Among diffuse large B-cell lymphomas, T-cell-rich/histiocyte-rich BCL and CD30+anaplastic B-cell subtypes exhibit distinct clinical features

Background: The EORTC clinical trial 20901, activated in 1990, was designed to treat non-Hodgkin's lymphomas (NHL) of intermediate/high-grade malignancy according to the Working Formulation. Established in 1994, the R.E.A.L. Classification on NHL has now replaced all former classifications. Patients and methods: We reanalysed all cases (n = 273) documented by material available for review according to the R.E.A.L. Classification. In addition, we subdivided cases recognised as diffuse large B-cell lymphoma (DLBCL) into three morphologically distinct categories, namely, large cleaved DLBCL (LC-DLBCL), T-cell-rich/histiocyte-rich B-cell lymphoma (T-cell-rich/histiocyte-rich BCL) and CD30+ DLBCL with anaplastic cell features (CD30+ DLBCL). Finally, T/NULL anaplastic large-cell lymphoma (ALCL) cases were subdivided into ALK+ and ALK- lymphomas. Review was performed independently by two pathologists from two different centres. Results: DLBCL (61%), T/NULL ALCL (15%) and mantle-cell lymphoma (MCL, 5%) were the main NHL categories represented in the study. Fifty-seven of one hundred sixty DLBCL cases were further subclassified as LC-DLBCL (33 cases), T-cell-rich/histiocyte-rich BCL (13 cases) or CD30+ DLBCL (11 cases). The remaining cases were indicated as unspecified DLBCL. A clinico-pathological correlation confirmed the findings of previous studies suggesting that MCL, DLBCL and ALCL represent distinct entities with MCL being characterised by a short survival, in contrast with the longer survival and less frequent progression typical of ALK+ compared to ALK- ALCL. Within DLBCL, T-cell-rich/histiocyte-rich BCL showed distinctive features at presentation whereas CD30+ DLBCL showed a trend towards a more favourable prognosis, that might be comparable to that of ALK+ ALCL. Conclusions: Our data further support the usefulness of the R.E.A.L. Classification and illustrate the feasibility of DLBCL subtyping. Moreover, our results demonstrate the distinct clinical characteristics of T-cell-rich/histiocyte-rich BCL and CD30+ DLBCL with anaplastic cell features suggesting that they may represent clinico-pathologic entities

Chromosomal gains and losses are uncommon in hairy cell leukemia: a study based on comparative genomic hybridization and interphase fluorescence in situ hybridization.

In contrast to other subtypes of lymphoproliferative malignancies, the genetic mechanisms underlying the pathogenesis of hairy cell leukemia (HCL) are unknown. We studied densely infiltrated splenic tissue of 14 cases of HCL for the presence of chromosomal gains and losses by comparative genomic hybridization (CGH). Chromosomal imbalances were detected in only four of the 14 cases. Chromosomal gains involved the regions 5q13-q31 (two cases) and 1p32-p36.2 (one case). A loss of the region 11q14-q22 was found in one additional patient. The imbalances affecting the regions 5q and 11q were confirmed by interphase fluorescence in situ hybridization (FISH) using PAC clone 144G9 (5q31) and YAC clones 755B11 (11q22.3-q23.1) and 801E11 (11q22.3-q23.1 spanning the ATM gene) and occurred in 61% to 75% of analyzed nuclei. The latter DNA probes and probes hybridizing to chromosomal regions, which are frequently deleted in other subtypes of non-Hodgkin lymphomas (NHL), namely 9p21/ P16(INK4A), 13q14/D13S25, and 17p13/P53 were subsequently applied to all 14 cases of HCL, but no additional abnormalities were found. We conclude that overrepresentation of chromosome 5 represents a recurrent aberration in HCL and that the commonly overrepresented region resides in 5q13-q31. Chromosomal imbalances including deletions of the tumor suppressor gene loci 9p21/P16(INK4A), 13q14/D13S25, and 17p13/P53 rarely occur in HCL in contrast to some other subtypes of B-cell NHL. The pathogenetic role of 11q/ATM alterations in HCL remains to be determined

Premature termination codon mutations in the von Willebrand factor gene are associated with allele-specific and position-dependent mRNA decay

Background. The FOXP1 forkhead transcription factor is targeted by rare but recurrent translocations in B-NHL, particularly marginal zone lymphoma (MZL) and diffuse large B-cell lymphoma (DLBCL). The most common is IGH-mediated t(3;14)(p14;q32) resulting in deregulation of FOXP1 transcription by regulatory sequences of IGH. Several translocations of FOXP1 involving non-IG loci have been described, but remain uncharacterized at the molecular level. Aims. This study aimed at genetic and molecular characterization of non-IG FOXP1 aberrations identified in 4 lymphoma cases. Methods. FISH with a panel of BAC probes was applied to map the affected breakpoints at 3p14/FOXP1 and 2q36, 3q11-q13 and 10q24. Expression of FOXP1 mRNA was analyzed by quantitative RT-PCR (QRT-PCR) with primers specific for exons 5-6, 7-8, 11-12, 14-15 and 17-18. Expression of FOXP1 protein was demonstrated by immunohistochemistry (IHC) with the JC12 antibody. Results. All 4 cases showed an aberrant expression of FOXP1 protein by IHC. Three of them displayed various 3p14 aberrations including t(2;3)(q36;p14) (C1) (MZL), inv(3)(p14;q11) (C2) (MZL) and t(3;10)(p14;q24) (C3) (CLL in Richter transformation). In one case of DLBCL (C4) a non-IG t(FOXP1) was detected by interphase FISH. In contrast to lymphomas with t(3;14) showing the 3p14 breakpoints in the 5’end of FOXP1, all cases with non-IG FOXP1 rearrangements displayed breakpoints in the 3’end of the gene. The reciprocal breakpoints were mapped within AP1S3 at 2q36 (C1), in a region at 3q11 lacking known genes (C2) and close to NFKB2 at 10q24 (C3). In C1, AP1S3 has an opposite transcriptional orientation to FOXP1, which precludes the role of its 5’ promoter in deregulation of FOXP1. Also the mechanism of FOXP1 overexpression in C2 with inv(3) affecting no known gene locus at 3q11 remains unknown. To check the hypothesis that non-IG translocations of FOXP1 result in an aberrant expression of variant FOXP1 transcripts, we performed exon-specific QRT-PCR analysis of two available cases (C2 and C4). As controls, we analyzed 2 cases with t(3;14) and 6 cases of DLBCL/MZL expressing FOXP1 but lacking FOXP1 rearrangements. These studies showed that both cases with t(3;14) expressed all analyzed coding exons (6-17) while cases with non-IGH translocations of FOXP1, as well as FOXP1+ DLBCL/MZL cases expressed sequences coded by exons 7-17, but not of exon 6. Conclusions. Our study demonstrates that the 3p14 breakpoints of non-IG FOXP1 rearrangements in lymphoma are clustered in the 3’end of the gene. Consequently, these aberrations result in expression of variant FOXP1 transcripts, likely encoding N-terminally truncated proteins, similar to potentially oncogenic smaller FOXP1 isoforms recently identified in ABC-DLBCL cell lines and primary DLBCLs. Which transcriptional regulatory elements are engaged to aberrantly express variant FOXP1 transcripts in these peculiar non-IG FOXP1 aberrations warrants further studies