Primary Plasma Cell Leukemia Associated with t(6;14)(p21;q32) and IGH Rearrangement: A Case Study and Review of the Literature

Transcription

1 Annals of Clinical & Laboratory Science, vol. 41, no. 3, 2011 Available online at Primary Plasma Cell Leukemia Associated with t(6;14)(p21;q32) and IGH Rearrangement: A Case Study and Review of the Literature 277 Sun Young Cho 1, Gayoung Lim 1, Seung Hwan Oh 2, Hee Joo Lee 1, Jin-Tae Suh 1, Juhie Lee 3, Woo-In Lee 1, Hong Ghi Lee 4, Hwi-Joong Yoon 5, and Tae Sung Park 1 Departments of 1Laboratory Medicine, 3Pathology, and 5Hematology-Oncology, School of Medicine, Kyung Hee University, Seoul; 2Department of Laboratory Medicine, Inje University College of Medicine, Busan; 4Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Korea Abstract. Because plasma cell leukemia (PCL) is a rare and distinct variant among plasma cell dyscrasias, recent clinical and cytogenetic studies have been performed in different ethnic groups to define the characteristics of these PCL patients. As far as we know, IGH rearrangements involving t(11;14) and (14;16) are significantly more frequent in PCL than in myeloma patients. However, PCL cases associated with t(6;14)(p21;q32) or IGH-CCND3 rearrangement are extremely rare in the literature; only one PCL case with t(6;14) has been documented. A 61-year-old female was admitted due to fatigue, weight loss, and exertional dyspnea. Plasmacytoid cells were counted up to 76% at a peripheral blood film, but bone marrow aspiration failed because of dry-tapping. Flow cytometric analysis showed positive for CD138 and cytoplasmic kappa light chain. Chromosome analysis revealed t(6;14)(p21;q32), which was confirmed by an IGH split-out probe in FISH analysis. Immunofixation electrophoresis also presented monoclonal bands identified as IgG and kappa light chain. Finally, she was diagnosed as primary PCL associated with t(6;14) and IGH rearrangement. Although considerable advances have been made in the understanding of the biology and molecular pathogenesis of PCL, further clinical, laboratory, and genetic studies of PCL associated with such a rare IGH rearrangement would be necessary in the future. To the best of our knowledge, this is the first report of PCL associated with t(6;14) as a sole chromosomal abnormality. Introduction Plasma cell myeloma (PCM) is a malignant disorder characterized by the proliferation of a single clone of a plasma cell, originating from a bone marrow B cell [1, 2]. According to the new 2008 World Health Organization (WHO) classification, the criteria for the differential diagnosis of plasma cell neoplasm includes monoclonal gammopathy of undetermined significance (MGUS), plasma cell myeloma, plasmacytoma, and monoclonal immunoglobulin deposit disease [1]. Plasma cell leukemia (PCL) is a rare lymphoproliferative disorder, Address correspondence to Tae Sung Park, M.D., Ph.D., Department of Laboratory Medicine, School of Medicine, Kyung Hee University, 1 Hoegi-dong, Dongdaemun-gu, Seoul , Korea; tel ; fax ; s 153jesus@hanmail.net or 153jesus@khmc.or.kr; or to Hwi-Joong Yoon, M.D., Ph.D., School of Medicine, Kyung Hee University; 1 Hoegi-dong, Dongdaemun-gu, Seoul , Korea; tel ; fax ; e mail address: hwijyoon@medimail.co.kr accounting for 1-2% of all plasma cell neoplasms [3]. Diagnostic criteria for PCL were previously suggested by Kyle et al. on the basis of plasma cell counts in peripheral blood (> cells/l or a plasma cell population accounting for >20% of the total peripheral leukocyte population) [4]. Although immunoglobulin heavy chain gene (IGH) rearrangements are primarily considered to be an initial event in the pathogenesis of PCM, the overall detection rate for 14q32 translocations increases significantly with disease progression, reaching up to 90% in advanced tumors and human myeloma cell lines [5]. Chromosomal regions/genes that act as translocation partners for 14q32 (IGH) in PCM include 4p16 (FGFR3, WHSC1), 4p13 (ARHH), 6p23-25 (IRF4), 6p21 (CCND3), 8q24 (c-myc), 11q13 (CCND1), 16q23 (MAF), 18q21 (BCL2), and 20q11-13 (MAFB). Of the IGH-related rearrangements identified, t(6;14)(p21;q32) has been /11/ by the Association of Clinical Scientists, Inc.

