Biomedical subjects

Masataka Okamoto

Publications and source records attributed to Masataka Okamoto.

17 recordsLinked to original sources

PubMed2007

Prognostic impact of chromosomal alteration of 3q27 on nodal B-cell lymphoma: correlation with histology, immunophenotype, karyotype, and clinical outcome in 329 consecutive patients.

Rearrangements involving the BCL6 gene are found in 30% of diffuse large B-cell lymphomas (DLBCLs). We evaluated the clinical characteristics and prognoses of patients with B-cell lymphoma carrying 3q27 translocations. Among the 59 patients having 3q27 translocation, 10.9% had follicular lymphoma (FL) and 23.1% had DLBCL. It is of interest that the prognostic significance was not found between FL and DLBCL with 3q27 translocations. Progression-free survival (PFS) rate was significantly higher in the FL patients with 3q27 translocation than in those with 18q21 translocation. PFS rate was significantly higher in the DLBCL patients with 3q27 translocation than in those with 18q21 translocation. These findings suggest that the presence of 3q27 translocation is a significant prognostic factor in DLBCL.

Adult↗

PubMed2006

Intravascular large B-cell lymphoma (IVLBCL): a clinicopathologic study of 96 cases with special reference to the immunophenotypic heterogeneity of CD5.

Intravascular large B-cell lymphoma (IVLBCL) is pathologically distinct with a broad clinical spectrum and immunophenotypic heterogeneity. A series of 96 patients with IVLBCL (median age, 67 years; range, 41-85 years; 50 men) was reviewed. Anemia/thrombocytopenia (84%), hepatosplenomegaly (77%), B symptoms (76%), bone marrow involvement (75%), and hemophagocytosis (61%) were frequently observed. The International Prognostic Index score was high or high-intermediate in 92%. For 62 patients receiving anthracycline-based chemotherapies, median survival was 13 months. CD5, CD10, Bcl-6, MUM1, and Bcl-2 were positive in 38%, 13%, 26%, 95%, and 91% of tumors, respectively. All 59 CD10- IVLBCL cases examined were nongerminal center B-cell type because they lacked the Bcl-6+MUM1- immunophenotype. CD5 positivity was associated with a higher prevalence of marrow/blood involvement and thrombocytopenia and a lower frequency of neurologic abnormalities among patients with CD10-IVLBCL. Compared with 97 cases of de novo CD5+CD10-diffuse LBCL, 31 cases of CD5+CD10-IVLBCL exhibited higher frequencies of poor prognostic parameters, except age. Multivariate analysis in IVLBCL revealed that a lack of anthracycline-based chemotherapies (P<.001, hazard ratio [HR]: 9.256), age older than 60 years (P=.012, HR: 2.459), and thrombocytopenia less than 100x10(9)/L (P=.012, HR: 2.427) were independently unfavorable prognostic factors; CD5 positivity was not. Beyond immunophenotypic diversity, IVLBCL constitutes a unique group with aggressive behavior.

Adult↗

PubMed2006

t(8;14)(q24;q32) in two patients with CD10-negative primary thyroid diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) with the 8q24 translocation is occasionally seen in the gastrointestinal tract, but has rarely been reported in the thyroid gland. We experienced two cases of primary thyroid DLBCL having t(8;14)(q24;q32). The immunophenotype and karyotype of Case 1 (66-year-old female) and Case 2 (70-year-old female) were: CD10-, CD20+, BCL-2+/add(13)(q34), t(8;14)(q24;q32) and CD10-, CD20-, CD79a+, BCL-2-/t(8;14)(q24;q32), respectively. Although long-term complete remission could be achieved in both of our patients by conventional chemotherapy with/without radiation therapy, accumulation of further such cases is necessary to develop a standard treatment protocol and also to elucidate the pathogenesis of t(8;14)(q24;q32)-positive primary thyroid DLBCL.

Aged↗

PubMed2006

Expression profiling analysis of the CD5+ diffuse large B-cell lymphoma subgroup: development of a CD5 signature.

