Multiple PCR analysis of the t(14;18)-MBR translocation of total DNA samples extracted from 3 reactive lymph nodes (RLN; cases a, b, and c). The amplified DNA was separated on 2% agarose/NuSieve gel electrophoresis, transferred to nylon membrane, and hybridized with³²P-endlabeled MBR-P⁺ oligonucleotide probe specific for the bcl-2/MBR region. BL (blank), PCR amplification without DNA template to rule out contamination; C+, positive control [t(14;18)-positive tumor)]. Analysis of the different samples shows rearranged bcl-2/J_H bands within the expected range of size (150 to 400 bp). Note the presence of rearranged bands of the same size in the five PCR runs performed on the same DNA sample (case a), whereas cases b and c present two bands of different size in two of the five runs performed from each sample. Note also that the sizes of the bands vary from one case to another.