RHOA and familial pancreatic carcinoma: CircIARS can enter human microvascular endothelial cells through exosomes derived from pancreatic cancer cells, downregulate the levels of miRNA-122 and tight junction protein-1 (zonula occludens-1), upregulate the levels of RhoA and RhoA-GTP, increase the expression of F-actin and adhesion plaques, increase endothelial monolayer permeability and promote tumor invasion and metastasis.