Techniques: Formalin-fixed, Paraffin-embedded (FFPE) tissue analysis..

Formalin-fixed, Paraffin-embedded (FFPE) tissue samples are useful for sample preservation and archiving. These are useful for profiling gene expression and studying many diseases.

(https://www.slideshare.net/ThermoFisher/ambion-webinar-ffpe)

The long-term storage of FFPE blocks at ambient temperature is more cost effective than storing frozen tissues at ultra-low temperatures due to maintenance, space, and labor costs

The DNA is of limited quantities, so amplification is essential.

FFPE is standard for histopathology and microscopic investigation (e.g., hematoxylin and eosin [H&E] staining, immunohistochemistry [IHC], and tissue microarray [TMA])

But, FFPE samples pose challenge for molecular pathologists, because nucleic acids are heavily modified and trapped by extensive protein-nucleic acid and protein-protein cross linking

The purified nucleic acids, although highly fragmented, are suitable for genomic and gene expression analyses, such as polymerase chain reaction (PCR), quantitative reverse transcription PCR (qRT-PCR), microarray, array comparative genomic hybridization (CGH), microRNA, and methylation profiling. 

The quality/quantity of genomic DNA, total RNA, and total protein in the FFPE blocks of malignant tumors of lung, thyroid, and salivary gland stored over several years can be studied. 

Proteins isolated from FFPE blocks have been  used in Western blot analysis, reverse-phase arrays, and surface-enhanced laser desorption/ionization time-of-flight MS.