This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Takahashi, H. Articles by Shipp, M. A. Search for Related Content PubMed PubMed Citation Articles by Takahashi, H. Articles by Shipp, M. A.

FAS Death Domain Deletions and Cellular FADD-like Interleukin 1ß Converting Enzyme Inhibitory Protein (Long) Overexpression: Alternative Mechanisms for Deregulating the Extrinsic Apoptotic Pathway in Diffuse Large B-Cell Lymphoma Subtypes

Authors' Affiliations: Departments of ¹ Medical Oncology and ² Biostatistics, Dana-Farber Cancer Institute; ³ Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts; and ⁴ Broad Institute, Cambridge, Massachusetts

Requests for reprints: Margaret A. Shipp, Department of Medical Oncology, Dana-Farber Cancer Institute, 44 Binney Street, Boston, MA 02115. Phone: 617-632-3874; Fax: 617-632-4734; E-mail: margaret_shipp{at}dfci.harvard.edu.

	Abstract

Top Abstract Materials and Methods Results Discussion References

 
Purpose: Large B-cell lymphomas (LBCL) arise from normal antigen-exposed B cells at germinal center (GC) or post-GC stages of differentiation. Negative selection of normal low-affinity or self-reactive GC B-cells depends on CD95 (FAS)-mediated apoptosis. FAS mutations that result in deletion of the cytoplasmic death domain destabilize the trimeric receptor and inhibit FAS-mediated apoptosis. This apoptotic pathway is also inhibited when the nuclear factor B (NFB) target, cellular FADD-like interleukin 1ß converting enzyme inhibitory protein (cFLIP), interacts with the death-inducing signaling complex, assembled around the FAS death domain. Herein, we ask whether FAS death domain mutations and NFB-mediated overexpression of cFLIP represent alternative mechanisms for deregulating the extrinsic apoptotic pathway in LBCL subtypes defined by gene expression profiling [oxidative phosphorylation, B-cell receptor/proliferation, and host response diffuse LBCLs and primary mediastinal LBCLs].

Experimental Design: The FAS receptor was sequenced, FAS death domain mutations identified, and cFLIP expression assessed in a series of primary LBCLs with gene expression profiling–defined subtype designations and additional genetic analyses [t(14;18) and t(3;v)].

Results: FAS death domain deletions were significantly more common in oxidative phosphorylation tumors, which also have more frequent t(14;18), implicating structural abnormalities of either the extrinsic or intrinsic pathway in this diffuse LBCL subtype. In marked contrast, host response tumors, which have up-regulation of multiple NFB target genes and increased NFB activity, express significantly higher levels of cFLIP_long.

Conclusions: These data suggest that the gene expression profiling–defined LBCL subtypes have different mechanisms for deregulating FAS-mediated cell death and, more generally, that these tumor groups differ with respect to their underlying genetic abnormalities.

Although mutations of the FAS death domain are rare in normal GC B-cells, such mutations have been directly linked with resistance to FAS-mediated apoptosis (5). In earlier in vitro studies, the triggering of FAS-mediated apoptosis in normal GC B-cells selected for surviving cells with FAS death domain mutations (5).

Germ-line mutations of FAS have been associated with lymphoproliferative syndromes in mice and men (4). Specifically, FAS-deficient lpr mice develop lymphadenopathy, splenomegaly, and B-cell lymphomas (6). In addition, patients with autoimmune lymphoproliferative syndrome and germ-line FAS mutations have a markedly increased incidence of B-cell non-Hodgkin's and Hodgkin's lymphomas (7). Of interest, the lymphoid malignancies in autoimmune lymphoproliferative syndrome patients all exhibit structural abnormalities of the intracytoplasmic FAS death domain (7). FAS mutations have also been identified in sporadic non-Hodgkin's lymphomas, including DLBCL (8–10).

