Clinical role of circulating Epstein-Barr virus DNA as a tumor marker in lymphoepithelioma-like carcinoma of the lung.

Nineteen Chinese patients with lymphoepithelioma-like carcinoma (LELC) of the lung were tested for Epstein-Barr virus (EBV) DNA in their serum samples by a quantitative polymerase chain reaction (PCR) technique. There was prospective serial monitoring of the serum in seven patients with advanced inoperable or relapsing disease. Five other patients at first diagnosis and two patients at relapse had only a single serum sample available. Serum samples were also taken from three other patients who had prior curative surgery and two patients with prolonged disease remission. Measurable levels of EBV DNA were detected in 11 of 12 patients with a pre-therapy serum sample and a clinically evident tumor. A low level of EBV DNA was also detectable in one of the two other patients whose first serum samples were obtained after some chemotherapy. There was no detectable EBV DNA in the five patients without evidence of tumor. The longitudinal serum EBV DNA profile of seven patients showed consistent correlation with response to therapy and clinical outcome. Patients with a pre-therapy serum EBV DNA >10,000 copies/mL had significantly inferior overall survival. This study suggests that circulating serum EBV DNA can be used as a tumor marker in the clinical management of patients with LELC of the lung.