PMC

Survival of t(14;18)-positive versus t(14;18)-negative patients in the GCB DLBCL subgroup. A: Overall survival; B: event-free survival. There is no significant difference 0in survival between the two subsets of patients.

Distribution of the t(14;18) among the DLBCL subgroups. Twenty-nine of 34 positive cases occurred in the GCB subgroup, whereas three cases occurred in the unclassifiable subgroup and none in the ABC subgroup. Among 12 PMBL cases identified using the PMBL predictor, 2 cases had the t(14;18).

Frequency of the t(14;18) in DLBCL. A: Among the 129 cases studied by interphase FISH for the presence of t(14;18), 22 cases were positive whereas 107 cases were negative. B: PCR analysis detected 26 positive cases, of which 14 were also shown to be positive by FISH. Therefore, an additional 12 positive cases detected by PCR were included in this study. Thus, of the 141 cases, 34 cases were BCL2 translocation-positive and 107 were negative.

Differential gene expression in the two cytogenetic subsets of GCB-DLBCL. A: Differential expression of genes in cases with or without t(14;18) in the GCB subgroup. Differentially expressed genes are illustrated with red indicating increased expression and green decreased expression. Each column represents a single GCB DLBCL case and each row represents a single gene. Among the 146 clones selected, 53 clones were overexpressed in the t(14;18)-positive group and 93 clones were overexpressed in the t(14;18)-negative group. Genes discussed in the text are listed on the right with the number of clones selected (when >1) indicated in the bracket. The full gene list is available in the supplemental table at http://ajp.amjpathol.org. B: BCL2 gene expression in cases with and without the t(14;18) in the GCB subgroup. BCL2 gene expression was calculated as detailed in the text to more accurately reflect the true expression levels. These new values avoided the false-negative measurements because of 3′ truncation of the transcript resulting from BCL2 translocation at the mbr and the falsely low values on many normal transcripts, when measured by the clone (232714). Using these values, BCL2 is significantly overexpressed in the t(14;18)-positive subset (P = 0.0015 and t-statistic value = 3.35).