Detail for microRNA 21

Full Name

microRNA 21

Gene Name



Related Disease

  • Breast Cancer [ref.1]
  • Pancreatic Cancer [ref.2, 4]
  • Non-Small Cell Lung Cancer [ref.3]
  • Renal Cancer [ref.5]

Therapy Method


microRNA 21 also known as hsa-mir-21 or miRNA21 is a mammalian microRNA that is encoded by the MIR21 gene. MIRN21 was one of the first mammalian microRNAs identified. The mature miR-21 sequence is strongly conserved throughout evolution. The human microRNA-21 gene is located on plus strand of chromosome 17q23.2 (55273409–55273480) within a coding gene TMEM49 (also called vacuole membrane protein). Despite being located in intronic regions of a coding gene in the direction of transcription, it has its own promoter regions and forms a ~3433-nt long primary transcription of miR-21 (known as pri-miR-21) which is independently transcribed. The stem–loop recursor of miR-21(pre-miR-21) resides between nucleotides 2445 and 2516 of pri-miR-21.

MiR-21 is one of the first microRNA to be described as an oncomir. As most of the targets of miR-21 are tumor suppressors, miR-21 is associated with a wide variety of cancers including that of breast, ovaries, cervix, colon, lung, liver, brain, esophagus, prostate, pancreas, and thyroid.


  • [1] Hyaluronan-CD44 interaction with protein kinase C(epsilon) promotes oncogenic signaling by the stem cell marker Nanog and the Production of microRNA-21, leading to down-regulation of the tumor suppressor protein PDCD4, anti-apoptosis, and chemotherapy resistance in breast tumor cells.
    Bourguignon, L. Y., et al. (2009). J Biol Chem 284(39): 26533-26546.. [ 19633292 ]
  • [2] Hypoxia-induced aggressiveness of pancreatic cancer cells is due to increased expression of VEGF, IL-6 and miR-21, which can be attenuated by CDF treatment.
    Bao, B., et al. (2012). PLoS One 7(12): e50165.23272057. [ 23272057 ]
  • [3] Silibinin suppresses EMT-driven erlotinib resistance by reversing the high miR-21/low miR-200c signature in vivo.
    Cufi, S., et al. (2013). Sci Rep 3: 2459.23963283. [ 23963283 ]
  • [4] Curcumin analogue CDF inhibits pancreatic tumor growth by switching on suppressor microRNAs and attenuating EZH2 expression.
    Bao, B., et al. (2012). Cancer Res 72(1): 335-345.22108826. [ 22108826 ]
  • [5] miR-21 inhibition of LATS1 promotes proliferation and metastasis of renal cancer cells and tumor stem cell phenotype.
    Oncol Lett.2017 Oct;14(4):4684-4688. [ 29085468 ]

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