since antibody titers against epstein-barr virus ( ebv ) antigens are often elevated in sera of patient with active undifferentiated and nonkeratinizing nasopharyngeal carcinoma , anti-ebv serologic tests have been applied for diagnosis of metastatic lymphadenopathy in the neck without an obvious source and/or suspicious tumor of the nasopharynx .
C0027442
nasopharyngeal
C0027439
tumor of the nasopharynx