PTF1A and permanent neonatal diabetes mellitus-pancreatic and cerebellar agenesis syndrome: Co-treatment of CD44v6−/− cells with soluble matrix (SM), produced by regular PaCa cells and PaCa-derived CD44v6-positive exosomes, can effectively restore the metastatic pattern of these cells, suggesting that PaCa may form a (pre-)metastatic niche microenvironment in distal metastasized organs by synergized effects derived of produced exosomes and other factors [136].