For example, lncRNA ZFAS1 directly recruited DDX21 protein through the specific motif (AAGA or CAGA) and positively regulated its expression, and then affected their downstream target gene POLR1B, the critical components of Pol I RNA polymerase complex, resulting in promotion of CRC cell proliferation, invasion, migration, and suppression of cell apoptosis in vitro and in vivo (135) (Figure 4). This evidence concerns the gene DDX21 and colorectal carcinoma.