PTEN and neoplasm: In their study, Sun et al. suggested that a reduction in miR-21 enhances PTEN tumor-suppressor expression in pancreatic cancer as well as leading to the suppression of pancreatic cancer cell proliferation by inhibiting the HIF-1α/VEGF signaling pathway and downregulating matrix metalloproteinase 2 (MMP-2) and MMP-9 expression [69].