During normal development, B cells in the T cell–rich perifollicular area and high-affinity GC B-cells are protected from FAS-induced apoptosis by the cellular FADD-like interleukin 1ß converting enzyme inhibitory protein (cFLIP; refs. 3, 11). In these circumstances, cFLIP is induced by signals from B-cell receptors, follicular dendritic cells, or CD40, rendering the death-inducing signaling complex nonfunctional, blocking caspase 8 activation, and preventing cellular apoptosis (3, 11, 12).

Many of the extracellular signaling mechanisms that induce cFLIP do so via activation of nuclear factor B (NFB; ref. 13). In a lymphoid malignancy with evidence of constitutive NFB activation, classic Hodgkin's lymphoma, cFLIP expression protects Hodgkin's/Reed-Sternberg cells from FAS-mediated apoptosis (14, 15). These observations prompt speculation that NFB-mediated up-regulation of cFLIP might limit FAS-mediated apoptosis in additional lymphoid malignancies including certain large B-cell lymphomas (LBCL).

The LBCLs include recently identified subtypes characterized by specific clinical features and/or transcriptional profiles (16–20). The LBCL subtype, primary mediastinal LBCL (MLBCL), shares important molecular features with classic Hodgkin's lymphoma, including constitutive activation of the NFB survival pathway (16–18). Recently, additional DLBCL subtypes with unique comprehensive transcriptional signatures—oxidative phosphorylation (OxPhos), B-cell receptor/proliferation (BCR), and host response (HR)—have been identified (20). HR tumors exhibit a host immune/inflammatory response including increased numbers of CD2⁺/CD3⁺ tumor-infiltrating lymphocytes and interdigitating -IFN-inducible lysosomal thiol reductase–positive dendritic cells (1, 20). HR DLBCLs share histologic and clinical features of the WHO subtype, T cell/histiocyte–rich LBCL, including presentation in younger patients with frequent bone marrow and splenic involvement (1, 20). Recent studies indicate that HR DLBCLs have increased expression of multiple NFB target genes, suggesting that these tumors may also be dependent on NFB-mediated tumor cell survival (16). In additional studies in which DLBCLs were segregated on the basis of developmental features, tumors and cell lines with activated B cell–like (ABC-like) signatures also had high levels of NFB activity and increased sensitivity to NFB inhibition (16, 21).

It is not yet known whether structural abnormalities of the FAS receptor and NFB-mediated overexpression of cFLIP represent alternative mechanisms for deregulating the extrinsic apoptotic pathway in LBCLs. Herein, we address this issue and the potential role of FAS-mediated apoptosis in the recently characterized LBCL subtypes.

	Materials and Methods

Top Abstract Materials and Methods Results Discussion References

 
LBCLs and normal GC B-cells. Diagnostic nodal or mediastinal biopsies from 117 previously untreated DLBCLs and 25 primary MLBCLs (17, 20) were analyzed for FAS mutations. All of the DLBCL samples were previously characterized for BCL2 and BCL6 translocations; 15 and 19 of the MLBCL series were similarly analyzed for BCL2 and BCL6 translocations, respectively (20). The previously described DLBCL gene expression profiles were used to assign the tumors to comprehensive consensus clusters, OxPhos, BCR, and HR (40 OxPhos, 55 BCR, and 22 HR tumors), and the differentiation-associated cell-of-origin categories, GC B-cell–like (GCB), ABC-like (ABC), and "other" (52 GCB, 17 ABC, and 48 other DLBCLs; ref. 20). Normal tonsillar GC B-cells were purified as previously described (22).