Diffuse large B-cell lymphoma (DLBCL) accounts for 30% of non-Hodgkin's lymphomas and is known to comprise heterogeneous groups. We previously reported that CD5+ DLBCL is a clinically distinct subgroup of these tumors that is associated with poor prognosis. In our current study, we have used gene expression profiling technology in an attempt to identify new markers and to further characterize the biological features of CD5+ DLBCL. Candidate genes, which showed the greatest difference in expression between 22 CD5+ and 26 CD5- DLBCL cases, were selected from our screening and subjected to clustering analysis. This resulted in identification of a specific mRNA profile (a CD5 signature) for CD5+ DLBCL. The CD5 signature included downregulated extracellular matrix genes such as POSTN, SPARC, COL1A1, COL3A1, CTSK, MMP9 and LAMB3, and comprised upregulated genes including TRPM4. We tested this CD5 signature for its potential use as a relevant marker for CD5+ DLBCL and found that it did indeed recognize this subgroup. The tumors identified by the CD5 signature contained most of the CD5+ DLBCL cases and some CD5- DLBCL cases. Moreover, the subgroup of cases with this CD5 signature showed a poorer prognosis. The subsequent application of the CD5 signature to the analysis of an independent series of DLBCL microarray data resulted in identification of a subgroup of DLBCL cases with a similar clinical outcome, further suggesting that the CD5 signature can be used as a clinically relevant marker of this disease.

Biomarkers, Tumor↗

PubMed2006

Multicenter phase II study of the CyclOBEAP (CHOP-like + etoposide and bleomycin) regimen for patients with poor-prognosis aggressive lymphoma.

Our aim was to study the efficacy of the addition of etoposide and bleomycin to a [cyclophosphamide (CPA), doxorubicin (DXR), vincristine (VCR), and prednisone (PDN)] CHOP-like regimen for the treatment of aggressive lymphoma. The CyclOBEAP regimen was administered over a total period of 12 weeks. Doxorubicin, 50 mg/m(2), was given every 2 weeks in combination with either cyclophosphamide, 1,000 mg/m(2), (weeks 1, 5, 9) or etoposide, 70 mg/m(2) qd x4 (weeks 3, 7, 11). During the alternate weeks, non-myelosuppressive vincristine, 1.4 mg/m(2) (maximum, 2.0 mg/body), was given either with bleomycin, 10 mg/m(2) (weeks 2, 6, 10), or alone (weeks 4,8,12). Prednisolone, 40 mg/m(2), was administered daily for 14 days during weeks 1-2, 5-6, and 9-10. There were 121 eligible patients and median age of 51 years. A complete response was achieved in 106 patients (88%) and a partial response in 11 patients. The 5-year overall survival (OS) rate was 72% and progression-free survival (PFS) rate was 62%. When the patients were divided according to the International Prognostic Index (IPI), the 5-year OS and PFS rates did not significantly differ among risk groups. When the patients with DLBCL were divided according to the IPI, the 5-year OS and PFS rates also did not significantly differ. World Health Organization (WHO) grade 4 neutropenia was observed in 91 patients and thrombocytopenia in 13 patients. No treatment-related deaths were observed. The addition of etoposide and bleomycin to CHOP therapy may enhance the effect of CHOP therapy for aggressive lymphoma. We will perform a prospective study of CyclOBEAP regimen combined with rituximab and test its safety and efficacy.

Adolescent↗

PubMed2006

Multicenter Phase II study of CyclOBEAP regimen for elderly patients with poor-prognosis aggressive lymphoma.

We treated elderly patients (65-69 years) who had aggressive lymphoma with the CyclOBEAP regimen, and we studied the safety and efficacy of this treatment. The CyclOBEAP regimen was administered over a total period of 12 weeks. Doxorubicin 40 mg/m(2) was given every 2 weeks in combination with either cyclophosphamide 800 mg/m(2) or etoposide 70 mg/m(2) qd x 3. During the alternate weeks, non-myelosuppressive vincristine 1.0 mg/m(2) was given either with bleomycin 10 mg/m(2) or alone. Prednisolone 40 mg/m(2) was administered daily for three 14-day periods during weeks 1-2, 5-6 and 9-10. There were 51 eligible patients. A complete response was achieved in 42 patients (82%). The 5-year overall survival (OS) rate was 60.6% and progression-free survival (PFS) rate was 51.8%. WHO grade 4 neutropenia was observed in 32 patients and thrombocytopenia in 8 patients. We showed that the CyclOBEAP regimen can be safely used in the treatment of aggressive lymphoma in elderly patients and it achieved a high rate of remission.

Aged↗

PubMed2006

Immunoglobulin VH genes in thymic MALT lymphoma are biased toward a restricted repertoire and are frequently unmutated.

