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Patients with autoimmune diseases (AIDs) may develop lymphoproliferative disorders (LPDs) during treatment with immunosuppressive agents (IS) such as methotrexate (MTX), biological agents, or tacrolimus. Some LPDs in patients with AIDs (AID-LPDs) regress after withdrawal of IS, and a high incidence of Epstein-Barr virus (EBV) positivity in such patients has been reported. To identify characteristics and factors predictive of the response to treatment and disease progression, we retrospectively analyzed clinical and histopathological data for 81 patients with AID-LPDs. Almost all of them (96%) had been treated with MTX. Diffuse large B cell lymphoma was the most common LPD type (61%) and seven patients (9%) had classical Hodgkin lymphoma (CHL). EBV was detected by in situ hybridization with an EBV-encoded small RNA (EBER) probe in 43% of the examined cases. In 59 patients, IS was discontinued as the initial treatment, resulting in regression of LPDs in 69% of them, and multivariate analysis showed that EBER positivity was an independent factor predictive of such regression (p = 0.022). Two-year progression-free survival (PFS) and overall survival for the patients overall were 63% and 83%, respectively. Poor PFS was associated with advanced stage (p = 0.024), worse performance status (PS, p = 0.031), CHL histology (p = 0.013), and reactivation of EBV-related antibodies (p = 0.029). In conclusion, EBV positivity demonstrated using an EBER probe is useful for prediction of successful regression after withdrawal of IS in patients with AID-LPDs. Patients with advanced stage disease, worse PS, CHL histology, or reactivation of EBV-related antibodies should be closely monitored after initial treatment., (© 2020 John Wiley & Sons Ltd.)

Tyrosine kinase inhibitors (TKI) are used for primary therapy in patients with newly diagnosed CML. However, a reliable method for optimal selection of a TKI from the viewpoint of drug sensitivity of CML cells has not been established. We have developed a FRET-based drug sensitivity test in which a CrkL-derived fluorescent biosensor efficiently quantifies the kinase activity of BCR-ABL of living cells and sensitively evaluates the inhibitory activity of a TKI against BCR-ABL. Here, we validated the utility of the FRET-based drug sensitivity test carried out at diagnosis for predicting the molecular efficacy. Sixty-two patients with newly diagnosed chronic phase CML were enrolled in this study and treated with dasatinib. Bone marrow cells at diagnosis were subjected to FRET analysis. The ΔFRET value was calculated by subtraction of FRET efficiency in the presence of dasatinib from that in the absence of dasatinib. Treatment response was evaluated every 3 months by the BCR-ABL1 International Scale. Based on the ΔFRET value and molecular response, a threshold of the ΔFRET value in the top 10% of FRET efficiency was set to 0.31. Patients with ΔFRET value ≥0.31 had significantly superior molecular responses (MMR at 6 and 9 months and both MR4 and MR4.5 at 6, 9, and 12 months) compared with the responses in patients with ΔFRET value <0.31. These results suggest that the FRET-based drug sensitivity test at diagnosis can predict early and deep molecular responses. This study is registered with UMIN Clinical Trials Registry (UMIN000006358)., (© 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Objectives: We conducted a phase-II study to evaluate the efficacy and safety of dasatinib in patients newly diagnosed with chronic-phase chronic myeloid leukaemia (CML-CP) in Japan (IMIDAS PART 2 study)., Methods: Seventy-nine patients were administered 100 mg dasatinib once daily. We examined pretreatment and post-treatment influences of various factors. The BCR-ABL1 international scale (IS), halving time (HT) and reduction rate of BCR-ABL1 transcript within the initial 1 or 3 months of therapy (RR-BCR-ABL1 1m,3m ) were the post-treatment factors investigated to predict the molecular response., Results: The estimated major molecular response (MMR), molecular response 4.0 (MR4.0) and molecular response 4.5 (MR4.5) rates were 77.2%, 49.4% and 35.4%, respectively, at 12 months. Grade 3/4 non-haematologic adverse events were infrequent. Multivariate analysis showed that age >65 years was significantly correlated with MR4.0 and MR4.5 (deep molecular response: DMR) at 12 months. All post-treatment factors at 3 months predicted DMR by univariate analysis. However, RR-BCR-ABL1 3m was the only significant landmark for predicting DMR by multivariate analysis., Conclusions: Primary treatment of CML-CP with dasatinib enabled early achievement of MMR and DMR, particularly in elderly patients, with high safety. Furthermore, RR-BCR-ABL1 3m was found to be a more useful predictor of DMR than HT-BCR-ABL1 and BCR-ABL1 IS., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Purpose: Dasatinib is a novel, oral, multi-targeted kinase inhibitor of breakpoint cluster region-abelson (BCR-ABL) and Src family kinases. The study investigated pharmacokinetic (PK) and pharmacodynamic (PD) analyses of dasatinib in 51 newly diagnosed, chronic phase, chronic myeloid leukemia patients., Methods: The dasatinib concentration required to inhibit 50 % of the CrkL (CT10 regulator of kinase like) phosphorylation in bone marrow CD34+ cells (half maximal (50 %) inhibitory concentration (IC50)CD34+cells) was calculated from each patient's dose-response curve using flow cytometry. PK parameters were obtained from the population pharmacokinetic analysis of dasatinib concentrations in plasma on day 28 after administration., Results: Early molecular responses were not significantly associated with PK or PD (IC50 CD34+cells) parameters. However, the PK/PD parameter-time above IC50 CD34+cells-significantly correlated with BCR-ABL transcript level at 3 months (correlation coefficient (CC) = -0.292, P = 0.0375) and the reduction of BCR-ABL level at 1 or 3 months (CC = -0.404, P = 0.00328 and CC = -0.356, P = 0.0104, respectively). Patients with more than 12.6 h at time above IC50 CD34+cells achieved a molecular response of 3.0 log reduction at 3 months and those more than 12.8 h achieved a deep molecular response less than 4.0 log reduction at 6 months at a significantly high rate (P = 0.013, odds ratio = 4.8 and P = 0.024, odds ratio = 4.3, respectively)., Conclusion: These results suggest that the anti-leukemic activity of dasatinib exhibits in a time-dependent manner and that exposure for more than 12.8 h at time above IC50 CD34+cells could significantly improve prognosis.