FAS mutation analysis. Total RNA from each frozen tumor specimen was reverse transcribed by oligo-dT primer using Ominiscript Reverse Transcription kit (Qiagen, Valencia, CA). Two sets of PCR primers were designed to encompass the entire coding region of FAS cDNA and generate two overlapping FAS PCR products, FAS A (nucleotides 166-863) and FAS B (nucleotides 813-1,330; ref. 23). The FAS PCR fragments were amplified by two rounds of PCR. The first-round PCR was done with FAS AF (forward primer, 5'-CTTTCACTTCGGAGGATTGC-3', bp 166-185) and FAS BR (reverse primer, 5'-GGCTCTTCAGCGCTAATAAATG-3', bp 1,330-1,309), generating a FAS cDNA fragment encompassing nucleotides 166-1,330 (23). Thereafter, 1 µL of the first-round reaction was used for the second-round PCR, done with either primers FAS AF and FAS AR (reverse primer, 5'-ATTTATTGCCACTGTTTCAGGATT-3', bp 863-840) or primers FAS BF (forward primer, 5'-CAAGGTTCTCATGAATCTCCAAC-3', bp 813-835) and FAS BR. The resulting overlapping FAS A and FAS B fragments (FAS nucleotides 166-863 and 813-1,330, respectively) were purified using QIAquick Gel Extraction Kit (Qiagen) and directly sequenced from both directions. If the initial direct sequencing indicated the presence of more than one FAS product, the PCR fragment was subcloned in pCR2.1-TOPO (Invitrogen) and four or five individual clones were sequenced. All identified FAS death domain mutations were confirmed by bidirectional sequencing.

When primary DLBCL cDNAs exhibited FAS death domain mutations, genomic DNAs from the same tumors were used to sequence FAS exons 7, 8, and 9 and the corresponding 3' and 5' splice junctions and intron branchpoints. Tumor genomic DNAs were amplified by PCR using the following primer pairs: Gen7F (forward primer, 5'-CTTGCTAGGCCAGCCTGTGGTAATTAGATG-3', bp 22,316-22,345) and 7R (reverse primer, 5'-CAGGGATAACAACAACACGGAACATGGAGG-3' bp 23,244-23,215); Gen8F (forward primer, 5'-GCAAGGCCGGAACCTTTCAGAATA-3', bp 23,699-23,722) and 8R (reverse primer, 5'-GCTGAGCAGGTAGAATTGTATGAG-3', bp 24,061-24,038); and Gen9F (forward primer, 5'-CAGGATTTGGAGTTAGAACTCAAGGTTGTC-3', bp 24,496-24,525) and 9R (5'-ACCAAGCAGTATTTACAGCCAGC-3', bp 25,091-25,069; bp designations as per GenBank accession no. AY450925). FAS PCR products were sequenced thereafter.

Analyses of BCL2 and BCL6 translocations. Air-dried touch preparations were obtained from fresh-frozen tumor specimens as previously described (20). Interphase nuclei were hybridized to commercially available probes flanking or spanning the IgH, BCL2, and BCL6 loci {LSI IGH/BCL2 Dual Color, Dual Fusion Translocation Probe for detection of t(14;18) and LSI BCL6 Dual Color, Break Apart Rearrangement Probe for detection of any rearrangement involving 3q27 [t(3;variable (v))]; Vysis, Downers Grove, IL; ref. 20}. After counterstaining with 4',6-diamidino-2-phenylindole, interphase nuclei were scored for the indicated chromosomal translocations by fluorescence microscopy.

Microarray analysis. FAS and cFLIP transcript abundance in DLBCLs and normal GC B-cells was evaluated using the previously described data set of DLBCL and normal GC B-cell transcriptional profiles (20).⁵

Statistical analysis. The association of each genetic abnormality with subtypes defined by comprehensive consensus clusters and cell of origin was assessed with a two-sided Fisher's exact test. The associations between FAS and cFLIP transcript levels (determined by microarray analyses) and comprehensive consensus cluster and cell-of-origin categories were analyzed by Kruskal-Wallis test. The Wilcoxon rank-sum test was used to compare FAS transcript levels in OxPhos tumors with and without death domain deletions and cFLIP_long transcript levels in HR tumors and normal GC B-cells. Significance was assessed with nominal P values.

