Liquid Biopsy Using CA 125 Salivary Biomarker for Diagnosis of Oral Potentially Malignant Disorders and Oral Squamous Cell Carcinoma

Histopathologic examination of biopsy specimen is the gold standard for diagnosis of oral malignancy. Non-invasive approaches, such as saliva-based biomarker assays, offer promise for screening and rapid on-site evaluation. Cancer Antigen 125 (CA125), a high molecular weight glycoprotein and transmembrane mucin, has demonstrated elevated levels in epithelial malignancies and is detectable in saliva. This study aims to evaluate the median salivary CA125 levels between healthy cohorts, patients with Oral Potentially Malignant Disorders (OPMDs) and patients with Oral Squamous Cell Carcinoma (OSCC). The cohort of subjects included comprised three groups: Group I (healthy controls), Group II (patients with OPMDs), and Group III (patients with OSCC). Unstimulated whole saliva was collected from all participants by passive drooling and analysed using CA125 Enzyme-linked immunosorbent assay (ELISA). 81 participants were included, healthy (n = 28), OPMD (n = 27), and OSCC (n = 26). There was no discrepancy between clinical and histopathological diagnoses of any patient. Median (IQR) salivary CA125 levels were 5.75 U/mL (2.90-10.26) in Control Group I, 14.11 U/mL (10.75–28.94) in OPMD Group II, and 72.81 U/mL (19.47-120.81) in OSCC Group III, which was statistically highly significant (p < 0.001). Further, CA125 levels correlated moderately with OSCC stages (Spearman’s rho = 0.524, p = 0.006). Salivary CA125 demonstrated potential as a non-invasive biomarker for OPMD & OSCC screening and detection but requires further validation.