2 278 Annals of Clinical & Laboratory Science, vol. 41, no. 3, 2011 Figure 1. Peripheral blood (PB) and bone marrow (BM) aspiration smears. PB (A, x1000) and BM touch imprints (B, x200 and C, x1000) showing atypical plasmacytoid lymphocytes and immature cells. A biopsy section (D, x200) revealed the bone marrow to be packed with leukemic cells. reported in 2-5% of PCM cases [5,6]. In contrast, cases of PCL involving t(6;14) are extremely rare. In this study, we present only the second case of PCL associated with t(6;14) and IGH rearrangement. We also provide a brief review of the literature. Materials and Methods Chromosomes were prepared from 24-hour unstimulated bone marrow culture. Standard procedures for cultures, harvests, and slide preparation were modified and performed in our laboratory. Chromosomes were analyzed with GTG-banding, and the karyotypes were Figure 2. Chromosome analysis. A t(6;14)(p21;q32) translocation was identified. Full karyogram (A), partial karyogram (B) and ideogram (C). described in accordance with International System for Human Cytogenetic Nomenclature (ISCN) FISH analysis was performed according to the manufacturer s instructions with commercially available FISH probes (IGH split-out probe, Abbott Molecular/ Vysis Des Plaines, IL). Under fluorescence microscopy, at least 200 interphase cells were scored for signal patterns. Clinical presentation A 61-year-old Caucasian female was admitted to Kyung Hee University Medical Center with a 1-month history of fatigue, weight loss, and exertional dyspnea. An initial complete blood count (CBC) revealed a hemoglobin (Hb) level of 6.7 g/dl (reference range g/dl), a platelet count of /L (reference range /L), and a white blood cell (WBC) count of /L (reference range /L), comprising 76% atypical cells (plasmacytoid cells), 13% segmented neutrophils, 6% monocytes, 2% eosinophils, 1% myelocytes, and 2% immature cells. Additionally, there were three normoblasts per 100 WBCs (3nRBCs/100WBCs). An abdominal CT scan revealed hepatosplenomegaly. Attempts to perform bone marrow (BM) aspirations to obtain samples for morphological examination failed due to the BM being packed with leukemic cells. Analysis of touch imprints and biopsy sections revealed a packed BM, with plasma cells with eccentric nuclei and perinuclear hofs accounting for 95.2% of all nucleated cells (Figure 1). The results of flow cytometric analysis (positive for CD138 [intermediate], CD56 [dim], and cytoplasmic kappa light chain [intermediate]; negative for CD45, TdT, CD10, CD19, CD20, CD22, CD3, CD5, CD4, and CD8) were consistent with the presence of clonal plasma cells. Chromosome analysis revealed a 46,XX,t(6;14)(p21;q32) karyotype in 19 of 26 metaphase cells analyzed (Figure 2). FISH signals (peripheral blood, PB) from an IGH split-out probe indicated nuc ish(igh 2)(5 IGH sep 3 IGH 1)[62/207] (Figure 3). Gel electrophoresis and protein staining revealed the presence of a monoclonal protein in the gamma region. Immunofixation electrophoresis confirmed the presence of two bands of

