GREM2 and posterior cortical atrophy: Notably, miR-27a and miR-423-5p shuttled by CAF-derived small vesicles have been shown to play a key role in the development of PCa resistance to standard chemotherapeutic drugs, through the modulation of the p53 and bone morphogenetic protein antagonist Gremlin 2 (GREM2)/TGF-β pathways [25, 26].