Primary bone lymphoma (PBL) comprises less than 1% of all malignant lymphomas. Because few studies of PBL have been conducted in Japan, the characteristics of Japanese patients with PBL have not been fully elucidated. We retrospectively analyzed 17 patients diagnosed with PBL at our institution between 2001 and 2011. Median patient age was 60 years. Eleven patients had diffuse large B-cell lymphoma and 2 patients had T-cell lymphoma histology. The spine was the most frequently involved site at the time of presentation. There were 11 patients with stage IV disease and 11 patients with high or high-intermediate risk according to the International Prognostic Index (IPI). Thirteen patients achieved complete response (CR) after initial treatment. At a median follow-up of 31 months, the 3-year overall survival (OS) and progression free survival were 63.5 and 49.9%, respectively. Localized disease, low or low-intermediate IPI, and CR after initial treatment were associated with a good outcome in patients with PBL and significantly associated with a better OS. Spine involvement and T/NK-cell phenotype are more frequent in Japanese than in Caucasian patients with PBL., (© 2015 S. Karger AG, Basel.)

A 70-year-old woman with rheumatoid arthritis treated with methotrexate (MTX) complained of right arm weakness. On CT and MRI, tumors were found in the right frontal lobe, bilateral lungs, and left renal parenchyma. She was diagnosed as having lymphomatoid granulomatosis (LYG) grade 2 on thoracoscopic biopsy of the left lung. We discontinued MTX and treated a mass lesion in the right frontal lobe with stereotactic radiotherapy. As a result, the tumors showed a gradual reduction in size, and the patient achieved complete remission. LYG is a rare lymphoproliferative disorder, and has various clinical characteristics. We describe herein a patient with LYG grade 2 with cerebral, pulmonary, and renal lesions, who has maintained a complete remission for six months, to date, after treatment.

