PDCD4 and pancreatic neoplasm: miR‐21 targets phosphatase and tensin homologue (PTEN), programed cell death 4 (PDCD4), tropomyosin 1 (TMP1), and tissue inhibitor of metalloproteinases 3 (TIMP3) genes in pancreatic cancer resulting in increased proliferation, invasion and chemoresistance [65, 66, 67].