Potential role of nuclear magnetic resonance spectroscopy to identify salivary metabolite alterations in patients with head and neck cancer

Abstract

The analysis of the salivary metabolomic profile may offer an early phase approach to assess the changes associated with a wide range of diseases including head and neck cancer. The aim of the present study was to investigate the potential of nuclear magnetic resonance (NMR) spectroscopy for detecting the salivary metabolic changes associated with head and neck squamous cell carcinoma (HNSCC). Unstimulated whole-mouth saliva samples collected from HNSCC patients (primary tumour was located either in the larynx or in the oral cavity) and healthy controls were analysed by 1 H-NMR spectroscopy. Reliably identified salivary metabolites were quantified and the determined concentration values were compared group-wise using a Mann-Whitney U-test. Multivariate discrimination function analysis (DFA) was conducted to identify such a combination of metabolites, when considered together, that gives maximum discrimination between the groups. HNSCC patients exhibited significantly increased concentrations of 1,2-propanediol (P=0.032) and fucose (P=0.003), while proline levels were significantly decreased (P=0.043). In the DFA model, the most powerful discrimination was achieved when fucose, glycine, methanol and proline were considered as combined biomarkers, resulting in a correct classification rate of 92.1%, sensitivity of 87.5% and specificity of 93.3%. To conclude, NMR spectrometric analysis was revealed to be a feasible approach to study the metabolome of saliva that is sensitive to metabolic changes in HNSCC and straightforward to collect in a non-invasive manner. Salivary fucose was of particular interest and therefore, controlled longitudinal studies are required to assess its clinical relevance as a diagnostic biomarker in HNSCC.

Saliva and Oral Diseases

“…Nuclear magnetic resonance (NMR) spectroscopy can detect and measure metabolites in a solution with minimal sample preparation. This quantitative technique is based on the magnetic properties of atomic nuclei [31]. Each compound has a characteristic resonance frequency that makes it easy to distinguish.…”

“…The Authors found two metabolites, fucose and 1,2-propanediol, to be significantly upregulated, whereas proline was significantly downregulated in patients affected by HNSCC. The combination of four salivary metabolites (fucose, glycine, methanol, and proline) together provided maximum discrimination among HNSCC patients and healthy controls [31]. The role of fucosylation of glycoproteins in the development of cancer has been studied in recent years [89].…”

Current Status of Magnetic Resonance on Saliva for Oral and Dental Health Early Diagnosis

“…These include the small amount of sample needed compared with other volume average techniques, as well as the swiftness of the experimental data acquisition that can be performed in as fast as a few minutes [21]. The amount of saliva supernatant used for NMR analysis ranged from 0.17 to 0.60 mL (Table 1A) [3][4][5][6][7][8][9][10][11][12][13][14][15]. A saliva sample does not need any complex pre-treatment or preparation for the solution state NMR analysis to be performed [17].…”

“…A saliva sample does not need any complex pre-treatment or preparation for the solution state NMR analysis to be performed [17]. Specifically, the NMR saliva sample preparation consists of centrifugation, and subsequent addition of a NMR solvent, standard, and buffer to the supernatant inside an NMR tube [3][4][5][6][7][8][9][10][11][12][13][14]. On the contrary, the more popular mass spectroscopic analysis requires multiple and more complex sample preparation steps (e.g., extraction, purification, digestion, separation), as well as costly labelling reference compounds for data acquisition and analysis.…”

“…Magnetic resonance analysis of saliva has identified significant biomarkers correlated with oral, dental, and periodontal pathology, as well as salivary biomarkers linked to the presence of head and neck squamous cell carcinoma and sarcoidosis. Interestingly, salivary biomarkers have been also used in order to verify and monitor established health after therapy of the pathology [3][4][5][6][7][8][9][10][11][12][13][14][15].…”