Invasive fungal infection (IFI) causes morbidity and mortality among patients with hematological malignancies who receive cytotoxic chemotherapy or hematopoietic stem cell transplantation (HSCT). We evaluated the incidence and treatment outcomes of proven and probable IFI in 22 institutions between 2006 and 2008 following the recent European Organization for Research and Treatment of Cancer/Mycosis Study Group (EORTC/MSG) consensus criteria. We analyzed 2,821 patients with hematological malignancies, including 597 who had undergone HSCT; these included patients with acute leukemia (n = 697), myelodysplastic syndrome (n = 284), lymphoma (n = 1465), or multiple myeloma (n = 375). IFIs were diagnosed in 38 (1.3%) patients (18 proven and 20 probable), including 20 patients who underwent HSCT and 18 who received chemotherapy alone; these included patients with aspergillosis (n = 23), candidiasis (n = 6), mucormycosis (n = 6), trichosporonosis (n = 2), and geotrichosis (n = 1). The incidence of IFI was 5.4 % in allogeneic HSCT patients, 0.4 % in autologous HSCT patients, and 0.8 % in patients receiving chemotherapy alone. Eighteen patients with aspergillosis were diagnosed with probable pulmonary IFI as determined by computed tomography scan and positive galactomannan assay. Overall, antifungal targeted therapies resulted in successful outcomes in 60.0 % of patients. IFI-attributable mortality rate was higher in HSCT patients than in those receiving chemotherapy alone, but the difference was not statistically significant.

A 76-year-old woman presented with vaginal bleeding and discharge in September 2009. She was admitted to our hospital because a tumor of 5 cm in diameter was found in the vagina in a nearby clinic. She was diagnosed with primary vaginal diffuse large B-cell lymphoma (DLBCL) on biopsy of the tumor because CT, MRI and FDG-PET showed no area of lymphomatous involvement other than the vagina and direct involvement into the bladder. She achieved complete response (CR) after chemotherapy followed by localized radiation therapy, but she had a relapse in the central nervous system (CNS) two months after CR. A study of 57 reported cases of primary vaginal lymphoma suggested that the most common histologic type was DLBCL, and most of patients were in a localized stage and responded well to combination of chemotherapy and radiation therapy. To date, two cases of primary vaginal lymphoma with a relapse in the CNS have been reported. We presumed that direct involvement into the bladder of vaginal lymphoma contributed to the relapse in the CNS in this case.

Histiocytic sarcoma (HS) is a rare but aggressive malignant neoplasm of histiocytic lineage with a poor prognosis. Immunohistochemically, the neoplastic cells are positive for CD163, CD68, and lysozyme, and negative for B and T cell markers. However, molecular studies on the origin of the neoplastic cells remain inconclusive. A 54-year-old woman was admitted to our hospital because of painful swelling of the left knee. Examination revealed generalized lymphadenopathy and splenomegaly. HS was diagnosed according to morphologic and immunohistochemical features observed on biopsy of the left inguinal lymph node. The tumor demonstrated a clonal immunoglobulin heavy chain gene rearrangement and a clonal cytogenetic abnormality including t(14;18) which was confirmed by fluorescence in situ hybridization analysis showing the IgH/BCL2 fusion gene. The neoplastic cells were negative for PAX5, a B cell associated transcription factor, and positive for CEBPβ, a transcription factor mediating macrophage and myeloid differentiation. Positron emission tomography showed disseminated areas of increased 18F-fluorodeoxyglucose uptake in multiple lymph nodes, the liver, spleen, both lungs, both kidneys, and many bony sites. The patient received localized irradiation therapy followed by chemotherapy, she failed to respond and died of the disease progression. The case findings suggest lineage promiscuity or plasticity related to the pathogenesis of HS.