	Results

Top Abstract Materials and Methods Results Discussion References

 
FAS death domain mutations in LBCLs
Eight of the 117 DLBCLs and none of the 25 MLBCLs were heterozygous for FAS alleles encoding proteins with deletions of the cytoplasmic death domain (Table 1 ). In the LBCL series, these FAS death domain abnormalities resulted from 1- to 20-bp deletions in exon 7 or 8 (five tumors), mutations of intron 8 5' splice junctions and associated exon 8 deletion (Exo8Del, two tumors), or a nucleotide transversion in exon 9 (one DLBCL; Table 1). In all tumors, the resulting frameshifts or amino acid substitutions created STOP codons upstream of or at the beginning of the FAS death domain (Table 1).

View larger version (30K): [in this window] [in a new window]   Fig. 1. The distribution of tumors with genetic abnormalities in the comprehensive clusters and cell-of-origin subtypes and in primary MLBCL. A, DLBCL comprehensive clusters and primary MLBCL. B, DLBCL cell-of-origin subtypes. Tumors were sorted by subtypes: FAS death domain deletions (first row); t(14;18) (second row); and t(3;v) (third row). Bottom blue bar, clusters with previous evidence of constitutive NFB activation and/or increased expression of NFB target genes (16, 17, 21). Of note, one OxPhos tumor had both FAS death domain deletion and t(14;18) or t(3;v); two OxPhos tumors had both t(14;18) and t(3;v).

View larger version (29K): [in this window] [in a new window]   Fig. 2. Assessment of the sensitivity of the FAS mutation detection assay. FAS cDNA sequence (bp 872-851) in RC-K8, a lymphoma cell line heterozygous for Exo8Del (A), SU-DHL-7, a line homozygous for wild-type FAS (B), and admixed cDNAs from RC-K8 and SU-DHL-7 (C). The RC-K8 Exo8Del was readily detected when as little as 40% RC-K8 cDNA was admixed with 60% SU-DHL-7 cDNA. Of note, RC-K8 and SU-DHL-7 have similar FAS transcript levels (data not shown).

View larger version (15K): [in this window] [in a new window]   Fig. 3. FAS and cFLIPlong transcript abundance in LBCL comprehensive clusters. A, FAS transcript abundance in comprehensive clusters (CCC), OxPhos tumors with (+) or without (–) FAS death domain deletions, and normal GC B-cells. OxPhos tumors expressed significantly higher FAS levels than BCR or HR tumors (P < 0.0001, representative probe 204780_s_at, Kruskal Wallis test). OxPhos tumors with FAS death domain deletions expressed significantly higher levels of FAS than those without death domain deletions (P = 0.02, probe 204780_s_at, Wilcoxon rank-sum test). B, cFLIPlong transcript abundance in comprehensive clusters and normal GC B-cells. HR tumors expressed significantly more abundant cFLIPlong transcripts than DLBCLs in the other comprehensive clusters (P < 0.0001, representative probe 211316_x_at, Kruskal Wallis test). The cFLIPlong expression in HR tumors was also higher than in normal GC B-cells (P = 0.03, Wilcoxon rank-sum test). The box plots were drawn by R software. The boxes are drawn with widths proportional to the square-roots of the number of observations in the groups. The whiskers extend from the box to the most extreme data point, which is within 1.5 times the interquartile range.

