XPA and nasopharyngeal carcinoma: Subgroup survival analysis also demonstrated that XPA expression level had more prediction value on OS and PFS in the subgroups of EBV VCA-IgA>1:160 or EA-IgA>1:20, though EBV antibody titer alone wasn't correlative with prognosis in these 129 NPC patients (Figures 3A, 3C, 3D, 4A, 4C and 4D).