PDE8A and neoplasm: Studies reveal that circPRMT5 in the serum and urine exosomes of urothelial carcinoma of the bladder tissue enhances the EMT process via sponging miR-30c through the SNAIL1/E-cadherin pathway (Chen X. et al., 2018), whereas circ-PDE8A from liver-metastatic pancreatic ductal adenocarcinoma (PDAC) cells acts as a ceRNA of miR-338 to upregulate MACC1 and MET to increase the invasive growth of PDAC cells, thereby affecting tumor progression and metastasis (Li Z. et al., 2018).