MicroRNAs (miRNAs) are small, noncoding RNAs with important functions in development, cell differentiation,
and regulation of cell cycle and apoptosis. Many studies have now shown that miRNAs are involved in the initiation
and progression of cancers. In this study, procedures based on the relative R-squared method (RRSM) are proposed to
investigate miRNA-mRNA regulatory relationships between 114 miRNAs and 16063 mRNAs for different organic
tissues. These procedures are based on comparing the expression profiles in tumor tissue and those in normal tissues, or
based on the expression profiles in tumor tissue only. The analyzed results are used to predict high-confident miRNAs for
tumor development and their targets. This study predicts many high-confident miRNAs which are associated with colon
cancer, prostate cancer, pancreatic cancer, lung cancer, breast cancer, bladder cancer and kidney cancer, respectively.