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Blood, 1 August 2005, Vol. 106, No. 3, pp. 1037-1041. Prepublished online as a Blood First Edition Paper on April 21, 2005; DOI 10.1182/blood-2005-01-0004.
NEOPLASIA Nuclear expression of BCL10 or nuclear factor kappa B helps predict Helicobacter pyloriindependent status of low-grade gastric mucosaassociated lymphoid tissue lymphomas with or without t(11;18)(q21;q21)From the Departments of Oncology, Internal Medicine, and Pathology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei; Cancer Research Center, Graduate Institute of Clinical Medicine, and Graduate Institute of Microbiology, National Taiwan University College of Medicine, Taipei; Division of Cancer Research, National Health Research Institutes, Taipei; Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung; Department of Pathology, Taipei Medical University, Taipei; and Department of Internal Medicine, Far Eastern Memorial Hospital, Taipei, Taiwan.
The t(11;18)(q21;q21) translocation is a specific marker for Helicobacter pyloriindependent status of low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma. However, there are no reliable markers to predict tumor response to H pylori eradication in patients without t(11;18)(q21;q21). Nuclear expression of BCL10 and nuclear factor kappa B (NF- B) was recently found to be closely associated with H pyloriindependent status of the high-grade counterpart of gastric MALT lymphoma, which usually lacks t(11;18)(q21;q21). This study examined whether these 2 markers can also predict H pyloriindependent status of low-grade gastric MALT lymphomas without t(11; 18)(q21;q21). Sixty patients who underwent successful H pylori eradication for low-grade gastric MALT lymphomas were included. Forty-seven (78.3%) patients were negative for t(11;18)(q21;q21); among them, 36 (76.6%) were H pylori dependent and 11 (23.4%) were H pylori independent. Nuclear expression of BCL10 was significantly higher in H pyloriindependent than in H pyloridependent tumors (8 of 11 [72.7%] vs 3 of 36 [8.3%]; P < .001). Nuclear expression of NF- B was also significantly higher in H pyloriindependent than in H pyloridependent tumors (7 of 11 [63.6%] vs 3 of 36 [8.3%]; P < .001). Further, nuclear translocation of BCL10 and NF- B was observed in 12 of the 13 patients with t(11;18)(q21;q21), and all these 12 patients were H pylori independent. In summary, nuclear expression of BCL10 or NF- B is predictive of H pyloriindependent status of low-grade gastric MALT lymphoma with or without t(11;18)(q21; q21).
Gastric mucosaassociated lymphoid tissue (MALT) lymphoma represents the most common type of MALT lymphoma and is characterized by its close association with Helicobacter pylori infection.1,2 Eradication of H pylori by antibiotics cures approximately 70% of this tumor.3 Although t(11;18)(q21;q21) is one of the most important predictors of H pylori independence in low-grade gastric MALT lymphomas, only 50% to 70% of H pyloriindependent low-grade gastric MALT lymphomas harbor this genetic aberration.4-6 In other words, 30% to 50% of H pyloriindependent low-grade gastric MALT lymphomas have no reliable markers to predict their H pyloriindependent status. Therefore, identification of other easily detected molecular markers that can provide high sensitivity in predicting H pyloriindependent status of low-grade gastric MALT lymphomas without t(11;18)(q21;q21) is mandatory.
Several genetic changes are implicated in the development of gastric MALT lymphoma. One of the most important genetic aberrations, t(1;14)(p22;q32) juxtaposes the BCL10 gene of chromosome 1p to the immunoglobulin gene locus of chromosome 14q and results in strong expression of a truncated BCL10 protein in the nuclei and cytoplasm.7,8 However, most MALT lymphomas with BCL10 nuclear localization do not have genetic aberrations of t(1;14)(p22;q32) or other BCL10 gene mutations.9-12 Surprisingly, BCL10 nuclear expression was found to be more closely associated with the genetic aberration t(11;18)(q21;q21), which is a specific marker for H pylori independence of low-grade gastric MALT lymphoma.13 In B lymphocyte, BCL10 is an intracellular protein that positively regulates lymphocyte proliferation by linking antigen receptor stimulation to activate nuclear kappa factor B (NF-
Recently, we demonstrated that a substantial portion of high-grade gastric MALT lymphomas remain H pylori dependent and can be cured by H pylori eradication.18 We also clarified that nuclear translocation of BCL10 or NF-
In this study, we analyzed the genetic aberration of t(11;18)(q21; q21) and the expression patterns of BCL10 and NF-
Patients, treatment, and evaluation of tumors Sixty patients who had participated in a prospective study of H pylori eradication for localized low-grade gastric MALT lymphomas and had subsequently had their gastric H pylori infection eradicated, as defined by negative results for biopsy urease test, histology, and bacterial culture, were included in this study. The diagnosis of low-grade gastric MALT lymphoma was made according to the histologic criteria described by Chan et al.22 Tumors were characterized by the presence of predominantly low-grade centrocytelike cell infiltrates and lymphoepithelial lesions and the absence of confluent clusters or sheets of large cells resembling centroblasts or lymphoblasts and of predominantly high-grade lymphoma cells. Histopathologic characteristics of all tumor specimens were independently reviewed by 2 experienced hematopathologists. Staging was classified according to Musshoff's modification of the Ann Arbor staging system.23 At the beginning of the study, the H pylori eradication regimen consisted of amoxicillin 500 mg and metronidazole 250 mg 4 times a day with either bismuth subcitrate 120 mg 4 times a day or omeprazole 20 