PTEN and neoplasm: Moreover, we believe that CAF-derived miRNAs could be valuable as biomarkers for assessing how effective exosome inhibitors are at attenuating tumor growth and/or metastasis in studies, considering miRs that target PTEN, like miR-21, are known to be overexpressed in PDAC cells [51], and also that miR-21 was found to be part of a miRNA signature that could distinguish PDAC from normal control samples [52].