Transformation of Follicular Lymphoma to Precursor B-Cell ...

Am J Clin Pathol 2008;129:157-166 157157 DOI: 10.1309/NKK3FEX2BE5L7EKB 157

© American Society for Clinical Pathology

Hematopathology / TRANSFORMATION OF FOLLICULAR LYMPHOMA

Transformation of Follicular Lymphoma to Precursor B-CellLymphoblastic Lymphoma With c-myc Gene Rearrangementas a Critical Event

Ken H. Young, MD, PhD,1 Qingmei Xie, MD,2 Guimei Zhou, MD,3 Jens C. Eickhoff, PhD,1

Warren G. Sanger, PhD,4 Patricia Aoun, MD,3 and Wing C. Chan, MD3

Key Words: Lymphoblastic lymphoma; Follicular lymphoma; Transformation; bcl-2; bcl-6; IgH; TP53; c-myc

DOI: 10.1309/NKK3FEX2BE5L7EKB

A b s t r a c t

Progression of follicular lymphoma (FL) to ahigher-grade lymphoma occurs in 25% to 60% of casesand frequently indicates a poor prognosis. Thetransformation is accompanied by alteration inmorphologic features and clinical behaviors. Herein,we report a case of FL occurring in a 59-year-oldwoman with the development of a precursor B-celllymphoblastic lymphoma (PBC-LBL) during a 6-monthperiod. Both lymphomas had identical bcl-2 andimmunoglobulin heavy-chain gene breakpoints asassessed by polymerase chain reaction amplificationand direct sequencing, indicating that the 2 tumorsoriginated from a common precursor B-cell clone or thePBC-LBL arose from clonal evolution of its precedingFL and “dedifferentiated” into a lymphoblastic stage.Immunohistochemical studies revealed that bothlymphomas displayed typical phenotypic characteristics.A c-myc gene translocation was observed in the PBC-LBL but not the FL by fluorescence in situ hybridization.The c-myc translocation is also reported in similarcases in the literature and likely is crucial in thepathogenesis of the PBC-LBL.

Follicular lymphoma (FL) constitutes approximately30% to 40% of all adult non-Hodgkin lymphomas in NorthAmerica.1-3 Cases of FL are characterized by an indolent clin-ical course that is interrupted in 25% to 60% of cases by thedevelopment of an aggressive high-grade lymphoma, resultingin marked worsening of the clinical outcome.4-7 Although avariety of cytogenetic and molecular aberrations have beenreported in association with the high-grade transformation, themechanistic basis of the transformation in FL is not wellunderstood.8-18

The majority of FL transforms into diffuse large B-celllymphoma (DLBCL) with only a small subset of cases show-ing transformation to immunoblastic, Burkitt-type lym-phomas and precursor B-cell lymphoblastic lymphoma (PBC-LBL).5,10,11,19-24 The t(14;18)(q32;q21) translocation has beenidentified in 85% to 90% of the FL cases and leads to overex-pression of BCL2 protein, which is believed to be a crucialprimary event in the lymphomagenesis through its antiapop-totic effect, but secondary genetic changes are necessary forthe development of FL.8,25-30 Additional genetic changes arealso known to be required for transformation and progressionof FL.5-18 Previous studies have demonstrated that severalgenetic abnormalities are associated with high-grade histolog-ic transformation of FL, including rearrangements of the mycgene,31 mutations of the TP53 tumor suppressor gene,32,33

mutations of the bcl-6 and translocated bcl-2 genes,14,17 andinactivation of the p16 and p14 genes by deletion, mutation, orhypermethylation.16 However, these alterations are eachobserved in a subset of transformed FL, suggesting that theprocess of histologic transformation is achieved by multipledistinct mechanisms. Although abnormalities of c-myc havebeen reported in approximately 8% of all transformed FL

Dow

nloaded from https://academ

ic.oup.com/ajcp/article/129/1/157/1765416 by guest on 11 January 2022

158 Am J Clin Pathol 2008;129:157-166158 DOI: 10.1309/NKK3FEX2BE5L7EKB


Young et al / TRANSFORMATION OF FOLLICULAR LYMPHOMA

cases, retrospective studies showed that all patients with PBC-LBL transformation from the preceding FL exhibited c-mycgene aberrations, implicating the important role of c-myctranslocations in lymphoblastic transformation.10,21-23,32,33

We report herein the case of a 59-year-old woman withconcurrent FL, grade 2, and DLBCL in whom PBC-LBL sub-sequently developed and provide evidence of a clonal relation-ship between the preceding FL and the transformed PBC-LBL. In addition, the current case exhibited rearrangements ofthe c-myc gene. These findings are compatible with thehypothesis that the PBC-LBL arises from its preceding FL, orboth types of tumor cells are derived from the same neoplas-tic precursor B-cell clone.

Case Report

A 59-year-old woman had a 3-month history of weightloss and left submandibular lymphadenopathy. A computedtomographic scan revealed lymphadenopathy in the left sub-mandibular, left jugular, right tracheal, and right hilar regions.Biopsy of a submandibular node revealed FL, grade 2, withareas of DLBCL. The patient underwent 3 cycles ofchemotherapy with cyclophosphamide, doxorubicin, vin-cristine, and prednisone (CHOP). She experienced partial res-olution of the lymphadenopathy, but the treatment wasstopped owing to respiratory distress symptoms.

