Detection of Fas mutations in NHL. (A) The 5′-end of exon 9 of the Fas gene was amplified using primers 9I-F and 9I-R, and mutations were detected by DGGE analysis in follicle center cell lymphoma (FCC) 17 (E256K), MALT 145 (N248K), DLC-B 156 (N248K), DLC-B 93 (L262F), and DLC-B 86 (D244V). PBL, DNA isolated from peripheral blood lymphocytes of a normal volunteer. (B) Direct sequence analysis of heteroduplexes recovered from the gel shown in (A), revealing the G1008A transition (E256K) in FCC 17.