High expression of CDKN2A in oral squamous cell carcinoma is associated with distant metastasis: Cell‑free DNA as a new prognostic feature

Oral squamous cell carcinoma (OSCC) shows a high incidence and is associated with a higher rate of mortality, particularly in developing countries. Although the development of treatment strategies has been remarkable, the 5-year survival rate remains low (often <50%). Surgery and chemoradiotherapy are the standard treatments; however, there are limited factors that can predict metastasis. Liquid biopsy is promising in treating various cancers, including OSCC. In previous studies on OSCC, associations were identified among circulating tumour cell clusters, cell-free DNA (cfDNA) size/quantity and prognosis. The present study aimed to explore the role of CDKN2A and TP53 in OSCC using immunohistochemistry. Next-generation sequencing analysis of both cfDNA and tissues from two patients with poor prognoses was performed, and two common mutated genes, <i>TP53</i> and <i>CDKN2A</i>, were detected. The CDKN2A-positive group showed metastasis in 50% of cases and shorter overall survival in OSCC. Overall, CDKN2A protein expression is a potential prognostic marker for OSCC.