One month later, liver infiltrates developed and werenoted by ultrasound evaluation, and CHOP chemotherapy wasresumed with reduced doses. However, a follow-up computedtomographic scan showed recurrent lymphadenopathy at theoriginal biopsy site. A biopsy obtained from the left side of theneck 6 months after initial diagnosis revealed PBC-LBL whilethe patient was receiving her fifth through seventh cycles ofthe CHOP regimen. Bone marrow biopsy at that time showedno evidence of involvement by PBC-LBL. Treatment withetoposide, cytarabine, and methylprednisolone (Solu-Medrol)salvage chemotherapy was begun with radiation to the neckregion. Her subsequent clinical course was complicated byextensive disease progression and respiratory distress symp-toms, and she died 13 months after initial diagnosis.

Materials and Methods

Histologic and Immunohistochemical Studies

The lymph node specimens were fixed in 10% neutralbuffered formalin and embedded in paraffin, and 4-µm sec-tions were cut and stained with H&E for histologic evaluation.Immunohistochemical stains were performed on formalin-fixed, paraffin-embedded tissue sections. Briefly, after

deparaffinization in xylene and rehydration in graded alco-hols, endogenous peroxidase was blocked with 3% hydrogenperoxide. Antigen retrieval was performed in 10 mmol/L ofcitrate buffer, pH 6.0, as appropriate for the antibodies. Afterrinsing in phosphate-buffered saline, antibodies against CD20,CD79a, bcl-2, terminal deoxynucleotidyl transferase (TdT),myeloperoxidase, IgM, IgG, IgA, and IgD (all from DAKO,Carpinteria, CA) and CD3 and CD43 (Ventana Biotek,Tucson, AZ) were used for immunohistochemical studies.These stains were performed on a Ventana ES automatedimmunostainer (Ventana Biotek) using a streptavidin-biotinperoxidase detection system. Antigen-retrieval methods andantibody dilutions were used according to manufacturer rec-ommendation.

In Situ Hybridization for Immunoglobulin Light ChainMessenger RNA

In situ hybridization for immunoglobulin light chain mes-senger RNA was performed according to the manufacturer’sinstructions (Ventana, AZ) with minor modification on aVentana ES automated immunostainer using a streptavidin-biotin peroxidase detection system.34 The optimum probeconcentration was titrated to eliminate background stainingwhile retaining good signal strength and contrast. Negativecontrol experiments consisted of assays with omission of theprobes in the hybridization protocol. The messenger RNAquality was estimated on each tissue section using poly Aprobes. Light chain expression was considered monotypic ifthe κ/λ light chain expression ratio was greater than 10:1 orgreater than 4:1 for λ/κ light chain expression evaluated froma minimum of 100 tumor cells.

Polymerase Chain Reaction Amplification and SequenceAnalysis for t(14;18)(q32;q21) Translocation (bcl-2/IgHGene)

DNA from the FL and PBC-LBL was extracted fromparaffin-embedded tissue samples by using the EX-WAXDNA Extraction Kit (Intergen, New York, NY) according tothe manufacturer’s instruction. Polymerase chain reaction(PCR) for IgH complementarity-determining region (CDR) 3rearrangement and for bcl-2 translocation at the major break-point region (MBR) was performed as previouslydescribed.35,36

Sequencing of PCR Products

The PCR products were purified using the QIAquick GelExtraction Kit (Qiagen, Valencia, CA) and were directlysequenced in both directions using the Big Dye TerminatorKit on the ABI 377 Sequencer (ABI, Foster City, CA). Thesequence was compared with the data from the GenBankdatabase by using Sequencer software (Gene Codes, AnnArbor, MI).

Dow





Fluorescence In Situ Hybridization AnalysisInterphase fluorescence in situ hybridization (FISH)

analysis was performed on formalin-fixed, paraffin-embeddedtissue sections according to previously established proceduresat the University of Nebraska Medical Center HumanGenetics Laboratories (Omaha).37 For the detection of the bcl-2, bcl-6, c-myc, and TP53 gene rearrangements, commercial-ly available dual-color LSI bcl-2, bcl-6, and LSI IgH/MYCbreak-apart probes and LSI TP53 Spectrum Orange probeswith CEP 17 were used (Vysis, Downers Grove, IL). Imageswere captured and archived using Cytovision software(Applied Imaging, Santa Clara, CA). To analyze thehybridization, a total of 50 cells were examined per probe forthe presence of the chromosomal aberrations. The observedsignals were considered significant if they were present ingreater than cutoff levels previously established for our labora-tory. The upper cutoff levels in paraffin-embedded tissue sam-ples are 8% for bcl-2 translocation, 6% for bcl-6 translocation,10% for c-myc translocation, and 18% for TP53 deletion.

We used χ2 tests to compare the proportions of abnormalsignals among the 3 groups for bcl-2 translocation and c-myctranslocations. Fisher exact tests were used to compare theproportions of abnormal signals among the 3 groups for bcl-6gene translocation and TP53 gene deletion. All P values were2-sided.

