The expression profiles of
microRNAs (
miRNAs) are associated with the initiation and progression of human
tumors.
DNA microarrays are widely used to explore the expression patterns of
miRNAs. Because of the limited sample size and experimental expense, the statistical power of individual research projects is not sufficient to yield a robust conclusion. However, collected microarray datasets of expression profiles provide opportunities to compile the information of individual studies. Our study carried out a comprehensive meta-analysis of
miRNA expression microarray datasets from 28 published
tumor studies; it comprises 33 comparisons and nearly 4,000
tumor and corresponding nontumorous samples. This work reports 52
miRNAs as common signatures that are dysregulated in
tumors. In addition to the commonly altered
miRNAs, five solid
cancers displayed specific tissue patterns of altered
miRNAs as well. The meta-analysis also revealed some novel
tumor-related
miRNAs such as
hsa-miR-144, hsa-miR-130b,
hsa-miR-132,
hsa-miR-154,
hsa-miR-192 and
hsa-miR-345. We further validated the expression pattern of
hsa-miR-154 in human
hepatocellular carcinoma by RT-PCR. Restoration of intracellular miR-154 inhibited
tumor cell malignance and the G(1)/S transition in
cancer cells. Both bioinformatic prediction and western blotting demonstrated that miR-154 could target CCND2. In addition, expression patterns of miR-154 were inversely correlated with those of CCND2 in
hepatocellular carcinoma. Overall, this study used a large-scale data analysis to identify a qualified list of
miRNAs that are consistently changed in
tumors, which could lead to a better understanding of human
tumor etiology.