Survival of patients 50 years or older at diagnosis analyzed by tumor EBV status. (A) Overall survival (OS) was significantly shorter for EBV-positive (n = 64) than EBV-negative (n = 62) patients; P = .003. (B) Disease-specific survival (DSS) was also significantly shorter, in the same cohort, among EBV-positive rather than -negative patients; P = .03. Dotted line indicates EBV-negative; solid line, EBV-positive.