Results

Histologic and Immunophenotypic Studies

The submandibular lymph node demonstrated effacementof the nodal architecture by neoplastic follicles with marked-ly attenuated mantle zones ❚Image 1A❚ and ❚Image 1B❚. Areasof DLBCL were also noted and constituted approximately40% to 50% of the tumor. The tumor cells within the neoplas-tic follicles were composed of an admixture of scattered cen-troblasts and small-cleaved centrocytes with elongated orangulated nuclei and condensed chromatin. Tingible-bodymacrophages were almost absent, and mitotic figures wereoccasionally seen.

The lymph node biopsy specimen obtained 6 months laterrevealed complete effacement of the nodal architecture by adiffuse, monomorphous, neoplastic infiltrate that extendedinto surrounding adipose tissue. The tumor cells were small tomedium-sized with round nuclei, fine chromatin, inconspicu-ous nucleoli, and scant cytoplasm ❚Image 2A❚ and ❚Image 2B❚.Mitotic figures and apoptotic bodies were frequently noted.No FL or DLBCL was present in the specimen.

Immunohistochemical analysis showed the characteristicFL phenotype in the first biopsy specimen for the FL andDLBCL components: CD20+, CD3–, CD10+, CD79a+, bcl-2+,

TdT–, IgM+, and IgG+ ❚Image 1C❚, ❚Image 1D❚, ❚Image 1E❚,❚Image 1F❚, and ❚Table 1❚. In contrast, immunohistochemicalanalysis performed on the second biopsy specimen showedthe characteristic phenotype for PBC-LBL: CD20–, CD3–,CD43+, bcl-2+, TdT+ ❚Image 2C❚, ❚Image 2D❚, ❚Image 2E❚,and ❚Image 2F❚ (Table 1). Additional stains for immunoglob-ulin heavy chains showed PBC-LBL cells to be positive for µ(IgM) but negative for γ (IgG) heavy chain (Table 1).Immunostains for CD23 highlighted the follicular dendriticcell network in the first specimen, whereas no follicular den-dritic network structure was seen in the second biopsy speci-men. In situ hybridization for κ and λ light chains showed apolyclonal pattern of light chain expression in a few scatteredplasma cells that were largely distributed between the neoplas-tic follicles in the first biopsy specimen and peripheral regionsof the second PBC-LBL biopsy specimen.

Molecular Studies

PCR for the t(14;18)(q32;q21) translocation yielded clon-al bands of identical size in both specimens (data not shown).Direct sequence analysis of these PCR products revealed anidentical translocation breakpoint for the FL and the PBC-LBL, with both tumors using the immunoglobulin heavy-chain joining region (JH)6b, the identical N-sequence, and thesame breakpoint at the MBR ❚Figure 1❚.

FISH Analysis

FISH analysis was performed to evaluate the status ofbcl-2, bcl-6, c-myc, and TP53 genes, and the results are sum-marized in ❚Table 2❚. A bcl-2 gene translocation was identifiedin 80%, 80%, and 100% of the FL, DLBCL, and PBC-LBLtumor cells, respectively (P = .003). In addition, the PBC-LBLdemonstrated a c-myc gene rearrangement in 100% of thenuclei. This rearrangement was also present in the DLBCLcomponent of the initial biopsy specimen (64%) but did notmeet the threshold for positivity in the low-grade FL compo-nent (P < .001). Translocation of the bcl-6 gene or deletion ofTP53 was not observed, and FISH findings did not meet thethreshold for positivity in any of the FL, DLBCL, and LBLcomponents (P = .999 and P = .148, respectively).

Discussion

We report a rare case of PBC-LBL with a preceding FL.Transformation of FL to a high-grade lymphoid malignancyoccurs in 25% to 60% of cases and is associated with poorclinical outcome and treatment resistance.4-11,19-24,38 Thecurrent case of PBC-LBL developed during chemotherapyfor FL. To our knowledge, only 8 similar cases have beenreported in the literature ❚Table 3❚.10,21-24 All reported casesshowed a diffuse growth pattern in bone marrow or lymph

Hematopathology / ORIGINAL ARTICLE

Dow






A B

C D

E F

❚❚Image 1❚❚ Histologic and immunophenotypic findings of follicular lymphoma. A, Sections of lymph node showing scatteredneoplastic follicles with attenuated mantle zones (H&E, original magnification ×100). B, The nodules were composed of anadmixture of small cleaved centrocytes and centroblasts (H&E, original magnification ×400). C and D, Section showing CD20+tumor cells (C) compared with scattered CD3+ reactive T cells (D). E and F, Section showing tumor cells positive for bcl-2 (E)and negative for terminal deoxynucleotidyl transferase (F) (C-F, original magnification ×400).

