Spectroscopic analysis of normal and neoplastic (WI-FTC) thyroid tissue Joanna Depciuch a, ⁎, Agata Stanek-Widera b , Dariusz Lange b , Magdalena Biskup-Frużyńska b , Jadwiga Stanek-Tarkowska c , Wojciech Czarny d , Jozef Cebulski e a Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Krakow, Poland b Department of Tumor Pathology, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, PL-44101 Gliwice, Poland c Faculty of Biology and Agriculture, University of Rzeszow, PL-35959 Rzeszow, Poland d Faculty of Physical Education, Department of Human Sciences, University of Rzeszow, PL-35959 Rzeszow, Poland e Center for Innovation and Transfer of Natural Sciences and Engineering Knowledge, University of Rzeszow, PL-35959 Rzeszow, Poland abstract article info Article history: Received 1 March 2018 Received in revised form 17 May 2018 Accepted 2 June 2018 Available online 07 June 2018 Thyroid cancer holds the first place of the malignant tumors of the endocrine system. One of the less common thyroid cancers is follicular thyroid carcinoma (FTC), which is very difficult to diagnose because it gives the same image as adenoma, which is benign. Certainty of the diagnosis is gained only when FTC gives metastases. Therefore, it was decided to compare normal and neoplastic (FTC) thyroid tissues with Fourier Transform Infra- red (FTIR) spectroscopy. The obtained FTIR spectra and Principal Component Analysis (PCA) allowed us to con- clude that there are differences in the FTIR spectrum between normal tissues and those affected by cancer. In addition, the results indicate that there is a decrease in the number of functional groups that build cellular and tissue structures in tumoral tissues. The shifts of wave numbers corresponding to the protein and lipid function group vibrations, as well as the calculated second derivative of the FTIR spectra showed the structural changes in neoplastic tissues. Moreover, the deconvolution of the amide I massif indicates that in cancerous tissues the pre- vailing secondary structure is β-sheet structure, while in normal tissues it is α-helix. The obtained results allow us to conclude that infrared spectroscopy, in addition to providing information on the composition of tested sam- ples, can be an excellent diagnostic tool contributing to understanding the FTC substrate. © 2018 Elsevier B.V. All rights reserved. Keywords: Follicular thyroid carcinoma (FTC) FTIR PCA 1. Introduction Thyroid cancer is the most common cancer of the endocrine system, and its frequency has increased since last few decades [1, 2]. Follicular thyroid carcinoma constitutes from 10 to 15% of thyroid cancer diagno- ses. Most thyroid cancers show an unstable phenotype. Survival predic- tions distribute between 97 and 46% [1, 3]. The incidence of thyroid cancer is three times higher in women than in men, and thyroid carci- noma itself is in the sixth place of the most common malignancies diag- nosed in women. Thyroid cancer can occur at any age, however, it is observed that most tumors are diagnosed from the third to the sixth de- cade of life. Most of the primary thyroid cancers are epithelial tumors that orig- inate from thyroid follicular cells. These divide into three major patho- logic types: papillary thyroid carcinoma (PTC), thyroid follicular carcinoma (FTC) and anaplastic thyroid carcinoma (ATC) [4, 5]. According to the World Health Organization (WHO), the diagnosis of FTC is determined by the presence of capsular and/or vascular inva- sion [6]. The risk of metastases to other organs is high for FTC. This is caused by the tendency of this cancer to invade blood vessels which re- sults in hematogenous dissemination [7]. The WHO classification di- vides FTC into minimally invasive follicular thyroid cancer (MI-FTC), where the presence of capsular and/or vascular invasion is limited, en- capsulated angioinvasive follicular thyroid carcinoma (EA-FTC) and widely invasive follicular thyroid carcinoma (WI-FTC) [6]. About half of the cases of FTC have mutations in Ras oncogenes, in particular in the HRAS, NRAS and KRAS genes. There are also mutations in the MINPP1 and PTEN genes, which are responsible for Cowden syndrome [8]. MI-FTC, EA-FTC and WI-FTC have a wide range of overlapping clin- ical and cytological features. A clear distinction between a benign and malignant lesion based solely on cytological examination of a fine nee- dle aspiration biopsy sample is impossible [9–13]. We therefore need di- agnostic tools that would make it possible to discriminate between a benign nodule, like follicular adenoma, and a malignant neoplasm that can give metastases [14, 15]. Oscillatory spectroscopy analyzes the vibrations of functional groups occurring within the molecule, which can be used to characterize the molecular structure of a given system, because each molecule has a unique spectrum that enables identification of the molecular compound and its content in the sample [16]. The exact energy required to excite molecular vibration depends on the mass of atoms involved in the Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 204 (2018) 18–24 ⁎ Corresponding author. E-mail address: joanna.depciuch@ifj.edu.pl (J. Depciuch). https://doi.org/10.1016/j.saa.2018.06.010 1386-1425/© 2018 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy journal homepage: www.elsevier.com/locate/saa