It was found that exosomal circRNA poly(A) binding protein cytoplasmic 1 (PABPC1) promoted the EMT-mediated CRC liver metastasis by increasing the expression of HMGA2 and bone morphogenetic protein 4/ADAM metallopeptidase domain (19 BMP4/ADAM19) (84). This evidence concerns the gene BMP4 and colorectal carcinoma.