Evidence for the importance of post-transcriptional regulatory changes in ovarian cancer progression and the contribution of miRNAs

High-throughput technologies have identified significant changes in patterns of mRNA expression over cancer development but the functional significance of these changes often resets upon the assumption that observed changes in levels of mRNA accurately reflect changes in levels of their encoded proteins. We systematically compared the expression of genes on the RNA and protein levels between discrete tumor samples collected from the ovary and from the omentum of the same OC patient. The overall correlation between global changes in levels of mRNA and their encoding proteins is low. The majority of differences are on the protein level with no corresponding change on the mRNA level. Indirect and direct evidence indicates that a significant fraction of the differences may be mediated by microRNAs. Cancer tissues from the right ovary and omental sites were collected from a woman with stage IIIc, grade 2/3 serous adenocarcinoma. Each individual RNA sample was analyzed both for miRNA and mRNA. miRNA profiling analysis was conducted on the GeneChip miRNA 3.0 Array (Affymetrix). mRNA transcriptome analysis was analyzed using GeneChip Human Transcriptome Array 2.0 (Affymetrix). In total, six miRNA and mRNA (two individual samples in triplicate) global expression data sets were generated in this study.