Invasive fungal infection is one of the major causes of death in neutropenic patients undergoing allogeneic stem cell transplantation (SCT). Although prophylactic antifungal therapy with fluconazole (FLCZ) has become the standard care for these patients, there remains a need for more effective and cost-beneficial alternative drugs. We conducted a prospective study to evaluate the usefulness of the administration of micafungin (MCFG) as a prophylactic antifungal therapy for patients undergoing allogeneic SCT. The results were compared with previous data for patients who had received FLCZ. A total of 44 patients who underwent allogeneic SCT were enrolled in the study. Data from 29 patients who received allogeneic SCT using prophylactic FLCZ before this study were used as historical control data. Underlying diseases included acute leukemia (n = 16), non-Hodgkin's lymphoma (n = 11), myelodysplastic syndrome (n = 6), and others (n = 11) in the MCFG group and acute leukemia (n = 18), chronic myelogenous leukemia (n = 6), and others (n = 5) in the FLCZ group. The median durations of administration of MCFG and FLCZ were 36 and 34 days, respectively. Prophylactic success, defined as the absence of proven, probable, and possible invasive fungal infection (IFI) until the end of prophylactic therapy was achieved in 36 (87.8%) of the 41 evaluated patients in the MCFG group and in 65.5% of the patients in the FLCZ group (P = 0.038). No patients in the MCFG group showed proven or probable IFI, whereas proven or probable IFI was observed in three patients in the FLCZ group. Four patients in the MCFG group required dose escalation due to febrile neutropenia. Although one patient in the MCFG group required the discontinuation of MCFG due to allergic skin eruption (grade 2), none of the other patients in either group required dose reduction due to adverse effects. Although the study design was not a prospective randomized trial, our results indicate that the administration of MCFG at a daily dose of 100 mg is promising for prophylactic antifungal therapy in patients undergoing allogeneic SCT.

MALT1, BCL10 (B-cell lymphoma 10), and API2 (apoptosis inhibitor 2)-MALT1 are key molecules in mucosa-associated lymphoid tissue (MALT) lymphomagenesis. We previously reported that MALT1 and API2-MALT1 were localized only in cytoplasm, where we suggested that both molecules were likely to be active. In the study presented here, we further examined the localization-determining region by generating various mutants and were able to demonstrate that there were nuclear export signal (NES)-containing domains in the MALT1 C-terminal region. The use of leptomycin B, an NES-specific inhibitor, demonstrated that both MALT1 and API2-MALT1 were predominantly retained in the nuclei, indicating that these molecules were shuttling between nucleus and cytoplasm in an NES-dependent manner. It was also found that MALT1 was involved in the nuclear export of BCL10, which is originally localized in both nucleus and cytoplasm. These results correlate well with the nuclear BCL10 expression pattern in both t(1;14) and t(11;18) MALT lymphomas. The nucleocytoplasmic shuttling of MALT1 and BCL10 complex may indicate that these molecules are involved not only in the nuclear factor kappaB (NF-kappaB) pathway but also in other biologic functions in lymphocytes.

The gastrointestinal tract is one of the common targets of acute graft-versus-host disease (GVHD), but accurate diagnosis is difficult because of the nonspecific nature of complicated diseases and the lack of diagnostic findings by conventional endoscopy. Recently, a magnifying endoscope has been developed and used for examining microstructures of the mucosa. Herein, we report the first use of a magnifying endoscope for a patient with gastrointestinal (GI) GVHD. Magnified endoscopic findings of atrophic and coalescent villi of the terminal ileum reflect histological findings of GVHD. Magnifying endoscopy of the terminal ileum may be useful for early detection and follow-up of GI GVHD.

Aleukemic leukemia cutis is a rare condition characterized by the invasion of leukemic blasts into the skin before their appearance in the peripheral blood. Leukemia cutis usually occurs in patients with myeloid leukemia, especially the myelomonocytic and monocytic types of acute myeloblastic leukemia. We describe the case of a 62-year-old woman with aleukemic leukemia cutis who developed Philadelphia-positive acute leukemia 1 month after skin involvement. Leukemic cells expressed both myeloid and B-cell lineage surface markers, and monoclonal rearrangement of the immunoglobulin heavy chain was detected by Southern blot analysis. This report is the first of a case of aleukemic leukemia cutis preceding Philadelphia-positive biphenotypic leukemia.

