CD44 and cancer: Since CD44 has been identified as a reliable marker for enriching cancer stem cells (CSCs) and it’s co-expression with other markers in the regulation of stemness and metastasis in various malignancies, including pancreatic cancer,37,38 we next collected the spheroids (after second plating) and stained with stemness markers (including CD44, ALDH1, and KLF4).39,40 The results showed that the expressions of stemness markers consistently mirrored spheroid formation capabilities in the above three groups (Supplementary Fig. 4c).