The role of Epstein–Barr virus in diagnosis of primary lesion in patients with squamous cell carcinoma metastases of unknown primary origin

Introduction. Human papilloma virus (HPV) – associated oropharyngeal squamous cell carcinoma is identified as a separate nosological entity of head and neck squamous cell carcinoma. This pathology is often associated with metastases with unknown primary origin. If they are located in the cervical lymph nodes, the primary lesion can be located in the nasopharynx. Considering that keratinizing and nonkeratinizing nasopharyngeal cancer is often accompanied by coexistence of HPV and Epstein–Barr virus (EBV), a theory was proposed that EBV can promote HPV infection. Aim. To determine the role of EBV in determination of the primary lesion in patients with squamous cell metastases of unknown origin. Materials and methods. For determination of the supposed link between metastases in the cervical lymph nodes from unknown primary origin and EBV DNA, we examined 151 patients with metastases of squamous cell carcinoma in the cervical lymph nodes from unknown primary origin. Surrogate EBV DNA marker was found in 33 patients. Results. An association between EBV DNA in serum and nasopharyngeal squamous cell carcinoma was found. Rare incidence of metastases from unknown primary origin is supposedly results from small size of the primary lesion and submucosal tumor location in combination with early lymphatic metastasis. Conclusion. To not miss clinically hidden nasopharyngeal cancer, interdisciplinary interaction and quantitative measurement of serum EBV DNA are necessary.