Development of a Rapid Method for the Isolation of Nucleic Acids From Formalin-Fixed, Paraffin-Embedded Malignant Tumor Tissues

Formalin-fixed, paraffin-embedded (FFPE) tissues constitute a valuable archival source for retrospective molecular studies, but DNA extraction from such material is often hampered by formalin-induced cross-linking and long-term storage. We developed a rapid, xylene-free protocol for isolating DNA from paraffin-embedded malignant tumor tissues of nonhuman primates. The method includes deparaffinization, incubation of tissue sections in a proteinase K-containing lysis buffer (30 mM Tris-HCl, 30 mM EDTA, 5% Tween 20, 0.5% Triton X-100, 800 mM guanidine HCl) at 60 °C, subsequent enzyme inactivation at 95 °C, alcohol precipitation, two-step washing and final elution in TE buffer. DNA obtained with this protocol was suitable for PCR amplification, and under optimal conditions fragments up to 400 bp were amplified irrespective of the storage time of FFPE blocks (1-10 years). The procedure offers an accessible laboratory alternative to commercial kits for the analysis of archival primate material.