Biological stability of RNA isolated from RNA later-treated pediatric central nervous system tumors

MA Grotzer MD, M Riesch, T Shalaby MD, PhD

University Children's Hospital, Zurich, Zurich Switzerland

Immediate freezing of tumor biopsy samples in liquid nitrogen and storage at -80oC is the most commonly used method of tissue preservation for future RNA analysis. To evaluate alternative methods of preserving tissue samples for subsequent RNA analysis, we tested a new RNA stabilization solution. Using tumor tissue of CNS tumor xenografts, we compared total RNA isolated from tumor tissue stored for 7 days at room temperature in stabilization solution with that of snap frozen tissue. The quality of the RNA was studied by spectrophotometry, gel electrophoresis, RT-PCR and gene expression profiling. No significant differences were observed in the quality of RNA isolated from tumor samples stored at room temperature in the RNA stabilization solution compared to snap frozen tumor samples stored at -80oC. Conclusions: High quality RNA can be prepared from tumor tissue stored at room temperature. Whenever snap freezing is not feasible, pieces of tumor tissue can be treated with RNA later for subsequent RNA analysis. Short-term storage and shipment of well-preserved tumor tissue is clearly feasible for all institutions, thereby facilitating large multi-institutional studies of biological prognostic factors. In addition, long-term storage of tumor tissue samples in national or international tumor banks becomes easier as shown by our experiences with the newly founded Central Tumor Bank for Children's Malignant Tumors of the Swiss Society for Paediatric Oncology and Haematology (SPOG) at the University Childrens Hospital Zürich

KEY WORDS: brain tumor, degregation.

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Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Gene Expression, Part 2.