PTEN and neoplasm: The carcinogenesis mechanism of miR-21 has been documented to target numerous tumor suppressor genes, including PTEN, PDCD4, TIMP3, and RHOB, which are associated with cell proliferation, migration, invasion, metastasis, and apoptosis [3], or are known to play important roles in signaling pathways such as the RAS/MEK/ERK, PTEN/PI3K/AKT, and Wnt/β-catenin pathways [4].