Pathogenesis and Etiology of Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy that originates from the nasopharynx, ubiquitously in the ostium of the Eustachian tube in the superior posterior wall of the nasopharynx (Sham et al. 1990). Nasopharynx is located on the back of the nose and the base of the skull. Consequently, NPC is also common to extend to adjacent organs, such as the nasal cavity, paranasal sinus, oropharynx, orbit, bone, and infratemporal fossa (Sze et al. 2004). Despite sharing a tissue lineage with other mucosal head and neck cancers, NPC exhibits significant differences in its epidemiological distribution, pathogenic subtypes, etiologic factors, clinical features, and therapeutic approaches (Chen et al. 2019). It is characterized by the strong etiological and pathological association with Epstein-Barr virus (EBV) infection. Free-circulating plasma EBV DNA serves as a prognostic biomarker of pretreatment and posttreatment in EBV-related NPC in both endemic and non-endemic areas, and several researchers proposed to add the biomarker into the NPC TNM staging system (Ferrari et al. 2012; Guo et al. 2019; Lee et al. 2019; Lorusso et al. 2019).