Methods and kits for extracting nucleic acids from paraffin embedded samples

A method for improving the recovery of nucleic acids in a protocol for isolating nucleic acids from wax-embedded biological samples,

• wherein the protocol comprises dissolving the wax-embedded sample in an organic solvent, extracting nucleic acids from the organic solvent into an aqueous buffer, and isolating the nucleic acids from the aqueous buffer;
• wherein the improvement comprises one or more of the following features in any combination:
• (1) using a saturated hydrocarbon comprising at least 10 carbon atoms (such as hexadecane) as the organic solvent;
• (2) causing the nucleic acids in the organic solvent to form a precipitate, which is then washed to remove the organic solvent and alcohol;
• (3) including the non-ionic detergent nonyl-phenoxypolyethoxylethanol (NP40) in the aqueous buffer;
• and
• (4) including an RNase inhibitor (such as sodium dodecyl sulfate, SDS) in the aqueous buffer.

A kit for extracting nucleic acids from a formalin-fixed paraffin-embedded (FFPE) biological sample, wherein the kit comprises in separate compartments:

• (a) an amount of a hexadecane sufficient to dissolve paraffin and at least some of the nucleic acids in the FFPE biological sample;
• (b) an amount of ethanol sufficient to remove hexadecane from the biological sample;
• (c) a lysis buffer formulated to dissolve nucleic acids from the sample that have been precipitated using the hexadecane and the ethanol;
• wherein the lysis buffer contains nonyl-phenoxypolyethoxylethanol (NP40) and at least one protease;
• and
• (d) beads that are adapted to bind nucleic acids from the sample that have been dissolved in the lysis buffer;
• wherein the kit further comprises instructions for extracting nucleic acids from the FFPE biological sample.