Akademik Veri Yönetim Sistemi
Uluslararası Biyokimya Kongresi 2022; 33. Ulusal Biyokimya Kongresi, İzmir, Türkiye, 26 - 30 Ekim 2022, cilt.50, ss.99, (Özet Bildiri)
BACKGROUND AND AIM: Formalin-fixed and paraffin-embedded(FFPE) tissues are valuable for mass spectrometry-based proteomic studies as they correlate with clinical data. Matrix-assisted laser desorption/ionization(MALDI)-Imaging mass spectrometry combines histological information with high resolution and accuracy and determines the spatial distributions of analytes on tissue. In this study, it was aimed to perform an optimization study for sample preparation for the analysis of peptide profiles by MALDI-Ima-ging mass spectrometry of FFPE tissues from different subgroups of breast cancer. MATERIALS and METHODS: Sections of 3 and 5µm from FFPE breast tissues were taken on indium tin oxide coated slides in the microtome. Washing with xylene and decreasing alcohol concentrations followed by two different antigen retrieval procedures with 10mM Tris-HCl and 10mM Citrate buffer solutions were applied. Trypsin enzyme was prepared different c oncentrations, 25ng/ µl, 50ng/µl, 75ng/µl, and 100ng/µl, for the digestion of proteins into peptides. For matrix coating of tissues, 5mg/ml, 7mg/ml and 10mg/ml α‐CHCA matrix was prepared in 50% and 70% acetonitrile(ACN) and different concentrations of trifluoroacetic acid(TFA). Analyzes were performed on the RapifleX-MALDI-Tissue-Typer-mass-spectrometer and positive ion reflectron mode range of 900-3500. RESULTS: In spectrum, more monoisotopic peptides were detected in 3µm. 10mM Tris-HCl buffer gave better results in terms of peptide count. The highest number of peptides was detected from tissues sprayed with 100ng/µl trypsin. Peptides of high signal intensity were obtained from tissues coated with matrix concentration of 70%ACN and 1%TFA α‐CHCA in 5 mg/ml. CONCLUSION: Successful results of analysis of FFPE tissues depend on optimization studies. Result of the study, appropriate parameters for breast tissues were optimized. Keywords: ffpe, peptide, sample preparation, optimization, maldi imaging mass spectrometry