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

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Abstract
Background Advances in molecular biological research have led to identification of prognostic factors such as Trk mRNA expression in primitive neuroectodermal tumors of the CNS and neuroblastoma. To study prospectively the importance of these prognostic factors in large groups of homogeneously treated patients, tumor specimens of good quality must be acquired, preserved, and stored at multiple institutions. Immediate freezing of tumor biopsy samples in liquid nitrogen and storage at −70°C are the most commonly used method of tissue preservation for future RNA analysis. Procedure To evaluate alternative methods of preserving tissue samples for subsequent RNA analysis, we tested a new RNA stabilization solution. Using tumor tissue of two CNS tumor and one neuroblastoma human xenografts, we compared total RNA isolated from tumor tissue stored for 7 days at room temperature in stabilization solution to that of snap‐frozen tissue. The quality of the RNA was studied by spectrophotometry, gel electrophoresis, RT‐PCR, and gene expression profiling. Results No major 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 −70°C. 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 RNAlater for subsequent RNA analysis. Short‐term storage and shipment of well‐preserved tumor tissue are clearly feasible for all institutions, thereby facilitating large multiinstitutional studies of biological prognostic factors. Med. Pediatr. Oncol. 34:438–442, 2000.