RESUMO
BACKGROUND: Methanol fixed and paraffin embedded (MFPE) cellblocks are an essential cytology preparation. However, MFPE cellblocks often contain limited material and their relatively small size has caused them to be overlooked in biomarker discovery. Advances in the field of molecular biotechnology have made it possible to extract proteins from formalin fixed and paraffin embedded (FFPE) tissue blocks. In contrast, there are no established methods for extracting proteins from MFPE cellblocks. We investigated commonly available CHAPS (3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate) buffer, as well as two commercially available Qiagen(®) kits and compared their effectiveness on MFPE tissue for protein yields. MATERIALS AND METHODS: MFPE blocks were made by Cellient™ automated system using human tissue specimens from normal and malignant specimens collected in ThinPrep™ Vials. Protein was extracted from Cellient-methanol fixed and paraffin embedded blocks with CHAPS buffer method as well as FFPE and Mammalian Qiagen(®) kits. RESULTS: Comparison of protein yields demonstrated the effectiveness of various protein extraction methods on MFPE cellblocks. CONCLUSION: In the current era of minimally invasive techniques to obtain minimal amount of tissue for diagnostic and prognostic purposes, the use of commercial and lab made buffer on low weight MFPE scrapings obtained by Cellient(®) processor opens new possibilities for protein biomarker research.
RESUMO
Formalin-fixed paraffin-embedded (FFPE) material presents a readily available resource in the study of various biomarkers. There has been interest in whether the storage period has significant effect on the extracted macromolecules. Thus, in this study, we investigated if the storage period had an effect on the quantity/quality of the extracted nucleic acids and proteins. We systematically examined the quality/quantity of genomic DNA, total RNA, and total protein in the FFPE blocks of malignant tumors of lung, thyroid, and salivary gland that had been stored over several years. We show that there is no significant difference between macromolecules extracted from blocks stored over 11-12 years, 5-7 years, or 1-2 years in comparison to the current year blocks.