Anti-Epstein-Barr virus antibody in patients with cancer of various sites and control groups.

Sera collected from patients with nasopharyngeal carcinoma (NPC, 321 cases), cancer of the other sites (297 cases), diseases of the ear, nose and throat (64 cases) and neighborhood controls matched for age and sex (817 cases) were titrated for antibodies to Epstein-Barr virus (EBV) by the indirect immunofluorescence antibody technique. High anti-EBV antibody titers (greater than or equal to 1:640) were noted in 55% in patients with NPC but only less than 31% were noted for the other 3 groups. The differences in the distributions of anti-EBV antibodies are statistically significant. The geometric mean levels of the antibody titers were 1:342 for the patients with NPC but less than 1:178 for the other 3 control groups. The relative risks shows that more than 40 times higher risk for those with equal to or higher than 1:640 antibody titers than those with lower than 1:40. The patients with NPC also show for higher ridit scales than the other 3 groups. The etiology of NPC was discussed with our findings.