Analysis of the molecular quality of human tissues: an experience from the Cooperative Human Tissue Network

The scientific usefulness of the data obtained from tissue analysis is related to specimen quality, which may be affected by conditions that may contribute to the degradation of the specimen before processing and analysis. We determined the usability of nucleic acids extracted from banked human tissues for further molecular analyses. We assayed 151 tissue specimens, storedfor various times at 4 divisions of the Cooperative Human Tissue Network, National Cancer Institute, Bethesda, MD, for DNA and RNA degradation. Simple electrophoresis, polymerase chain reaction (PCR), reverse-transcriptase (RT)-PCR, and Northern blot analysis were compared to determine the optimal quality control procedure. In addition, a time course degradation procedure was performed on human lung tissue. Gel electrophoresis was as informative as PCR, RT-PCR, and Northern blot analysis in determining the molecular usefulness of the human tissues. Overall, 80% of the stored human tissues had good-quality DNA, and 60% had good-quality RNA. Electrophoresis procedures for DNA and RNA offer a quick and valuable measure of the molecular quality of stored human tissues. The DNA and RNA degradation of one tissue type (lung) was stable for both nucleic acids for up to 5 hours after excision.