The Epstein-Barr virus nuclear antigen 1 variant associated with nasopharyngeal carcinoma defines the sequence criteria for serologic risk prediction.

Although EBNA1 IgA was present in healthy sera, most epitopes localized to the immunodominant GAr. We conclude that a refined EBNA1 antigen deleted for the GAr but with residues consistently detected in Southeast Asian NPC tumors is optimal for risk prediction with an extended sojourn time of 7.5 years. Furthermore, distinct EBNA1 serologic profiles enhanced the utility of the EBNA1 IgA assay for risk stratification. This illustrates the importance of serologically relevant EBNA1 sequences for NPC risk prediction and early detection.