LBCL subtypes with increased NFB activation lack structural abnormalities of FAS, BCL2, and BCL6

DLBCLs which share features with normal in vitro activated lymphocytes (ABC-like) also exhibit constitutive NFB activation and express a restricted subset of NFB target genes (16, 21). Because our DLBCL series was also characterized with respect to cell-of-origin signatures (GCB, 52 tumors; ABC, 17 tumors; other/unclassifiable, 48 tumors; ref. 20), we were able to assess the frequency of FAS, BCL2 and BCL6 genetic lesions in tumors sorted into these developmental categories. There was no association between cell-of-origin groupings and the incidence of FAS death domain deletions (Table 2; Fig. 1). As previously reported (19), BCL2 translocations were somewhat more common in the GCB subgroup (P = 0.08; Table 2; Fig. 1). Tumors with BCL6 translocations in association with a FAS death domain deletion or BCL2 translocation could not be classified using cell-of-origin criteria, falling into the default other category; many DLBCLs with only BCL6 translocations also fell into this unassigned other category (Fig. 1; ref. 24). Like HR tumors and primary MLBCLs, ABC-like DLBCLs had a lower incidence of the examined structural abnormalities (no FAS death domain deletions or BCL2 translocations, one BCL6 translocation; Table 2; Fig. 1).

Taken together, the near absence of FAS death domain deletions, t(14;18) and t(3;v), in LBCLs with significant NFB activity (HR DLBCLs, MLBCLs, and DLBCLs with ABC-like features) suggests that these tumors are not dependent on the additional examined structural abnormalities for tumor cell survival (Fig. 1).

LBCL subtypes with increased NFB activity have alternative mechanisms for inhibiting FAS-mediated apoptosis: the role of cFLIP_long
Given the absence of FAS death domain deletions in DLBCLs with increased NFB activity (Fig. 1), we sought evidence of alternative mechanisms of inhibiting FAS-mediated apoptosis in these tumors. We noted that FLIP was one of the previously described NFB target genes that was more abundant in HR tumors (and primary MLBCLs; ref. 16). There are two alternatively spliced forms of cFLIP, a short form that lacks the COOH-terminal caspase-like domain and a long form that includes this additional region. Given the known role of cFLIP_long in inhibiting FAS-induced apoptosis in normal GC B-cells and Hodgkin's lymphomas (3), we identified cFLIP probe sets from the long form–specific COOH-terminal domain and formally assessed cFLIP_long transcript abundance in the DLBCL consensus clusters and highly purified normal GC B-cells.

Of interest, the expression of cFLIP_long was highest in HR tumors and lowest in OxPhos DLBCLs (P < 0.0001, Kruskal-Wallis test; Fig. 3B). In addition, HR tumors expressed significantly more abundant cFLIP_long transcripts than did normal GC B-cells (P = 0.03, Wilcoxon rank-sum test; Fig. 3B). Taken together, these data suggest that NFB-mediated up-regulation of cFLIP_long may represent an alternative method of inhibiting FAS-mediated apoptosis in a DLBCL subtype without structural abnormalities of the FAS receptor (Fig. 4 ).

View larger version (42K): [in this window] [in a new window]   Fig. 4. Mechanisms of FAS deregulation in DLBCL subtypes. A, normal FAS-mediated apoptosis. B, prevention of FAS-mediated apoptosis by death domain deletion (mainly OxPhos tumors; left) and NFB-induced cFLIPlong expression (mainly HR DLBCLs; right).

	Discussion

Top Abstract Materials and Methods Results Discussion References

OxPhos DLBCLs have increased expression of genes involved in oxidative phosphorylation and mitochondrial function and more common structural abnormalities of BCL2, suggesting a potential link between deregulated BCL2 and perturbed mitochondrial membrane potential, decreased cytochrome c release, and caspase-mediated apoptosis in these tumors (Fig. 1; ref. 20). Given the increased incidence of FAS death domain deletions in OxPhos DLBCLs, our data indicate that these tumors have more common, largely nonoverlapping, structural abnormalities affecting either the extrinsic or intrinsic apoptotic pathway.