mg twice a day for 4 weeks, but it was changed after March 1996 to amoxicillin 500 mg 4 times a day, clarithromycin 500 mg twice a day, and omeprazole 20 mg twice a day for 2 weeks. Patients were scheduled to undergo first follow-up upper gastrointestinal endoscopic examination 4 to 6 weeks after the completion of antimicrobial therapy, and follow-up was then repeated every 6 to 12 weeks until histologic evidence of remission was found. At each follow-up examination, 4 to 6 biopsy specimens were taken from the antrum and body of the stomach for the evaluation of H pylori infection, and a minimum of 6 biopsy specimens were taken from each of the tumors and suspicious areas for histologic evaluation. Diagnosis of H pylori infection was based on histologic examination, biopsy urease test, and bacterial culture. Tumor regression after eradication therapy was histologically evaluated according to the criteria of Wotherspoon et al.24 Tumors that resolved to Wotherspoon grade 2 or less after successful H pylori eradication were considered H pylori dependent. Tumors that had objective evidence of progression any time during follow-up or tumors that failed to show histologic regression 12 months after successful H pylori eradication were considered H pylori independent.5 The Institutional Review Board at National Taiwan University Hospital approved the prospective clinical trial, the pathologic review, and the genetic studies of archived tumor tissues. Informed consent was provided according to the Declaration of Helsinki. Immunohistochemistry and confocal laser scanning microscopy
Formalin-fixed, paraffin-embedded sections cut at a thickness of 4 µm were deparaffinized and rehydrated through xylenes and a graded alcohol series. After antigen retrieval by heat treatment in 0.1 M citrate buffer at pH 6.0, endogenous peroxidase activity was blocked by 3% H2O2. Briefly, slides were incubated for 30 minutes in 2.5% normal donkey serum or goat serum. The slides were then incubated overnight at 4°C either with polyclonal goat antihuman BCL10 (1:10; sc-9560; Santa Cruz Biotechnology, Santa Cruz, CA) or polyclonal rabbit antihuman RelA (p65; 1:100; sc-7151; Santa Cruz Biotechnology) and were incubated with secondary antibodies (BCL10, donkey antigoat immunoglobulin; RelA, goat antirabbit immunoglobulin; Santa Cruz Biotechnology) according to the manufacturer's instructions. Finally, antibody binding was detected by the avidin-biotin-peroxidase method. Reaction products were developed using 3', 5'-diaminobenzidine (DAKO, Glostrup, Denmark) as a substrate for peroxidase. Sections were counterstained with Mayer hematoxylin. All washes were performed in phosphate-buffered saline (pH 7.4). Staining was considered positive for BCL10 or NF- For double-immunolabeling studies, fluorescein isothiocyanate-labeled donkey antigoat immunoglobulin G (IgG) or rhodamine-labeled goat antirabbit IgG was incubated as a secondary antibody for 60 minutes at room temperature in the dark. The sections were further evaluated under a confocal laser-scanning microscope (model TC-SP; Leica, Heidelberg, Germany) equipped with argon and argon-krypton laser sources. Multiplex reverse transcriptionpolymerase chain reaction for the API2-MALT1 fusion transcript Total cellular RNA was extracted from formalin-fixed, paraffin-embedded tissues using an Ambion RNA isolation kit (AMS Biotechnology, Oxon, United Kingdom). Briefly, 2 to 3 pieces of 10-µm paraffin sections were deparaffinized in xylene. The tissue was digested with proteinase K (Roche Diagnostics, Mannheim, Germany) for 1 hour at 45°C and solubilized in a guanidinium-based buffer. RNA extracted from the paraffin-embedded tissues was analyzed for API2-MALT1 fusion using multiplex reverse transcriptionpolymerase chain reaction (RT-PCR) as described previously.21 RNA was subjected to first-round multiplex 1-tube RT-PCR, then to second-round nested multiplex PCRs (3 parallel: second PCR-A, second PCR-B, and second PCR-C). The final PCR products were run on 3% agarose gel and stained with ethidium bromide. The band size ranged from 80 to 179 bp. PCR of low-grade gastric MALT lymphoma samples known to possess API2-MALT1 fusion was used as a positive control. Beta-actin (190 bp) was amplified in parallel as an internal control. Where indicated, PCR products of the API2-MALT1 transcript were directly sequenced or were cloned into a vector (TOPO TA Cloning Kit; Invitrogen, Paisley, United Kingdom) and sequenced with vector primers using dye-labeled terminators (BigDye Terminators; Applied Biosystems, Foster City, CA) and analyzed on a DNA sequencer (model 310; Applied Biosystems). Statistical analysis
Fisher exact test and the
Patients and tumor response to H pylori eradication Thirty-seven patients were H pylori dependent, and 23 patients had H pyloriindependent tumors. Clinicopathologic features of these patients and their tumor responses to H pylori eradication are summarized in Table 1. The median duration between H pylori eradication and complete histologic remission was 2.6 months (range, 0.9-17 months), and 34 of 37 (91.9%) patients did so within 12 months of H pylori eradication. The median duration between H pylori eradication and commencement of other treatments for the 23 H pyloriindependent patients was 13 months (range, 4-27 months). Eight patients who had persistent or increasing epigastric discomfort and endoscopically or pathologically documented progressive tumors during regular follow-up were considered H pylori independent and were started with salvage treatments within 12 months of H pylori eradication. At a median follow-up of 69.2 months (range, 12-124 months), 35 patients who had achieved complete histologic remission after eradication of H pylori were alive and free of lymphoma. Two patients experienced histologic relapse.