3 Primary plasma cell leukemia associated with t(6;14)(p21; q32) 279 Figure 3. Fluorescent in situ hybridization analysis. FISH analysis using an IGH split-out probe indicated the presence of nuc ish(igh 2) (5 IGH sep 3 IGH 1) [62/207] at diagnosis. One green signal (1), two red signals (2) and one fusion signal (3) were detected. These FISH signal patterns are consistent with the karyotyping data. restricted mobility in the gamma region, subsequently identified as IgG and kappa light chain (Figure 4).The patient was diagnosed with PCL, and referred to Konkuk University Hospital, where chemotherapy (VAD regimen, vincristine + adriamycin + dexamethasone) was conducted. Subsequently, the patient received autologous peripheral blood stem cell transplantation (PBSCT) on two separate occasions following 6 cycles of VAD regimen and maintained complete remission during follow-up. After the latest PBSCT, the patient is scheduled to receive 200 mg thalidomide daily, as well as 40 mg dexamethasone for 4 days per month for the following 2 years. Discussion Dysregulation of oncogenes by translocation near a strong enhancer in an Ig heavy chain (IGH) (14q32) or Ig light chain (kappa 2p11 or lambda 22q11) gene is a key event in the pathogenesis of B-lymphocyte tumors [7]. FISH studies have demonstrated that translocations involving IGH (14q32) are the major chromosomal abnormalities in PCM [8]. The three most frequent partner loci in these IGH-related rearrangements are 4p16.3 (FGFR3 and MMSET), 11q23 (CCND1), and 16q23 (MAF) [7, 9]. IGH rearrangements involving t(6;14)(p21;q32) are relatively rare in PCM, occurring in approximately 3-5% of cases. In a balanced chromosomal translocation, the IGH gene on the long arm of chromosome 14 (14q32) juxtaposes with the CCND3 gene on the short arm of chromosome 6 (6p21), resulting in an IGH- CCND3 rearrangement (juxtaposition). t(6;14) have also been reported in other mature B-cell malignancies, such as diffuse large B-cell lymphoma, splenic marginal zone lymphoma and mantle cell lymphoma [10-12]. Although the t(6;14) translocation was first described in a patient with PCL, this chromosomal abnormality is extremely rare in PCL [13,14]. A thorough review of the Mitelman database and the literature did not reveal any additional case of PCL associated with t(6;14) translocation [13-24] (Tables 1 and 2). Table 1 shows a detailed comparison of the present case with the previous case of PCL involving t(6;14) translocation [13,14]. CCND proteins interact with CCND-dependent kinases, which phosphorylate and inactivate retinoblastoma protein (Rb), thereby facilitating the G1/S phase transition [9]. Despite differences in Figure 4. Results of gel electrophoresis performed at diagnosis. (A) Electrophoretic analysis of serum protein revealed monoclonal gammopathy in the gamma region (horizontal arrow). (B) Immunofixation electrophoresis (IFE) confirmed the presence of two restriction bands in the gamma region, which were subsequently identified as IgG and kappa light chain (vertical arrows). Each IFE lane was treated with antisera that bound individual Ig heavy chains (IgG, IgA and IgM) or free light chains (kappa and lambda). expression patterns and in certain functional properties, it has been reported that CCND1, CCND2, and CCND3 are virtually

4 280 Annals of Clinical & Laboratory Science, vol. 41, no. 3, 2011 Table 1. Reported cases of plasma cell leukemia with t(6;14)(p21;q32). Case No.1 Case No.2 Diagnosis PCL PCL Age (yr) Sex F F Karyotype 46,XX,t(6;14)(p12orp21;q32),del(1)(p13)/45,X,-X, 46,XX, t(6;14)(p21;q32) t(2;6)(6;14)(q23;q13)(p12orp21;q32) del(1)(p13) [19]/46,XX[7] Hb (g/dl) WBC (109/L ) PLT (109/L ) Plasma cell % in PB Plasma cell % in BM NA 95.2 M-component Non-producer type IgG, Kappa References [13,14] present case F, female; PCL, plasma cell leukemia; Hb, hemoglobin; WBC, white blood cell; PLT, platelet; PB, peripheral