In addition to lacking the FAS death domain deletions, HR tumors were much less likely to exhibit BCL2 translocations (1 of 22 tumors); these DLBCLs also had no BCL6 translocations. Taken together, these data strongly suggest the existence of an alternative pathogenetic mechanism in HR DLBCLs. In recent analyses, HR tumors were found to have significant up-regulation of a large series of bona fide NFB target genes, potentially implicating the NFB survival pathway in this DLBCL subtype (16). More specifically, the NFB target genes up-regulated in HR DLBCLs include cFLIP_long, a critical inhibitor of FAS-mediated apoptosis in normal high-affinity GC B-cells and B cells in the T cell–rich perifollicular zones (Fig. 4; ref. 3). Given the T-cell infiltrate in HR DLBCLs, it is possible that the observed NFB activation and increased expression of cFLIP_long in tumor cells are a consequence of T-cell/B-cell interactions.

Our studies further suggest that additional LBCLs with evidence of constitutive NFB activation, such as primary MLBCLs, or additional developmentally defined ABC-like DLBCLs have rare or no evidence of FAS death domain deletions or translocations of BCL2 or BCL6 (Fig. 1). Recent analyses of NFB target genes in primary LBCLs indicate that MLBCLs and the developmentally defined ABC-like tumors also express higher levels of cFLIP isoforms (16). Taken together, the pattern is suggestive of alternative mechanisms of transformation in tumors with evidence of NFB activation and the near absence of structural abnormalities of FAS and other common LBCL genetic lesions such as translocations of BCL2 and BCL6. These data further support the notion that gene expression profile–defined subtypes of LBCL differ with respect to underlying genetic lesions and that these molecular signatures may be of therapeutic relevance.

	Footnotes

 
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

⁵ URL: http://www.broad.mit.edu/cgi-bin/cancer/datasets.

Received 1/13/06; revised 3/ 8/06; accepted 3/22/06.

	References

Top Abstract Materials and Methods Results Discussion References

 