Dow






A B

C D

E F

❚❚Image 2❚❚ Histologic and immunophenotypic findings of lymphoblastic lymphoma. A and B, Sections of lymph node showing adiffuse pattern of neoplastic lymphoid infiltrate composed of monotonous intermediate-sized cells with fine chromatin andinconspicuous nucleoli (H&E; A, original magnification ×400; B, original magnification ×1,000). C and D, Section showing scatteredCD3+ (D) and CD20+ (C, original magnification ×400) lymphoid cells, and the tumor cells are negative for CD3 and CD20. E and F,Section showing tumor cells positive for bcl-2 (E) and terminal deoxynucleotidyl transferase (F) (D-F, original magnification ×1,000).

Dow






node sections with typical lymphoblastic morphologic fea-tures. The cytologic features in these cases were character-ized by medium-sized nuclei, finely dispersed chromatin, andinconspicuous nucleoli. The interval from initial diagnosis to

lymphoblastic transformation ranged from early in the dis-ease course to 10 years. In 3 cases, there was earlierDLBCL transformation.21,24 In 4 cases, lymphoblasticleukemia developed, and in the other 4 cases extensive bonemarrow involvement by lymphoblastic lymphoma occurred.In 6 cases, Southern blot– or PCR-based molecular/sequence analysis was done for definitive confirmation ofrelated clonality, whereas the remaining 2 cases were eval-uated by immunohistochemical stain for TdT orblastic/blastoid morphologic features only.10,21,22,24 All 9cases (including the present case) showed bcl-2 proteinexpression, and 8 of these cases showed bcl-2 gene translo-cation. Of 9 transformed PBC-LBL cases, 8 contained thet(14;18)(q32;q21). One altered chromosome 8 (8q–) waspresent in 4 cases, and 1 altered chromosome 22 (22q–) inthe other 3 cases was present with either the classic or vari-ant c-myc gene translocation. Complex karyotypes withhighly atypical karyotypic abnormalities were found in 5cases (Table 3). The survival after initial diagnosis rangedfrom 0.75 to 9 months, with a median survival of 3 months,indicating very poor outcome for these patients in whomlymphoblastic transformation occurred.

❚Table 1❚Comparison of Immunophenotypic Findings in FollicularLymphoma and Precursor B-Cell Lymphoblastic Lymphoma

Follicular Lymphoma and Diffuse Large Lymphoblastic

Phenotype B-Cell Lymphoma Lymphoma

CD3 – –CD20 + –CD43 – +CD79a + –Terminal deoxynucleotidyl – +

transferasebcl-2 + +Myeloperoxidase – –IgH-γ (IgG) + –IgH-µ (IgM) + +IgH-α (IgA) – –IgH-δ (IgD) – –κ light chain* – –λ light chain* – –

* In situ hybridization.

CTGTTTCAAC

Nested bcl-2 primer

Germline

FL

PBC-LBL

Germline

N Sequence

Nested IgJH primer

IgJH6b gene

FL

PBC-LBL

Germline

FL

PBC-LBL

bcl-2 gene exon 3 (3,014-3,055 bp)

ACAGACCACC CAGAGCCCTC CTGCCCTCCT

T

GTC TGGGGCC AAGGGACCCT GCT

TGGAGCCCT CAAT ATTACT ACTACTACTA CGGTATGGAC

❚❚Figure 1❚❚ Nucleotide sequence comparison of bcl-2/JH fusion gene in follicular lymphoma (FL) and lymphoblastic lymphoma.The bcl-2/JH junctional sequence of FL and lymphoblastic lymphoma was amplified using the specific bcl-2 and immunoglobulin(Ig) JH primers. Nucleotide sequences from both specimens are aligned with the germline JH and bcl-2 sequences. Sequenceidentity is indicated by dashes; the arrows indicate the location of bcl-2 gene exon 3 (2992-3055 base pairs), the N sequence,and the IgJH 6b gene. The locations of nested bcl-2 and IgJH primers for amplification of the bcl-2/JH fusion gene are indicated.PBC-LBL, precursor B-cell lymphoblastic lymphoma.

Dow





In the present case, PCR analysis for bcl-2/IgH transloca-tion revealed identical bcl-2 and JH6b breakpoints and an iden-tical N-sequence. From the previously reported 8 cases, a clon-al relationship was inferred from 6 cases based on the presenceof a t(14;18)(q32;q21) in the PBC-LBL component,21-23

whereas in another 2 cases, the clonal relationship was pre-sumed on the basis of the similar sizes of the rearranged bandsin Southern blot analysis of the immunoglobulin heavy chainand bcl-2 rearrangements.10,24 The immunoglobulin VHDJHand light chain rearrangement analyses were performed onlyin 1 case, and results revealed the same rearrangement in bothtypes of tumor cells.24 This study indicates that FL and sub-sequent PBC-LBL are clonally related and the PBC-LBL

arises from clonal evolution of its preceding FL germinal cen-ter B cells that “dedifferentiate” into a lymphoblastic stage. Wedid not perform IgH CDR 3 analysis owing to unamplifiabili-ty by PCR, and origins of these 2 tumors from a commonimmature B-cell precursor that already had a rearranged bcl-2gene cannot be excluded.

Although several molecular events have been implicatedin the process of FL transformation, consistent cytogenetic andmolecular mechanisms underlying the transformation have notbeen identified. FLs undergoing transformation typically retainthe t(14;18)(q32;q21) translocation, and subsequent secondarygenetic abnormalities are believed to be important for the evo-lution of the disease.7,9,29,30 Several cytogenetic events have


❚Table 2❚Molecular Cytogenetic Abnormalities of bcl-2, bcl-6, TP53, and c-myc Genes Identified by Fluorescence In Situ HybridizationAnalysis in 50 Specimens

Follicular Diffuse Large B-Cell LymphoblasticGenes (Threshold of Abnormal Signals) Lymphoma Lymphoma Lymphoma P

bcl-2 gene translocation (>8%) 40 (80) 40 (80) 50 (100) .003bcl-6 gene translocation (>6%) 0 (0) 0 (0) 1 (2) .999TP53 gene deletion (>18%) 2 (4) 1 (2) 6 (12) .148c-myc gene translocation involving 8q24 (>10%) 4 (8) 32 (64) 50 (100) <.001

* Data are given as number (percentage) of abnormal signals.

❚Table 3❚Reported Cases of PBC–Lymphoblastic Lymphoma/Leukemia Transformed From Preceding FL

InitialLBL

Time to Cytogenetic Time to Death Reference/Case Assay for Diagnosis Clinical Findings in Addi- Treatment After Diag-No./Sex/Age (y) Manifestation Diagnosis t(14;18) Treatment (mo) Manifestations tion to t(14;18) After Diagnosis nosis (mo)

Gauwerky et al,21 19881/F/50 Hard palate FL-1 + Chem /RT 60 Pancytopenia; PB t(8;14) None 1

lesion and BM involvementDe Jong et al,10 1988

2/M/44 Generalized FL-1;PBC- + Chemo 0 Pancytopenia; PB t(8;14) None 3 LAD LBL (CHOP) and BM involvement

Thangavelu et al,22 19903/M/62 Cervical LAD FL-2 + RT 22 Pleural effusion; PB Complex with Chemo 4

and BM involvement t(8;14)4/M/64 Right inguinal FL-1 + Chemo/RT 108 Enlarged inguinal node; Complex with Chemo 1

LAD PB and BM involvement t(8;14)Fiedler et al,23 1991

5/M/68 LAD FL-2 + RT 4 Pancytopenia; PB and Complex with Chemo (CHOP, 4 BM involvement t(8;22) MTX, ARA-C)

6/F/59 LAD FL-2 + Chemo/RT 25 Pancytopenia; PB and Complex with Chemo (CHOP, 3 (CHOP) BM involvement t(8;22) MTX, ARA-C)

7/F/55 LAD FL-2 + Chemo 10 Pancytopenia; PB Complex with Chemo 0.75 (CHOP) and BM involvement t(8;22)

Kroft et al,24 20008/F/45 Inguinal LAD FL-1 – (by Chemo/RT 120 Right axillary mass with Negative for Combined 9

PCR) BM involvement c-myc (by chemo/RT/BMT Southern blot) (CHOP, CPX,

Present report ARA-C)9/F/59 Left subman- FL-2 with + Chemo 5 Enlarged cervical node Complex with Combined 8

dibular LAD DLBCL (CHOP) t(8;14) chemo/RT

ARA-C, cytarabine; BM, bone marrow; BMT, bone marrow transplantation; Chemo, chemotherapy; CHOP, cyclophosphamide, doxorubicin, vincristine, and prednisone; CPX,cyclophosphamide; DLBCL, diffuse large B-cell lymphoma; FL, follicular lymphoma (with grade); LAD, lymphadenopathy; LBL, lymphoblastic lymphoma; MTX,methotrexate; PB, peripheral blood; PBC, precursor B-cell; PCR, polymerase chain reaction; RT, radiation therapy.

Dow






been implicated in the pathogenesis of transformation, includ-ing a number of nonrandom chromosomal changes.7-9,12,13

These include gains in 2q, 6p, 7p, 12q, and 17q and losses in5p and 8q,9,39-41 c-myc gene rearrangement,11 TP53 gene muta-tions,30,31 bcl-6 gene mutations,17 and somatic mutations of thetranslocated bcl-2 gene.16 A recent gene expression profilingand comparative genomic hybridization study suggests thattransformed DLBCL can be delineated into 2 subsets based onexpression of c-myc–associated genes.18 However, the genom-ic imbalances are quite variable and heterogeneous, and somechanges have not been previously shown to be associated withhigh-grade transformation.17,18

The c-myc gene translocations [both t(8;14) and t(8;22)]have been associated with aggressive transformation of FL toDLBCL and LBL.42,43 Only approximately 8% of transformedDLBCL cases were reported to have c-myc gene aberrations,although the expression of c-myc protein was found to rangeup to 80% in FL-transformed DLBCL.44,45 Interestingly, 7 of 8previously described cases of transformed PBC-LBL werereported to have translocations involving 8q24.1 (c-myc genelocus) in addition to t(14;18)(q32;q21). Of these cases, t(8;14)was found in 4 cases and the variant t(8;22) in the other 3 cases.Rearrangements of c-myc are usually associated with Burkittlymphomas.46,47 Biologically, the c-myc protein normally hasa central role in the transcriptional regulation of a large set ofdownstream genes that control diverse cellular processes,including cell growth, cell cycle progression, and programmedcell death (apoptosis). Dysregulated expression of the c-mycgene causes cell growth and proliferation, but also inducesapoptotic cell death.48 Dysregulated c-myc expression, alongwith blockade of c-myc–induced death signaling (eg, by coex-pression of an antiapoptotic gene), is sufficient to inducemalignant transformation of cells in a variety of systems.49-51

