Diffuse large B-cell lymphoma (DLBCL) has been shown to be comprised of at least two prognostic entities, depending on its resemblance to normal germinal center or activated B cells, using global gene expression profiling. Also, the expression patterns of bcl-6, CD10 and IRF-4 (also known as MUM1) have been suggested as alternative means of identifying the germinal-and nongerminal center (activated B-cell like) groups. In the present study, we evaluated by immunohistochemistry the expression patterns of CD10, bcl-6, IRF-4 and bcl-2 in a large material of 161 DLBCL patients. Using two different approaches, patients with germinal center phenotype displayed a significantly better survival than the nongerminal center group. Positive staining for bcl-6 or CD10 predicted for superior survival, while expression of IRF-4 alone showed no association with prognosis. Furthermore, expression of bcl-2 was associated with worse event-free survival and overall survival. In a multivariate analysis, a high international prognostic index score (3-5), non-GC phenotype and bcl-2 were independent adverse prognostic factors. Here we confirm the prognostic importance of determining the germinal-or nongerminal center phenotype in patients with DLBCL.

In 231 diffuse large B-cell lymphomas, the expression of cyclin D1 and CD5 was evaluated. All cases were CD5-. Ten (4.3%) were positive for cyclin D1 and were subjected to fluorescence in situ hybridization at the CCND1 locus. One case showed the t(11;14). In another case, the telomeric probe signal for cyclin D1 was lost in most tumor cells, and in a small proportion of the cells, there were fluorescence signals indicative of the t(11;14). Two other cases displayed additional cyclin D1 signals in the absence of the t(11;14). All cases but 1 were positive for bcl-6 or MUM1, disfavoring the possibility of misdiagnosed blastoid variants of CD5- mantle cell lymphomas. Thus, contrary to the current view, there seems to exist a certain number of cyclin D1+ and CD5- diffuse large B-cell lymphomas, some of which have structural aberrations at the CCND1 locus, including the t(11;14).

The results call for increased awareness and evaluation of reasons for long-term work disability following intensive chemotherapy among young HL survivors.

Patients diagnosed with diffuse large B-cell lymphoma (DLBCL) show varying responses to conventional therapy, and this might be contributed to the differentiation stage of the tumor B-cells. The aim of the current study was to evaluate a panel of kinases (ZAP70, PKC-beta I and II and phosphorylated PKB/Akt) and phosphatases (PTEN, SHP1 and SHP2) known to be frequently deregulated in lymphoid malignancies. De novo DLBCL cases were divided into two subgroups, the germinal center (GC) group (14/28) and the non-germinal center (non-GC) or activated B-cell (ABC) group (14/28). ZAP70 and PKC-beta II were expressed in a significantly higher percentage of tumor cells in the clinically more aggressive non-GC group compared with the prognostically favourable GC group. Also, the subcellular localization of PKC-beta I and II differed in DLBCL cells, with the PKC-beta I isoform being expressed in both the cytoplasm and nucleus, while PKC-beta II was found exclusively in the cytoplasm. Loss of nuclear PTEN correlated with poor survival in cases from both subgroups. In addition, five cell lines of DLBCL origin were analyzed for protein expression and for mRNA levels of PTEN and SHP1. For the first time, we show that ZAP70 is expressed in a higher percentage of tumor cells in the aggressive non-GC subgroup of DLBCL and that PKC-beta I and II are differently distributed in the two prognostic subgroups of de novo DLBCL.

Follicular lymphoma (FL) frequently transforms into the more aggressive diffuse large B cell lymphoma (DLBCL‐tr), but no protein biomarkers have been identified for predictive or early diagnosis. Gene expression analyses have identified genes changing on transformation but have failed to be reproducible in different studies, reflecting the heterogeneity within the tumor tissue and between tumor samples. Gene expression analyses on Affymetrix Human Genome U133 Plus 2.0 arrays were performed, using flow cytometry sorted tumor cells derived from FL and transformed DLBCL. To identify molecular targets associated with the transformation, subsequent immunohistochemistry (IHC) analyses of the corresponding proteins were performed. Using highly purified cells, this study identified 163 genes, which were significantly deregulated during the transformation in a majority of cases. Among the upregulated transcripts, 13 genes were selected for validation using IHC, based on the availability of commercial antibodies, and galectin‐3 and NEK2 proteins specifically identify DLBCL‐tr, when compared with FL. We demonstrate that by purifying tumor cells through cell sorting, thereby reducing the heterogeneity due to infiltrating cells, it was possible to identify distinct differences between tumor entities rather than variations due to cellular composition. Galectin‐3 and NEK2 both identified a subgroup of DLBCL‐tr, and the function of these protein markers also suggests a biological role in the transformation process. Am. J. Hematol. 2009. © 2009 Wiley‐Liss, Inc.