1. Abramson J, Shipp M. Advances in the biology and therapy of diffuse large B-cell lymphoma-moving towards a molecularly targeted approach. Blood 2005;106:1164–74.[Abstract/Free Full Text]
2. Kuppers R, Klein U, Hansmann M-L, Rajewsky K. Cellular origin of human B-cell lymphomas. N Engl J Med 1999;341:1520–9.[Free Full Text]
3. van Eijk M, Defrance T, Hennino A, de Groot C. Death-receptor contribution to the germinal-center reaction. Trends Immunol 2001;22:677–82.[CrossRef][Medline]
4. Muschen M, Rajewsky K, Kronke M, Kuppers R. The origin of CD95-gene mutations in B-cell lymphoma. Trends Immunol 2002;23:75–80.[CrossRef][Medline]
5. Muschen M, Re D, Jungnickel B, Diehl V, Rajewsky K, Kuppers R. Somatic mutation of the CD95 gene in human B cells as a side-effect of the germinal center reaction. J Exp Med 2000;192:1833–40.[Abstract/Free Full Text]
6. Davidson WF, Giese T, Fredrickson TN. Spontaneous development of plasmacytoid tumors in mice with defective Fas-Fas ligand interactions. J Exp Med 1998;187:1825–38.[Abstract/Free Full Text]
7. Straus SE, Jaffe ES, Puck JM, et al. The development of lymphomas in families with autoimmune lymphoproliferative syndrome with germ line Fas mutations and defective lymphocyte apoptosis. Blood 2001;98:194–200.[Abstract/Free Full Text]
8. Gronbaek K, Straten PT, Ralfkiaer E, et al. Somatic Fas mutations in non-Hodgkin's lymphoma: association with extranodal disease autoimmunity. Blood 1998;92:3018–24.[Abstract/Free Full Text]
9. Montesinos-Rongen M, Van Roost D, Schaller C, Wiestler OD, Deckert M. Primary diffuse large B-cell lymphomas of the central nervous system are targeted by aberrant somatic hypermutation. Blood 2004;103:1869–75.[Abstract/Free Full Text]
10. Wohlfart S, Sebinger D, Gruber P, et al. FAS (CD95) mutations are rare in gastric MALT lymphoma but occur more frequently in primary gastric diffuse large B-cell lymphoma. Am J Pathol 2004;164:1081–9.[Abstract/Free Full Text]
11. Thome M, Tschopp J. Regulation of lymphocyte proliferation and death by FLIP. Nat Rev Immunol 2001;1:50–8.[CrossRef][Medline]
12. Hennino A, Berard M, Krammer PH, Defrance T. FLICE-inhibitory protein is a key regulator of germinal center B cell apoptosis. J Exp Med 2001;193:447–58.[Abstract/Free Full Text]
13. Micheau O, Lens S, Gaide O, Alevizopoulos K, Tschopp J. NF-kB signals induce the expression of c-FLIP. Mol Cell Biol 2001;21:5299–305.[Abstract/Free Full Text]
14. Dutton A, O'Neil JD, Milner AE, et al. Expression of the cellular FLICE-inhibitory protein (c-FLIP) protects Hodgkin's lymphoma cells from autonomous Fas-mediated death. Proc Natl Acad Sci U S A 2004;101:6611–6.[Abstract/Free Full Text]
15. Mathas S, Lietz A, Anagnostopoulos I, et al. c-FLIP mediates resistance of Hodgkin/Reed-Sternberg cells in death receptor-induced apoptosis. J Exp Med 2004;199:1041–52.[Abstract/Free Full Text]
16. Feuerhake F, Kutok J, Monti S, et al. NFkB activity, function and target gene signatures in primary mediastinal large B-cell lymphoma and diffuse large B-cell lymphoma subtypes. Blood 2005;106:1392–9.[Abstract/Free Full Text]
17. Savage K, Monti S, Kutok J, et al. The molecular signature of mediastinal large B-cell lymphoma differs from that of other diffuse large B-cell lymphomas and shares features with classical Hodgkin lymphoma. Blood 2003;102:3871–9.[Abstract/Free Full Text]
18. Rosenwald A, Wright G, Leroy K, et al. Molecular diagnosis of primary mediastinal B cell lymphoma identifies a clinically favorable subgroup of diffuse large B cell lymphoma related to Hodgkin lymphoma. J Exp Med 2003;198:851–62.[Abstract/Free Full Text]
19. Rosenwald A, Wright G, Chan WC, et al. The use of molecular profiling to predict survival after chemotherapy for diffuse large B-cell lymphoma. N Engl J Med 2002;346:1937–47.[Abstract/Free Full Text]
20. Monti S, Savage KJ, Kutok JL, et al. Molecular profiling of diffuse large B-cell lymphoma identifies robust subtypes including one characterized by host inflammatory response. Blood 2005;105:1851–61.[Abstract/Free Full Text]
21. Davis RE, Brown KD, Siebenlist U, Staudt LM. Constitutive nuclear factor B activity is required for survival of activated B cell-like diffuse large B cell lymphoma cells. J Exp Med 2001;194:1861–74.[Abstract/Free Full Text]
22. Aguiar R, Yakushijin Y, Kharbanda S, Tiwari S, Freeman G, Shipp M. PTPROt: an alternatively spliced and developmentally regulated B-lymphoid phosphatase that promotes G₀/G₁ arrest. Blood 1999;94:2403–13.[Abstract/Free Full Text]
23. Itoh N, Yonehara S, Ishii A, et al. The polypeptide encoded by the cDNA for human cell surface antigen Fas can mediate apoptosis. Cell 1991;66:233–43.[CrossRef][Medline]
24. Wright G, Tan B, Rosenwald A, Hurt E, Wiestner A, Staudt L. A gene expression-based method to diagnose clinically distinct subgroups of diffuse large B cell lymphoma. Proc Natl Acad Sci U S A 2003;100:9991–6.[Abstract/Free Full Text]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Takahashi, H. Articles by Shipp, M. A. Search for Related Content PubMed PubMed Citation Articles by Takahashi, H. Articles by Shipp, M. A.