There is a marked synergy between bcl-2 and c-myc indoubly transgenic mice with hyperproliferation of pre–B cellsand development of a highly malignant lymphoid precursortumor much faster than in Eµ-MYC mice.52 Studies on celllines confirmed that bcl-2 specifically abrogates c-myc–induced apoptosis, an activity that may partially explainthe synergism with c-myc in the development of lymphoidmalignancies.50,51,53 It is possible that a similar mechanismmay also occur in the human counterpart in that bcl-2–translo-cated PBCs may rarely acquire c-myc translocation (or othergenetic aberrations) and develop into PBC–acute lymphoblas-tic leukemia/LBL due to the synergistic effect of dual bcl-2and c-myc translocation.

Molecular identity/relatedness of the immunoglobulinVHDJH gene rearrangement for the FL and PBC-LBL lesionswas confirmed in a recent case study,24 suggesting that thePBC-LBL transformed from the preceding FL rather than froma precursor B cell. However, biologically, it remains difficult toenvision c-myc as a “second hit” that changes an FL cell from

a differentiated state to a precursor B-cell phenotype. Additionalchanges that reprogram cellular differentiation must have beenacquired. The other 7 reported cases in the literature have notshown clonal identity of the immunoglobulin VHDJH generearrangement in the FL and PBC-LBL lesions owing to tech-nical reasons or absence of suitable materials. The alternativepathway that the PBC-LBL arises from precursor B cells withtranslocated bcl-2 abnormality remains a possibility. Some ofthe PBCs may mature into germinal center B cells that subse-quently develop into FL, whereas others may remain undiffer-entiated and develop into PBC-LBL by acquiring a c-myctranslocation. In our case, the diffuse large B-cell componentand the LBL had c-myc translocations that may be in favor ofan interesting transformation event initiated by c-myc translo-cation that leads to different cellular differentiation resulting ina DLBCL and a PBC-LBL.

Our study demonstrates the presence of the same bcl-2/JH

translocation in the PBC-LBL and FL, suggesting that thetumors are clonally related and the PBC-LBL may arise fromits preceding FL. It remains possible that the PBC-LBL andFL may be alternatively derived from the common clonal pre-cursor B cell harboring the t(14;18)(q32;q21) translocation asthe primary genetic aberration. Patients with this type of trans-formation have a very poor clinical outcome and often haveextensive peripheral blood and bone marrow involvement.Clinical, morphologic, and immunophenotypic evaluation,along with molecular and cytogenetic studies, are necessary tofully characterize this type of case.

From the Departments of 1Pathology and Laboratory Medicine,Biostatistics and Medical Informatics, UW Paul P. CarboneComprehensive Cancer Center, University of Wisconsin School ofMedicine and Public Health, Madison; 2Pathology, CreightonUniversity Medical Center, Omaha, NE; and 3Pathology andMicrobiology and 4Center for Human Genetics, University ofNebraska Medical Center, Omaha.

Supported in part by US Public Health Service grantsCA36727 and CA84967 awarded by the National Cancer Institute,Department of Health and Human Services, Bethesda, MD.

Address reprint requests to Dr Young: Dept of Pathology andLaboratory Medicine, University of Wisconsin School of Medicineand Public Health, Madison, WI 53792-2472; or to Dr Chan:Dept of Pathology and Microbiology, University of NebraskaMedical Center, 983135 Nebraska Medical Center, Omaha, NE68198-3135.

Acknowledgments: We thank Anne Ratashak, Diane Pickering,Eric Haas, and Gregory Cochran for technical assistance.

References1. Warnke RA, Weiss LM, Chan JKC, et al. Malignant

lymphoma, follicular. In: Tumors of the Lymph Nodes andSpleen. Washington, DC: Armed Forces Institute of Pathology;1995:63-118. Atlas of Tumor Pathology; Third series, Fascicle14.

Dow





2. Harris NL, Jaffe ES, Diebold J, et al. World HealthOrganization Classification of Neoplastic Diseases of theHematopoietic and Lymphoid Tissues: report of the ClinicalAdvisory Committee Meeting. J Clin Oncol. 1999;17:3835-3849.

3. Nathwani BN, Harris NL, Weisenburger DD, et al. Follicularlymphoma. In: Jaffe ES, Harris NL, Stein H, et al, eds.Pathology and Genetics of Tumours of Haematopoietic andLymphoid Tissues. Lyon, France: IARC Press; 2001:162-167.World Health Organization Classification of Tumours.

4. Rohatiner A, Lister TA. Management of follicular lymphoma.Curr Opin Oncol. 1994;6:473-479.

5. Yuen AR, Kamel OW, Halpern J, et al. Long-term survivalafter histologic transformation of low-grade follicularlymphoma. J Clin Oncol. 1995;13:1726-1733.

