Recent progress of biomarkers in oral cancers

Oral cancers are the seventh most common cancer globally. While progresses in oral cancer treatment have been made, not all patients respond to these therapies in the same way. To overcome this difficulty, numerous studies have been devoted to identifying biomarkers, which enable early identification of patients who may benefit from a particular treatment modality or at risk for poor prognosis. Biomarkers are protein molecules, gene expression, DNA variants, or metabolites that are derived from tumors, adjacent normal tissue or bodily fluids, which can be acquired before treatment and during follow-up, thus extending their use to the evaluation of cancer progression and prediction of treatment outcome. In this review, we employed a basic significance level (<0.05) as the minimal requirement for candidate biomarkers. Effect sizes of the biomarkers in terms of odds ratio, hazard ratio, and area under the receiver operating characteristic curves were subsequently used to evaluate the potential of their clinical use. We identified the CCND1 from the tumor, human papillomavirus, HSP70, and IL-17 from the peripheral blood, and high density of CD45RO⁺tumor-infiltrating lymphocytes as the clinically relevant biomarkers for oral cancers.