Downregulated expression and enrichment of cancer genes among highly targeted genes. (a) In a comparison of highly targeted genes (n > 20) versus less targeted genes (1 ≤ n ≤ 5) in normal tissue samples , 121 out of 158 samples exhibited decreased expression among highly targeted genes (P = 1 × 10-11). (b) Out of 58 NCI60 cancer cell line samples, 58 exhibited decreased expression among highly targeted genes (P = 7 × 10-18). (c) Highly targeted genes are enriched for cancer genes, with cancer genes targeted by >30 miRNAs having the most enrichment. In (c,d), asterisks denote P < 0.01 and crosses denote P < 0.05.(d) This enrichment for cancer genes remains after removing transcriptional regulators, which are prevalent among cancer genes and, as shown earlier, overrepresented among highly targeted genes.
Hon and Zhang Genome Biology 2007 8:R166 doi:10.1186/gb-2007-8-8-r166