Introduction: A combination of fractionated total body irradiation (TBI) with etoposide (VP-16) and cyclophosphamide (CY) as a preconditioning regimen (VP/CY/TBI) has been reported to be safe and effective for both adults and children undergoing allogeneic bone marrow transplantation (allo-BMT). However, the reported doses of VP-16 were different. We evaluated the efficacy and safety of a VP-16 (at less than the usual dose)/CY/TBI regimen for adults with hematological malignancies who are required to receive allo-BMT., Patients and Methods: Thirty-eight patients received VP-16, CY and TBI (VP/CY/TBI) as a preconditioning regimen for allo-BMT. Twenty-one patients were in first complete remission (1CR), six patients were in second remission (2CR) and 11 patients were in non-remission status (non-CR) before allo-BMT. These patients received allo-BMT from related donors (n=14) and unrelated donors (n=24). The preconditioning regimen consisted of VP-16 (15 mg/kg/d for 2 d), CY (60 mg/kg/d for 2 d) and 12 Gy TBI in six fractions for 3 d., Results: Two patients died on day 30 after transplantation. The median follow-up period for all patients was 35.0 months (range 0.8-159.6 months). At the time of analysis, 10 patients had died. Seven of those 10 patients died because of relapse. The estimated 5-yr disease-free survival (DFS) rates for all cases and acute myelogenous leukemia and acute lymphoblastic leukemia cases were 73.6, 66.7 and 100%, respectively. The estimated 5-yr DFS rates for 1CR, 2CR and non-CR cases were 90.5, 83.3 and 40.9%, respectively (p < 0.05)., Conclusion: Based on these findings, we suggest that a VP/CY/TBI regimen is effective and safe for adult patients with hematological malignancies in 1CR and 2CR.

A 44-year-old man was referred to Hakodate Chuo Hospital because of progressive fatigue in April 2001, and was diagnosed as having adult T-cell leukemia (ATL; acute type). Complete remission was not obtained even with the application of multiple anti-leukemic agents including CHOP-V-MMV. The patient received an allogeneic bone marrow transplant from his HLA-identical, HTLV-I antibody-negative sibling donor in June 2002. The conditioning regimen consisted of cyclophosphamide, etoposide and total body irradiation. Cyclosporine A and a short course of methotrexate were given as prophylaxis for graft-versus-host disease (GVHD). Engraftment was achieved on day 16, while ATL cells were detected in the peripheral blood throughout the transplantation. ATL cells were also detected in bone marrow on day 20. Withdrawal of the immunosuppressant induced the eradication of the residual ATL cells in the peripheral blood on day 24 and in the bone marrow on day 40. Grade III of acute GVHD developed in the bowel on day 40, which lasted for over 5 months and was gradually resolved by administration of prednisolone and tacrolimus. The patient remains in complete remission 23 months after the transplantation. The clinical consequence of our case clearly shows that a graft-versus-leukemia (GVL) effect combined with graft-versus-host disease (GVHD) plays a curative role even in an early phase after bone marrow transplantation for patients with adult T-cell leukemia.

Complementarity-determining region (CDR3) size spectratyping has often been used to analyze the clonal expansion of T-cells. CDR3 size spectratyping has been useful in the analysis of the oligoclonal expansion of T-cells in virus infection, graft-versus-leukemia effect (GVL), graft-versus-host disease (GVHD), and immune reconstitution of T-cells after allogeneic stem cell transplantation (allo-SCT). We analyzed 26 T cell receptor (TCR)-beta-chain subfamilies (VB) in 25 patients who underwent allo-SCT. Fifteen of these patients developed acute GVHD (aGVHD). Many TCR-VB were skewed in the early stage. In these TCR-VB subfamilies, VB6 was most often skewed at the time of skin aGVHD. We then analyzed the average score of the complexity of 26 TCR-VB spectratypings in patients with or without cGVHD. The patients who developed chronic GVHD (cGVHD) had a lower average score of TCR-VB complexity than that of patients without cGVHD (P = 0.010). In particular. the patients who developed the quiescent type and de novo type of cGVHD from 4 months after allo- SCT had a lower average score of TCR-VB complexity at 3 months than that of the patients who had no cGVHD (P = 0.0055). These results suggest that we might be able to consider a possible development of cGVHD by analyzing TCR-VB spectratyping after allo-SCT.

