PCR-SSCP analysis of mutations of the 5′ noncoding regions of BCL-6 in AIDS-NHL. Representative results obtained for PCR products E1.8 (located within BCL-6 exon 1), E1.10, and E1.11 (both located within BCL-6 intron 1) are shown. Each AIDS-NHL sample is indicated at the top of each lane by a numbered code or, in the case of AIDS-NHL cell lines, by its conventional denomination. A positive control (POS), represented by a tumor sample known to harbor BCL-6 mutations,19 as well as a normal (N) sample, represented by a B-lymphoblastoid cell line, are also included for each PCR-SSCP fragment shown. Samples were scored positive when their migration pattern differed from the normal control (N) and their migration abnormalities could not be ascribed to population polymorphisms. Among the AIDS-NHL samples shown in the figure, cases scored as positive included cases 1251 (for PCR product E1.8), 1141, 184A, 642, 1249 (for PCR product E1.10), 1142, 1143, PA682, HBL-3, As283A and 1220 (for PCR product E1.11).