Thymic MALT lymphoma shows certain distinctive features among MALT lymphomas, such as expression of IgA isotype, consistent lack of API2-MALT1 gene fusion, and very strong association with autoimmune disease, especially Sjogren's syndrome. To help clarify the nature of the clonal lymphoid infiltrates, we analysed the usage and somatic hypermutation of the Ig heavy chain variable region (V(H)) genes in nine different cases. The V(H) rearrangement was potentially functional in all cases and was restricted to the V(H)3 family. V(H) usage was biased toward V(H)3-30 (five cases) and V(H)3-23 (three cases) segments, which have both been frequently expressed by autoimmune B cells. Somatic hypermutation was absent in five cases. Fewer than the expected replacement mutations were found in the framework regions in two cases, indicating a negative antigen selection pressure. Ongoing mutation was absent in all cases. D segment usage was varied, whereas J(H) segment usage was restricted to J(H)4. The observed patterns of V(H) usage and mutations suggested that specific antigens may play a pathologically relevant role in the genesis or progression of thymic MALT lymphoma.

Aged↗

PubMed2006

Multicentre phase II study of the baseline BEACOPP regimen for patients with advanced-stage Hodgkin's lymphoma.

A German Hodgkin's lymphoma (HL) study group designed the BEACOPP (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, prednisolone) regimen. In the BEACOPP regimen, treatment intervals were shortened and the dose-intensity was increased compared with those in the ABVD regimen (doxorubicin, bleomycin, vinblastine and darcarbacine), resulting in a long-term disease-free survival rate of approximately 75-80%. In the present study, we evaluated the safety and efficacy of the BEACOPP regimen. Between April 2001 and February 2004, 20 patients with HL of stage IIB or higher who had received no previous treatment were enrolled. The patients were aged 17-69 years (median 22 years). The histologic types were mixed cellularity in four cases and nodular sclerosis in 16 cases. The stages were stage IIB in four cases, stage III in 12 cases, and stage IV in four cases. Nineteen (95%) of the 20 patients achieved complete remission. The 3-year survival rate was 100% and the 3-year progression-free survival rate was 89.7%. Adverse drug reactions were grade 4 neutropenia in 12 patients, grade 3-4 thrombocytopenia in seven patients, and grade 3 or higher non-hematologic toxicities in two patients (stomatitis in one patient and ALT/AST elevation in one patient). The BEACOPP regimen for advanced-stage HL showed an excellent complete remission rate and high efficacy even in stage III/IV patients. However, a long-term risk of the BEACOPP regimen is the development of secondary leukemia or myelodysplastic syndrome. Therefore, long-term follow-up of these patients, including monitoring for toxicities, is necessary.

Adolescent↗

PubMed2005

Comparison of genome profiles for identification of distinct subgroups of diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) comprises molecularly distinct subgroups such as activated B-cell-like (ABC) and germinal center B-cell-like (GCB) DLBCLs. We previously reported that CD5(+) and CD5(-)CD10(+) DLBCL constitute clinically relevant subgroups. To determine whether these 2 subgroups are related to ABC and GCB DLBCLs, we analyzed the genomic imbalance of 99 cases (36 CD5(+), 19 CD5(-)CD10(+), and 44 CD5(-)CD10(-)) using array-based comparative genomic hybridization (CGH). Forty-six of these cases (22 CD5(+), 7 CD5(-)CD10(+), and 17 CD5(-)CD10(-)) were subsequently subjected to gene-expression profiling, resulting in their division into 28 ABC (19 CD5(+) and 9 CD5(-)CD10(-)) and 18 GCB (3 CD5(+), 7 CD5(-)CD10(+), and 8 CD5(-)CD10(-)) types. A comparison of genome profiles of distinct subgroups of DLBCL demonstrated that (1) ABC DLBCL is characterized by gain of 3q, 18q, and 19q and loss of 6q and 9p21, and GCB DLBCL is characterized by gain of 1q, 2p, 7q, and 12q; (2) the genomic imbalances characteristic of the CD5(+) and CD5(-)CD10(+) groups were similar to those of the ABC and GCB types, respectively. These findings suggest that CD5(+) and CD5(-)CD10(+) subgroups are included, respectively, in the ABC and GCB types. Finally, when searching for genomic imbalances that affect patients' prognosis, we found that 9p21 loss (p16(INK4a) locus) marks the most aggressive type of DLBCL.

