Main author: Ólöf Gerður Ísberg
Institution or Company: Háskóli Íslands
Co-Authors, Institution or Company:
Margrét Þorsteinsdóttir, Háskóli Íslands. Sigríður Klara Böðvarsdóttir, Háskóli Íslands.
Introduction: Today, most pathological tissue samples are stored as formalin-fixed paraffin embedded (FFPE) tissue blocks, which is the gold standard for histopathological analysis. Mass spectrometry imaging (MSI) is a powerful tool that enables us to investigate the regional distribution of a variety of molecules in biological samples. Desorption electrospray ionization mass spectrometry imaging (DESI-MSI) is particularly suited to investigate the spatial distribution of metabolites. Currently, fresh frozen (FF) samples are preferred over FFPE samples in tissue based MSI studies. This is due to the concern that small molecules will be lost during fixation and chemical processing as well as the belief that that paraffin will cause ion suppression.
Methods: For high-throughput analysis, ten tissue microarray (TMA) slides including breast cancer tissue from approx. 225 patients and two TMAs including adjacent normal breast tissue from approx. 30 individuals were analysed using DESI-MSI (XEVO G2-XS QTof). An in-house developed DESI-MSI toolbox was used to process raw imaging data.
Results: Using statistical analysis we were able to distinguish between normal and cancerous FFPE despite most of the lipids being washed away in FFPE samples. Additionally we got a good classification for few metadata groups.
Conclusions: Our results indicate that DESI-MSI shows a potential to differentiate between breast cancer FFPE TMA and normal breast FFPE TMA based on their metabolic profile.
