CDKN1B and cancer: In PDAC, exosomal miR-222 transmission to cancer cells is functional to promote proliferation, invasion, and migration through two ways: (i) decreasing cyclin-dependent kinase inhibitor 1B (p27Kip1) (p27) expression levels directly; (ii) activating AKT by inhibition of serine/threonine-protein phosphatase 2A 55 kDa regulatory subunit B alpha isoform (PPP2R2A), which increases p27 phosphorylation and cytoplasmic p27 expression coupled with reduced nucleus expression [35].