Prospective collection of tissue samples at autopsy in children with diffuse intrinsic pontine glioma

Abstract

Background: Brain tissue obtained at autopsy has been used in research for non-oncologic disorders. However, to the best of the authors' knowledge, this tool has never been systematically used in large investigational studies for cancer. A prospective, multicenter study was conducted to assess the feasibility of tissue collection at autopsy and its suitability for molecular analyses in children with diffuse intrinsic pontine glioma.

Methods: Tumor tissue was collected at the time of diagnosis, if clinically indicated, or at autopsy. Normal brain tissue was also collected at autopsy. The integrity of DNA and RNA was evaluated in all samples. Logistic data regarding autopsies were recorded. The feasibility of tissue collection at autopsy was assessed for patients treated at a single institution over a 43-month period.

Results: Tumor samples were collected at the time of diagnosis (n = 3) or at autopsy (n = 38) at 29 centers across the United States; samples were obtained at diagnosis and autopsy in 2 cases. The median interval from death to autopsy was 7.7 hours. DNA and RNA with minimal or partial degradation, which were suitable for genome-wide analysis, were obtained from 100% and 63% of tumor samples, respectively. At the coordinating institution, approximately 40% of parents consented to autopsy and 40% declined. During the study period, 12 autopsies were performed on patients who did not receive therapy at the coordinating center.

Conclusions: Multicenter, biological studies based on tissue obtained at autopsy appear to be feasible in children with brain cancer. The current experience established a new paradigm for brain tissue collection, which may increase the potential for research studies in patients with cancer.

Figure 1

Representative DNA and RNA extracted from tissue obtained at autopsy. (A) Agarose gel electrophoresis of DNA extracted from two paired sets of normal brain and tumor (lanes 1-4). All lanes except lane 4 show minimal DNA degradation. Lane 4 shows partial DNA degradation. M indicates 1-kilobase ladder molecular weight marker. (B) RNA analysis (Agilent 2100 Bioanalyzer) of the same samples shown in A. Lanes 1 and 2 show minimal degradation (RNA Integrity Number [RIN] 8.9 and 8, respectively), lane 3 shows partial degradation (RIN= 6), and lane 4 shows degraded RNA (RIN= 2.2). Migration of 28S and 18S ribosomal RNA is indicated.