The Impact of Tissue Preparation on Salivary Gland Tumors Investigated by Fourier-Transform Infrared Microspectroscopy

Abstract

Due to the wide variety of benign and malignant salivary gland tumors, classification and malignant behavior determination based on histomorphological criteria can be difficult and sometimes impossible. Spectroscopical procedures can acquire molecular biological information without destroying the tissue within the measurement processes. Since several tissue preparation procedures exist, our study investigated the impact of these preparations on the chemical composition of healthy and tumorous salivary gland tissue by Fourier-transform infrared (FTIR) microspectroscopy. Sequential tissue cross-sections were prepared from native, formalin-fixed and formalin-fixed paraffin-embedded (FFPE) tissue and analyzed. The FFPE cross-sections were dewaxed and remeasured. By using principal component analysis (PCA) combined with a discriminant analysis (DA), robust models for the distinction of sample preparations were built individually for each parotid tissue type. As a result, the PCA-DA model evaluation showed a high similarity between native and formalin-fixed tissues based on their chemical composition. Thus, formalin-fixed tissues are highly representative of the native samples and facilitate a transfer from scientific laboratory analysis into the clinical routine due to their robust nature. Furthermore, the dewaxing of the cross-sections entails the loss of molecular information. Our study successfully demonstrated how FTIR microspectroscopy can be used as a powerful tool within existing clinical workflows.

Roadmap for Postnatal Brain Maturation: Changes in Gray and White Matter Composition during Development Measured by Fourier Transformed Infrared Microspectroscopy

“…In this work, we fixed our samples for preservation purposes and to be able to directly compare our samples in the histochemical study. The effect of fixation in the IR spectra has shown contradictory results in several works. – Our results in the GM and WM areas of P28, the age closer to adult mice, are consistent with those shown in mice, rats, and humans independently of tissue processing. ,– In our study, the main limitations of sample fixation were the inability to analyze phosphate and carbohydrate regions due to the use of phosphate buffer (PB) and sugar-based cryoprotectants.…”

Translating Biospectroscopy Techniques to Clinical Settings: A New Paradigm in Point-of-Care Screening and/or Diagnostics

“…The paradigm shift in biospectroscopy is that the spectrum-derived image map, in addition to showing tissue architecture, also contains and exhibits underlying biochemical information [28]. Such capability to be integrated into clinical workflows [29] could facilitate the objective prediction of disease [30] and even response to treatment [31], e.g., platinum-based chemotherapy. To further advance the combination of spectroscopy and imaging, hyperspectral techniques can be employed.…”

Deep learning analysis of mid‐infrared microscopic imaging data for the diagnosis and classification of human lymphomas

“…However, excluding single wavenumbers would not provide insight into the network's sensitivity regarding the different spectral regions. This is due to shifts and spectra broadening due to various tissue processing effects [44][45][46][47].…”