Biological stability of RNA isolated from RNAlater-treated brain tumor andneuroblastoma xenografts

Background. Advances in molecular biological research have led to identific ation of prognostic factors such as Trk mRNA expression in primitive neuroe ctodermal tumors of the CNS and neuroblastoma. To study prospectively the i mportance of these prognostic factors in large groups of homogeneously trea ted patients, tumor specimens of good quality must be acquired, preserved, and stored at multiple institutions. immediate freezing of tumor biopsy sam ples in liquid nitrogen and storage at -70 degrees C are the most commonly used method of tissue preservation for future RNA analysis. Procedure. To e valuate alternative methods of preserving tissue samples for subsequent RNA analysis, we tested a new RNA stabilization solution. Using tumor tissue o f two CNS tumor and one neuroblastoma human xenografts, we compared total R NA isolated from tumor tissue stored for 7 days at room temperature in stab ilization solution to that of snap-frozen tissue. The quality of the RNA wa s studied by spectrophotometry, gel electrophoresis, RT-PCR, and gene expre ssion profiting. Results. No major differences were observed in the quality of RNA isolated from tumor samples stored at room temperature in the RNA s tabilization solution compared to snap-frozen tumor samples stored at -70 d egrees C. Conclusions. High-quality RNA can be prepared from tumor tissue s tored at room temperature. Whenever snap freezing is not feasible, pieces o f tumor tissue can be treated with RNAlater for subsequent RNA analysis. Sh ort-term storage and shipment of well-preserved tumor tissue are clearly fe asible for all institutions, thereby facilitating large multi-institutional studies of biological prognostic factors. (C) 2000 Wiley-Liss, Inc.