify a pathway in an unbiased way that may be involved in the regulation of the CD44+/CD24− CSC population, a qPCR array of 84 genes related to cancer stemness was performed on the subpopulations of both OE21 and OE33 cells and were compared to previously harvested OE21- and OE33-derived xenograft tumor controls representing a more differentiated population [16].