Rapid techniques for DNA extraction from routinely processed archival tissue for use in PCR

Area of Science:

• Molecular Biology
• Genetics
• Histopathology

Background:

• Archival tissues fixed in paraffin wax are valuable resources for molecular studies.
• Efficient DNA extraction is crucial for successful downstream applications like PCR.
• Rapid DNA extraction methods are needed for routine analysis of large sample cohorts.

Purpose of the Study:

• To assess the efficacy of four distinct rapid DNA extraction techniques.
• To determine the suitability of extracted DNA for polymerase chain reaction (PCR) amplification.
• To compare DNA yield and quality from paraffin-embedded archival tissues using different methods.

Main Methods:

• Four DNA extraction methods were tested: water boiling, Chelex-100 boiling, proteinase K digestion, and a combined proteinase K-Chelex method.
• DNA was extracted from 45 paraffin-embedded tissue samples, including normal tissues, cervical cancer, and B cell lymphomas.
• Amplification of p53 gene, HPV 16, and IgH gene rearrangements was performed using the extracted DNA.

Main Results:

• Chelex boiling, proteinase K digestion, and the combined method successfully yielded amplifiable DNA from all 45 samples.
• Water boiling resulted in insufficient DNA for PCR in 7% of cases and weaker amplification in 14% of positive cases.
• Amplicon lengths varied, with proteinase K methods yielding the longest fragments (up to 984 bp), while water boiling yielded up to 408 bp.

Conclusions:

• Chelex boiling, proteinase K digestion, and proteinase K-Chelex methods are effective for extracting PCR-ready DNA from diverse paraffin-embedded archival tissues.
• The 20-minute Chelex boiling method is particularly advantageous due to its speed and minimal sample handling.
• These rapid methods facilitate routine molecular analysis of large collections of archival specimens.