SSCP analysis of representative first intron segments of the BCL-6 gene in PT-LPDs. Samples corresponding to radiolabeled, PCR-amplified fragments from the E1.10 (top) and E1.11 (bottom) regions of BCL-6 are shown. Numbers above the lanes indicate the corresponding cases. Among the patients with more than one PT-LPD lesion are Cases 23 and 36. The histological classification of each case is indicated above the corresponding lanes. Several identical bands were seen in all of the samples in the cases containing the wild-type sequence. Three different wild-type patterns are seen in the E1.11 region (bottom) due to a known polymorphism; polymorphic cases are indicated with a P beneath the corresponding lanes (Cases 11, 15, 17, and 18 are heterozygous and Case 13 is homozygous for this polymorphism). Cases 15, 27, and 36 showed a different pattern (arrows) in region E1.10 (top), and Cases 12, 15, 16, and 36 showed a different pattern (arrows) in region E1.11 (bottom), as a result of the presence of mutations in the corresponding region, indicated with an M beneath the corresponding lanes. ND, amplified DNA that was not denatured before electrophoresis; —, the same PCR reaction in the absence of DNA; C, positive control known to contain BCL-6 mutations in the region examined.