Proteome analysis of microdissected formalin-fixed and paraffin-embedded tissue specimens

Area of Science:

• Biochemistry
• Oncology
• Proteomics

Background:

• Formalin-fixed and paraffin-embedded (FFPE) tissues are valuable for retrospective biomarker studies.
• Targeted proteomics can identify diagnostic and prognostic markers from clinical samples.

Purpose of the Study:

• To investigate the utility of FFPE tissues for targeted proteomics.
• To identify protein biomarkers in glioblastoma using FFPE samples.
• To validate a novel antigen retrieval technique for FFPE proteomics.

Main Methods:

• Proteins were extracted from microdissected FFPE glioblastoma tissues using a heat-induced antigen retrieval (AR) technique.
• Combined capillary isoelectric focusing/nano-reversed-phase liquid chromatography with nano-electrospray ionization-tandem mass spectrometry was employed.
• Protein extraction protocols utilized detergent-based methods.

Main Results:

• A total of 14,478 distinct peptides were identified.
• 2733 non-redundant SwissProt protein entries were identified.
• Eighty-three percent protein overlap was observed between FFPE and fresh-frozen tissues.

Conclusions:

• Targeted proteomics on FFPE tissues is a viable approach for biomarker discovery.
• The antigen retrieval technique effectively preserves proteins in FFPE samples.
• Detergent-based extraction contributes to high protein recovery from FFPE tissues.