API2-MALT1 fusion transcript of t(11;18)(q21;q21) The API2-MALT1 fusion transcript for t(11;18)(q21;q21) was detected in 13 (21.7%) patients (Figure 1). Sequencing analysis of the RT-PCR products confirmed the presence of API2-MALT1 fusion transcript in all 13 patients, and the characteristics of all API2-MALT1 fusion variants were in keeping with those reported previously.21
Correlation of nuclear expression of BCL10 and NF- B with tumor response to H pylori eradication in low-grade gastric MALT lymphoma without t(11;18)(q21;q21)
Among the 47 patients without t(11;18)(q21;q21), the frequency of nuclear expression of BCL10 was significantly higher in H pyloriindependent than in H pyloridependent tumors (8 of 11 [72.7%] vs 3 of 36 [8.3%]; P < .001) (Table 1; Figure 2). The frequency of nuclear expression of NF-
Correlation of nuclear expression of BCL10 and NF-
As expected, 12 (92.3%) of the 13 patients with t(11;18)(q21;q21) had H pyloriindependent lymphoma. The MALT lymphoma of all these 12 patients had nuclear translocation of both BCL10 and NF-
Correlation of nuclear expression of BCL10 and NF- B with tumor response to H pylori eradication in all patients with low-grade gastric MALT lymphoma
As a single variable, the frequency of nuclear expression of BCL10 was significantly higher in H pyloriindependent than in H pyloridependent tumors (20 of 23 [86.9%] vs 3 of 37 [8.1%]; P < .001). The frequency of nuclear expression of NF-
In this study, we demonstrated that nuclear expression of BCL10 and nuclear expression of NF- B are 2 highly useful markers for predicting the H pyloriindependent status of low-grade gastric MALT lymphomas with or without t(11;18)(q21;q21). t(11;18)(q21;21) results in the expression of a chimeric protein with the amino terminal of the API2 fusing the carboxyl terminal MALT125 and is closely associated with the H pyloriindependent state of low-grade gastric MALT lymphoma.4,5 In a large retrospective study, t(11;18)(q21;21) was detected in 60% of stage IE H pyloriindependent low-grade gastric MALT lymphomas.5 These results are in line with our observation that t(11;18)(q21;21) was found in only half of H pyloriindependent, early-stage low-grade gastric MALT lymphomas. For the other half of H pyloriindependent tumors, other predictive markers should be pursued.
In our previous studies, we showed that nuclear translocation and coexpression of BCL10 and NF-
Nuclear translocation of BCL10 and NF-
This study did not examine other rare genetic aberrations that may relate to nuclear BCL10 expression. However, several recent studies detected t(1;14)(p22;q32) in less than 5% of low-grade MALT lymphomas.9,31 Indeed, 30% to 40% of gastric MALT lymphomas lacking both t(11;18)(q21;q21) and t(1; 14)(p22;q32) showed a moderate degree of nuclear expression of BCL10.31 Moreover, a recent study of 71 patients with gastric MALT lymphoma found that none harbored t(1;14)(p22;32),32 suggesting that the latter genetic aberration is so rare that it may not be useful as a predictor. Because immunohistochemical staining for detection of BCL10 or NF-
Submitted January 13, 2005; accepted March 31, 2005.
Prepublished online as Blood First Edition Paper, April 21, 2005; DOI 10.1182/blood-2005-01-0004.
Supported by research grants NSC91-3112-B-002-009, NSC92-3112-B-002-027, and NSC93-3112-B-002-007 from the National Science Council; NHRI-CN-CA9201S, 92A084, and 93A059 from the National Health Research Institutes; and NTUH 93-N012 and NTUH 94S155 from National Taiwan University Hospital, Taiwan.
The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked "advertisement" in accordance with 18 U.S.C. section 1734.
Reprints: Ann-Lii Cheng, Department of Internal Medicine and Department of Oncology, National Taiwan University Hospital, No. 7, Chung-Shan S Rd, Taipei, Taiwan; e-mail: andrew{at}ha.mc.ntu.edu.tw; and Li-Tzong Chen, Division of Cancer Research, National Health Research Institutes, Taipei, Taiwan; e-mail: leochen{at}nhri.org.tw.
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