CD79A and nasopharyngeal carcinoma: Figure 4 depicts VCA IgA serologic changes observed among the 56 NPC cases detected from the seropositive group over the periods 8–172 months before cancer was diagnosed. Among the 39 cases which had been followed up at least once, the results show that 14 became seronegative after enrollment and thereafter antibody levels fluctuated with time, with antibody titre rising to and beyond cutoff (solid circles) and declining below cutoff (open circles), such as seen among non-NPC subjects (see Figure 3).