FOURIER-TRANSFORM INFRARED SPECTROSCOPY AS A LIQUID BIOPSY OPTION FOR ORAL CANCER DIAGNOSIS FROM SALIVA

Lip and oral cavity cancers are an important health concern and is associated with high rates of mortality and morbidity. It ranks among the top 16th in most common malignant neoplasm in World. Two-thirds of cases occur in developing countries and on average the rates for men are currently twice as high as for women. Despite advances in diagnostic methods and therapies, patient survival has not yet improved significantly in recent years, still being a challenge to medical sciences and public health policies. Liquid biopsy applying infrared absorption spectroscopy represents a new non-invasive approach and a promise to contribute to cheaper, minimally invasive and molecular specific diagnosis, especially in diseases such as oral cancer . In this work, saliva from patients with squamous cell carcinoma and patients without the pathology was subjected to micro-reflectance infrared absorption spectroscopy to identify their spectral signatures, compare them and observe the separation of the study groups and discover biomarkers of oral cancer. Multivariate PLS-DA statistical analysis showed that the diagnostic accuracy was greater than 90% being six significant bands identified as spectral biomarkers for oral squamous cell carcinoma (AUC > 0.70) at 883, 898, 1770, 1818, 1855, and 1878 cm-1. These vibrational bands are related to histidine and 2-Keto adipic acid, palmitic acid and acetoacetic acid, respectively, and can be considered biomarkers for oral squamous cell carcinoma being suitable to be probed by infrared spectroscopy.
This research was funded by brazilian agencies Fundação de Amparo a Pesquisa do Est. de S. Paulo (FAPESP) proc. 2019/11077-0, 2022/00153-0; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) proc. 311933/2021-1 and INCT INTERAS, and CCNH/UFABC. The authors are grateful for experimental resources provided by Multiuser Central Facilities at UFABC (CEM/UFABC).