miR-21 can participate in tumor pathogenesis and development, including cell proliferation, migration, invasion, metastasis, and apoptosis, by targeting PTEN, PDCD4, TIMP3, and RHOB, or signaling pathways, such as RAS/MEK/ERK, PTEN/PI-3 K/AKT, and Wnt/β-catenin [13, 14]. This evidence concerns the gene PTEN and neoplasm.