Histine, carbohydrates/polysaccharides, and proteins with β -sheet conformation as promising staging markers for oral squamous cell carcinoma

Cancers of the oral cavity and lip ranks 15th cancer mortality being oral squamous cell carcinoma (OSCC) the predominant malignant neoplasm in the head and neck region. Liquid optical biopsy using infrared absorption spectroscopy offers rapid and accurate diagnosis of several diseases, including oral cancer. Here we investigated saliva samples from patients with OSCC and healthy individuals using micro-reflectance Fourier-transform infrared absorption spectroscopy. Partial least squares discriminant (PLSDA) and support vector machine (SVM) analysis were employed to mining the set of data. SVM analysis validated the PLSDA findings and presented excellent results with sensitivity of 98.6%, specificity of 97.3%, and area under ROC curve of 0.965. Interestingly we found that bands assigned to histidine, carbohydrates/polysaccharides, and content of proteins with β-sheet conformation contributed to discrimination among groups. Moreover we found that specific changes in these bands could be related to OSCC staging being promising disease gravity markers.