Adult↗

PubMed2005

Cytogenetic features of de novo CD5-positive diffuse large B-cell lymphoma: chromosome aberrations affecting 8p21 and 11q13 constitute major subgroups with different overall survival.

De novo CD5-positive diffuse large B-cell lymphoma (CD5(+)DLBCL) is regarded as a different clinicopathological entity from CD5-negative DLBCL (CD5(-)DLBCL) and mantle cell lymphoma (MCL). Because only a few published cytogenetic studies of de novo CD5(+)DLBCL are available, we investigated chromosomal changes in 23 Japanese patients who had de novo CD5(+)DLBCL. A characteristic of cytogenetic abnormalities in de novo CD5(+)DLBCL was a high incidence of chromosomal aberrations affecting 8p21 and 11q13. Major chromosomal breakpoints were concentrated at 8p21, 11q13, and 3q27. Patients with 8p21 aberrations showed aggressive clinical features, including advanced stage of disease, elevated serum LDH level, poor performance status, and an inferior survival curve compared with patients who had 11q13 changes (P = .043). Chromosomal abnormalities of both 8p21 and 11q13 were not observed in the same patient, and each abnormality showed different chromosomal gains and losses. These results indicate that de novo CD5(+)DLBCL may occur in previously unidentified subgroups that differ in their chromosomal abnormalities. The conflicting results of previous studies on prognosis may thus be explained in part by the differences in chromosomal changes.

Adult↗

PubMed2004

Genome-wide array-based comparative genomic hybridization of diffuse large B-cell lymphoma: comparison between CD5-positive and CD5-negative cases.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin's lymphoma and exhibits aggressive and heterogeneous clinical behavior. To genetically characterize DLBCL, we established our own array-based comparative genomic hybridization and analyzed a total of 70 cases [26 CD-positive (CD5+) DLBCL and 44 CD5-negative (CD5-) DLBCL cases]. Regions of genomic aberrations observed in >20% of cases of both the CD5+ and CD5- groups were gains of 1q21-q31, 1q32, 3p25-q29, 5p13, 6p21-p25, 7p22-q31, 8q24, 11q23-q24, 12q13-q21, 16p13, 18, and X and losses of 1p36, 3p14, 6q14-q25, 6q27, 9p21, and 17p11-p13. Because CD5 expression marks a subgroup with poor prognosis, we subsequently analyzed genomic gains and losses of CD5+ DLBCL compared with those of CD5-. Although both groups showed similar genomic patterns of gains and losses, gains of 10p14-p15 and 19q13 and losses of 1q43-q44 and 8p23 were found to be characteristic of CD5+ DLBCL. By focusing on the gain of 13q21-q34 and loss of 1p34-p36, we were also able to identify prognostically distinct subgroups among CD5+ DLBCL cases. These results suggest that array-based comparative genomic hybridization analysis provides a platform of genomic aberrations of DLBCL both common and specific to clinically distinct subgroups.

CD5 Antigens↗

PubMed2004

Phase I study of Rituximab-CHOP regimen in combination with granulocyte colony-stimulating factor in patients with follicular lymphoma.

PURPOSE: Rituximab is an anti-CD20 monoclonal antibody, and it is used to treat B-cell lymphomas. Antibody-dependent cellular cytotoxicity (ADCC) is considered one of the mechanisms through which rituximab exerts its effects. Granulocyte colony-stimulating factor (G-CSF) enhances the cytotoxicity of neutrophils through ADCC, and it can be speculated that a combination of rituximab and G-CSF may augment the treatment efficacy of rituximab. EXPERIMENTAL DESIGN: We administered rituximab with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) treatment with G-CSF to 15 patients with follicular lymphoma, and we investigated the safety and efficacy of this regimen. We investigated ADCC activity in neutrophils and the expression of cell surface antigens including Fcgamma receptor type I [FcgammaRI (CD64)] on neutrophils to determine the optimal dose of G-CSF. RESULTS: Adverse reactions occurred in 14 of 15 patients and consisted mainly of grade 3/4 hematological toxicity. The response rate was 100%, with complete remission in 12 patients (80%) and partial remission in 3 patients (20%). At 14 months, the median length of the observation period, 2 of 12 patients had relapsed. G-CSF administration increased both FcgammaRI expression and ADCC activity. There were no significant differences in the levels of FcgammaRI expression or ADCC activity between the 2 microg/kg G-CSF and 5 microg/kg G-CSF groups, indicating that the optimal dose of G-CSF was 2 microg/kg. CONCLUSIONS: We conclude that the combination of rituximab-CHOP and G-CSF is well tolerated. We plan to carry out a randomized trial to compare efficacy between rituximab-CHOP treatment and treatment with a combination of rituximab-CHOP and G-CSF.