A 60-year-old woman was admitted to our hospital to receive treatment for relapse of biphenotypic leukemia 4 years after her initial presentation. Bone marrow examination revealed 53.5% lymphoblasts, which were classified as ALL-L2 with a normal karyotype. Lymphoblast surface markers were positive for cells of both B-cell and myeloid lineage. Immunoglobulin heavy chain and T-cell receptor gene rearrangements were investigated with PCR. Clonal rearrangement of TCR delta V delta 2-D delta 3 was detected. The same clonal rearrangement of TCR delta was found using frozen initial leukemic cells. Rather than secondary leukemia, the patient's leukemia was confirmed as relapse of the initial clone. Detection of the clonal rearrangement was also useful as a patient-specific marker for minimal residual disease.

t(11; 18) (q21; q21) is a chromosomal aberration specific to low-grade mucosa-associated lymphoid tissue (MALT) lymphoma, and generates the chimeric product apoptosis inhibitor 2 (API2)-MALT1, which has been suggested to play an important role in MALT lymphomagenesis. However, little is known about the characteristics of API2, MALT1, and API2-MALT1 proteins. We therefore investigated the subcellular localization and stability of these products. API2 was localized in the nucleus and the cytoplasm, and MALT1 and API2-MALT1 in the cytoplasm only. Western blot analysis showed that the products of API2 and MALT1 were unstable, while the API2-MALT1 product was stable. The API2 deletion mutants at the end of the C-terminal and the MALT1 deletion mutants at the end of the N-terminal were stable compared with the full-length products. These results indicate that the domains responsible for protein instability are located in the end of the C-terminal of API2 and in that of the N-terminal of MALT1, and also that API2-MALT1 became stable because it lacks these domains. It has been suggested that NF-kappaB activation plays an important role in the tumorigenesis of MALT lymphoma. Our findings further suggest that the stabilized expression of API2-MALT1 products may continuously stimulate the NF-kappaB activating pathway, thus leading to MALT lymphomagenesis.

We analysed 26 T-cell receptor (TCR) beta chain subfamilies (VB) of a patient with aplastic anaemia (AA) who underwent allogeneic bone marrow transplantation (allo-BMT). The patient developed pancytopenia at d 80. The patient's T cells were skewed in 10 of 26 TCR-VB on d 83. These TCR-VB, especially VB15, which were almost entirely CD8-positive cells, were skewed throughout her clinical course. Chimaerism analysis of the CD8-positive cells indicated that they were of recipient origin. Therefore, some immune responses induced by the recipient CD8-positive T cells had an important role in pancytopenia in AA patients after allo-BMT.

t(11;18)(q21;q21) has been recognized as a characteristic chromosomal translocation in mucosa-associated lymphoid tissue (MALT)-type lymphoma, and recent studies have demonstrated that this translocation results in the chimaeric transcript of API2 (apoptosis inhibitor 2)-MALT1 (mucosa-associated lymphoid tissue lymphoma translocation gene 1). In this study, we used reverse transcription polymerase chain reaction (RT-PCR) to analyse the incidence of this fusion product in a large series of MALT lymphoma, nodal marginal zone B-cell lymphoma (nMZBCL) and extranodal diffuse large B-cell lymphoma (DLBL) cases. RT-PCR analysis revealed that 17 of the 95 (17.9%) MALT lymphomas but none of the nine nMZBCLs or 16 DLBLs had API2-MALT1 fusion transcripts. The incidence of API2-MALT1 varied among MALT lymphomas arising from different sites and was highest for pulmonary MALT lymphomas (10 out of 16 cases, 62.5%). The presence of the API2-MALT1 fusion gene was also confirmed by long and accurate (LA)-PCR with genomic DNA, and the result correlated well with that obtained with the RT-PCR assay, thus demonstrating the usefulness of LA-PCR for the detection of the API2-MALT1 fusion gene.

At least two distinct recurrent chromosomal translocations have been implicated in the pathogenesis of MALT lymphoma. The first, t(1;14), results in the transfer of the entire Bcl10 gene to chromosome 14 wherein Bcl10 expression is inappropriately stimulated by the neighboring Ig enhancer. The second, t(11;18), results in the synthesis of a novel fusion protein, API2-MALT1. Until now, no common mechanism of action has been proposed to explain how the products of these seemingly unrelated translocations may contribute to the same malignant process. We show here that Bcl10 and MALT1 form a strong and specific complex within the cell, and that these proteins synergize in the activation of NF-kappaB. The data support a mechanism of action whereby Bcl10 mediates the oligomerization and activation of the MALT1 caspase-like domain. This subsequently activates the IKK complex through an unknown mechanism, setting in motion a cascade of events leading to NF-kappaB induction. Furthermore, the API2-MALT1 fusion protein also strongly activates NF-kappaB and shows dependence upon the same downstream signaling factors. We propose a model whereby both the Bcl10.MALT1 complex and the API2-MALT1 fusion protein activate a common downstream signaling pathway that originates with the oligomerization-dependent activation of the MALT1 caspase-like domain.

The reported regression of mucosa-associated lymphoid tissue (MALT) type gastric low-grade B-cell lymphoma following treatment for Helicobacter pylori (H. pylori) infection has not yet been comprehensively analyzed, especially in relation to the recently identified c-IAP2-MALT1 / MLT gene alteration resulting from the t(11;18)(q21;q21) chromosomal translocation found in MALT lymphoma. The relationship between MALT lymphomas and H. pylori was investigated in 30 patients who received an antibacterial treatment. Patients were followed up by means of endoscopy and biopsy. Molecular genetic analyses focused on the presence or absence of the immunoglobulin heavy chain (IgH) gene and / or MALT1 / MLT gene alteration resulting from t(11;18)(q21;q21) translocation. H. pylori was positive in 26 of the 30 patients. The overall success rate of cure of H. pylori infection was 96% (25 / 26). Thirteen patients (52%) showed complete remission (CR) of lymphoma, nine (36%) partial remission (PR), and three (12%) registered no change (NC). Statistical analysis revealed significant differences between CR and PR / NC patients in age ( < 60 or 60), in lymphoma location (single or multiple sites) and in the presence or absence of gene rearrangement before eradication (P < 0.05). Endoscopy showed a cobblestone appearance only in PR cases and polypoid features predominantly in NC cases. Two NC patients with polypoid gross appearance showed rearrangements involving either c-IAP2 or MALT1 gene in Southern blot analysis, while none of seven other resected patients with non-polypoid superficial gross appearance showed rearrangement. Gastric MALT lymphoma could be pragmatically subdivided into three groups, CR (MALT-A), PR (MALT-B), and NC (MALT-C) on the basis of the reaction to eradication of H. pylori. We speculate that MALT-A may represent an incipient neoplasm or dysplasia, MALT-B a neoplasm activated by antigenic stimulation of H. pylori, and MALT-C a lymphoma independent of H. pylori. Polypoid lesions in MALT-C were associated with c-IAP2-MALT1 / MLT gene alteration resulting from t(11;18)(q21;q21). This classification is thought to be clinically significant for deciding the most appropriate mode of treatment of MALT-type lymphoproliferative disorders.

Recent progress in molecular analysis of low-grade B cell lymphoma has revealed that API2 at 11q21 and a novel gene, MALT1 at 18q21, are involved in t(11;18)(q21;q21), a characteristic chromosome aberration for mucosa-associated lymphoid tissue (MALT) type lymphoma. We describe here the establishment of a reverse transcription-polymerase chain reaction (RT-PCR) assay that we used to analyze 22 cases of MALT lymphoma. All five cases that were shown to possess t(11;18)(q21;q21) showed the specific amplification of API2-MALT1 chimeric transcripts. Of the remaining 17 cases for which cytogenetic data were not available, three cases demonstrated the presence of fusion transcripts, indicating that a significant percentage of MALT lymphoma cases of the present series appeared to possess t(11;18). A single fragment was observed in each of these cases, but the size varied from case to case. Sequencing analysis revealed that there are two breakpoints in API2 and three in MALT1, and that all of the fusion transcripts are in-frame. On the basis of these results, four kinds of chimeric proteins can be predicted for the present series. Thus, the RT-PCR assay used here should serve as an effective molecular tool for understanding molecular pathogenesis and the clinical significance of API2-MALT1 for MALT lymphomas.