2023 Volume 72 Issue 2 Pages 256-263
AIM: In ordinary community hospitals, how to store and use archives of histopathological specimens is usually up to their policies, and there are no general rules for the disposal, storage, and usage of such specimens. In this study, we evaluated the feasibility of DNA and RNA analyses of 50-year-old formalin-fixed, paraffin-embedded (FFPE) tissue blocks. METHODS: DNA and RNA were extracted from 50-year-old FFPE tissue blocks immunohistologically positive for TP53, and the concentrations and degradation of DNA and RNA were analyzed. Polymerase chain reaction (PCR) analysis of p53 exons 4 to 7 was conducted, and in the samples that yielded PCR products, DNA sequencing (Sanger sequencing) was conducted. RESULTS: The concentrations of DNA and RNA were 60–330 ng/μL and 450–1,145 ng/μL, and the OD ratios of DNA and RNA at 260 nm/280 nm were 1.4–1.8 and 1.8–1.9, respectively. The DNA and RNA integration numbers were 1.1–1.7 and 1.4–2.4, respectively. PCR products were successfully obtained when using primers covering 170 base pairs (bps) and less, such as the first half of exon 5 (successful in 6 out of 6 cases), the last half of exon 5 (successful in 6 out of 6 cases), and the first half of exon 7 (successful in 6 out of 6 cases); they were not successfully obtained when using primers covering 200–300 bps. Several p53 mutations were identified. RESULTS: Although degraded, DNA and RNA could be extracted from 50-year-old FFPE tissue blocks, and archived blocks could be used for research and training in a community hospital. Determination of better storage conditions would be a challenge to be addressed in future studies.