6. Bastion Y, Sebban C, Berger F, et al. Incidence, predictivefactors, and outcome of lymphoma transformation in follicularlymphoma patients. J Clin Oncol. 1997;15:1587-1594.

7. Knutsen T. Cytogenetic mechanisms in the pathogenesis andprogression of follicular lymphoma. Cancer Surv. 1997;30:163-192.

8. Levine EG, Arthur DC, Frizzera G, et al. There are differencesin cytogenetic abnormalities among histologic subtypes of thenon-Hodgkin’s lymphomas. Blood. 1985;66:1414-1422.

9. Yunis JJ, Frizzera G, Oken MM, et al. Multiple recurrentgenomic defects in follicular lymphoma; a possible model forcancer. N Engl J Med. 1987;316:79-84.

10. De Jong D, Voetdijk BM, Beverstock GC, et al. Activation ofthe c-myc oncogene in a precursor-B-cell blast crisis of follicularlymphoma, presenting as composite lymphoma. N Engl J Med.1988;318:1373-1378.

11. Yano T, Jaffe ES, Longo DL, et al. MYC rearrangements inhistologically progressed follicular lymphomas. Blood.1992;80:758-767.

12. Tilly H, Rossi A, Stamatoullas A, et al. Prognostic value ofchromosomal abnormalities in follicular lymphoma. Blood.1994;84:1043-1049.

13. Raghoebier S, Broos L, Kramer MH, et al. Histologicalconversion of follicular lymphoma with structural alterationsof t(14;18) and immunoglobulin genes. Leukemia.1995;9:1748-1755.

14. Matolesy A, Casali P, Warnke RA, et al. Morphologictransformation of follicular lymphoma is associated withsomatic mutation of the translocated bcl-2 gene. Blood.1996;88:3937-3944.

15. Nomdedeu JF, Baiget M, Gaidano G, et al, p53 mutation on a case of blastic transformation of follicular lymphoma withdouble bcl-2 rearrangement (MBR and VCR). LeukLymphoma. 1998;29:595-605.

16. Pinyol M, Cobo F, Bea S, et al. p16(INK4a) gene inactivationby deletions, mutations, and hypermethylation is associatedwith transformed and aggressive variant of non-Hodgkin’slymphomas. Blood. 1998;91:2977-2984.

17. Lossos IS, Levy R. Higher-grade transformation of folliclecenter lymphoma is associated with somatic mutation of the 5'noncoding regulatory region of the bcl-6 gene. Blood.2000;96:635-639.

18. Martinez-Climent JA, Alizadeh AA, Segraves R, et al.Transformation of follicular lymphoma to diffuse large celllymphoma is associated with a heterogeneous set of DNA copynumber and gene expression alterations. Blood.2003;101:3109-3117.

19. Acker B, Hoppe RT, Colby TV, et al. Histologic conversion inthe non-Hodgkin’s lymphomas. J Clin Oncol. 1983;1:11-16.

20. Aventin A, Mecucci C, Guanyabens C, et al. Variant t(2;18)translocation in a Burkitt conversion of follicular lymphoma.Br J Haematol. 1990;74:367-369.

21. Gauwerky CE, Hoxie J, Nowell PC, et al. Pre-B-cell leukemiawith a t(8;14) and a t(14;18) translocation is preceded byfollicular lymphoma. Oncogene. 1988;2:431-435.

22. Thangavelu M, Olopade O, Beckman E, et al. Clinical,morphologic, and cytogenetic characteristics of patients withlymphoid malignancies characterized by botht(14;18)(q32;q21) and t(8;14)(q24;q32) or t(8;22)(q24;q11).Genes Chromosomes Cancer. 1990;2:147-158.

23. Fiedler W, Weh HJ, Zeller W, et al. Translocation (14;18) and (8;22) in three patients with acute leukemia/lymphomafollowing centrocytic/centroblastic non-Hodgkin’s lymphoma.Ann Hematol. 1991;63:282-287.

24. Kroft SH, Domiati-Saad R, Finn WG, et al. Precursor B-lymphoblastic transformation of grade I follicle centerlymphoma. Am J Clin Pathol. 2000;113:411-418.

25. Weiss LM, Warnke RA, Sklar J, et al. Molecular analysis ofthe t(14;18) chromosomal translocation in malignantlymphomas. N Engl J Med. 1987;317:1185-1189.

26. Pezzella F, Gatter KC, Mason DY, et al. Bcl-protein expressionin follicular lymphomas in absence of 14;18 translocation.Lancet. 1990;336:1510-1511.

27. Pezzella F, Ralfkiaer E, Gatter KC, et al. The 14;18 translocationin European cases of follicular lymphoma: comparison ofSouthern blotting and the polymerase chain reaction. Br JHaematol. 1990;76:58-64.

28. Pezzella F, Tse AG, Cordell JL, et al. Expression of the bcl-2oncogene protein is not specific for the 14;18 chromosomaltranslocation. Am J Pathol. 1990;137:225-232.

29. Tsujimoto Y, Cossman J, Jaffe E, et al. Involvement of the bcl-2gene in human follicular lymphoma. Science. 1985;228:1440-1443.

