Nucleotide sequencing analyses of mutations of the 5′ noncoding regions of BCL-6 in AIDS-NHL. For each sample, a mixture of ≥ 20 subclones was subjected to nucleotide sequencing (see Materials and Methods). The sequence of each AIDS-NHL case shown in the figure is matched to the sequence of a normal control (N) displaying germline BCL-6 alleles. The position of mutations is indicated by the nucleotide number of the corresponding BCL-6 germline sequence (the first nucleotide of the BCL-6 cDNA was arbitrarily chosen as position +1). Arrowheads point to bands corresponding to mutations.