The prospects and challenges of the use of cell-free DNA as a diagnostic and prognostic biomarker for oral cancer in Sub-Saharan Africa

Oral cancer (OC) represents a group of malignant disorders which affect the oral cavity structures. The majority of oral cancer patients present with oral squamous cell cancer (90%) which is an epithelial-derived malignancy of oral tissues. OC is considered a public health disease of concern in Sub-Saharan Africa (SSA) due to the rise in the morbidity and mortality associated with this disease. This increase in disease-associated morbidity and mortality has been attributed to factors such as delayed presentation, late diagnosis of the disease, inadequate/ poor state of health infrastructure, genetic factors, social practices and poverty. Cell-free DNA (cfDNA) has emerged as a viable liquid biopsy-based technology that can be explored and harnessed for early diagnosis, treatment and monitoring of progress OC disease in SSA due to it's minimal invasiveness and the ability to repeat the test without surgical invasion of the primary tumour. However, the differences in genetic, demographic, environmental and socioeconomic features between the SSA population and that of advanced countries, where most of the available liquid biopsy (LB) studies in the management of OC were done, need to be given the needed consideration prior to application of cfDNA technology in an African population. Also, the lack of standardised technique and databases on OC would require a multicentre SSA studies to contribute information to create a data panel for investigating OC in SSA population. This review article examines the promising application of circulating cfDNA in blood and saliva of OC patients with a focus on African studies. This article also examines the challenges and future opportunities in the use of cfDNA technology in the management of OC in SSA. The understanding of the application of cfDNA technology in the diagnosis and prognosis of OC will be vital for efficient and effective management of the disease entity in the SSA population.