30. Tsujimoto Y, Gorham J, Cossman J, et al. The t(14;18)chromosome translocations involved in B-cell neoplasms resultfrom mistakes in VDJ joining. Science. 1985;229:1390-1393.

31. Lee JT, Innes DJ Jr, Williams ME. Sequential bcl-2 and c-myconcogene rearrangements associated with the clinicaltransformation of non-Hodgkin’s lymphoma. J Clin Invest.1989;84:1454-1459.

32. LoCoco F, Gaidano G, Louis DC, et al. p53 mutations areassociated with histologic transformation of follicularlymphoma. Blood. 1993;82:2289-2295.

33. Sander CA, Yano T, Clark HM, et al. p53 mutation isassociated with progression in follicular lymphomas. Blood.1993;82:1994-2004.

34. Pringle JH, Ruprai AK, Primrose L, et al. In situ hybridizationof immunoglobulin light chain mRNA in paraffin sectionsusing biotinylated or hapten-labelled oligonucleotide probes. J Pathol. 1990;162:197-207.

35. Ohno T, Stribley JA, Wu G, et al. Clonality in nodularlymphocyte-predominant Hodgkin’s disease. N Engl J Med.1997;337:459-465.

36. Wu GQ, Sharp JG, Wu G, et al. The detection of minimallymphoma by molecular and combined culture-molecularmethods. Br J Haematol. 1997;99:873-881.

37. Iqbal J, Sanger WG, Horsman DE, et al. BCL2 translocationdefines a unique tumor subset within the germinal centerB-cell-like diffuse large B-cell lymphoma. Am J Pathol.2004;165:159-166.

38. Horning SJ, Rosenberg SA. The natural history of initiallyuntreated low-grade non-Hodgkin’s lymphomas. N Engl J Med.1984;311:1471-1475.


Dow






39. Armitage JO, Sanger WG, Weisenburger DD, et al.Correlation of secondary cytogenetic abnormalities withhistologic appearance in non-Hodgkin’s lymphomas bearingt(14;18)(q32;q21). J Natl Cancer Inst. 1988;80:576-580.

40. Richardson ME, Chen QG, Filippa DA, et al. Intermediate- to high-grade histology of lymphomas carrying t(14;18) isassociated with additional nonrandom chromosome changes.Blood. 1987;70:444-447.

41. Hough RE, Goepel JR, Alcock HE, et al. Copy number gain at 12q12-14 may be important in the transformation fromfollicular lymphoma to diffuse large B cell lymphoma. Br JCancer. 2001;84:499-503.

42. Knezevich S, Ludkovski O, Salski C, et al. Concurrenttranslocation of BCL2 and MYC with a singleimmunoglobulin locus in high-grade B-cell lymphomas.Leukemia. 2005;19:659-663.

43. Hecht JL, Aster JC. Molecular biology of Burkitt’s lymphoma.J Clin Oncol. 2000;18:3707-3721.

44. Cooper K, Haffajee Z. bcl-2 and p53 protein expression infollicular lymphoma. J Pathol. 1997;182:307-310.

45. Nguyen PL, Zukerberg LR, Benedict WF, et al.Immunohistochemical detection of p53, bcl-2, andretinoblastoma proteins in follicular lymphoma. Am J ClinPathol. 1996;105:538-543.

46. Dalla-Favera R, Bregni M, Erikson J, et al. Human c-myconcogene is located on the region of chromosome 8 that istranslocated in Burkitt lymphoma cells. Proc Natl Acad Sci U S A. 1982;79:7824-7827.

47. Taub R, Kirsch I, Morton C, et al. Translocation of the c-mycgene into the immunoglobulin heavy chain locus in humanBurkitt lymphoma and murine plasmacytoma cells. Proc NatlAcad Sci U S A. 1982;79:7837-7841.

48. Thompson EB. The many roles of c-myc in apoptosis. AnnuRev Physiol. 1998;60:575-600.

49. Strasser A, Harris AW, Bath ML, et al. Novel primitivelymphoid tumours induced in transgenic mice by cooperationbetween myc and bcl-2. Nature. 1990;348:331-333.

50. Bissonnette RP, Echeverri F, Mahboubi A, et al. Apoptotic cell death induced by c-myc is inhibited by bcl-2. Nature.1992;359:552-554.

51. Fanidi A, Harrington EA, Evan GI. Cooperative interactionbetween c-myc and bcl-2 proto-oncogenes. Nature.1992;359:554-556.

52. Strasser A, Elefanty AG, Harris AW, et al. Progenitor tumoursfrom Eµ-bcl-2-myc transgenic mice have lymphomyeloiddifferentiation potential and reveal developmental differencesin cell survival. EMBO J. 1996;15:3823-3834.

53. Land H, Parada LF, Weinberg RA. Tumorigenic conversion of primary embryo fibroblasts requires at least two cooperatingoncogenes. Nature. 1983;304:596-602.

Dow



Transformation of Follicular Lymphoma to Precursor B-Cell ...

Documents

Transcript of Transformation of Follicular Lymphoma to Precursor B-Cell ...