blood; BM, bone marrow; NA, not available interchangeable in terms of their ability to regulate phosphorylation [7]. The CCND3 gene is located approximately 65 kb telomeric to the breakpoint at 6p21 and has been suggested to be a candidate oncogene [9]. Like CCND1, which is already widely used as a mantle cell lymphoma marker, unregulated CCND3 expression would be expected to promote cellular proliferation, especially in B-cell lineages [1, 9]. The retrospective nature of the present study and lack of adequate specimens at the time of diagnosis of PCL prevented us from further evaluating the IGH-CCND3 rearrangement. However, we feel that concomitant t(6;14) and IGH rearrangement (break apart FISH analysis) suggest the presence of IGH-CCND3 rearrangement in our patient. Nevertheless, the possibility that another novel partner gene exists at this locus (6p21) cannot be excluded. Interestingly, while the plasmacytoid cell count on PB smear was 76%, FISH analysis with IGH split-out probe showed a 30% positive ratio with the same PB specimen. This suggested a meaningful difference in the number of clonal plasma cell between the two test results. Therefore, the authors conducted another review of PB films and observed two populations that showed a typical appearance of a plasma cell and a mature lymphocytic feature, respectively. Such a morphological variety may have caused the

5 Primary plasma cell leukemia associated with t(6;14)(p21; q32) 281 discrepancy to a certain degree as well. However, both the BM morphology and FISH data were consistent with the diagnosis of PCL. Although considerable advances in our understanding of the biology and molecular pathogenesis of PCM and PCL have been made, further clinical, laboratory, and genetic studies of t(6;14) are necessary. Additionally, we believe that further investigations would help to estimate the frequency of t(6;14)/ IGH-CCND3 rearrangement in PCL in different ethnic groups, and to evaluate treatment responses, prognosis and survival in PCL patients with such a rare IGH rearrangement. Acknowledgements This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology ( ). References 1. Jaffe ES, Harris NL, Stein H,VardimanJW, editors.world Health Organization classification of tumours. Pathology and genetics. Tumours of haematopoietic and lymphoid tissues. Lyon, France: IARC Press; Lloveras E, Solé F, Espinet B, Besses C, Asensio A, Abella E, Woessner S, Florensa L.Cytogenetic and fluorescence in situ hybridization studies in four cases of plasma cell leukemia. Cancer Genet cytogenet 2000;121: Jimenez-Zepeda VH, Dominguez-Martinez VJ. Plasma cell leukemia: a highly aggressive monoclonal gammopathy with a very poor prognosis.int J Hematol 2009;89: Jiménez-Zepeda VH, Domínguez VJ. Plasma cell leukemia: a rare condition. Ann Hematol 2006;85: Naeim F, Rao PN, Grody WW, editors.hematology; Morphology, Immunophenotype, Cytogenetics and Molecular Approches. San Diego, USA: Elsevier; Gabrea A, Martelli ML, Qi Y, Roschke A, Barlogie B, Shaughnessy JD Jr, Sawyer JR, Kuehl WM. Secondary genomic rearrangements involving immunoglobulin or MYC loci show similar prevalences in hyperdiploid and nonhyperdiploid myeloma tumors. Gene Chromosomes Cancer 2008;47: Shaughnessy J Jr, Gabrea A, Qi Y, Brents L, Zhan F, Tian E, Sawyer J, Barlogie B, Bergsagel PL, Kuehl M. Cyclin D3 at 6p21 is dysregulated by recurrent chromosomal translocations to immunoglobulin loci in multiple myeloma. Blood 2001;98: Heim S, Mitelman F, editors. Cancer cytogenetics. New Jersey, USA: Wiley-Blackwell; Joy Ho P. Chromosomal and genetic abnormalities in myeloma. Clin Lab Haematol 2002;24: Shaughnessy Jr J, Gabrea A, Qi Y, Brents L, Zhan F, Tian E, Sawyer J, Barlogie B, Bergsagel PL, Kuehl M. Cyclin D3 at 6p21 is dysregulated by recurrent chromosomal translocations to immunoglobulin loci in multiple myeloma. Blood 2001;98: Sonoki T, Harder L, Horsman DE, Karran L, Taniguchi I, Willis TG, Gesk S, Steinemann D, Zucca E, Schlegelberger B, Solé F, Mungall AJ, Gascoyne RD, Siebert R, Dyer MJ. Cyclin D3 is a target gene of t(6;14)(p21.1;q32. 3) of mature B-cell malignancies. Blood 2001;98: Wlodarska I, Dierickx D, Vanhentenrijk V, Van Roosbroeck K, Pospisilova H, Minnei F, Verhoef G, Thomas J, Vandenberghe P, De Wolf-Peeters C. Translocations targeting CCND2, CCND3, and MYCN do occur in t(11;14)-negative mantle cell lymphomas. Blood 2008;111: Tominaga N, Katagiri S, Hamaguchi Y, Nishiura T, Kanakura Y, Kanayama Y, Nagao K, Kakiuchi Y, Nishida K, Abe T, Honzo T, Yonezawa T, Tarui S. Plasma cell leukaemia of nonproducer type with missing light chain gene rearrangement. Br J Haematol 1988;69: Nishida K, Taniwaki M, Misawa S, Abe T. Nonrandom rearrangement of chromosome 14 at band q32.33 in human lymphoid malignancies with mature B-cell phenotype. Cancer Res 1989;49: Tiedemann RE, Gonzalez-Paz N, Kyle RA, Santana-Davila R, Price-Troska T, Van Wier SA, Chng WJ, Ketterling RP, Gertz MA, Henderson K, Greipp PR, Dispenzieri A, Lacy MQ, Rajkumar SV, Bergsagel PL, Stewart AK, Fonseca R. Genetic aberrations and survival in plasma cell leukemia. Leukemia 2008;22: Avet-Loiseau H, Daviet A, Brigaudeau C, Callet-Bauchu E, Terré C, Lafage-Pochitaloff M, Désangles F, Ramond S, Talmant P, Bataille R. Cytogenetic, interphase, and multicolor fluorescence in situ hybridization analyses in primary plasma cell leukemia: a study of 40 patients at diagnosis, on behalf of the Intergroupe Francophone du Myélome and the Groupe Français de Cytogénétique Hématologique. Blood 2001;97: Peijing Q, Yan X, Yafei W, Dehui Z, Zengjun L, Junyuan Q, Yaozhong Z, Lugui Q. A retrospective analysis of thirty-one cases of plasma cell leukemia from a single center in China. Acta Haematol 2009;121: Colović M, Janković G, Suvajdzić N, Milić N, Dordević V, Janković S. Thirty patients with primary plasma cell leukemia: a single center experience.med Oncol 2008;25: García-Sanz R, Orfão A, González M, Tabernero MD, Bladé J, Moro MJ, Fernández-Calvo J, Sanz MA, Pérez-Simón JA, Rasillo A, Miguel JF. Primary plasma cell leukemia: clinical, immunophenotypic, DNA ploidy, and cytogenetic characteristics. Blood 1999;93: Avet-Loiseau H, Li JY, Facon T, Brigaudeau C, Morineau N, Maloisel F, Rapp MJ, Talmant P, Trimoreau F, Jaccard A, Harousseau JL, Bataille R. High incidence of translocations t(11;14)(q13;q32) and t(4;14)(p16;q32) in patients with plasma cell malignancies. Cancer Res 1998;58: Chiecchio L, Dagrada GP, White HE, Towsend MR, Protheroe RK, Cheung KL, Stockley DM, Orchard KH, Cross NC, Harrison CJ, Ross FM; UK Myeloma Forum. Frequent upregulation of MYC in plasma cell leukemia. Genes Chromosomes Cancer 2009;48: Jiménez-Zepeda VH, Domínguez VJ. Plasma cell leukemia: a rare condition. Ann Hematol 2006;85: Dimopoulos MA, Palumbo A, Delasalle KB, Alexanian R. Primary plasma cell leukaemia. Br J Haematol 1994;88: Noel P, Kyle RA. Plasma cell leukemia: an evaluation of response to therapy. Am J Med 1987;83: