Preparation of Formalin-fixed Paraffin-embedded Tissue Cores for both RNA and DNA Extraction

Area of Science:

• Molecular Biology
• Histopathology
• Biotechnology

Background:

• Formalin-fixed paraffin-embedded tissue (FFPET) is a valuable resource for molecular studies.
• Challenges in FFPET analysis include heterogeneous tissue composition and low nucleic acid yields.
• Existing protocols lack validated methods for simultaneous RNA and DNA extraction from specific regions of interest.

Purpose of the Study:

• To develop and validate a method for simultaneous RNA and DNA extraction from FFPET.
• To improve nucleic acid yields and quality from targeted tissue areas.
• To enable downstream molecular analyses using FFPET samples.

Main Methods:

• Tissue regions of interest were identified and mapped from microscope slides to FFPET blocks.
• Microarray punches (0.6 mm) were used to harvest tissue cores from targeted areas.
• A commercial FFPET extraction system was modified with enhanced homogenization, deparaffinization, and Proteinase K digestion.

Main Results:

• The modified protocol successfully yielded sufficient quantity and quality of both RNA and DNA.
• The extracted nucleic acids were suitable for various downstream applications.
• Successful downstream applications included gene expression profiling and methylation-specific PCR (MSP).

Conclusions:

• This optimized protocol effectively addresses challenges in FFPET molecular analysis.
• The method enables simultaneous extraction of high-yield RNA and DNA from specific tissue regions.
• The protocol supports diverse downstream molecular investigations, including gene expression and DNA methylation analysis.