Adult↗

PubMed2004

Clinical significance of intracytoplasmic nm23-H1 expression in diffuse large B-cell lymphoma.

PURPOSE: Recently, we established an ELISA technique for measuring nm23-H1 protein in serum and found that the serum nm23-H1 level is a potential prognostic factor for patients with non-Hodgkin's lymphoma. EXPERIMENTAL DESIGN: We used immunohistochemistry to examine the expression of nm23-H1 by the lymphoma cells in patients with diffuse large B-cell lymphoma (DLBCL). RESULTS: By analyzing a consecutive series of 172 untreated DLBCL patients, we found that 100 (58.1%) were strongly positive. The cytoplasmic nm23 expression in lymphoma cells correlated significantly with the serum nm23-H1 level. There was a significant correlation between patients with cytoplasmic nm23-positive lymphoma and those with performance status 2-4, stage III/IV, bulky mass, B symptoms, elevated serum level of soluble interleukin 2 receptor, and elevated serum level of C-reactive protein. Overall and progression-free survival rates were significantly lower in patients with nm23-H1-positive lymphomas than in those with nm23-H1-negative lymphomas. Similar difference was seen between patients with high and low serum levels of nm23-H1. Thus, the correlation between presence or absence of cytoplasmic nm23-H1 expression and serum nm23-H1 levels suggests that serum nm23-H1 is produced directly by lymphoma cells. CONCLUSION: We suggest that nm23-H1 expression is a prognostic factor for DLBCL, and that it is as important as serum nm23-H1, both of which are useful for planning a treatment strategy.

Adolescent↗

PubMed2004

Analysis of chromosomal imbalances in de novo CD5-positive diffuse large-B-cell lymphoma detected by comparative genomic hybridization.

We recently demonstrated that the prognosis for de novo CD5-positive (CD5+) diffuse large-B-cell lymphoma (DLBCL) is markedly worse than that for CD5-negative (CD5-) DLBCL. Our findings also suggested that on the basis of its clinical features CD5+ DLBCL may constitute a unique disease category. However, the genetic basis for these two categories has not been established. Therefore, we performed comparative genomic hybridization analysis (CGH) of 26 cases of CD5+ DLBCL and 44 cases of CD5- DLBCL. Several identical changes in CD5+ and CD5- DLBCLs were found, such as gains of 3q, 9p, 12q, 13q, and 18q and losses of 1p, 6q, 17p, and 19p. However, distinct differences between the two categories were also detected. These included gains of 11q21-q24 (P=0.032) and 16p (P=0.005) in CD5+ DLBCL, and loss of 16p (P=0.028) in CD5- DLBCL. A comparison with results reported for mantle cell lymphoma, chronic lymphocytic leukemia, and Richter's syndrome demonstrated that the CGH pattern of CD5+ DLBCL was markedly different. This indicates that CD5+ DLBCL constitutes a disease category distinct from that of CD5- DLBCL and other CD5+ malignancies.

Adult↗

PubMed2003

Expression of nm23-H1 is associated with poor prognosis in peripheral T-cell lymphoma.

We have reported previously that the serum nm23-H1 level is a prognostic factor for non-Hodgkin's lymphoma. In this study, we examined nm23-H1 expression in T- and natural killer (NK)-cell lymphoma in order to evaluate whether lymphoma cells produce the protein. The clinical significance of the cytotoxic molecules, T-cell intracellular antigen-1 (TIA-1) and granzyme B and nm23-H1 expression were also examined. Expression of nm23-H1, TIA-1, or granzyme B was examined by immunohistochemistry in 137 previously untreated lymphoma patients. The relationship between the results and clinical outcome was examined in 81 patients with angioimmunoblastic T-cell lymphoma, anaplastic large cell lymphoma, or peripheral T-cell lymphoma, unspecified. The neoplastic cells of some lymphomas produced nm23-H1 and the expression rates of nm-23-H1, TIA-1 and granzyme B were 36.5%, 78.8% and 32.8% respectively. The nm23-H1-positive or TIA-1-positive groups had significantly shorter overall and disease-free survivals. Multivariate analysis confirmed nm23-H1 expression to be an independent prognostic factor. The nm23-H1 protein can be an important prognostic factor in the lymphomas studied here. New treatments that target nm23 overexpression could be developed as a result of nm23-HI production by lymphoma cells.

