This bar graph illustrates the codon substitution and their frequency in the carboxy fragment of EBNA-1 sequenced from 39 nasal lymphomas. Only those codons that showed mutations are depicted. The prototype P-ala sequence is shown in the x-axis. The top panel shows the substitutions in the respective codons in the subtypes previously described. The most frequent substitutions observed in NL are shown above the graph. At codon 487, **T means ACT, CCT, CTT, and/or GTT.