The global repression effect of a miRNA expression profile on a specific miRNA. Generally, for miRNA microarray or deep sequencing data analysis, miRNAs (circle) with significantly changed expression profiles are selected through fold-change analysis. The target mRNAs (triangle) of the selected miRNA are predicted by miRNA target prediction tools such as miRanda (A). Theoretically, a mRNA may be targeted by several miRNAs with different context scores, which are regarded as the repression ratio score of a miRNA for its target (B). Thus, the total repression ratio score of the total miRNA expression profile for a specific mRNA can be calculated based on the combined repression effects of the miRNAs on their target mRNA (C, see formula (1)).