Adult↗

PubMed2002

De novo CD5+ diffuse large B-cell lymphoma: a clinicopathologic study of 109 patients.

De novo CD5+ diffuse large B-cell lymphoma (CD5+ DLBCL) is known to have phenotypically and genotypically different characteristics than CD5- DLBCL and mantle cell lymphoma (MCL). To further characterize CD5+ DLBCL, 109 patients with CD5+ DLBCL were reviewed, and the results were compared with those of 384 CD5- DLBCL and 128 cyclin D1+ MCL patients. Patients with CD5+ DLBCL showed a higher age distribution (median, 66 years; P =.0083) and a female predominance (male-female ratio, 49:60, P =.011) compared with those with CD5- DLBCL. CD5+ DLBCL was more closely associated with many aggressive clinical features or parameters than CD5- DLBCL: 69% older than 60 years (P =.039), 34% with performance status greater than 1 (P =.0016), 69% with serum lactate dehydrogenase level higher than normal (P <.0001), 62% with stage III/IV disease at diagnosis (P =.0023), 35% with more than one extranodal site (P =.023), and 40% with B symptoms (P =.0031). The overall International Prognostic Index score was thus significantly higher for the patients with CD5+ DLBCL than for those with CD5- DLBCL (P =.00005). The most frequent site of extranodal involvement was bone marrow (28%), a higher frequency than that for CD5- DLBCL (P <.0001) but lower than that for cyclin D1+ MCL (P =.0015). Histopathologically, CD5+ DLBCL showed centroblastic morphology except for 3 patients with immunoblastic disease, and interfollicular growth pattern (7%) and intravascular or intrasinusoidal infiltration (19%) were observed. Immunophenotypically, CD5+ DLBCL was characterized by a CD5+CD10-CD19+CD20+CD21-CD23- cyclin D1- phenotype and a predominance of surface IgMkappa. Of particular interest is that CD5+ DLBCL was characterized by a survival curve significantly inferior to that for patients with CD5- DLBCL (P =.0026). These findings suggest that CD5+ DLBCL may constitute a unique subgroup of DLBCL.

Adolescent↗

PubMed2002

Primary thymic extranodal marginal-zone B-cell lymphoma of mucosa-associated lymphoid tissue type exhibits distinctive clinicopathological and molecular features.

Extranodal marginal-zone B-cell lymphoma (MZBL) of mucosa-associated lymphoid tissue (MALT) arising in the thymus is rare, with the largest series in the literature including only three cases. In the present study, we investigated 15 cases of thymic MALT lymphoma to systematically characterize its clinical, histopathological, and molecular features. There was a marked female predilection (male:female = 1:4), with a mean age of 55 years at diagnosis. There was a strong association with autoimmune disease, especially Sjögren's syndrome. Histologically, the thymic lymphoma showed the characteristic morphological features of extranodal MZBL of MALT type. Cysts were common. Prominent lymphoepithelial lesions were formed by centrocyte-like cells infiltrating and expanding the Hassall's corpuscles and epithelium lining the cysts. Plasmacytic differentiation was apparent in all cases. Notably, 13 of 15 cases expressed immunoglobulin (Ig) A phenotype; IgA expression in thymic MALT lymphoma was in striking contrast with the IgM phenotype observed in most of the Sjögren's syndrome-associated MZBLs and MALT lymphomas at other sites. Epstein-Barr virus was absent, and API2-MALT1 gene fusion, a recently reported MALT lymphoma-specific gene abnormality, was not detected in any case. Although one patient died of disease 85 months after the diagnosis, other patients were alive with overall 3-year and 5-year survival rates being 89% and 83%, respectively. Among the 22 patients reported previously and in the present series, at least 17 patients (77%) were Asians. These data indicate that thymic MALT lymphoma may represent a distinct subgroup of MALT lymphoma characterized by apparent predilection for Asians, a strong association with autoimmune disease, frequent presence of cysts, consistent plasma cell differentiation, tumor cells expressing IgA phenotype, and consistent lack of API2-MALT1 gene fusion.

Adult↗