CD44 and neoplasm: Overall, the above findings indicate that although both cell lines contain a high percentage of CD133−/CD44− cells which range from 30 to 50%, their aggressive phenotype may be largely attributed to the presence of the underrepresented CD133+/CD44+ PDAC subpopulation, as it harbors CSC characteristics, including abilities of self-renewal, the establishment of tumor heterogeneity, drug resistance, and dysregulated expression of EMT and inflammation markers.