Study of the Spectral-Luminescent Properties of Saliva in Patients With Lung Cancer

This study evaluated whether multimodal spectroscopic analysis of saliva can differentiate patients with lung cancer from healthy individuals. Unstimulated saliva samples were collected from 57 patients with lung cancer and 36 healthy controls. TEM and DLS revealed increased heterogeneity of the salivary colloidal fraction and a shift toward larger particle populations in lung cancer. UV-Vis spectroscopy showed a hypsochromic shift of the main absorption peak (279-261 nm), while fluorescence intensity at 510 nm increased 1.9-fold with additional emission bands at 617 and 680 nm. Reflectance decreased across the measured spectral range. ATR-FTIR identified the Amide III/asymmetric PO₂ ^- region (1350-1180 cm^-1) as the most discriminative interval (AUC = 0.854). Fluorescence-based classification achieved an AUC of 0.706, with 73.1% sensitivity and 76.3% specificity. ¹H NMR revealed alterations in metabolites associated with metabolic reprogramming.