Salivary Biomarkers for Early Detection of Oral Cancer in a High-Risk Population in Ogun State: A Diagnostic Accuracy Study

Saliva-based diagnostics represent a non-invasive and potentially scalable approach to early oral cancer detection, leveraging the proximity of saliva to oral mucosal pathology. Several salivary proteins, metabolites, and nucleic acids have been proposed as biomarkers for oral squamous cell carcinoma. However, diagnostic accuracy data from West African high-risk populations are absent. This diagnostic accuracy study evaluates the sensitivity and specificity of three salivary biomarkers (interleukin-8, DUSP1 mRNA, and 8-OHdG) for detecting oral squamous cell carcinoma and high-grade epithelial dysplasia in a tobacco-using high-risk population in Ogun State, South West Nigeria. Seventy patients with biopsy-confirmed OSCC or severe dysplasia and 70 matched controls with normal oral mucosa were recruited at Olabisi Onabanjo University Teaching Hospital, Sagamu. Unstimulated whole saliva was collected and processed for ELISA-based quantification of IL-8 and 8-OHdG, while DUSP1 mRNA expression was analyzed by RT-PCR. ROC curve analysis was used to determine optimal cutoff values, sensitivity, specificity, and area under the curve (AUC) for each biomarker. IL-8 demonstrated the highest diagnostic accuracy with AUC of 0.83, sensitivity of 78.6%, and specificity of 80%, followed by DUSP1 mRNA at AUC of 0.76. A combined biomarker panel improved sensitivity to 88.6%. The study provides preliminary validation evidence for salivary biomarkers in a Nigerian high-risk population and advocates for a multi-centre confirmatory study across the South West zone. Keywords: salivary biomarkers, oral cancer, IL-8, diagnostic accuracy, Ogun State.