Table 1.

Targets of eight highly tissue-specific miRNAs and four miRNAs up-regulated in cancer are expressed at significantly lower levels in the tissue of miRNA expression compared with other tissues

miRNA (ref.)Tissue expressionRank
miR-122a (12)Liver1
miR-1 (12)Heart/skeletal muscle1, 2
miR-133a (12)Heart/skeletal muscle1, 2
miR-9 (12)Brain1, 4
miR-7Pituitary1
miR-216 (12)Pancreas4
miR-204 (12)Testis1, 5
miR-223 (12)Bone marrow/lung6, 4
miR-17-5p (13)Cancer1, 2, 5
miR-19a/b (13)Cancer1, 2, 3
miR-18a/b (13)Cancer2, 5
miR-25 (13)Cancer1, 5
  • The second column shows the tissues where the miRNAs (first column) are expressed. The third column reports the rank of the tissues of miRNA expression when sorting all 79 tissues by the significance of how predicted miRNA targets were expressed at lower levels relative to other tissues compared with a background set of mRNAs (gene-centric analysis; see Methods). The last four miRNAs represent all unique families of miRNAs present in the mir-17–92 cluster (13) and in the PicTar data set. Expression data for miR-122a, miR-1, miR-133a, miR-9, miR-7, and miR-216 were provided by P. Landgraf and T. Tuschl (personal communication).